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S1359836819339058 | The aim of the study was to produce and characterize the modified starches and their suitability as wood adhesive for the particleboard manufacturing . The adhesive properties and particleboard manufactured from rubberwood using the modified starch and modified starch mixed with polyvinyl alcohol were evaluated . Mixing of PVA with modified starch reduced the viscosity but increased the solid content and thermal property of the modified starch . Particleboard bonded with modified starch mixed with PVA also had improvement in physical and mechanical properties showing great potential of modified starch and PVA as an adhesive for the green particleboard with good properties . | Commercial wheat starch was modified to carboxymethyl starch by carboxymethylation. Modified starch mixed with polyvinyl alcohol had better starch adhesive properties. Particleboard bonded with modified starch was more resistant to heat. Particleboard bonded with modified starch mixed with PVA showed better performance. Mechanical properties of modified starch mixed with PVA satisfied the standard used. |
S135983681933985X | Extrusion processing and properties of fiber reinforced polymer matrix composites may be influenced by the fiber feeding route upon extrusion . The purpose of the present study was to investigate the effect of fiber feeding route on the fiber length distribution electromagnetic interference shielding effectiveness tensile and flexural properties and heat deflection temperature of resulting composites with different fiber contents . HNiCF polypropylene and SNiCF polypropylene pellets were produced through two different feeding routes of nickel coated carbon fiber hopper feeding and side feeding upon extrusion process respectively . NiCF reinforced polypropylene composites were fabricated by means of compression molding using each pellet respectively . The effect of fiber feeding route on the electromagnetic mechanical and thermal properties of the composites with various NiCF contents was studied . SNiCF PP composites exhibited the EMI SE tensile and flexural properties and heat deflection temperature higher than HNiCF PP composites . The improved properties of SNiCF PP composites were ascribed to higher aspect ratio and longer fiber distribution of NiCF remaining in the composite than HNiCF PP counterparts due to less shearing and fiber damages during extrusion . | Comparisons of hopper and side feeding routes of nickel coated carbon fiber upon extrusion. Improvement of EMI SE electrical tensile flexural and thermal properties by side feeding. Supported by NiCF distribution and peel off behavior of nickel coated layers during extrusion. |
S1359836819341630 | The flexural test was conducted to investigate crack resistance loading bearing capacity deformation characteristics and failure modes of damaged reinforced concrete beams strengthened by reinforced ultra high performance concrete layer . Also their mechanical properties were compared with those of the unstrengthened RC beam . Additionally the effects of pre damage degrees in the RC beams and three strategies for the improvement of toughness of the reinforced UHPC layer on the cracking and flexural performance of UC were discussed . The results showed that UC acted monolithically under flexure without interfacial debonding before typically flexural failure . Compared with IC cracking and ultimate loads of UC increased by 1.573.32 times and 1.722.21 times respectively . The reinforced UHPC layer effectively suppressed the cracking of the RC beam making crack width in the RC beam propagate slowly with the load . Moreover the severer the pre damage degree of the RC beam the smaller improvement of the flexural performance of UC . The addition of steel wire mesh orientation of steel fibers and moderate temperature steam curing further improved the cracking and flexural performance of UC with the most evident improvement in the addition of steel wire mesh . Finally the theoretical model and formula were proposed for the calculation of load bearing capacity of UC with consideration of the influence of the pre damage degrees in the RC beams and the experimental results verified that the theoretical formula can accurately predict the load bearing capacity of UC . | The flexural behavior of damaged RC beams strengthened by reinforced UHPC layer UC was investigated. The effect of pre damage degrees in the RC beams on the flexural performance of UC was discussed. The three strategies for improvement of toughness of the reinforced UHPC layer was discussed. The theoretical formulas were proposed for the calculation of load bearing capacity of UC with the pre damage degrees. |
S1359836819341691 | Thermal barrier coatings endow metal components with exceptional endure capability to withstand high temperatures over their bearable limits . Thus TBCs are indispensable in a wide range of applications related to high temperatures . However the thermal barrier performance degrades by at least 50 during service which remains a critical challenge for these coatings . Herein degradation resistant TBCs were achieved using composited structures . Thermal insulation 2D pores were spontaneously formed during thermal exposure . Moreover the degree of resistance was optimized from 20 to 50 by tailoring the orientation of the 2D pores . Thus the thermal barrier performance was self improved . A detailed examination suggests that scale progressive healing of the initial pores is primarily responsible for the degradation mechanism . Analysis of the orientation of the spontaneously formed 2D pores on thermal resistance reveals that this accounts for the self improved thermal barrier performance . These results will guide the advanced design of TBCs for future applications . | Degradation resistant TBCs were achieved by spontaneously forming new pore. Resistant degree was optimized from 20 to 50 by tailoring the orientation of 2D pores. Self improving thermal barrier performance was realized. Mechanisms of degradation and anti degradation of TBCs were revealed. |
S1359836819341903 | This work reports our recent effort on the preparation of Phenyl N imine Nickel containing polyhydroxy groups and its application in improving the fire performance of PLA composites in combination with ammonium polyphosphate . The flame retardant evaluation revealed that the presence of 1.7 Ni MOF and 3.3 APP in PLA increased the LOI value to 31.0 upgraded the UL 94 level to V 0 decreased the peak heat release rate total heat release and total smoking production by 27 19 and 50 respectively and substantially delayed the time to ignition from 67 to 97s . It was proposed that the flame retardants take effect in both vapor and condensed phases and Ni MOF nanosheets can synergistically improve the flame resistance of PLA with APP . The incorporation of Ni MOF effectively inhibited the deterioration of mechanical properties for PLA composites caused by the presence of APP . | The Ni MOF nanosheets containing polyhydroxy groups was prepared. APP and Ni MOF nanosheets significantly improved the fire safety of PLA composite. The possible synergistic flame retardant mechanism of Ni MOF and APP was proposed. Ni MOF effectively improved the mechanical properties of PLA composites. |
S135983681934257X | Aluminium hybrid foam core sandwich structures with carbon fiber cold setting resin as face sheets have been made . The flexural properties and energy absorption of these sandwich structures have been analyzed through three point bending test . It is found that with the use of a double layer carbon fiber sheet the flexural load carrying capacity of the sandwich structure increases up to eight times as compared to that of bare foam structure . Whereas the bending stiffness of the structure is nine times to that of BFs and energy absorption is 58 more than that of BF . It is also found that with the increase in foam core thickness the flexural load carrying capacity bending stiffness and energy absorption capacity of the sandwich structure increases significantly . The specific strength and bending stiffness increase as compared to that of face sheet due to the addition of foam at the core . The deformation behavior of different sandwich structures was analyzed to investigate the different modes of failure during bending . | HFs with cenosphere reinforcement has been used as core for sandwich structure. Single and double layer carbon fiber reinforced acrylic resin composite has been used as face sheet of sandwich structure. 3PB test were conducted mechanical properties such as peak load bending stiffness and energy absorption were examined. Investigated the effect of HFs core thickness and number of layers of carbon fiber on flexural behavior. Mode of failure of sandwich structures under different conditions has been studied. |
S1360138519302468 | Plant oxylipins are produced under a wide range of stress conditions and although they are well known to activate stress related signalling pathways the nonsignalling roles of POs are poorly understood . We describe oxylipins as direct biocidal agents and propose that structurefunction relationships play here a pivotal role . Based on their chemical configuration POs such as reactive oxygen and electrophile species activate defence related gene expression . We also propose that their ability to interact with pathogen membranes is important but still misunderstood and that they are involved in cross kingdom communication . Taken as a whole the current literature suggests that POs have a high potential as biocontrol agents . However the mechanisms underlying these multifaceted compounds remain largely unknown . | Many studies have shown that specific oxylipin signatures are shaped during a biotic stresses. It is generally accepted that divinyl keto and hydroxy fatty acids and fatty acid hydroperoxides exhibit strong direct antimicrobial activities whereas the roles of jasmonic acid and some volatile aldehydes seem to be related to signalling activities only. Oxylipins chemical structures are related to their biological activities. Current studies show that the lipid composition of the plasma membrane has important roles in the interaction of plant oxylipins with plant cells. It is becoming clear that many organisms use the oxylipin pathways as a common process for interkingdom communication |
S136013851930247X | Challenges to food security under conditions of global change are forcing us to increase global crop production . Focussing on belowground plant traits especially root exudation has great promise to meet this challenge . Root exudation is the release of a vast array of compounds into the soil . These exudates are involved in many biotic and abiotic interactions . Wild relatives of crops provide a large potential source of information and genetic material and have desirable traits that could be incorporated into modern breeding programs . However root exudates are currently underexploited . Here we highlight how the traits of root exudates of crop wild relatives could be used to improve agricultural output and reduce environmental impacts particularly by decreasing our dependence on pesticides and fertilisers . | Root exudates are the compounds that roots release into the soil. Root exudates show a large amount of variation in composition between species. Crop wild relatives contain different root exudate traits compared with crops. Exploitation of root exudate traits in crop wild relatives offers opportunities to reduce the use of fertilisers and pesticides. |
S1360138519302493 | In optogenetics light sensitive proteins are specifically expressed in target cells and light is used to precisely control the activity of these proteins at high spatiotemporal resolution . Optogenetics initially used naturally occurring photoreceptors to control neural circuits but has expanded to include carefully designed and engineered photoreceptors . Several optogenetic constructs are based on plant photoreceptors but their application to plant systems has been limited . Here we present perspectives on the development of plant optogenetics considering different levels of design complexity . We discuss how general principles of light driven signal transduction can be coupled with approaches for engineering protein folding to develop novel optogenetic tools . Finally we explore how the use of computation networks circular permutation and directed evolution could enrich optogenetics . | Optogenetics uses light to stimulate cells that have been genetically modified to express light sensitive proteins. Despite their potential several experimental and computational approaches in optogenetics remain underutilized. Although most optogenetic systems were developed from plant photoreceptors optogenetics has rarely been applied to plants. |
S136013851930250X | Strawberry is a fruit crop species of major horticultural importance for which fruit quality and the control of flowering runnering and the trade off between the two are main breeding targets . The octoploid cultivated strawberry has a limited genetic basis . This raises the question of how to identify important gene targets and successfully exploit them for strawberry improvement . In this Opinion article we propose to apply to woodland strawberry a wild diploid species displaying wide diversity the strategies successfully employed in recent years for the identification of genetic variations underlying fruit quality and fruit yield traits in solanaceous crops . Next we propose to use gene editing technologies to translate the findings to cultivated strawberry . | Cultivated octoploid strawberry whose production increases continuously displays limited genetic variability which impedes its improvement. Woodland strawberry one of its wild diploid ancestors exhibits wide phenotypic diversity. Tomato and potato are major crops of the Solanaceae family. Fruit yield and quality are major breeding targets in strawberry and tomato. Stolon production is a trait important for both strawberry vegetative propagation and potato tuber production that has recently received much attention. In tomato the exploitation of genetic diversity combined with multiomics and or gene editing strategies recently led to considerable improvement of fruit yield and quality. |
S1360138519302535 | Aromatic amino acid deaminases are key enzymes mediating carbon flux from primary to secondary metabolism in plants . Recent studies have uncovered a tyrosine ammonia lyase that contributes to the typical characteristics of grass cell walls and contributes to about 50 of the total lignin synthesized by the plant . Grasses are currently preferred bioenergy feedstocks and lignin is the most important limiting factor in the conversion of plant biomass to liquid biofuels as well as being an abundant renewable carbon source that can be industrially exploited . Further research on the structure evolution regulation and biological function of functionally distinct ammonia lyases has multiple implications for improving the economics of the agri food and biofuel industries . | It has been generally accepted that all plants synthesize lignin from the aromatic amino acid L phenylalanine. Recent studies indicate that true grasses Poaceae are able to make up to nearly half of their lignin from L tyrosine via the enzyme L tyrosine ammonia lyase. Understanding the interface between tyrosine and phenylpropanoid metabolism is of particular interest because grasses include the major food crops of the world e.g. corn wheat rice as well as ideal bioenergy feedstocks e.g. switchgrass. and lignin is a key limiting factor in the conversion of plant biomass to liquid biofuels and an abundant renewable carbon source that can be industrially exploited. |
S1360138519302559 | Under high irradiance light becomes dangerous for photosynthetic organisms and they must protect themselves . Cyanobacteria have developed a simple mechanism involving a photoactive soluble carotenoid protein the orange carotenoid protein which increases thermal dissipation of excess energy by interacting with the cyanobacterial antenna the phycobilisome . Here we summarize our knowledge of the OCP related photoprotective mechanism including the remarkable progress that has been achieved in recent years on OCP photoactivation and interaction with phycobilisomes as well as with the fluorescence recovery protein which is necessary to end photoprotection . A recently discovered unique mechanism of carotenoid transfer between soluble proteins related to OCP is also described . | The orange carotenoid protein OCP is a blue light photoactive protein involved in cyanobacterial photoprotection. OCP binds one keto carotenoid which spans both C and N terminal OCP domains CTD and NTD . Upon photoactivation the carotenoid is translocated to the NTD and the color of the protein changes to red. Then the domains are separated and OCP becomes active. The red OCP binds to the phycobilisome inducing thermal dissipation of excess energy. Paralogs of the OCP domains namely CTDH CTD like and HCP NTD like are also carotenoid proteins. The principal role of CTDH is to transport the carotenoid from the membrane to HCP and perhaps to OCP. HCPs are excellent singlet oxygen quenchers. Only one subfamily is able to interact with the phycobilisome. A unique mechanism of carotenoid transfer between soluble proteins has been discovered and characterized. |
S1360138519302717 | In agriculture plant transformation is a versatile platform for crop improvement with the aim of increased pest resistance and an improved nutrient profile . Nanotechnology can overcome several challenges that face conventional methods of gene delivery . Specifically nanomaterials offer an optimal platform for biomolecule delivery with unique physiochemical properties as well as the ability to traverse the challenging barrier of the plant cell wall . We review the potential of diverse nanovehicles for biomolecule delivery in plant systems to obtain desired genetic traits . The efficacy of nanoparticles against pests or pathogens is also explored as well as the interaction of nanovehicles with plant organelles with due consideration of the effects and toxic profile of nanoparticles . | To enhance crop productivity genetic engineering is an important technique for introducing traits of interest into plant species. The desired trait can provide increased pest resistance and an improved nutrient profile ultimately ensuring food security. Compared with conventional methods of biomolecule delivery modern nanotechnology offers high efficiency and diverse cargo delivery options. The unique properties of nanomaterials such as tunable physicochemical properties and the ability to traverse the plant cell wall can be exploited to deliver species dependent biomolecules. Nanoparticles are also effective as micronutrients and as agents against pests or bacterial infections. |
S1360138519302729 | Plant function is the result of the concerted action of single cells in different tissues . Advances in RNA seq technologies and tissue processing allow us now to capture transcriptional changes at single cell resolution . The incredible potential of single cell RNA seq lies in the novel ability to study and exploit regulatory processes in complex tissues based on the behaviour of single cells . Importantly the independence from reporter lines allows the analysis of any given tissue in any plant . While there are challenges associated with the handling and analysis of complex datasets the opportunities are unique to generate knowledge of tissue functions in unprecedented detail and to facilitate the application of such information by mapping cellular functions and interactions in a plant cell atlas . | Plant tissues comprise a diverse set of cell types that can be distinguished by their functions. The concerted interplay of these cell types determines the functionality and plasticity of plant tissues. Deciphering the different functions of cell types in a tissue is essential to understand plant development and adaptation to changing environments. Single cell RNA seq technologies enable us now to capture transcriptional profiles in each cell type to describe the genetic basis of their identity and function. This knowledge of cell type defining gene networks is as equally significant for fundamental science as it is for the development of crops with improved resilience capacities against climatic and other environmental stresses. |
S136013851930278X | Retrograde signals are signals that originate in organelles to regulate nuclear gene expression . In plant cells retrograde signaling from both chloroplasts and mitochondria is essential for plant development and growth . Over the past few years substantial progress has been made in unraveling the linkages between chloroplast retrograde signaling and nuclear RNA metabolism processes or plastidial RNA editing . These findings add to the complexity of the regulation of organelle to nucleus communication . Chloroplast development and function rely on the coordinated regulation of chloroplast and nuclear gene expression especially under stress conditions . A better understanding of retrograde signaling and RNA metabolism as well as their connection is essential for breeding stress tolerant plants to cope with the dynamic and rapidly changing environment . | Chloroplast development and function rely on the coordinated regulation of chloroplast and nuclear gene expression. RNA metabolism including RNA editing alternative splicing and RNA turnover is an important regulatory process for plant development and function. During development or stress situations organelles such as chloroplasts and mitochondria generate signals that regulate the expression of nuclear genes a process called retrograde signaling. Retrograde signaling generated by the chloroplast PQ pool redox state regulates the alternative splicing of nuclear genes. GUN1 an integrator of multiple chloroplast retrograde signaling pathways regulates RNA editing efficiency in damaged chloroplasts. Abnormal RNA editing may play a role in chloroplast to nucleus retrograde signaling. Signals from tocopherols metabolism in chloroplasts regulate nuclear microRNA biogenesis. |
S136013851930281X | The pangenome provides genomic variations in the cultivated gene pool for a given species . However as the crops gene pool comprises many species especially wild relatives with diverse genetic stock here we suggest using accessions from all available species of a given genus for the development of a more comprehensive and complete pangenome which we refer to as a super pangenome . The super pangenome provides a complete genomic variation repertoire of a genus and offers unprecedented opportunities for crop improvement . This opinion article focuses on recent developments in crop pangenomics the need for a super pangenome that should include wild species and its application for crop improvement . | Pangenome studies conducted so far have been limited mainly to one species and mostly cultivated accessions. The challenge with the current pangenomes is lack of representation of genomic diversity at the genus level. Crop wild relatives possess unearthed genetic diversity that has been lost during domestication and breeding. Pangenomics of crop wild relatives is the way forward to catalogue the complete gene repertoire of a genus. The super pangenome is the approach of developing a pangenome of the pangenomes of different species for a given genus. Currently available methods and tools to develop pangenomes are mainly restricted to bacterial prokaryotic genomes. It is important now to develop novel effective and user friendly tools for the development of super pangenomes for crop eukaryotic genomes. |
S1360138519302845 | Root systems determine the water and nutrients for photosynthesis and harvested products underpinning agricultural productivity . We highlight 11 programs that integrated root traits into germplasm for breeding relying on phenotyping . Progress was successful but slow . Todays phenotyping technologies will speed up root trait improvement . They combine multiple new alleles in germplasm for target environments in parallel . Roots and shoots are detected simultaneously and nondestructively seed to seed measures are automated and field and laboratory technologies are increasingly linked . Available simulation models can aid all phenotyping decisions . This century will see a shift from single root traits to rhizosphere selections that can be managed dynamically on farms and a shift to phenotype based improvement to accommodate the dynamic complexity of whole crop systems . | Root and rhizosphere traits have been selected and incorporated into germplasm since the 1970s proving the value of roots and phenotyping in prebreeding programs. Past examples show how todays noninvasive phenotyping technologies that measure roots shoots and seeds can be strategically combined to speed up germplasm enhancement. Models are available to test and incorporate root phenotypes at different stages of selection programs. The rootsoil rhizosphere can be phenotyped noninvasively in soils revealing new combinatorial traits relevant to the reality of farming systems and to select for crop improvement. |
S1360138519303012 | The discovery of visible fluorescence in the plant pigments betalains revealed the existence of fluorescent patterns in flowers of plants of the order Caryophyllales where betalains substitute anthocyanins . The serendipitous initial discovery led to a systemized characterization of the role of different substructures on the photophysical phenomenon . Strong fluorescence is general to all members of the family of betaxanthins linked to the structural property that the betalamic acid moiety is connected to an amine group . This property has led to bioinspired tailor made probes and to the development of novel biotechnological applications in screening techniques or microscopy labeling . Here we comprehensively review the photophysics photochemistry and photobiology of betalain fluorescence and describe all current applications . | The discovery of betalains fluorescence property opened up new fields in the research and applications of the pigments. Similarities in fluorescence characteristics point to betalamic acid as the active compound. Fluorescence allows visualization and staining of biomolecules cells tissues and parasites. Novel microscopy biosensing and high throughput techniques have been developed based on the fluorescence of natural or tailor made betalains. |
S1360138519303024 | Fatty acid amide hydrolase is an enzyme that belongs to the amidase signature superfamily and is widely distributed in multicellular eukaryotes . FAAH hydrolyzes lipid signaling molecules namely | Fatty acid amide hydrolase FAAH is the signal terminating enzyme of the. acylethanolamine signaling pathway with an established role in seedling development. The crystal structure of. FAAH was recently solved revealing for the first time the structural features of FAAH from plants and explaining the enzymes promiscuity toward. acyl amide substrates. A second group of FAAH enzymes in angiosperms has been identified with conserved substitutions in the substrate binding pocket altering the size shape and physicochemical properties for substrate recognition. |
S1360138519303036 | There is growing interest in the application of alternative stable state theory to explain major vegetation patterns of the world . Here we introduce the theory as applied to the puzzle of nonforested biomes growing in climates that are warm and wet enough to support forests . Long thought to be the product of deforestation diverse lines of evidence indicate that many open ecosystems are ancient . They have also been characterized as early successional even where they persist for millennia . ABS is an alternative framework to that of climate determinism and succession for exploring forest nonforest mosaics . This framework explains not only tropical forestsavanna landscapes but also other landscape mosaics across the globe . | There are many ancient open vegetation formations worldwide that maintain a high diversity of shade intolerant species where the climate is suitable for forests. Fire and herbivores are ancient consumers of plant biomass that maintain open ecosystems and shape shade intolerant species. Therefore open ecosystems are not necessarily either produced by deforestation or early successional but have been maintained by consumers as ABSs to forests. ABSs are not only found in tropical environments but also in temperate and Mediterranean conditions. |
S1360138519303048 | Allelopathy is a biochemical interaction between plants in which a donor plant releases secondary metabolites allelochemicals that are detrimental to the growth of its neighbours . Traditionally considered as bilateral interactions between two plants allelopathy has recently emerged as a cross kingdom process that can influence and be modulated by the other organisms in the plants environment . Here we review the current knowledge on plantinterkingdom interactions with a particular focus on benzoxazinoids . We highlight how allelochemical producing plants influence not only their plant neighbours but also insects fungi and bacteria that live on or around them . We discuss challenges that need to be overcome to study chemical plantinterkingdom interactions and we propose experimental approaches to address how biotic and chemical processes impact plant health . | Plants make use of secondary metabolites to communicate with their environment. Allelopathic plants release secondary metabolites to gain a competitive advantage over other plants. Grassy crops release benzoxazinoid compounds which impact plants animals and microbes. Plantinterkingdom interactions in particular those with soil dwelling organisms are key factors in plant health and fitness. Recent findings indicate that research on how allelopathic compounds modulate plant fitness in natural settings needs to integrate interkingdom interactions. |
S136013851930305X | The study of transcriptional regulation of tomato ripening has been led by spontaneous mutations in transcription factor genes that completely inhibit normal ripening suggesting that they are master regulators . Studies using CRISPR Cas9 mutagenesis to produce knockouts of the underlying genes indicate a different picture suggesting that the regulation is more robust than previously thought . This requires us to revisit our model of the regulation of ripening and replace it with one involving a network of partially redundant components . At the same time the fast rise of CRISPR Cas mutagenesis resulting in unexpectedly weak phenotypes compared with knockdown technology suggests that compensatory mechanisms may obscure protein functions . This emphasises the need for assessment of these mechanisms in plants and for the careful design of mutagenesis experiments . | A string of recent publications has put into question the function of TFs which were previously considered master regulators in the control of tomato fruit ripening. RNA interference and CRISPR Cas9 mutagenesis have enabled a re evaluation of their proposed functions which were previously thought to be mostly derived from the phenotype of spontaneous ripening mutations. Three spontaneous mutations in TF genes all appear to be gain of function mutations and interestingly probably represent three different mechanisms of this phenomenon. These observations raise interesting fundamental and practical questions related to the manipulation of fruit ripening and other processes. Although CRISPR Cas9 mutagenesis has dramatically improved our options for addressing gene function recent results suggest that compensatory mechanisms in CRISPR mutants also hide true gene functions. |
S1360138519303280 | Expansion of the human population demands a significant increase in cereal production . The main component of cereal grains is endosperm a body of starchy endosperm cells surrounded by aleurone cells with transfer cells at the base and embryo surrounding cells adjacent to the embryo . The data reviewed here emphasize the modular nature of endosperm by first suggesting that sucrose promotes development of the fertilized triploid endosperm cell . Next that the basal syncytial endosperm responds to glucose by turning on TC development . The default endosperm cell fate is SE and ESR differentiation is likely activated by signaling from the embryo . Cells on the exterior surface of the endosperm are specified as AL cells . | The initial state of the grass endosperm may have been a body of starchy endosperm SE cells the three other cell types aleurone AL transfer cells TC and embryo surrounding cells ESR evolving at later stages. TC and possibly also ESR are initiated by signals from outside of the endosperm. Apart from the external initiation of TC and ESR the developmental control of endosperm is largely endosperm autonomous. SE and AL differentiation proceeds similarly. and. on medium with high sucrose but not on low sucrose. Transcriptome analysis has identified most if not all genes expressed in the endosperm of the major cereal species. |
S1360138519303309 | The use of the omics techniques in environmental research has become common place . The most widely implemented of these include metabolomics proteomics genomics and transcriptomics . In recent years a similar approach has also been taken with the analysis of volatiles from biological samples giving rise to the so called volatilomics in plant analysis . Developments in direct infusion mass spectrometry techniques have made it possible to monitor the changes in the composition of volatile flux from parts of plants single specimens and entire ecosystems in real time . The application of these techniques enables a unique insight into the dynamic metabolic processes that occur in plants . Here we provide an overview of the use of DI MS in real time volatilomics research involving plants . | Direct infusion mass spectrometry DI MS techniques are a valuable tool for real time monitoring of the plant volatilome. DI MS techniques are particularly useful in detecting brief episodes of increased biogenic volatile organic compound emissions caused for instance by herbivore attacks. Current studies on the use of DI MS techniques for the determination of plant volatiles are conducted at several scales from parts of plants and whole specimens to entire ecosystems. Proton transfer reaction MS is the preeminent technique used for the monitoring of volatile plant metabolites. Current developments in DI MS solutions are focused on the application of tandem MS. |
S1360138519303322 | In the quest for sustainable intensification of crop production we discuss the option of extending the root depth of crops to increase the volume of soil exploited by their root systems . We discuss the evidence that deeper rooting can be obtained by appropriate choice of crop species by plant breeding or crop management and its potential contributions to production and sustainable development goals . Many studies highlight the potentials of deeper rooting but we evaluate its contributions to sustainable intensification of crop production the causes of the limited research into deep rooting of crops and the research priorities to fill the knowledge gaps . | Recent studies have documented highly significant differences among current and potential crops as well as genotypic differences in the ability for deep rooting. Results have shown significant effects of deep roots on deep soil water and nutrient uptake. Technological improvements of nondestructive methods such as rhizotron and image analysis based root observations soil water sensors and isotope tracers for uptake studies allow combined and dynamic studies of root development and function. The quest for sustainable intensification of crop production promotes the interest in understanding and exploiting the potential contribution by deeper soil layers. Deep layers may contribute to resource supply for crop growth reducing losses to the environment and deep C sequestration to mitigate climate change. |
S1360138519303334 | Flowering plants are the foundation of human civilization providing biomass for food fuel and materials to satisfy human needs dependent on fertile soil adequate water and favorable weather . Conversely failure of any of these inputs has caused catastrophes . Today human appropriation of biomass is threatening planetary boundaries inducing social and political unrest worldwide . Human societies are bound to rethink agriculture and forestry to restore and safeguard natural resources while improving the overall quality of life . Here we explore why and how . Through an evolutionary and quantitative analysis of agriculture and bridging plant and Earth sciences we anticipate the advent of a research and policy framework integrating plant science in all sectors the economy local and global governance and geopolitics . | Our civilization depends on a triad encompassing soil water and food biomass all of which ultimately depend on plants. A retrospective view of evolution highlights unique attributes of flowering plants that allow the production of biomass that supports modern civilization. Through excessive human appropriation of biomass while ignoring crucial plant needs for soil and water this renewable resource is becoming limiting and exhaustible. Plant blindness remains pervasive and flowering plants are the forgotten item on the stakeholders menu even though plant biomass can be the main renewable solution in our finite world. Agriculture in the 21st century needs long term resilience rather than short term performance. |
S1360138519303346 | Strigolactones are a class of plant hormones involved in several biological processes that are of great agricultural concern . While initiating plantfungal symbiosis SLs also trigger germination of parasitic plants that pose a major threat to farming . In vascular plants SLs control shoot branching which is linked to crop yield . SL research has been a fascinating field that has produced a variety of different signaling models reflecting a complex picture of hormone perception . Here we review recent developments in the SL field and the crystal structures that gave rise to various models of receptor activation . We also highlight the increasing number of discovered SL molecules reflecting the existence of cross kingdom SL communication . | SLs are a class of plant hormones that are involved in agriculturally important processes such as shoot branching arbuscular mycorrhizal symbiosis and germination of parasitic plants. An increasing number of different SLs have been identified. Structural biology has been a treasure trove for SL research but has also been a source of confusion. Recent studies show that different species have independently developed similar features to regulate the architecture of their SL receptors. New findings suggest that the intact SL molecule is part of a catalytically arrested D14 D3 MAX2 interaction but that a histidine butenolide complex stabilizes the complex with the transcriptional repressor. |
S1360138519303358 | After the ice caps tropical forests are globally the most threatened terrestrial environments . Modern trees are not just witnesses to growing contemporary threats but also legacies of past human activity . Here we review the use of dendrochronology radiocarbon analysis stable isotope analysis and DNA analysis to examine ancient tree management . These methods exploit the fact that living trees record information on environmental and anthropogenic selective forces during their own and past generations of growth making trees living archaeological sites . The applicability of these methods across prehistoric historic and industrial periods means they have the potential to detect evolving anthropogenic threats and can be used to set conservation priorities in rapidly vanishing environments . | Tropical forests now known to be key sites of ancient human occupation and modification from the Late Pleistocene intensifying into the Late Holocene. Dendrochronology and radiocarbon dating demonstrate that living tropical trees can provide stratigraphic records of human influences on growth patterns over the past millennium. Stable isotope analysis of tree rings identify climate related influences on tree growth enabling differentiation of natural versus human induced forest disturbance. Genetic studies of modern trees can reconstruct impacts of past human activity on the population structure of species that have been deforested selected against or promoted selected for by humans. Tropical trees are not just key organisms for global climate biodiversity and carbon stock but also represent surviving time capsules of cultural heritage. |
S1360138519303371 | Potassium regulates a plethora of metabolic and developmental response in plants and upon exposure to biotic and abiotic stresses a substantial K | GORK channels possess the binding motifs and domains that may enable them to operate as ligand gated channels. Activity of GORK channels may be modulated by cyclic nucleotides gamma aminobutyric acid G proteins protein phosphatases inositol and ATP. As all aforesaid molecules are known to operate upstream of plant signaling pathways mediating their adaptation to abiotic stresses GORK channel may therefore operate as a master switch of the cell metabolism inhibiting energy consuming anabolic reactions and saving energy for adaptation and repair. This function of the GORK channel may give species a competitive advantage under energy limiting conditions imposed by environmental stresses and explain a reported increase in GORK transcript levels under abiotic stress conditions. |
S1360138519303425 | Crossovers that drive genetic exchange between homologous chromosomes are strongly biased toward subtelomeric regions in plant species . Manipulating the rate and positions of COs to increase the genetic variation accessible to breeders is a longstanding goal . Use of genome editing reagents that induce double stranded breaks or modify the epigenome at desired sites of recombination and manipulation of CO factors are increasingly applicable approaches for achieving this goal . These strategies for controlled recombination have potential to reduce the time and expense associated with traditional breeding reveal currently inaccessible genetic diversity and increase control over the inheritance of preferred haplotypes . Considerable challenges to address include translating knowledge from models to crop species and determining the best stages of the breeding cycle at which to control recombination . | The genetic diversity accessible to plant breeders has traditionally been limited by chromosomal COs but recent advances in targeted DNA cleavage and epigenetic modification are increasing access. Overcoming the low frequency and uneven distribution of COs in plants can reveal allelic diversity and may increase control over the inheritance of preferred haplotypes. The frequency and location of COs can be altered with manipulation of pro and anti CO factors site directed nucleases or epigenetic modifiers we refer to such alteration as controlled recombination. Epigenetic modifiers can induce COs near centromeres which are otherwise very low frequency CO regions. Controlled recombination may enable breeders and geneticists to unlock otherwise inaccessible genetic diversity. |
S1360138519303449 | Bt crops have been grown commercially for more than two decades . They have proven remarkably effective in the control of target insect pests . However Bt crops can become less effective under various forms of environmental stress . Most studies in this area have considered the effect of environmental stress on Bt insecticidal protein levels or target pest mortality but not both resulting in a lack of mechanistic analysis . In this review we critically examine previous research addressing the impact of environmental stress on the effectiveness of Bt crops . We find that the body of research data is not sufficiently robust to allow the reliable prediction of the performance of Bt crops under extreme climatic conditions . | Reduced effectiveness of Bt crops to control target pests has been largely attributed to the fluctuation in Bt toxin levels caused by various forms of environmental stress. The current body of data shows that downregulation of Bt genes does not always reduce levels of Bt toxin and that lower levels of Bt toxin do not always reduce the effectiveness of Bt crops against target pests. Current approaches do not consider the environmental impact on Bt toxin accumulation and the environmental impact on pest insect mortality in an integrative manner. To successfully predict the performance of Bt crops in future climatic scenarios multidisciplinary research that considers how both the plants and the pest insect are affected by the environmental stress as well as the interactions between the plant and pest is required. |
S1360138519303462 | Due to the ongoing prevalence of vitamin A deficiency in developing countries there has been a large effort towards increasing the carotenoid content of staple foods via biofortification . Common strategies used for carotenoid biofortification include altering flux through the biosynthesis pathway to direct synthesis to a specific product generally carotene or via increasing the expression of genes early in the carotenoid biosynthesis pathway . Recently carotenoid biofortification strategies are turning towards increasing the retention of carotenoids in plant tissues either via altering sequestration within the cell or via downregulating enzymes known to cause degradation of carotenoids . To date little attention has focused on increasing the stability of carotenoids which may be a promising method of increasing carotenoid content in staple foods . | Combining strategies targeting multiple metabolic levels including synthesis storage and turnover will be necessary to achieve optimal outcomes for biofortification projects. The plastidial proteome is a key to understanding the sequestration and storage of carotenoids. Attenuating the activity of carotenoid cleavage dioxygenases and lipoxygenases enzymes that drive carotenoid turnover can improve carotenoid retention. Increasing the vitamin E content of crops may have a similar effect. Carotenoids are often found esterified to fatty acids. This process increases carotenoid sequestration accumulation and stability and may be a novel target for future biofortification projects. |
S1360138519303474 | The study of insular systems has a long history in ecology and biogeography . Island plants often differ remarkably from their noninsular counterparts constituting excellent models for exploring eco evolutionary processes . Trait based approaches can help to answer important questions in island biogeography yet plant trait patterns on islands remain understudied . We discuss three key hypotheses linking functional ecology to island biogeography plants in insular systems are characterized by distinct functional trait syndromes these syndromes differ between true islands and terrestrial habitat islands and island characteristics influence trait syndromes in a predictable manner . We are convinced that implementing trait based comparative approaches would considerably further our understanding of plant ecology and evolution in insular systems . | Trait based approaches may provide important insights into the dynamics of insular systems i.e. true islands and terrestrial habitat islands and can help to address key questions in island biogeography. However the study of plant traits on islands is in its infancy and a robust framework tailored to island biogeography is lacking. Plants in insular systems compared with the mainland experience unique eco evolutionary histories and are influenced by specific processes such as those related to isolation. These factors should be reflected in specific patterns of plant traits. |
S1360138519303498 | Woody plant declines have multifactorial determinants as well as a biological and economic reality . The vascular system of WPs involved in the transport of carbon nitrogen and water from sources to sinks has a seasonal activity which places it at a central position for mediating plantenvironment interactions from nutrient cycling to community assembly and for regulating a variety of processes . To limit effects and to fight against declines we propose to consider the WP and its associated microbiota as an holobiont and as a set of functions to consider simultaneously without looking at what comes first the physiological or pathogenic disorders and to define pragmatic strategies including preventive and curative agronomical practices based on microbiota engineering . | WPs provide several ecosystem services such as climate regulation nutrient cycling carbon sink production reservoir of biodiversity and creative and cultural added values. WP diseases or diebacks result from the combination of various factors e.g. abiotic factors fungi bacteria inadequate technical practices and also unidentified ones . Microbial communities associated with plants are complex and dynamic with mutualistic and commensal species that coexist with pathogenic species. Declines could be related to microbiome modifications or imbalance meaning that essential functions for keeping the holobiont fitness are not covered. The selection and engineering of microbiota based on their ecosystem services targeting some declines resulting from microbiome and interaction analysis will ensure promising tools to improve WP health and management. |
S1360138519303504 | Plant glandular trichomes are epidermal secretory structures producing various specialized metabolites . These metabolites are involved in plant adaptation to its environment and many of them have remarkable properties exploited by fragrance flavor and pharmaceutical industries . The identification of genes controlling glandular trichome development is of high interest to understand how plants produce specialized metabolites . Our knowledge about this developmental process is still limited but genes controlling glandular trichome initiation and morphogenesis have recently been identified . In particular R2R3 MYB and HD ZIP IV transcription factors appear to play essential roles in glandular trichome initiation in | Glandular trichomes are multicellular organs that cover the surface of more than 30 of all land plants. Glandular trichomes synthesize store and secrete diverse specialized metabolites. Recent studies have reported genes and protein complexes regulating glandular trichome development in. and tomato. We propose a genetic model to explain the glandular trichome initiation in each species. R2R3 MYB and HD ZIP IV transcription factor families play essential roles in glandular trichome initiation. Glandular trichome density and size are important factors regulating metabolic content. Increasing glandular trichome density by genetic engineering successfully enhanced specialized metabolite content without any adverse effect on plant growth. |
S1360138520300157 | Plants regulate the synthesis of specialized compounds through the actions of individual transcription factors or sets of TFs . One such compound artemisinin from | It is increasingly recognized that different TFs act conjointly to regulate the production of plant metabolites. However their dual functionality in regulating distinct pathways of synthesis has not been well studied. The identification of. regulatory elements within the promoter regions of genes encoding different pathway enzymes enables the identification of TF families that regulate their expression. Parallel regulation of the enzyme coding genes for distinct pathways can simplify overexpression strategies. This provides an excellent starting point to unravel how individual TFs act in a coordinated manner to simultaneously regulate different pathways of specialized metabolism. |
S1360138520300170 | Foliar water uptake has been identified as a mechanism commonly used by trees and other plants originating from various biomes . However many questions regarding the pathways and the implications of FWU remain including its ability to mitigate climate change driven drought . Therefore answering these questions is of primary importance to adequately address and comprehend drought stress responses and associated growth . In this review we discuss the occurrence pathways and consequences of FWU with a focus predominantly on tree species . Subsequently we highlight the tight coupling between FWU and foliar fertilizer applications discuss FWU in a changing climate and conclude with the importance of including FWU in mechanistic vegetation models . | Foliar water uptake FWU has been identified as a mechanism commonly used by plants originating from a range of biomes. FWU can rehydrate tissues and result in turgor driven growth. FWU and the absorption of foliar fertilizers are interlinked making FWU research important for both natural and agricultural ecosystems. As the number of climate change induced drought events increases so too will the relative importance of FWU. Future models should include FWU to correctly assess the impact of climate change on tree growth. |
S1360138520300212 | Salicylic acid is a key plant hormone required for establishing resistance to many pathogens . SA biosynthesis involves two main metabolic pathways with multiple steps the isochorismate and the phenylalanine ammonia lyase pathways . Transcriptional regulations of SA biosynthesis are important for fine tuning SA level in plants . We highlight here recent discoveries on SA biosynthesis and transcriptional regulations of SA biosynthesis . In addition SA perception by NPR proteins is important to fulfil its function as a defense hormone . We highlight recent work to give a full picture of how NPR proteins support the role of SA in plant immunity . We also discuss challenges and potential opportunities for future research and application related to the functions of SA in plants . | Salicylic acid SA serves as a key hormone in plant innate immunity including resistance in both local and systemic tissue upon biotic attacks hypersensitive responses and cell death. Key components involved in the complete metabolic steps of SA biosynthesis through the isochorismate pathway and their detailed functions have been identified. Recent breakthroughs have revealed new mechanisms by which the endogenous SA level controls the transcriptional reprogramming via the perception of NPR proteins and their protein turnovers. Both positive and negative transcriptional regulations of SA biosynthesis are required for fine tuning the levels of SA for optimal defense without causing unnecessary fitness cost. |
S1360138520300224 | It is well documented that ancient sickle harvesting led to tough rachises but the other seed dispersal properties in crop progenitors are rarely discussed . The first steps toward domestication are evolutionary responses for the recruitment of humans as dispersers . Seed dispersalbased mutualism evolved from heavy human herbivory or seed predation . Plants that evolved traits to support human mediated seed dispersal express greater fitness in increasingly anthropogenic ecosystems . The loss of dormancy reduction in seed coat thickness increased seed size pericarp density and sugar concentration all led to more focused seed dispersal through seed saving and sowing . Some of the earliest plants to evolve domestication traits had weak seed dispersal processes in the wild often due to the extinction of animal dispersers or short distance mechanical dispersal . | Archaeobotanical and genetic evidence demonstrates that the first morphological changes in all of the earliest domesticated plants were associated with wild seed dispersal strategies that were no longer advantageous under human cultivation. Domestication was is a natural response of plants to heavy seed predation by humans. Many plants in the wild have formed a similar seed dispersalbased mutualism with animals as a response to herbivory. Rather than viewing domestication as an intentional human driven process domestication is best modeled as a natural evolutionary response to herbivory. Early domestication traits gave plants a selective advantage through the recruitment of humans as seed dispersers. Many of the progenitors of our modern domesticated crops relied on animals for seed dispersal. The natural dispersal processes of many of these crop progenitors were weakened by megafaunal extinctions. |
S1360138520300236 | The need to reduce pollinator exposure to harmful pesticides has led to calls to expedite the adoption of integrated pest management . We make the case that IPM is not explicitly pollinator friendly but rather must be adapted to reduce impacts on pollinators and to facilitate synergies between crop pollination and pest control practices and ecosystem services . To reconcile these diverse needs we introduce a systematic framework for integrated pest and pollinator management . We also highlight novel tools to unify monitoring and economic decision making processes for IPPM and outline key policy actions and knowledge gaps . We propose that IPPM is needed to promote more coordinated ecosystem based strategies for sustainable food production against the backdrop of increasing pesticide regulation and pollinator dependency in agriculture . Twitter @ Paul A Egan . | Integrated pest management IPM has been promoted as a response to mitigate pollinator decline yet IPM itself is not explicitly pollinator friendly. IPM strategies require adapting to reconcile crop pollination trade offs and to the harmonise the delivery of pollination and pest regulation practices and ecosystem services. A systematic framework for integrated pest and pollinator management IPPM is proposed to enhance IPM compatibility with crop pollination management and is underpinned by a novel approach to unify economic decision making. Highlighted policy actions and cutting edge support tools can assist the design and implementation of IPPM strategies. |
S136013852030025X | Vacuoles are the largest membrane bounded organelles and have essential roles in plant growth and development but several important questions on the biogenesis and dynamics of lytic vacuoles remain . Here we summarize and discuss recent research and models of vacuole formation and propose with testable hypotheses that besides inherited vacuoles plant cells can also synthesize LVs | Recent studies have uncovered that plant vacuoles can be inherited from the mother cell as well as synthesized. Recent studies have suggested that vacuole biogenesis is a cell type specific process in plants and multiple models and mechanisms for vacuole biogenesis have been proposed. Various populations and or groups of LVs are derived from different organelles and transport routes with unique functions in plant life. Plant vacuoles constantly undergo dynamic morphological and quantitative changes in response to various growth and environmental signals. The formation of the central vacuole is required for the maintenance of cell expansion. Multiple approaches with advantages and limitations have been used to study vacuole formation and dynamics in plants. |
S1360138520300273 | In photosynthetic cells chloroplasts and mitochondria are the sites of the core redox reactions underpinning energy metabolism . Such reactions generate reactive oxygen species when oxygen is partially reduced . ROS signaling leads to responses by cells which enable them to adjust to changes in redox status . Recent studies in | The malate valve has long been proposed to release excess reducing equivalents from the chloroplast but mutants lacking the proposed key enzyme NADP dependent malate dehydrogenase show little impairment of chloroplast function suggesting the involvement of an alternative pathway. New research suggests a central role for a malate valve employing chloroplast NAD dependent malate dehydrogenase which also has additional non enzymatic functions in chloroplast biogenesis. The new malate circulation model proposes that malate exported from the chloroplast is oxidized in the mitochondrion triggering ROS production which can modulate growth and ultimately induce cell death. It is proposed that the chloroplast to mitochondrion CTM pathway in conjunction with direct import of NAD. leads to elevated levels of NADH in the mitochondrion. |
S1360138520300492 | Plants possess an effective immune system to combat most microbial attackers . The activation of immune responses to biotrophic pathogens requires the hormone salicylic acid . Accumulation of SA triggers a plethora of immune responses . A tradeoff of strong immune responses is the active suppression of plant growth and development . The tradeoff also works the opposite way where active growth and developmental processes suppress SA production and immune responses . Here we review research on the role of SA in the growthimmunity tradeoff and examples of how the tradeoff can be bypassed . This knowledge will be instrumental in resistance breeding of crops with optimal growth and effective immunity . | The phytohormone salicylic acid SA stimulates plant immune responses to a broad range of plant pathogens. SA induced immune responses contribute to the growthimmunity tradeoff immune responses actively suppress growth and development and also the other way around growth and developmental processes can suppress immunity. Immune signaling and growth related processes directly affect SA biosynthesis and metabolism to allow for a robust but transient immune response after which growth and developmental processes are reactivated. The growthimmunity tradeoff can be uncoupled by modifying signaling pathways downstream of SA. Bypassing the antagonism of SA on growth is a desirable trait for resistance breeding in crops as this bypass can allow for sustainable resistance without yield losses. |
S1360138520300522 | Nighttime warming poses a threat to global food security as it is driving yield declines worldwide but our understanding of the physiological basis of this phenomenon remains very limited . Furthermore it is often assumed that such declines are driven solely by increases in nighttime temperature T | Nighttime warming is reducing crop yields worldwide threatening global food security. This phenomenon is more complex than may be assumed likely to involve interaction between two driving forces nighttime temperature and evaporative demand. The two conspire to limit carbon availability for yield and end use quality traits while decreasing water use efficiency potentially enhancing vulnerability to droughts. An ecophysiological framework is proposed as a guide to implement future research efforts to mitigate yield declines. Such efforts should integrate physiology with crop modeling breeding and management to identify sustainable pathways for mitigation as climate change intensifies. |
S1360138520300534 | Shifting the life cycle of grain crops from annual to perennial would usher in a new era of agriculture that is more environmentally friendly resilient to climate change and capable of soil carbon sequestration . Despite decades of work transforming the annual grain crop wheat | Current grain crops are annuals that must be sown every year giving their root systems little time to develop during the growing season. A perennial grain crop with a long lived extensive root system would improve soil quality store carbon belowground and utilize water and minerals more efficiently. Domestication genes of the annual grass wheat are highly conserved in the perennial intermediate wheatgrass. providing an opportunity for accelerated domestication of a perennial grain using a mutagenesis approach. |
S1360138520300546 | In plants high carbon flux is committed to the biosynthesis of phenylalanine tyrosine and tryptophan owing to their roles not only in the production of proteins but also as precursors to thousands of primary and specialized metabolites . The core plastidial pathways that supply the majority of aromatic amino acids have previously been described in detail . More recently the discovery of cytosolic enzymes contributing to overall AAA biosynthesis as well as the identification of intracellular transporters and the continuing elucidation of transcriptional and post transcriptional regulatory mechanisms have revealed the complexity of this intercompartmental metabolic network . Here we review the latest breakthroughs in AAA production and use the newest findings to highlight both longstanding and newly developed questions . | and. analyses have increased our depth of understanding of the plastidial AAA biosynthetic pathway. A newly discovered cytosolic Phe biosynthetic pathway and the presence of cytosolic Tyr biosynthetic enzymes in some plant species has revealed that AAA biosynthesis is a complex intercompartmental network. Characterization of transporters has answered questions about the physiological importance of the intracellular movement of AAAs. Transcriptional and post transcriptional regulatory mechanisms are responsible for the tight control of carbon flux distribution into and within the AAA network. |
S136013852030056X | With increasing calls for improving terrestrial carbon sequestration and sustainable water use scientists are faced with the challenge of predicting changes in carbonwater relations from organisms to landscapes . We propose an integrative framework to help in answering basic and applied questions pertaining to coupled carbonwater functions in a variety of ecosystems . The conceptual framework is based on data from a globally representative set of ecosystems that hold vast amounts of carbon and provide water for rural and urban land uses . We focus on examples that demonstrate the value of an integrated approach that combines fast and slow changing state factors to improve predictions of carbonwater relations across scales . | There is a growing need for land use management and prioritization for optimal carbon gain and water conservation. Interdisciplinary research will be necessary to better understand and improve the limits of carbon gain per water lost across scales. A state factor approach inspired by soil and ecosystem science can be used to improve basic and applied knowledge of carbonwater relations. |
S1360138520300571 | Plants have evolved a sophisticated innate immune system to defend against pathogen infection and intracellular nucleotide binding leucine rich repeat immune receptors are one of the main components of this system . NLR activity is fine tuned by intra and intermolecular interactions . We survey what is known about the conservation and diversity of NLR interacting proteins and divide them into seven major categories . We discuss the molecular mechanisms by which NLR activities are regulated and how understanding this regulation has potential to facilitate the engineering of NLRs for crop improvement . | NLR proteins are the major intracellular immune receptors in plants. Their transition between autoinhibited and activated states is fine tuned by intra and intermolecular interactions. NLR interacting proteins play important roles in NLR mediated immunity. Many NLR interacting proteins have been identified however they have not been systematically classified. |
S1360138520300583 | Ubiquitously expressed in plants the plant specific insert of typical plant aspartic proteases has been associated with plant development stress response and defense processes against invading pathogens . Despite sharing high sequence identity structural studies revealed possible different mechanisms of action among species . The PSI induces signaling pathways of defense hormones | Plant specific inserts PSIs of typical plant aspartic proteases demonstrate different activities despite sharing conserved sequences and structures among plants. At acidic pH electrostatic interactions between the PSI and negatively charged membrane lipids initiate PSImembrane interactions such as membrane fusion and disruption. PSIs display broad spectrum antimicrobial activity against plant and human pathogens. and participate in plant defense. The mechanism of PSI excision during the activation of its parent proenzyme varies among plants. PSI glycosylation appears to influence whether vesicle trafficking of proteins involved with plant development and defense is conducted through conventional or nonconventional endoplasmic reticulum to vacuole transport pathways. |
S136013852030087X | Post translational modifications of histone residues shape the landscape of gene expression by modulating the dynamic process of RNA polymerase II transcription . The contribution of particular histone modifications to the definition of distinct RNAPII transcription stages remains poorly characterized in plants . Chromatin immunoprecipitation combined with next generation sequencing resolves the genomic distribution of histone modifications . Here we review histone PTM ChIP seq data in | PTMs of histone residues affect gene expression by defining transcription stages. ChIP seq reveals the distribution of histone PTMs during transcription. A GPS based on the distribution profile of histone PTMs and histone variants underlies RNAPII transcription stages in plants. Misalignment of GPS and transcription units suggests novel transcription activity and regulation. Histone PTM reader writer and eraser enzyme trios maintain the chromatin based GPS and guide RNAPII transcription. |
S1360138520300881 | Fungal pathogens are major destructive microorganisms for land plants and pose growing challenges to global crop production . Chitin is a vital building block for fungal cell walls and also a broadly effective elicitor of plant immunity . Here we review the rapid progress in understanding chitin perception and signaling in plants and highlight similarities and differences of these processes between arabidopsis and rice . We also outline moonlight functions of CERK1 an indispensable chitin coreceptor conserved across the plant kingdom which imply potential crosstalk between chitin signaling and symbiotic or biotic abiotic stress signaling in plants via CERK1 . Moreover we summarize current knowledge about fungal counterstrategies for subverting chitin triggered plant immunity and propose open questions and future directions in this field . | Chitin perception systems in both arabidopsis and rice consist of multiple LysM containing proteins which undergo chitin induced oligomerization to trigger intracellular signaling. An oligomer size dependent chitin sensing mechanism is conserved across plants and mammals. Receptor like cytoplasmic kinase VII members are essential players of chitin signaling in both arabidopsis and rice. Both arabidopsis and rice CERK1 proteins play multifaceted functions beyond chitin signaling and may mediate the crosstalk between chitin signaling and symbiotic or other biotic or abiotic stress signaling. Most uncovered fungal countermeasures to subvert chitin triggered plant immunity involve blocking the generation and perception of chitin oligomers in plant apoplast whereas fungal cytoplasmic effector mediated strategies to disrupt chitin signaling inside plant cells remain poorly understood. |
S1360138520300911 | Ecological niches are crucial for species coexistence and diversification but the niche concept has been underutilized in studying the roles of pollinators in plant evolution and reproduction . Pollination niches can be objectively characterized using pollinator traits abundance and distributions as well as network topology . We review evidence that floral traits represent adaptations to pollination niches where tradeoffs in trait deployment reinforce niche specialization . In turn specialized pollination niches potentially increase speciation rates foster species coexistence and constrain species range limits . By linking studies of adaptation with those on speciation and coexistence the pollination niche provides an organizing principle for research on plant reproduction and conceptually unites these studies with fields of biology where the niche perspective is already firmly established . | Pollination is a crucial niche component for plants. The niche concept can apply to both occupied and currently unoccupied niches. Floral traits associated with pollination can be considered to be functional traits that can have similar or even better predictive capacity than functional traits in other areas of ecology. Plantpollinator network methods provide opportunities for objective recognition of pollination niches and can form the basis for testing relationships between niches and both floral and pollinator functional traits. The basis of specialization of pollination systems may be tradeoffs that favor adaptation to particular niches. Evidence suggests that like abiotic niches pollination contributes to species coexistence within communities affects the geographic range of plants and explains the evolution of reproductive isolation as well as differences in diversification rates between lineages. |
S1360138520301114 | At the subcellular level the cytoskeleton regulates cell structure organelle movement and cytoplasmic streaming . Autophagy is a process to remove unwanted biomaterials or damaged organelles through double membrane compartments known as autophagosomes . Autophagosome biogenesis requires vesicle trafficking between donor and acceptor compartments membrane expansion and fusion which is very likely to be regulated by the cytoskeleton . Recent studies have demonstrated that by knocking out key actin regulating proteins autophagosome biogenesis is inhibited . However the formation of ATG8 positive structures are not affected when the entire actin network is disrupted . Here we discuss this paradox and propose the function of the actin cytoskeleton in plant autophagy . | The actin network is regarded as the prevalent cytoskeleton system for subcellular membrane dynamics in plants. Autophagosome biogenesis involves vesicle trafficking and membrane fusion both of which require a functional cytoskeleton network. In animal yeast and plant cells actin and actin associated proteins participate in the process of autophagosome formation at various stages. Recent studies in plants have shown that mutation in components of the actin nucleator the ARP2 3 complex and two of its activators the SCAR WAVE complex and AtEH Pan1 significantly inhibit autophagosome formation and as a consequence mutant plants are more susceptible to stress conditions. However chemically induced actin network depolymerization does not affect autophagosome formation suggesting that the actin network could be dispensable for bulk autophagy. |
S1360138520301138 | Plasma membranes act as primary cellular checkpoints for sensing signals and controlling solute transport . Membrane proteins communicate with intracellular processes through protein interaction networks . Deciphering these signaling networks provides crucial information for elucidating | Membrane receptors kinases and transporters communicate with intracellular processes through protein interaction networks. Characterization of plant PM proteins especially hydrophobic proteins remains challenging despite advances in separation and analysis techniques. Rapid advances in MS instrumentation and data analysis have enabled marked progress in deciphering the membrane proteome and mapping protein interaction partners leading to a better understanding of PM protein complexes. Analysis of membrane protein phosphorylation under specific cellular conditions is crucial for elucidating the molecular mechanisms underlying signal sensing transport and metabolic processes. Phosphoproteomics allows unbiased localization and site specific quantification of. protein phosphorylation thus facilitating the dissection of membrane signaling networks. |
S136013852030114X | Plants are subjected to diverse biotic and abiotic stresses in life . These can induce changes in transcriptomics and metabolomics resulting in changes to root and leaf exudates and in turn altering the plant associated microbial community . Emerging evidence demonstrates that changes especially the increased abundance of commensal microbes following stresses can be beneficial for plant survival and act as a legacy enhancing offspring fitness . However outstanding questions remain regarding the microbial role in plant defense many of which may now be answered utilizing a novel synthetic community approach . In this article building on our current understanding on stress induced changes in plant microbiomes we propose a DefenseBiome concept that informs the design and construction of beneficial microbial synthetic communities for improving fundamental understanding of plantmicrobial interactions and the development of plant probiotics . | The recent advances in using synthetic communities together with metagenomics and metabolomics has begun to unravel mechanistic understanding of how stressed plants modulate their microbiomes. Stresses change plant transcriptomics and metabolomics below and above ground. Molecules such as flavonoids coumarins and other organic compounds have been recognized as plant signals that shape host microbiomes. A crucial regulating role of the interactions between the microbiome and plant immune system in stress tolerance is emerging. Experimental validation of such interactions and determination of how they influence plant fitness should now be prioritized. The plant associated microbes that increase in abundance by plant stresses coined the DefenseBiome could benefit plant health and be used for designing functionally reliable synthetic communities to improve plant fitness. |
S1360138520301151 | is one of the most studied plant viral pathogens because it is the most damaging virus for global tomato production . In order to combat this global threat it is important that we understand the biology of TYLCV and devise management approaches . The prime objective of this review is to highlight management strategies for efficiently tackling TYLCV epidemics and global spread . For that purpose we focus on the impact TYLCV has on worldwide agriculture and the role of recent advances for our understanding of TYLCV interaction with its host and vector . Another important focus is the role of recombination and mutations in shaping the evolution of TYLCV genome and geographical distribution . | Whitefly transmitted. TYLCV causes up to 100 yield loss in tomato. Studies have dissected the TYLCV genome and investigated the interaction of genomic components with both plant and vector. Recombination during mixed infections and mutations are the driving force for TYLCV evolution. Recombinant TYLCV with resistance breaking capabilities have caused serious epidemics. Strategies for disease management and imparting durable tolerance using advanced tools have been developed. |
S1360138520301187 | The current trend towards linking stomata regulation to plant hydraulics emphasizes the role of xylem vulnerability . Using a soilplant hydraulic model we show that xylem vulnerability does not trigger stomatal closure in medium wet to dry soils and we propose that soil hydraulic conductivity loss is the primary driver of stomatal closure . This finding has two key implications transpiration response to drought can not be derived from plant traits only and is related to soilroot hydraulics in a predictable way roots and their interface with the soil the rhizosphere are key hydraulic regions that plants can alter to efficiently adapt to water limitations . We conclude that connecting below and aboveground hydraulics is necessary to fully comprehend plant responses to drought . | There is an increasing need for mechanistic and predictive models of transpiration and stomatal response to drought and soil water availability. It has been hypothesized that stomatal regulation is predictable based on plant and soil hydraulics. The current trend towards a greater consideration of plant hydraulics in earth system science emphasizes xylem vulnerability neglecting the explicit role of soil and root hydraulics. The importance of root and soil hydraulic conductivity on plant water status is well accepted but difficult to measure. There is increasing evidence that plants adapt the conductivity of their roots as well as that of the soil in their vicinity the rhizosphere to match the soil conditions and atmospheric water demand contributing to the regulation of plant water status and transpiration. |
S1360138520301199 | Small RNAs mainly including miRNAs and siRNAs are ubiquitous in eukaryotes . sRNAs mostly negatively regulate gene expression via transcriptional gene silencing through DNA methylation mRNA cleavage or translation inhibition . The mechanisms of sRNA biogenesis and function in diverse biological processes as well as the interactions between sRNAs and environmental factors like biotic stress have been deeply explored . Phytohormones are central in the plants response to stress and multiple recent studies highlight an emerging role for sRNAs in the direct response to or the regulation of plant hormonal pathways . In this review we discuss recent progress on the unraveling of crossregulation between sRNAs and nine plant hormones . | An increasing number of studies identified a large variety of sRNAs responding to diverse phytohormones and in depth validation revealed molecular mechanisms underneath this. Conversely multiple sRNAs and central proteins in sRNAs pathways can regulate biosynthesis or signaling of nine phytohormones. Some sRNA modules interconnect with more than one hormonal pathway thereby providing new bridges in plant hormonal crosstalk. In response to environmental stimuli phytohormones enable plant adaptation and part of this reaction could be attributed to sRNAs and their targets. |
S1360138520301229 | Cannabis has been used as a medicine for millennia . Crude extracts of cannabis inflorescence contain numerous phytomolecules including phytocannabinoids terpenes and flavonoids . Combinations of phytomolecules have been recently established as superior to the use of single molecules in medical treatment owing to the entourage effect . Two types of entourage effects are defined intra entourage resulting from interactions among phytocannabinoids or terpenes and inter entourage attributed to interactions between phytocannabinoids and terpenes . It is suggested that the phytomolecule assemblages found in cannabis chemovars today derive from selective breeding during ancient cultivation . We propose that the current cannabis chemotaxonomy should be redefined according to chemical content and medicinal activity . In parallel combinations of phytomolecules that exhibit entourage activity should be explored further for future drug development . | Cannabis has been used for millennia by humanity for social ritual and medical purposes. Humans bred and selected for cannabis strains based on their needs. Today patients are treated by cannabis strains without a clear definition of activity or known chemical content. strain taxonomy is based on the content of two phytocannabinoids only. tetrahydrocannabinolic acid THCA and cannabidiolic acid CBDA . produces hundreds of phytomolecules including phytocannabinoids terpenes and flavonoids. Some cannabis phytomolecules interact causing enhanced biological activity. Defining this phenomenon known as the entourage effect is one of the leading challenges in the field of research. |
S1360138520301242 | Severe acute respiratory syndrome coronavirus 2 is a novel coronavirus responsible for an ongoing human pandemic . There is a massive international effort underway to develop diagnostic reagents vaccines and antiviral drugs in a bid to slow down the spread of the disease and save lives . One part of that international effort involves the research community working with plants bringing researchers from all over the world together with commercial enterprises to achieve the rapid supply of protein antigens and antibodies for diagnostic kits and scalable production systems for the emergency manufacturing of vaccines and antiviral drugs . Here we look at some of the ways in which plants can and are being used in the fight against COVID 19 . | The current COVID 19 pandemic has created an immediate massive demand for diagnostic reagents based on SARS CoV 2 RNA proteins and corresponding antibodies placing immense strain on the supply and distribution chain. Transient expression in plants could address the shortage by achieving rapid larger scale production complemented by longer term higher volume production in transgenic plants. The same technology used to produce diagnostic reagents could also be used to produce vaccine candidates SARS CoV 2 subunits and virus like particles as well as therapeutic antibodies and antiviral proteins. It will be necessary to pool the international resources of molecular farming research groups and industry to capitalize on expertise although distributed production using local infrastructure is the key to reaching all parts of the world. |
S1360138520301278 | Programmed cell death is a genetically regulated process for the selective demise of unwanted and damaged cells . Although our understanding of plant PCD pathways has advanced significantly doubts remain on the extent of conservation of animal apoptosis in plants . At least at the primary sequence level plants do not encode the regulators of animal apoptosis . Structural analyses have enabled the identification of the B cell lymphoma 2 associated athanogene family of co chaperones in plants . This discovery suggests that some aspects of animal PCD are conserved in plants while the varied subcellular localization of plant BAGs indicates that they may have evolved distinct functions . Here we review plant BAG proteins with an emphasis on their roles in the regulation of plant PCD . | Plants do not encode homologs of the core regulators of animal apoptosis. The plant Bcl 2 associated athanogene BAG family is conserved at the structural level is localized in a variety of subcellular locations and may have diverged unique functions not observed for animal BAGs. Arabidopsis BAG proteins have been implicated in multiple plant PCD pathways. The presence of the calmodulin binding domain in three family members AtBAG57 is unique to plants and may suggest potential roles for BAGs in calcium signaling as part of plant PCD pathway regulation. |
S136013852030128X | We are facing unprecedented phosphorus challenges namely P scarcity associated with increasing food demand and an oversupply of P fertilisers resulting in eutrophication . Although we need a multidisciplinary approach to systematically enhance P use efficiency monodisciplinary studies still prevail . Here we propose to tighten the P cycle by identifying P efficient crop genotypes integrating four plant strategies increasing P acquisition efficiency photosynthetic P use efficiency and P remobilisation efficiency and decreasing seed phytate P concentrations . We recommend P efficient genotypes together with diversified cropping systems involving complementary P acquisition strategies as well as smart P fertiliser management to enhance P use efficiency in agriculture dependent on soil P status . These strategies will reduce P fertiliser requirements and offsite environmental impacts while enhancing seed quality for human and livestock nutrition . | Adopting a multidisciplinary approach is crucial to tighten the P cycle however current research still focusses on monodisciplinary approaches. Crop genotypes with high efficiency of P acquisition photosynthetic P use or P remobilisation or low seed phytate P concentrations are crucial to reduce P fertiliser input and P related environmental impact and to enhance micronutrient availability of food and feed. While native plant species differ substantially in their strategies for P acquisition under low P availability there is also considerable genotypic variation in P acquisition strategies in crop species and genotypes. At the leaf level P is preferentially allocated to photosynthetic cells to enhance photosynthetic P use efficiency while at the cellular level plants maintain a higher ratio of metabolic P to lipid P and function at very low levels of ribosomal RNA. |
S1360138520301291 | Like communities of people communities of cells must continuously communicate to thrive . Polypeptide signaling molecules that act as mobile ligands are widely used by eukaryotic organisms to transmit information between cells to coordinate developmental processes and responses to environmental cues . In plants the | The advent of genome editing has accelerated analysis of the arabidopsis. peptide gene family revealing novel functions for multiple family members. New components of the CLAVATA3 CLV3 shoot stem cell signaling pathway have been identified that include the CIK subfamily of receptor kinases several MAP kinases and the HAM family of transcription factors. CLE peptides regulate root biological processes such as protophloem development root hair formation and response to nutrient availability. CLE signaling in vascular tissues requires the integration of auxin and cytokinin responses as well as a feed forward loop comprising several transcription factors. CLE peptides limit cell division activity during stomata formation and promote stomatal closure in an abscisic acid responsive manner. |
S1360138520301485 | It is generally accepted that plants locally influence the composition and activity of their rhizosphere microbiome and that rhizosphere community assembly further involves a hierarchy of constraints with varying strengths across spatial and temporal scales . However our knowledge of rhizosphere microbiomes is largely based on single location and time point studies . Consequently it remains difficult to predict patterns at large landscape scales and we lack a clear understanding of how the rhizosphere microbiome forms and is maintained by drivers beyond the influence of the plant . By synthesizing recent literature and collating data on rhizosphere microbiomes we point out the opportunities and challenges offered by advances in molecular biology bioinformatics and data availability . Specifically we highlight the use of exact sequence variants coupled with existing and newly generated data to decipher the rules of rhizosphere community assembly across large spatial and taxonomic scales . | The processes shaping rhizosphere microbial communities are currently unclear because of both a lack of knowledge about biogeographical patterns and the disconnection between plant and microbial scales. Sequence databases have now collected a sufficient amount of data covering a range of biomes and plant taxa to allow synthesis across studies. Recently new bioinformatic methods have been developed that allow us to overcome former spatial and taxonomic limitations. Understanding the processes that shape rhizosphere microbial communities will provide important insights into plant ecology and evolutionary biology and can enable us to manage microbial and plant ecosystem services. |
S1360138520301497 | The development of genomics and epigenomics has allowed rapid advances in our understanding of plant biology . However conventional bulk analysis dilutes cell specific information by providing only average information thereby limiting the resolution of genomic and functional genomic studies . Recent advances in single cell sequencing technology concerning genomics and epigenomics open new avenues to dissect cell heterogeneity in multiple biological processes . Recent applications of these approaches to plants have provided exciting insights into diverse biological questions . We highlight the methodologies underlying the current techniques of single cell genomics and epigenomics before covering their recent applications potential significance and future perspectives in plant biology . | The rapidly developing fields of single cell genomics and epigenomics provide powerful approaches to dissect cell heterogeneity in plants. The sensitivity and specificity of detecting single nucleotide variations and copy number variations via single cell whole genome amplification technologies have been continuously improving over the past decades. Recent applications highlight their feasibility and utility in plant single cell genomics. Recent technical advances in single cell epigenomics have enabled comprehensive and accurate profiling of diverse epigenomic features. The cell specific epigenome facilitates the dissection of molecular mechanisms underlying biological processes in plants. Overcoming current technical issues and integrating multiomic single cell sequencing data in plants will provide far greater understanding of plant functional genomics. |
S1360138520301503 | Gene expression in individual cells can be surprisingly noisy . In unicellular organisms this noise can be functional for example by allowing a subfraction of the population to prepare for environmental stress . The role of gene expression noise in multicellular organisms has however remained unclear . In this review we discuss how new techniques are revealing an unexpected level of variability in gene expression between and within genetically identical plants . We describe recent progress as well as speculate on the function of transcriptional noise as a mechanism for generating functional phenotypic diversity in plants . | Gene expression levels can be surprisingly noisy both between individual cells and between individual plants even in the absence of genetic and environmental variation. is a promising system to study interindividual gene expression variability since it is an inbreeding species with extremely low heterozygosity. Noise in gene expression in plants is widespread as revealed by studies that have begun to systematically quantify it at the between cell and between individual levels. This could be detrimental or by contrast used to drive developmental patterns or create phenotypic diversity without genetic diversity. The sources and roles of gene expression noise in plants are still not well understood. New experimental techniques now allow the analysis of plant to plant and cell to cell gene expression noise in plants. |
S1360138520301680 | Arbuscular mycorrhizal fungi are plant root symbionts that continuously carry thousands of nuclei in their spores and hyphae . This unique cellular biology raises fundamental questions regarding their nuclear dynamics . This review aims to address these by synthesizing current knowledge of nuclear content and behavior in these ubiquitous soil fungi . Overall we find that that nuclear counts as well as the nuclei shape and organization vary drastically both within and among species in this group . By comparing these features with those of other fungi we highlight unique aspects of the AMF nuclear biology that require further attention . The potential implications of the observed nuclear variability for the biology and evolution of these widespread plant symbionts are discussed . | Arbuscular mycorrhizal fungi AMF can carry thousands of nuclei in their cells at all times. The number shape and frequency of these nuclei vary substantially among and within species. Some AMF strains referred to as AMF dikaryons carry two distinct nuclear genotypes within their cells. The frequency of two coexisting genotypes may vary across AMF dikaryons raising questions about its significance for mycorrhizal symbiosis. |
S1360138520301862 | Together with sugars and proteins lipids constitute the main carbon reserves in plants . Lipids are selectively recycled and catabolized for energy production during development and in response to environmental stresses . Autophagy is a major catabolic pathway operating in the recycling of cellular components in eukaryotes . Although the autophagic degradation of lipids has been mainly characterized in mammals and yeast growing evidence has highlighted the role of autophagy in several aspects of lipid metabolism in plants . Here we summarize recent findings focusing on autophagy functions in lipid droplet metabolism . We further provide novel insights regarding the relevance of autophagy in the maintenance and clearance of mitochondria and peroxisomes and its consequences for proper lipid usage and energy homeostasis in plants . | Our understanding of autophagy function in lipid degradation in plants is understudied compared with the elucidated mechanisms in animals and yeast. However the potential roles of plant autophagy in lipid recycling and metabolism are beginning to come to light. Macroautophagy is a versatile mechanism involved in lipid metabolism operating both in the turnover of membrane components and in various aspects of reproduction like pollen and seed metabolism. A mechanism resembling yeast microlipophagy was recently proposed in plant cells and is specifically active under starvation. The interplay between microlipophagy and lipolysis in plants seems to drive the efficient usage of lipid reserves. The autophagic maintenance of mitochondria and peroxisomes is essential for the optimal operation of these organelles further enabling proper lipid turnover. |
S1360138520301874 | Phytocannabinoids are bioactive natural products found in some flowering plants liverworts and fungi that can be beneficial for the treatment of human ailments such as pain anxiety and cachexia . Targeted biosynthesis of cannabinoids with desirable properties requires identification of the underlying genes and their expression in a suitable heterologous host . We provide an overview of the structural classification of phytocannabinoids based on their decorated resorcinol core and the bioactivities of naturally occurring cannabinoids and we review current knowledge of phytocannabinoid biosynthesis in | Phytocannabinoids are bioactive terpenoids that were thought to be exclusive to. but have now also been discovered in. species some legumes the liverwort genus. and some fungi. Many cannabinoids display promising non hallucinogenic bioactivities that are determined by the variable nature of the side chain and prenyl group defined by the enzymes involved in their synthesis. The biosynthesis of cannabinoids in. is fully elucidated whereas the pathways in. and. have only recently gained research attention. Cannabinoid biosynthesis is highly modular enabling use of the modules identified in synthetic biology based combinatorial approaches as demonstrated by the generation of new to nature cannabinoids in. The ecological functions of cannabinoids include protection against UV light and desiccation as well as in plant defense. |
S1360138520301886 | Hormesis is a biphasic doseresponse relationship with contrasting effects of low versus high doses of stress . Hormesis is rapidly developing in plant science research and has wide implications for risk assessment stress biology and agriculture . Here we explore selected areas of importance to the concept of hormesis and suggest that hormesis is a highly generalizable phenomenon . We address the questions of whether hormesis occurs in high risk groups or in response to mixtures of stress inducing agents whether there is a single biological mechanism of hormesis and what the temporal features of hormesis are . | Hormesis occurs not only in normal but also in high and low risk subpopulation groups. Some high risk subpopulation groups show different quantitative features of hormetic responses from normal and low risk subpopulation groups. Some differences in hormetic dose responses exist between fast growing and slow growing individuals within populations. Hormesis is widely induced by various mixtures of stress inducing agents in plants microbes and other life forms potentially interacting with plants. No single biological mechanism of hormesis exists but some general mechanistic strategies can be suggested. Chemical induced hormesis exhibits significant temporal variation with an initial increase of the maximum stimulation followed by a significant decline but maintained at biologically beneficial enhanced levels. |
S1360138520301916 | High stress resistance and yield are major goals in crop cultivation which can be addressed by modifying plant architecture . Significant progress has been made in recent years to understand how plant architecture is controlled under various growth conditions recognizing the central role phytohormones play in response to environmental stresses . miRNAs transcription factors and other associated proteins regulate plant architecture mainly via the modulation of hormone homeostasis and signaling . To generate crop plants of ideal architecture we propose simultaneous editing of multiple genes involved in the regulatory networks associated with plant architecture as a feasible strategy . This strategy can help to address the need to increase grain yield and or stress resistance under the pressures of the ever increasing world population and climate change . | Plant hormone homeostasis modulates plant architecture crop yield and resistance to environmental stresses. miRNAs phytohormones key transcription factors and other important signaling proteins form complex networks to regulate plant hormone homeostasis. Some transcription factors act as system integrators of internal and external signals to regulate lateral organ angles and or orientations and or branch and tiller numbers. Modification of plant architecture by fine tuning the expression of key genes has proved to be a promising strategy to improve yield and or stress resistance. |
S1360138520301965 | Establishing laws of plant and ecosystems functioning has been an overarching objective of functional and evolutionary ecology . However most theories neglect the role of human activities in creating novel ecosystems characterized by species assemblages and environmental factors that are not observed in natural systems . We argue that agricultural weeds as an emblematic case of such an ecological novelty constitute an original and underutilized model for challenging current concepts in ecology and evolution . We highlight key aspects of weed ecology and evolutionary biology that can help to test and recast ecological and evolutionary laws in a changing world . We invite ecologists to seize upon weeds as a model system to improve our understanding of the short term and long term dynamics of ecological systems in the Anthropocene . | Agricultural weeds constitute an original model to understand the impact of anthropogenic changes on ecological and evolutionary dynamics. A combination of environmental factors in cultivated fields has driven the selection of novel functional trait combinations in agricultural weeds. Therefore agricultural weeds can be considered as rule breakers of ecological and evolutionary laws. Weeds in cropped fields are particularly valuable for assessing the consequences of out of equilibrium and transient dynamics on community assembly. Weed herbicide resistance and crop mimicry syndromes represent some of the best documented examples of rapid evolution in plants and provide a promising context for the study of eco evolutionary feedbacks. |
S1360138520302016 | Strigolactones control plant development enhance symbioses and act as germination stimulants for some of the most destructive species of parasitic weeds making SLs a potential tool to improve crop productivity and resilience . Field trials demonstrate the potential use of SLs as agrochemicals or genetic targets in breeding programs with applications in improving drought tolerance increasing yields and controlling parasitic weeds . However for effective translation of SLs into agriculture understanding and exploiting SL diversity and the development of economically viable sources of SL analogs will be critical . Here we review how manipulation of SL signaling can be used when developing new tools and crop varieties to address some critical challenges such as nutrient acquisition resource allocation stress tolerance and plantparasite interactions . | Proof of principle for strigolactone SL application in agriculture has now been demonstrated at field trial scale for parasitic weed control increasing fruit yield enhancing nutrient uptake and improving yield under drought conditions. The agricultural potential of many emerging and established activities of SLs remains under investigated. Specificity of activity in the landscape of many complex SL responses can be achieved through exploitation of differences in SL structures and receptor specificities. |
S1360138520302041 | Salt stress is one of the major environmental stresses limiting plant growth and productivity . To adapt to salt stress plants have developed various strategies to integrate exogenous salinity stress signals with endogenous developmental cues to optimize the balance of growth and stress responses . Accumulating evidence indicates that phytohormones besides controlling plant growth and development under normal conditions also mediate various environmental stresses including salt stress and thus regulate plant growth adaptation . In this review we mainly discuss and summarize how plant hormones mediate salinity signals to regulate plant growth adaptation . We also highlight how in response to salt stress plants build a defense system by orchestrating the synthesis signaling and metabolism of various hormones via multiple crosstalks . | Both stress hormones and growth hormones are important in the mediation of plant salinity stress responses. Sophisticated crosstalk occurs among the different hormones in plant growth adaptation under salinity stress. The cooperation or antagonism among different plant hormones is dependent on growth stages. Plants adapt to salinity stress through flexible regulation of hormone levels and or signaling. Glycosyl inositol phosphorylceramide GIPC sphingolipids in the plasma membrane act as Na. receptors for sensing Na. in the apoplastic space and then gate Ca. influx channels in plants. |
S1360138520302077 | Plastoquinone 9 is an essential component of photosynthesis that carries electrons in the linear and alternative electron transport chains and is also a redox sensor that regulates state transitions and gene expression . However a large fraction of the PQ pool is located outside the thylakoid membranes in the plastoglobules and the chloroplast envelopes reflecting a wider range of functions beyond electron transport . This review describes new functions of PQ in photoprotection as a potent antioxidant and in chloroplast metabolism as a cofactor in the biosynthesis of chloroplast metabolites . It also focuses on the essential need for tight environmental control of PQ biosynthesis and for active exchange of this compound between the thylakoid membranes and the plastoglobules . Through its multiple functions PQ connects photosynthesis with metabolism light acclimation and stress tolerance . | Plastoquinone PQ 9 is an electron carrier that plays an essential role in photosynthesis where it is involved in linear and alternative electron flows. However the functions of PQ go far beyond photosynthesis. PQ 9 is a multilocation compound that is partitioned in the chloroplast between thylakoids plastoglobules and envelopes. Its distribution is modulated dynamically by various regulatory enzymes as a function of the environmental conditions. The redox state of the PQ pool plays a crucial role in various functional and metabolic processes such as light acclimation biosynthesis of metabolites and gene expression. PQ is a potent antioxidant that scavenges reactive oxygen species and mitigates lipid peroxidation. supplementing the photoprotection provided by carotene in photosystem II and tocopherols in the thylakoid lipid phase. |
S136013852030217X | Rootsoil interactions in the rhizosphere are central to resource acquisition and crop production in agricultural systems . However apart from studies in idealized experimental systems rhizosphere processes in real agricultural soils | Rootsoil interactions involving rhizosphere sensing root architecture and function as well as root induced rhizosphere processes are crucial for soil health sustainable food security and resource use efficiency. Heterogeneity is an important feature of the rhizosphere and this poses a challenge to a thorough understanding of rootsoil processes. Uneven distribution of soil particles and resources shapes root activities and the consequent root induced modification of the rhizosphere. Understanding and integrating root biology with soil processes in the context of the heterogeneous physical structure and resource distribution in soil will help close the application gap between rhizosphere research and agricultural practice thereby contributing to sustainable crop production. |
S1360138520302193 | Plantmicrobearthropod three way interactions have important implications for plant health . However our poor understanding of the underlying regulatory mechanisms hampers their biotechnological applications . To this end we searched for potential common patterns in plant responses regarding taxonomic groups or lifestyles . We found that most signaling modules regulating two way interactions also operate in three way interactions . Furthermore the relative contribution of signaling modules to the final plant response can not be directly inferred from two way interactions . Moreover our analyses show that three way interactions often result in the activation of additional pathways as well as in changes in the speed or intensity of defense activation . Thus detailed basic knowledge of plantmicrobearthropod regulation will be essential for the design of environmentally friendly crop management strategies . | Plantmicrobearthropod PMA interactions have important impacts on plant fitness and recent studies shed light on how plants regulate responses in such complex interactions. Biosynthetic pathways for the production of defensive and signaling compounds and the corresponding signaling modules mostly related to phytohormones are key regulators both in interactions of the plant with either microbes or arthropods two way interactions or when exposed to both PMA three way interactions . Most signaling modules regulating two way interactions of plants with microbes or arthropods also operate in three way PMA interactions but changes in their speed or intensity e.g. defense priming and or activation of additional pathways frequently occur. These differences shape the outcome of PMA interactions and may have implications for ecologically based crop protection. |
S1360138520302478 | Seeds were a key evolutionary innovation . These durable structures provide a concerted solution to two challenges on land dispersal and stress . Lipid droplets that act as nutrient storage reservoirs are one of the main cell biological reasons for seed endurance . Although LDs are key structures in spermatophytes and are especially abundant in seeds they are found across plants and algae and increase during stress . Further the proteins that underpin their form and function often have deep homologs . We propose an evolutionary scenario in which the generation of LDs arose as a mechanism to mediate general drought and desiccation resilience and the required protein framework was co opted by spermatophytes for a seed specific program . | The generation of LDs is a mechanism that arose to mediate general drought and desiccation resilience. We provide an evo devo perspective on the deep evolutionary roots of a key trait of seeds the genetic chassis for LD formation. We ponder the question of how the evolution of these key components is tied to ancient circuits for stress responses. A comparative perspective on the proteins that define LDs across the streptophyte tree of life allows definition of their core set and of the additions that emerged during the course of evolution. |
S136468261730175X | GNSS can provide high accuracy positioning at low cost . But depending on the sources of error e.g . the atmospheric effects this accuracy can be degraded . The ionosphere is one of the most important error sources in GNSS positioning . Among several effects caused by the ionosphere irregularities such as ionospheric scintillations are very relevant . They can cause cycle slips degrade the positioning accuracy and when severe enough can even lead to a complete loss of signal lock . Brazil in particular is located in one of the regions most affected by ionospheric scintillations and these effects were intensified during the last solar maximum . The main goal of this paper is to evaluate the impact of scintillation effects on the degradation of positioning during the last solar maximum . Data from 2012 to 2014 of three reference stations located in different regions of Brazil was used . Statistically significant correlations were identified from Spearman s correlation coefficient . Using Odds Ratio an effect size statistic it was possible to see that the chance of large discrepancies in 3D positioning coordinates could be three times greater under strong scintillation effects | Evaluation of Ionospheric scintillation effects on positioning degradation. Data considering the last solar maximum 20122014 . Evaluation in different regions of Brazil one of the most affect countries. Robust statistical analysis using different methods. Large discrepancies in positioning obtained under strong scintillation effect. |
S1364682618306874 | A systematic investigation and greater understanding of the precipitation chemistry with respect to the altitude gradient in mountainous areas is necessary to promulgate the detrimental consequences of pollution on various ecosystems . Studies on the chemical compositions of wet precipitation were performed on the northern slopes of Mt . Taibai Qinling Mountains one of the highest mountains in East China from different lateral monitoring stations over the period from 2011 to 2014 . All samples were analyzed for major ions SO | Aims to assess altitudescale variation of precipitation chemistry in the Mt. Taibai. Ions concentrationaltitude gradient for the precipitation is found to be 6.58 and 34.04 eq L. 100 m during monsoon and non monsoon period respectively. Ionic concentrations showed a negative logarithmically decreasing trend with increasing altitude. |
S1364682619304122 | This study assesses the possibility of using Global Navigation Satellite System observations in combination with measurements of surface pressure and temperature to derive Integrated Water Vapor IWV | SIRGAS zenith total delays contribute to water vapor monitoring in Latin America. GNSS stations contribute to the monitoring of tropospheric water vapor in Argentina. IWV increases and relative atmospheric pressure falls preceding onset of precipitation. |
S1364682619304183 | Dust plays an important role in the modification of microphysical and optical properties of clouds . The presence of dust at an elevated level significantly increases snow mass and rain concentration . A rare phenomenon of rain and snowfall with dust was occurred simultaneously in the eastern Iraq Syria and west and south west of Iran on 19 and 20 January 2018 . In the meantime while the dust impact was dominating over a large area within Syria Iraq Saudi Arabia Kuwait and Iran it consequently caused extreme temperature drop rain and snowfall problems for the residents living in the Middle East . Likewise a visibility drop together with rainfall was also observed in the same region . The visibility was reduced to less than 500m over most of the region . Further an image showing dust mass taken from the satellite with higher amount of AOD indicated the severe dust activity . It is worth to mention that a dynamic low pressure system covering the surface and also the cold and warm fronts and the relevant occluded front caused such a phenomenal problem . The dust storm on 19th January was mainly prefrontal typed and transported from Horolazim Lagoon Ad Dahna and An Nafud deserts under the impact of the south easterly winds . The cold front was displaced to the eastward with a consequent dust storm on 20th January originated from the vaster parts in Iraqian and Syrian deserts and Ad Dahna and An Nafud deserts . The back trajectory analysis of HYSPLIT MODEL shows the different sources of dust in the study region during 1920th January . On the whole it can be concluded that the dust concentration and atmospheric quantities including the wind the precipitation and the cold and warm fronts having a permissible effect on simulation processes are well simulated by the WRF Chem model . The comparison of WRF Chem and NAAPS outputs revealed that the dust pattern and the procedure of vertical transfer of particles of each model are very identical but the amounts of dust in the Model NAAPS are underestimated . | Occurrence of rain and snowfall during dust episode in the Middle East. The visibility has been reduced to less than 500m in the study period. The model shows the formation of the prefrontal dust in the region. |
S1364682619304262 | Air quality in Delhi is largely dependent on concentration of aerosol particulate matter with aerodynamic diameter less than 2.5m . Diurnal variation of PM2.5 is mainly determined by rates of emission deposition chemical reactions and turbulent mixing caused by vertical wind shear and buoyancy . Continuous observations of PM2.5 NOx and O | Continuous tracking of Mixed Layer Height MLH by ceilometer. PM2.5 and NOx correlate inversely with MLH during daytime. PM2.5 decreases by 14 13 and 7gm. in December January and February respectively for every 100m increase in MLH. Effect of dilution and accumulation by MLH on PM illustrated. |
S1364682619304328 | The Upper Troposphere and Lower Stratosphere region plays an important role in the climate system . Quantifying the processes that control UTLS represents a crucial task . We assess UTLS trends and associated tropopause parameters Lapse Rate Tropopause temperature altitude Convective outflow level temperature altitude and Tropical Tropopause Layer thickness . This study is based on high resolution daily radiosonde data from 2006 to 2018 over a tropical station Gadanki in south India supported by satellite measurements . The results show an increase of CPH of 0.06km decrease of CPT of 1.09K increase of COH of 0.29km and decrease of TTL thickness of 0.23km in the recent decade . The vertical temperature trends show a strong cooling trend at lower stratosphere with a maximum cooling rate of 1.30.86K per decade at 19.4km altitude unlike reported recently using global radiosonde network . A warming trend is observed in the entire troposphere with maximum warming rate of 0.440.55Kat 11.6km during the last decade . Distinct variability in the temperature is noticed below and above the tropopause with the strong seasonal change above the tropical tropopause compared to the below the tropopause . The observed trends are explained in relation to the ozone O | Long term trends in the UTLS temperature obtained using high accuracy radiosonde over Indian region is presented. Unlike reported recently cooling trend in the lower stratosphere is still persistent over Indian region. Compare to the ozone changes the WV increasing trend was found strongly influencing the LS cooling trend over ISM region. |
S1364682619304407 | In this paper we obtain multiple attractors and periodicity using differential and integral operators with power law and Mittag Leffler law for the coupled dynamical El Nio La Nia Southern oscillation model and the continuous time Vallis model for El Nio . Also we consider the extension of these models considering a stochastic approach where the given parameters are converted to normal distributions . Additionally we consider for both models novel differential and integral operators with fractional order and fractal dimension . These novel operators predict chaotic behaviors involving the fractal derivative in convolution with power law and the Mittag Leffler function also these operators can capture self similarities for both chaotic attractors . We have presented the conditions of existence of uniquely exact solutions of the system using the fixed point theorem approach . Each model is solved numerical via the Adams Bashforth Moulton Adams Moulton and the Atangana Toufik schemes . We presented numerical simulations for different values of fractional order to show the applicability and computational efficiency of these methods . The results obtained presents more information that were not revealed in the models with local derivative . | We obtain multiple attractors and periodicity using differential and integral operators with powerlaw and Mittag Leffler law. Liouville Caputo and Atangana Baleanu fractional derivatives are considered. Novel differential and integral operators with fractional order and fractal dimension are considered. Numerical simulations are presented for specific parameters. The results obtained presents more information that were not revealed in the models with local derivative. |
S1364682619304419 | The Arctic seas are mainly located inside the polar vortex under conditions of low temperature . Sea ice extent in these seas in the winter spring period reaches maximum values with negligible interannual changes . The exception is the Barents Sea where interannual variability of sea ice extent increases from December to February . In winter the vortex edge is often located near the Barents Sea which leads to an increase in surface temperature and a decrease in sea ice extent . We show that the Barents Sea ice extent in winter can be determined by the shape and location of the tropospheric polar vortex . | The interannual variability of the Barents Sea ice extent reaches 32 in January. The tropospheric polar vortex edge is often located near the Barents Sea in winter. The Barents Sea ice cover can be determined by the changes in the polar vortex edge. |
S1364682619304444 | This study employed ultraviolet images and particle data to investigate isolated auroral spots away from the Earth s auroral oval . Data from SSUSI and SSJ mounted on the DMSP spacecraft were examined . The isolated auroral spots were observed by DMSP F16 SSUSI and F17 SSUSI on 29 May 2010 during the recovery phase of a moderate geomagnetic storm with a minimum SYM H index of 70 nT . The auroral spots were observed between 18 0021 00 MLT and corotated with the Earth but stayed almost at the same magnetic latitude of 60 . It is found that the isolated auroral spots were produced mainly by energetic ring current ions at energies above 10keV . The enhancement in the electron flux with energy below 200eV was also observed for the isolated auroral spots . The MLAT of the electron flux was nearly 2higher than that for the precipitating ions . | Isolated auroral spots were observed in the evening sector and corotated with the Earth. The isolated auroral spots were produced mainly by energetic ions with energies above 10keV. Weak electron precipitation 200 eV was observed but the intensity was likely too weak to generate isolated auroral spots. |
S1364682619304456 | Understanding the global distribution pattern of aerosol particles is of paramount importance as it has applications of many fields that include but are not limited to energy and environment the study of aerosol particles is building blocks for nanotechnology . Therefore the keen observation of aerosols through satellite remote sensors namely MODIS and CALIOP is important . The newly launched MODIS collection 6.1 aerosol product are containing three different aerosol inversion algorithms such as the Dark Target algorithm for land the DT algorithm for the ocean and the Deep Blue algorithm for land . In this study we have used a combined aerosol product based on DT and DB to present emerging patterns in global and regional aerosol characteristics over short term and long term observation periods . The CALIOP a Lidar instrument on aboard of the Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite which presents the 3 dimensional view of aerosol climatology is also used during special cases to investigate the aerosol distribution patterns . Based on MODIS observations the aerosol distribution patterns show strong seasonal differences . The seasonal characteristics vary with latitude and longitude across the globe . The regional characteristics clearly showed their region specific behavior . Interestingly MODIS observations captured high concentrations over the regions traced in the developing countries particularly South and East Asia where observations show strong seasonality . The averaged MODIS AOD trend over global is found slightly negative . On regional scales positive trends found over the Arabian Peninsula Africa Eastern China Northern part of India . These regions are next to major monsoon regions . The increasing concentration of aerosols over these regions may modulate the monsoon rainfall distribution pattern . In contrast the negative trend observed over Eastern America Europe the southeast part of Africa as well as in the associated dust outflow over the North Atlantic . | Satellites observations identify emerging patterns in global aerosol distribution. Aerosol hotspot regions shows strong seasonality. AOD reflects distinct characteristics at regional scale. Satellites observations captured high aerosol concentrations over region located in the developing countries. |
S1364682619304468 | Ionospheric delay error is one of the most significant error sources for single frequency SBAS users and its error bound is the key point for PL calculation . To satisfy the integrity specifications for users anywhere in the service region the error bound need to be inflated according to various threat . Among them the undersampled threat plays an important role in the inflation . The fundamental reason for the undersampled threat lies in the disagreement of the linear planar model to the actual ionosphere characteristics which can not be accurately described by the discrete IPP samples . Ionosphere threat model is established to handle this problem . It uses historical irregular ionosphere data to generate the two dimensional lookup table which illustrates the relationship between the IPP distribution and the maximum estimation error . How to abstract the metrics to describe the discrete two dimensional IPP distribution is the key to the establishment of ionosphere threat model . In this paper we conclude the properties of a good metric from a physical point of view and propose the Relative COVerage metric . Based on the measured data from IGS stations taking the regions of Europe as an example the ionosphere threat model based on RCOV metric is established and compared with the RCM model used in WAAS and MSAS . At the same time the integrity of the ionosphere GIVE results is verified . The experimental results show that under the experimental configuration given in this paper the RCOV metric proposed can improve the system availability on the premise of meeting the integrity requirements . | We conclude the properties of a good metric and propose the RCOV metric. Taking the regions of Europe as an example the RCOV threat model is established and compared with the RCM used in WAAS. RCOV metric proposed can improve the system availability on the premise of meeting the integrity requirements. |
S136468261930447X | Altitude structure of turbulence in the troposphere and lower stratosphere over the Indian peninsula is delineated using radiosonde observations carried out from six stations as part of the Tropical Tropopause Dynamics Campaign under the GPS Aided Radiosonde Network Experiment for Tropospherestratosphere Studies program . Thorpe analysis applied to the potential temperature profiles taking into account the impact of atmospheric moisture and instrumental noise is used to estimate the turbulence parameters . This study shows that while the occurrence of turbulence is high in the lower and upper troposphere the region 38km is relatively devoid of turbulence at all the six stations . In general 60 of the Thorpe scale L | Altitude structure of turbulence studied over six locations of Indian peninsula. Occurrence of turbulence is high in the lower and upper troposphere. There is no systematic station to station variations in the turbulent structure. Convective and dynamical instabilities are responsible for the turbulence generation. Thorpe method appears to be good in identifying convectively induced turbulence. |
S1364682619304481 | Black carbon aerosols always existing as complicated mixtures of various species have important impacts on the global and regional climate whereas their effective aerosol complex refractive index is a must for modeling their radiative effects . Retrieval of optically effective ACRI from accurately calculated scattering and absorption properties of an internal mixed aerosol model with BC and dust coated with sulfate roughly representing ambient aged multicomponent BC particles are performed . The sensitivities of retrieved optically effective ACRI to particle size distribution and composition ratio are explored and the popular volume weighted average method and Bruggeman effective medium theory are also considered for comparison . The optically effective ACRIs depicts dramatic variation for monodisperse size parameter larger than as opposed to almost a constant for size parameter less than whereas the VWA and BEM can hardly provide acceptable effective ACRIs for coarse BC composite particles . The retrieved optically effective ACRI are sensitive to both size distribution and composition ratio and becomes more sensitive to particle size distribution with aerosols containing more BC content . As BC volume content reaches 4 the VWA overestimates the imaginary part of effective ACRI with significant bias when compared with the optically effective ACRI indicating overestimated aerosol absorption in most atmospheric environments in aerosol climate models employing the VWA . We suggest that the optically effective ACRI rather than the ACRI given by the VWA should be applied to account for coarse BC containing particles in the state of the art aerosol climate models . | Optically effective ACRIs of black carbon composite aerosols are exactly retrieved. Optically effective ACRIs depict dramatic variation for size parameter larger than . Effects of particle microphysics on retrieved optically effective ACRIs are studied. |
S1364682620300109 | The abnormal behavior of the precipitation in recent years has caused shrinkage of water supplies floods and rising seas and rivers in all over the world . Pakistan is one of those countries which are highly effected from this abnormal behavior . In this paper we utilized the concept of drought indices for the calculation and exploratory analysis of the agricultural and hydrological droughts with its intensities at multiple locations . The concept of point processes to analyze the drought periods at different locations was also investigated . The 3 months and 12 months Standardized Precipitation Index were used to calculate the agricultural and hydrological drought events . The accumulated number of agricultural and hydrological drought events are calculated by considering the threshold of 1.0 and analyzed the drought periods by using Non Homogeneous Poisson Process . The parameters of the model were estimated by using Bayesian approach with Gibbs sampling under Markov Chain Monte Carlo algorithm . The results revealed that SPI provides the better and detailed structure of the agricultural and hydrological droughts with different intensity levels at multiple locations . The study showed that every region of Pakistan was significantly influenced by the agricultural and hydrological droughts with different intensity levels and magnitudes . The NHPP was found to be better in the assessment and analysis of drought events occur during a specific period . The findings of this study can be an important reference for the policymakers and government to take decisions in advance for sustainable environmental management in Pakistan . | Agricultural and hydrological drought periods Pakistan. Non homogeneous Poisson models. Pakistan was influenced by agricultural and hydrological droughts. The NHPP performed better in the assessment and analysis of drought |
S1364682620300110 | In situ observations have significant importance for calibration and validation of satellite data processes studies etc however in situ observations are often available with less spatio temporal coverage due to practical limitations in making observations as well as cost effectiveness . Albeit satellite observations have better spatial and temporal coverage they have certain limitations like obstacles of cloud coverage retrieval algorithms etc . Hence worthy inferences on the processes can be obtained only through skillful utilization of both in situ observations satellite and or reanalysis products . We have illustrated a method for deriving synthetic parallel tracks to in situ track survey . Using this method the satellite and or reanalysis products can be extracted over these synthetic parallel tracks to derive worthy understanding conclusions on the processes . The points on the original track are reproduced in terms of slope and distance which can be utilized to construct a new synthetic parallel track initiating at a predetermined distance to the starting point of original track . As an example we have demonstrated variations in oceanic physical properties along synthetic parallel tracks to the track of the Khai muk cyclone . It is easy to understood using this technique that the variations in sub surface heat content have a relatively major role in controlling the intensity of the system compared to the changes in surface temperature . The method illustrated here is applicable to any geophysical track survey with varying spatial and or temporal extension . | A novel method for constructing synthetic parallel tracks. This method illustrated here is applicable to any geophysical track survey with varying spatial and or temporal extension. Tropical cyclone physical process are studied using this method. |
S1364682620300122 | The present study reports the chemical composition and source identification of the total suspended particulate matter in the sub urban environment Ballari . There were 28 particulate matter aerosol sampled between February 2017July 2018 . The surface mass concentration ranged from 103gm | The total mass concentration varied from 103gm. to 367gm. over Bellary. EDX results showed aluminosilicate group contains about 31 during study period. ICP OES analysis confirmed the inorganic ions dominant over study region. CWT results showed the major sources were mining and anthropogenic sources over location. |
S1364682620300134 | The propagation characteristics of two upward negative lightning flashes which were initiated from the tops of two tall grounded structures immediately after the return stroke initiation of one nearby positive cloud to ground lightning flash have been investigated and compared based on high speed video observations . Two upward flashes show significant difference in their propagation characteristics mainly due to the existence of lower cloud layer near the Canton tower . Upward flash initiated from the top of Canton tower produces several large luminous pulses with the enhanced luminosity mostly concentrating near the lower cloud and it propagates faster beyond the lower cloud while the brightness of the other upward flash does not vary much and distributes almost uniformly along the discharge channel . The major reason for these differences might lie in the instantaneous negative charge neutralization inside the lower cloud with the positive charges along the discharge channel when the positive leader propagates upward across the lower cloud layer . After about 90ms the upward flash initiated from the tall building produces a dart leader subsequent RS but it extinguishes faster than the other one . | Two upward flashes were immediately triggered by a nearby positive CG lightning. Two upward negative flashes have obviously different propagation characteristics. Lower cloud near Canton tower has a great influence on the behavior of upward flash. |
S1364682620300146 | In 2017 CARPET cosmic ray detector was installed at KACST at Riyadh latitude 24.67 longitude 46.74 alt . 613 m geomagnetic cuttoff rigidity R | CARPET cosmic ray detector was installed at Riyadh cut off rigidity R. 14.4 GV Saudi Arabia. One of the main goal of this detector is to investigate CR correlations with solar activity and atmospheric phenomena. The detector performance was tested and showed comparable results to our existing 1 m. scintillator and multi wire detectors. Short periodicities of the CR recorded by CARPET were found to be in good agreement with those reported by different researchers. |
S1364682620300158 | We report observations of auroral spots s at sub auroral latitudes . The auroral spots occurred during storm recovery phases and corotated with the Earth at a speed either higher or lower than the Earth s rotation rate . In the dawn side the spots have a slightly higher probability of super rotation than that of the duskside auroral spots . The super and sub rotation is likely due to dynamics of the plasmasphere that is controlled by both drag and solar wind driven plasma convection . | Ring current auroral spots at sub auroral latitudes corotate with the Earth. The corotation can be slower or faster than Earth s rotation rate and depends on local time. Plasmaspheric dynamics structures drag and solar wind driven convection is likely the source of above phenomena. |
S1364682620300171 | Bubble like structures that grow in the post sunset F region of the equatorial ionosphere have continued to raise concern and research interest among scientists . These structures commonly referred to as Equatorial Plasma Bubbles have depleted electron densities surrounded by a denser plasma . When Trans ionospheric radio signals interact with the EPBs the signals get attenuated and scattered due to reflective refractive and diffractive scattering effects of the EPBs on the signals . This compromises the quality accuracy and reliability of information obtained from Global Navigation Satellite Systems . In this study we have used the Global Positioning System slant Total Electron Content data to identify and characterize EPBs . This data was obtained from International GNSS Service receivers located within the East African region identified by the geographic latitudes | The percentage occurrence of EPBs increases with distance from the magnetic equator and peaks at the EIA region. The occurrence of EPBs over East Africa is greater during equinoxes than during solstices. The western side of East Africa experience more frequent occurrence of EPBs than the eastern side. The majority of the EPBs that occur over the East African region have moderate depletion depths. |
S1364682620300183 | The effect of Coronal Mass Ejection and Corotating Interaction Region driven storms on the occurrence of ionospheric irregularities over the African equatorial and low latitude region are studied statistically for the first time . In addition to the CME and CIRs catalogs we have used the disturbance storm time | The SP in the OIIs during CME and CIR driven storms are more prevalent than the EN. The EN SP and NE of CME and CIR storms on the OIIs show dependence on the LT at which the storm main phase occurs. The SP in the OIIs during CME and CIR storms show a positive and linear correlation with solar activity represented by SSN. |
S1364682620300195 | In this study we use the level 2 Aeronet inversion products of 19 stations of North Africa the Middle East or downwind of them . The objective is to characterize the degree of anthropization of the corresponding sub regions . For this we define a new dust index I | A new anthropization index based on Aeronet data is defined. The AERONET inversions do not show any spatial variability of the Saharan dust aerosol. The spatial variability of the dust forcing efficiencies at TOA and BOA reflects that of the surface albedo. |
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