Host plant traits play a crucial role in shaping the composition of epiphytic microbiota in the arid desert,Northwest China

Phyllosphere microorganisms are a crucial component of environmental microorganisms,highly influenced by host characteristics,and play a significant role in plant health and productivity.Nonetheless,the impact of host characteristics on shaping phyllosphere microbial communities of plants with different life forms remains ambiguous.Utilizing high-throughput sequencing technology,this study analyzed the diversity and community composition of phyllosphere epiphytic microorganisms(e.g.,bacteria and fungi)of various plant life forms in the hinterland of the Gurbantunggut Desert,Northwest China.Functional annotation of prokaryotic taxa(FAPROTAX)and fungi function guild(FUNGuild)were employed to assess the ecological functions of microorganisms and to investigate the role of stochastic and deterministic processes in shaping phyllosphere microbial communities.Result showed a diverse array of phyllosphere epiphytic microorganisms in the desert plants,with Proteobacteria,Cyanobacteria,and Actinobacteriota dominating bacterial community,while Ascomycota and Basidiomycota were prevalent in fungal community.Comparison across different plant life forms highlighted distinct microbial communities,indicating strong filtering effects by plant characteristics.FAPROTAX prediction identified intracellular parasites(accounting for 27.44%of bacterial community abundance),chemoheterotrophy(10.12%),and phototrophy(17.41%)as the main functions of epiphytic bacteria on leaves of different life form plants.FUNGuild prediction indicated that phyllosphere epiphytic fungi primarily served as Saprotrophs(81.77%),Pathotrophs(17.41%),and Symbiotrophs(0.82%).Co-occurrence network analysis demonstrated a predominance of positive correlations among different microbial taxa.Raup-Crick dissimilarity index analysis revealed that deterministic processes predominantly influenced phyllosphere bacterial and fungal community assembly.Variance partitioning analysis and random forest modeling suggested that plant leaf functional traits significantly impacted both bacterial and fungal community composition,with fungal community composition showing a closer association with leaf nutrients and physiology compared with bacterial community composition.The distinct responses of bacterial and fungal communities to plant traits were attributed to the differing properties of bacteria and fungi,such as bacteria having higher potential dispersal rates and broader ecological niches than fungi.Overall,the results indicate that phyllosphere bacterial and fungal communities undergo similar community assembly processes,with fungi being more influenced by plant characteristics than bacteria.These findings offer novel insights into the ecology of phyllosphere microbial communities of desert plants.

Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China

Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate.

Unveiling the adaptation strategies of woody plants in remnant forest patches to spatiotemporal urban expansion through leaf trait networks

Background:With the expansion of urban areas,the remnants of forested areas play a crucial role in preserving biodiversity in urban environments.This study aimed to explore the impact of spatiotemporal urban expansion on the networks of leaf traits in woody plants within remnant forest patches,thereby enhancing our understanding of plant adaptive strategies and contributing to the conservation of urban biodiversity.Methods:Our study examined woody plants within 120 sample plots across 15 remnant forest patches in Guiyang,China.We constructed leaf trait networks (LTNs) based on 26 anatomical,structural,and compositional leaf traits and assessed the effects of the spatiotemporal dynamics of urban expansion on these LTNs.Results and conclusions:Our results indicate that shrubs within these patches have greater average path lengths and diameters than trees.With increasing urban expansion intensity,we observed a rise in the edge density of the LTN-shrubs.Additionally,modularity within the networks of shrubs decreased as road density and urban expansion intensity increased,and increases in the average path length and average clustering coefficient for shrubs were observed with a rise in the composite terrain complexity index.Notably,patches subjected to‘leapfrog’expansion exhibited greater average patch length and diameter than those experiencing edge growth.Stomatal traits were found to have high degree centrality within these networks,signifying their substantial contribution to multiple functions.In urban remnant forests,shrubs bolster their resilience to variable environmental pressures by augmenting the complexity of their leaf trait networks.

Convergent relationships between flower economics and hydraulic traits across aquatic and terrestrial herbaceous plants

Maintaining open flowers is critical for successful pollination and depends on long-term water and carbon balance.Yet the relationship between how flower hydraulic traits are coordinated in different habitats is poorly understood.Here,we hypothesize that the coordination and trade-offs between floral hydraulics and economics traits are independent of environmental conditions.To test this hypothesis,we investigated a total of 27 flower economics and hydraulic traits in six aquatic and six terrestrial herbaceous species grown in a tropical botanical garden.We found that although there were a few significant differences,most flower hydraulics and economics traits did not differ significantly between aquatic and terrestrial herbaceous plants.Both flower mass per area and floral longevity were significantly positively correlated with the time required for drying full-hydrated flowers to 70%relative water content.Flower dry matter content was strongly and positively related to drought tolerance of the flowers as indicated by flower water potential at the turgor loss point.In addition,there was a trade-off between hydraulic efficiency and the construction cost of a flower across species.Our results show that flowers of aquatic and terrestrial plants follow the same economics spectrum pattern.These results suggest a convergent flower economics design across terrestrial and aquatic plants,providing new insights into the mechanisms by which floral organs adapt to aquatic and terrestrial habitats.

Do aeolian deposits and sand encroachment intensity shape patterns of vegetation diversity and plant functional traits in desert pavements?

The effects of sand encroachment on composition,diversity,and functional patterns of vegetation in drylands are rarely studied,and yet addressing these aspects is important to deepen our understanding of the biodiversity conservation.This study aimed to investigate the effect of sand encroachment on plant functional biodiversity of desert pavements(gravel deserts)in the Sahara Desert of Algeria.Plants were sampled and analyzed in three desert pavements with different levels of sand encroachment(LSE)and quantity of aeolian deposits(low,LLSE;medium,MLSE;and high,HLSE).Within the sample-plot area(100 m^(2)),density of every plant species was identified and total vegetation cover was determined.Plant taxonomic and functional diversity were analyzed and compared between LSE.Result showed that 19 plant species in desert pavements were classified into 18 genera and 13 families.Asteraceae and Poaceae were the most important families.The species Anabasis articulata(Forssk)Moq.characterized LLSE desert pavements with 11 species,whereas Thymelaea microphylla Coss.&Durieu ex Meisn.and Calobota saharae(C&D)Boatwr.&van Wyk were dominant species of desert pavements with MLSE(14 species)and HLSE(10 species),respectively.The highest values of species richness and biodiversity were recorded in desert pavements with MLSE,while low values of these ecological parameters were obtained in desert pavements with HLSE.Desert pavements with LLSE were characterized with the highest values of species abundances.Plant communities were dominated by chamaephytes,anemochorous,arido-active,and competitive stress-tolerant plants.The increase in LSE along the gradient from LLSE to HLSE induced significant changes in plant community variables including decreases in plant density,plant rarity,lifeform composition,morphological type,and aridity adaptation.Desert pavements with HLSE favor the degradation of vegetation and trigger biodiversity erosion.

Differences in leaf functional traits between exotic and native Compositae plant species

This study aims to determine the differences in leaf functional traits and phenotypic plasticity of leaf functional traits between exotic and native Compositae plant species. Leaf width of exotic plants was significantly lower than that of native species. Leaf length, specific leaf area(SLA), single-leaf wet and dry weights, leaf moisture, and leaf thickness of exotic plants were also lower than those of native species but not significantly. The leaf shape index of exotic plants was higher than that of native species but not significantly. This implies that the relatively low leaf construction cost for exotic plants may play an important role in the success of their invasions. The higher leaf shape index and lower leaf width of exotic plants can enhance the efficiency of resource capture(especially sunlight capture) via adjustments to leaf shape and size, thereby increasing the survival of exotic plants. The plasticity indices of single-leaf wet weight and leaf thickness of exotic plants were significantly lower than those of native species. The lower phenotypic plasticity of single-leaf wet weight and leaf thickness of exotic plants may be the result of a cost to plasticity. That is, if the plasticity is too high, the fitness of plant species might be reduced sharply under unfavorable environments. Thus, lower plasticity of leaf functional traits may compensate for the negative impact of adverse environments and stabilize leaf construction costs for exotic plants. Moreover, reduced phenotypic plasticity might be one of the key competitive strategies by which exotic plants successfully invade new habitats. Overall, exotic plants did not always exhibit higher values of leaf functional traits or increased phenotypic plasticity of leaf functional traits compared with native species.

Genetic variations in plant architecture traits in cotton(Gossypium hirsutum) revealed by a genomewide association study

Plant architecture traits influence crop yield. An understanding of the genetic basis of cotton plant architecture traits is beneficial for identifying favorable alleles and functional genes and breeding elite cultivars. We collected 121 cotton accessions including 100 brownfiber and 21 white-fiber accessions, genotyped them by whole-genome resequencing, and phenotyped them in multiple environments. This genome-wide association study(GWAS)identified 11 quantitative trait loci(QTL) for two plant architecture traits: plant height and fruit spur branch number. Negative-effect alleles were enriched in the elite cultivars. Based on these QTL, gene annotation information, and published QTL, candidate genes and natural genetic variations in four QTL were identified. Ghir_D02 G017510 and Ghir_D02 G017600 were identified as candidate genes for qD02-FSBN-1, and a premature start codon gain variation was found in Ghir_D02 G017510. Ghir_A12 G026570, the candidate gene of qA12-FSBN-2, belongs to the pectin lyase-like superfamily, and a significantly associated SNP, A12_105366045(T/C), in this gene represents an amino acid change. The QTL, candidate genes, and associated natural variations in this study are expected to lay a foundation for studying functional genes and developing breeding programs for desirable architecture in brown-fiber cotton.

Plant Traits for Phytoremediation in the Tropics

Water is a limited and valuable resource.Singapore has four national sources of water supply,one of which is natural precipitation.Pollutants collected in stormwater runoff are deposited into drainage systems and reservoirs.Major nutrient pollutants found in local stormwater runoff include nitrate and phosphate,which may cause eutrophication.Bioretention systems are efficient in removing these pollutants in the presence of plants.This paper discusses plant traits that can enhance the phytoremediation of nutrient pollutants in stormwater runoff for application in bioretention systems.The plant species studied showed variations in chlorophyll florescence,leaf greenness,biomass production,and nitrate and phosphate removal.In general,dry biomass was moderately correlated to nitrate and phosphate removal(r=0.339–0.501).Root,leaf,and total dry biomass of the native tree species showed a moderate to strong correlation with nitrate removal(r=0.811,0.657,and 0.727,respectively).Leaf dry biomass of fastgrowing plants also showed a moderate to strong relationship with the removal of both pollutants(r=0.707 and 0.609,respectively).Root dry biomass of slow-growing plants showed a strong relationship with phosphate removal(r=0.707),but the correlation was weaker for nitrate removal(r=0.557).These results are valuable for choosing plants for application in bioretention systems.

Changes in leaf vein traits among vein types of alpine grassland plants on the Tibetan Plateau

Vein traits influence photosynthesis and drought resistance and are sensitive to climate change.It is unclear whether vein traits,similar to other leaf traits,have obvious regional characteristics and covariance with other leaf traits,especially in Tibetan Plateau grasslands.We collected 66 species from 37 sites in late July of 2012 and early August of 2013 to investigate leaf vein traits and their relationships with other leaf traits in comparison with the available global database data and to elucidate vein investment of plants with different vein types.The average vein length per area(VLA)of plants in the Tibetan Plateau was within the range of the global dataset,and the relationships among vein traits and other leaf traits of alpine plants were consistent with the global models.The VLAs of parallel-veined grasses and pinnateveined forbs were significantly lower and higher than the global mean value,respectively.The leaf mass perarea and total nitrogen content of parallel-veined grasses were significantly lower and higher,respectively,than the global mean values;the opposite was observed in pinnate-veined forbs.The parallel-veined grasses exhibited almost a four-fold higher vein biomass investment(i.e.,vein mass per leaf mass)than pinnate-veined forbs in the same region.The average VLA and its relationships with other leaf traits of the alpine grassland plants on the Tibetan Plateau had no regional characteristics,suggesting a convergence in plant leaf functioning.Plants with different leaf types differ in their adaptation strategies to plateau environments,and this may relate to biomass investment into leaf veins.Our study fills the gap with regard to vein density in alpine grassland species and provides a new perspective for understanding plant physiology and ecology by calculating and comparing the proportion of vein investment among different vein types.

Impacts of snow on seed germination are independent of seed traits and plant ecological characteristics in a temperate desert of Central Asia

Seed germination profoundly impacts plant community composition within the plant life cycle.Snow is an important source of water for seed germination in the temperate deserts of Central Asia.Understanding how seed germination responds to variations in snow cover in relation to seed traits and plant ecological characteristics can help predict plant community sustainability and stability in Central Asia under a scenario climate change.This study investigated the seed germination of 35 plant species common to the Gurbantunggut Desert in Central Asia under the three snow treatments:(1)snow addition;(2)ambient snow;and(3)snow removal.Two-way analysis of variance(ANOVA)tests were performed to assess interactions among the impacts of snow treatments,seed traits and plant ecological characteristics on seed germination.Phylogenetic generalized least-squares(PGLS)model was used to test the relationships between seed traits and seed germination.The results demonstrated that snow variations had no significant impacts on seed germination overall.Seed germination under the snow addition treatment was similar with that under the ambient snow treatment,irrespective of seed traits and plant ecological characteristics.Snow removal only had negative impacts on seed germination for certain groups of seed traits and plant ecological characteristics.Seed mass positively affected seed germination,showing a linear increase of arcsin square root-transformed seed germination with log-transformed seed mass.Seed shape also profoundly impacted seed germination,with a higher germination percentage for elongated and flat seeds.Seed germination differed under different plant life forms,with semi-shrub species showing a significantly higher germination percentage.Most importantly,although snow treatments,seed traits and plant ecological characteristics had no interactive effects on seed germination overall,some negative impacts from the snow removal treatment were detected when seeds were categorized on the basis of seed mass and shape.This result suggests that variations of snow cover may change plant community composition in this temperate desert due to their impacts on seed germination.

Evaluation of cotton germplasm for morphological and biochemical host plant UPdates resistance traits against sucking insect pests complex

Background:Sucking insect pests cause severe damage to cotton crop production.The development of insect resistant cotton cultivars is one of the most effective measures in curtailing the yield losses.Considering the role of morphological and biochemical host plant resista nee(HPR)traits in plant defense,12 cotton genotypes/varieties were evaluated for leaf area,leaf glanding,total soluble sugars,total soluble proteins,total phenolics,tannin and total flavonoids against fluctuating populations of whitefly,thrips and jassid under field conditions.Results:The population of these insects fluctuated during the growing seas on and remained above threshold level(whitefly>5,thrips>(8-10)f or jassid>1 per leaf)during late June and early July.Strong and negative association of whitefly(r=-0.825)and jassid(r=-0.929)with seed cotton yield was observed.Mean population of insects were the highest in Glandless-1 followed by NIA-82 and NIA-M30.NIAB-Kiran followed by NI AB-878 and Sadori were the most resistant,with the mean population of 1.41,1.60,1.66(whitefly);2.24,232,2.53(thrips)and 037,0.31,036(jassid),respectively.The resistant variety NIAB-Kiran showed less soluble sugars(8.54 mg.g^(-1)),soluble proteins(27.11 mg.g^(-1))and more phenolic(36.56 mg.g^(-1))and flavonoids(13.10mg.g^(-1))as compared with the susceptible check Glandless-1.Moreover,all insect populations were positively correlated with total soluble sugars and proteins.Whitefly populations exhibited negative response to leaf gossypol glands,total phenolics,tannins and flavonoids.The thrips and jassid populations had a significant and negative correlation with these four biochemical HPR traits.Conclusion:The ide ntified resistant resources and HPR traits can be deployed against sucking in sect pests'complex in future breeding programs of developing insect resistant cotton varieties.

Characterization of QTL for unique agronomic traits of new-plant-type rice varieties using introgression lines of IR64

To enhance the yield potential of an elite indica rice cultivar,an introgression(BC_3-derived) line of IR64,YTH288,was developed using a new-plant-type cultivar,IR66215-44-2-3,as a donor parent.YTH288 has agronomically valuable characteristics such as large panicles,few unproductive tillers,and large leaves inherited from NPT.To identify the genetic basis of these traits,we used 167 F_2 plants derived from a cross between IR64 and YTH288 to conduct QTL analysis for five agronomic traits:days to heading(DTH),culm length(CL),flag leaf length(FLL),flag leaf width(FLW),and filled spikelet number per panicle(FSN).Six putative QTL were detected:four on chromosome4(for CL,FLL,FLW,and FSN) and two on chromosome 2(for DTH and FLL).All QTL with the IR66215-44-2-3 allele,except that for FLL on chromosome 2,had positive effects on each trait.To confirm the effects of these putative QTL,we developed NILs with the IR64 genetic background by marker-assisted selection.We observed significant differences in several agronomic traits between IR64 and NILs that carried these QTL on chromosomes2 and 4.Additionally,four IR64-NILs carrying chromosomal segments derived from different NPT varieties on the long arm of chromosome 4 exhibited similar pleiotropic To enhance the yield potential of an elite indica rice cultivar, an introgression(BC3-derived) line of IR64, YTH288, was developed using a new-plant-type cultivar,IR66215-44-2-3, as a donor parent. YTH288 has agronomically valuable characteristics such as large panicles, few unproductive tillers, and large leaves inherited from NPT.To identify the genetic basis of these traits, we used 167 F2 plants derived from a cross between IR64 and YTH288 to conduct QTL analysis for five agronomic traits: days to heading(DTH), culm length(CL), flag leaf length(FLL), flag leaf width(FLW), and filled spikelet number per panicle(FSN). Six putative QTL were detected: four on chromosome4(for CL, FLL, FLW, and FSN) and two on chromosome 2(for DTH and FLL). All QTL with the IR66215-44-2-3 allele, except that for FLL on chromosome 2, had positive effects on each trait. To confirm the effects of these putative QTL, we developed NILs with the IR64 genetic background by marker-assisted selection. We observed significant differences in several agronomic traits between IR64 and NILs that carried these QTL on chromosomes2 and 4. Additionally, four IR64-NILs carrying chromosomal segments derived from different NPT varieties on the long arm of chromosome 4 exhibited similar pleiotropiceffects for unique agronomic traits. These NILs can be used as research materials for studying each trait and as breeding materials for yield improvement of indica rice cultivars.

Assessing Adaptability of Planted Trees Using Leaf Traits: A Case Study with Robinia pseudoacacia L. in the Loess Plateau, China

Leaf trait patterns and their variations with climate are interpreted as an adaptive adjustment to environment.This study assessed the adaptability of planted black locust (Robinia pseudoacacia L.) based on the analysis of leaf traits and the comparison of its leaf traits with inter-specific ones existing in the same area.We measured some water and N use related leaf traits: leaf dry mass per unit area (LMA) and N,P and K concentrations based on both leaf area (Narea,Parea and Karea) and leaf mass (Nmass,Pmass and Kmass) of R.pseudoacacia at 31 sites along a water stress gradient in North Shaanxi Province,China.The results show that leaves of R.pseudoacacia have high Nmass and low LMA in the study area.High Nmass and low LMA are usually representative of luxurious resource use,and will advance plant resource competitiveness in high-resource conditions.As a whole,LMA-nutrient relationships of R.pseudoacacia display patterns that are fairly similar to the inter-specific relationships in both direction and intensity.The tendency for LMA and Narea to increase with decreasing water availability and the positive correlation between LMA and Narea reflect the trend for R.pseudoacacia to enhance water use efficiency (WUE) at the expense of down-regulated photosynthetic N use efficiency (PNUE) and high construction cost in dry conditions.However,the positive relationship between LMA and Narea in high mean annual precipitation (MAP) area is either unremarkable or reversed with decreasing water availability.This implies a lower photosynthetic capacity and a higher construction cost for high-LMA leaves.The inter-specific relationship between LMA and Narea is positive and does not change with water availability.This difference between inter-species and intra-species may be due to more diversified anatomies and more specialised structures for inter-species than intra-species.The failure of R.pseudoacacia adaption to dry conditions reflected by LMA-Narea relationship may be partially responsible for the emergence of rampike and dwarf forms found frequently in dry conditions.Incorporating intrinsic characteristics of planted trees into vegetation restoration project will be instructive and meaningful for species selection.

Phenotypic plasticity of floral traits and pollination adaption in an alpine plant Pedicularis siphonantha D. Don when transplanted from higher to lower elevation in Eastern Himalaya

Phenotypic plasticity and/or pollinatormediated selection may be responsible for the changes in floral traits of plants when they are forced to live in new conditions. Although the two events could be independent, we hypothesized that phenotypic plasticity in floral traits might help to coordinate plant-pollinator interactions and enhance plant reproductive success in changing habitats. To test this hypothesis, we investigated floral traits and pollination on three natural populations of a lousewort(Pedicularis siphonantha) ranging at different elevations, as well as two downward transplanted populations in Shangeri-La County and Deqin County, northwest Yunnan, China. The results indicated that floral traits, i.e. phenology, longevity,display size, corolla tube length and pollen production differed significantly among populations. Moreover,or the two transplanted populations, floral traits diverged from their original populations, but converged to their host populations. Although the phenotypic plasticity in floral traits might be a rapid response to abiotic factor such as warmer environment, the changes in floral traits were found to be well adapted to pollination environment of the host population. Compared with plants of their original habitats in higher elevation, the transplanted individuals advanced flowering time, shortened flower longevity, reduced floral display size and pollen production, received higher visiting frequency and yielded more seeds. These findings suggested that phenotypic plasticity of floral traits might help plants adjust their resource allocation strategy between preand post-pollination stages in response to harsh or temperate conditions, which might correspondingly meet a pollinator-poor or hyphen rich environment.This would be beneficial for the widely-distributed species to adapt to various environmental changes.

Identification of Original Plants, Traits, Microstructure and Powder of Leontopodium franchetii Beauv.

[Objectives] This study aimed to provide experimental data for the identification and application of Leontopodium franchetii Beauv. [Methods] The original plants, traits, microstructure and powder of L. franchetii Beauv. were identified. [Results] The identification characteristics of L. franchetii Beauv. in the original plants, traits and microstructure were obvious. [Conclusions] This study can provide reference for the identification of original plants and herbs and the development of quality standards of L. franchetii Beauv. and provide a basis for further research and development.

Do Plants Have a Choice of Traits to Be Modulated? Evidence from an Invasive Plant <i>Mikania micrantha</i>Kunth in Different Urban Environments

The successful establishment of an invasive plant in a novel environment has been attributed to the phenotypic plasticity of plant traits, with most studies focussing on vegetative trait plasticity in either experimental and/or natural habitat conditions. This study explores the role of phenotypic plasticity, in both vegetative and reproductive traits, of an invasive plant Mikania micrantha growing as a ground cover in diverse urban areas in the city of Kolkata, India. Quadrat based plant and soil sampling was conducted in three habitat types, namely roadsides, natural areas and abandoned plots, from four regions within the city. The above ground biomass and fitness related vegetative and seed traits were estimated from the plant samples whereas soil macro-and micro-nutrients as well as soil health (in terms of organic carbon and microbial biomass carbon) were estimated from the soil samples. Habitat-specific selection of traits in M. micrantha was observed in this study. In roadside population which has more chances of long distance dispersal, the excessive production of reproductive biomass as a compensatory response to the low germination ability of the seeds was evident. In natural areas which are more prone to anthropogenic disturbance and where the plant has greater chances of local spread, modulation of both vegetative (higher SLA) and reproductive traits (lighter seeds with faster germination ability) helped the plant to maintain its population. In abandoned plots where there was more number of associated species, the longer span of germination and increased population height ensured the survivability of M. micrantha in the community. Thus, a continuous monitoring program to check for M. micrantha growth should be prioritized in urban areas due to its immense trait plasticity in different habitat conditions where uncontrolled growth can lead to its establishment and spread, thereby making its control more difficult.

Endophytic bacteria associated with halophyte Seidlitzia rosmarinus Ehrenb.ex Boiss.from saline soil of Uzbekistan and their plant beneficial traits

Endophytic bacteria of halophytic plants play essential roles in salt stress tolerance.Therefore,an understanding of the true nature of plant-microbe interactions under extreme conditions is essential.The current study aimed to identify cultivable endophytic bacteria associated with the roots and shoots of Seidlitzia rosmarinus Ehrenb.ex Boiss.grown in the salt-affected soil in Uzbekistan and to evaluate their plant beneficial traits related to plant growth stimulation and stress tolerance.Bacteria were isolated from the roots and the shoots of S.rosmarinus using culture-dependent techniques and identified by the 16S rRNA gene.RFLP(Restriction Fragment Length Polymorphism)analysis was conducted to eliminate similar isolates.Results showed that the isolates from the roots of S.rosmarinus belonged to the genera Rothia,Kocuria,Pseudomonas,Staphylococcus,Paenibacillus and Brevibacterium.The bacterial isolates from the shoots of S.rosmarinus belonged to the genera Staphylococcus,Rothia,Stenotrophomonas,Brevibacterium,Halomonas,Planococcus,Planomicrobium and Pseudomonas,which differed from those of the roots.Notably,Staphylococcus,Rothia and Brevibacterium were detected in both roots and shoots,indicating possible migration of some species from roots to shoots.The root-associated bacteria showed higher levels of IAA(indole-3-acetic acid)synthesis compared with those isolated from the shoots,as well as the higher production of ACC(1-aminocyclopropane-1-carboxylate)deaminase.Our findings suggest that halophytic plants are valuable sources for the selection of microbes with a potential to improve plant fitness under saline soils.

Genetic Variation for Achene Traits in Cup Plant (<i>Silphium perfoliatum</i>L.)

Cup plant (Silphium perfoliatum L.) has demonstrated potential for biomass production in studies using transplants in poorly drained cropland not suitable for conventional crops, but little is known about its establishment from seeding. The success rate for stand establishment of perennial plants is usually positively correlated with seed weight. Therefore, objectives of this study were to determine contribution of genetic effects to variation in achene weight, seed weight, achene length, and achene width of cup plant in a population with high biomass potential. Seedlings of 33 half-sib (HS) families were transplanted at Brookings, SD in 1999 and 2010. Achene/seed traits were determined at seed maturity in 2000, 2011 and 2012. Narrow-sense heritability was higher for achene weight and seed weight than that for dimensional achene traits. Within-population genetic variation occurred for achene and seed weight, both of which varied in response to temporal variation in precipitation and temperature. Results of this study indicated the presence of sufficient additive genetic variation for progress from among-family selection for achene weight. Thus, since families with heavy achenes had higher percent seedling emergence and superior seedling vigor compared to families with light achenes, achene weight may be useful for indirect selection for enhanced seed quality in development of new cultivars of cup plant for biomass production on marginal crop land.

Effects of Region and Elevation on Adaptation of Leaf Functional Traits of an Invasive Plant Erigeron annuus in China

A key scientific challenge relating to the threat of invasive plants on agriculture at the region level is to understand their adaptation and evolution in functional traits.Leaf functional traits,related to growth and resource utilization,might lead to adaptation of invasive plants to the geographical barriers(region or elevation).In the field experiment,we discussed the effects of region and elevation on leaf functional traits on invasive plant Erigeron annuus in farmland habitats in China.We compared leaf size,coefficient of variation(CV)of leaf traits,and fluctuating asymmetry(FA)of E.annuus from three regions(east vs.center vs.west)and two leaf types(vegetative vs.reproductive leaf),and from nine elevations(980-2100 m)in the west region of China.Our results indicated region and leaf type influenced leaf functional traits,and leaf size was significantly higher and CV of leaf traits and FA in reproductive leaves were significantly lower in the east region than in the west and center regions.Elevation and leaf type affected leaf functional traits,and leaf size was significantly higher and CV of leaf traits in reproductive leaves were significantly lower in moderate elevation.E.annuus has higher leaf size and developmental stability(lower CV and FA)in the eastern region due to the longer adaptation period.Therefore,leaf functional traits play an important role in the adaptation of different longitudes and elevations.It can also facilitate the understanding of the invasiveness and adaptation of leaf traits of invasive plants in the agricultural ecosystem during their spread process in China.

Effect of Planting Density on Physiological Indexes, Agronomic Traits and Yield of Buckwheat ( Fagopyrum esculentum Moench.)

Ningqiao 1 was selected as the material to study the effects of planting density on physiological indices,agronomic traits and yield of buckwheat.The results showed that high density resulted in decreases of chlorophyll content,soluble protein content and activity of SOD,POD and CAT,and acceleration of MDA accumulation under drought conditions.Low density could effectively improve the grain number per plant,grain weight per plant,1000-grain weight and yield in drought conditions.