Effects of Soil Nutrient Heterogeneity and Earthworms on Aboveground Biomass of Experimental Plant Communities

Soil nutrients are commonly heterogeneously distributed and earthworms are one of the most common soil organisms.While effects of both soil nutrient heterogeneity and earthworms have been well studied,their interactive effect on plant community productivity has rarely been tested.In a greenhouse experiment,we constructed experimental plant communities by sowing seed mixtures of four grasses,two legumes and two forbs in either a heterogeneous soil consisting of low and high nutrient soil patches or a homogeneous soil where the low and high nutrient soil patches were evenly mixed.The earthworm Eisenia fetida was either added to these soils or not.Aboveground biomass of the whole communities,grasses and legumes did not differ between the homogeneous and heterogeneous soils or between the soils with and without earthworms.However,soil nutrient heterogeneity reduced aboveground biomass of forbs,and such an effect did not interact with earthworms.In response to soil heterogeneity and earthworms,biomass ratio of the three functional groups showed similar patterns as that of their biomass.At the patch level,aboveground biomass of the whole community,grasses and legumes were greater in the high than in the low nutrient soil patches within the heterogeneous soil.A similar pattern was found for the forbs,but this was only true in the absence of earthworms.Our results suggest that soil nutrient heterogeneity and earthworms may not influence aboveground biomass of plant communities,despite the fact that they may modify the growth of certain plant functional groups within the community.

Genome sequencing provides insights into Caprifoliaceae genome evolution and the mechanism underlying second blooming phenomenon in Heptacodium miconioides

Plants of the Caprifoliaceae family are widely cultivated worldwide as ornamental plants owing to their numerous,sweet-smelling,beautiful flowers and fruits.Heptacodium miconioides Rehd.,a member of the family,is endemic to eastern China and is cultivated as a popular ornamental plant in North America and European countries.It has a rather novel and beautiful trait of high horticultural value,that is,its sepals persist and enlarge,turning purplish red.Here,we report the chromosome-level genome assembly of H.miconioides to understand its evolution and floral characteristics.The 622.28 Mb assembled genome harbored a shared whole-genome duplication with a related species,Lonicera japonica.Comparative genomic analysis suggested that chromosome fission events following genome duplication underlie the unusual chromosome number of these two species,as well as chromosome fission of another five chromosomes in H.miconioides,giving rise to a haploid chromosome number of 14(versus 9 in L.japonica).In addition,based on transcriptome and chloroplast genome analysis of 17 representative species in the Caprifoliaceae,we assumed that large structural variations in the chromosomes of H.miconioides were not caused by hybridization.Changes in the candidate genes of the MADS-box family were detected in the H.miconioides genome,including AP1-,AP3-,and SEPexpanded,which might underlie the sepal elongation and development in this species.The current findings provided a critical resource for genome evolution studies in Caprifoliaceae and it was an example of how multi-omics data can elucidate the regulation of important ornamental traits.

The changes in soil organic carbon stock and quality across a subalpine forest successional series

Soil organic carbon(SOC)affects the function of terrestrial ecosystem and plays a vital role in global carbon cycle.Yet,large uncertainty still existed regarding the changes in SOC stock and quality with forest succession.Here,the stock and quality of SOC at 1-m soil profile were investigated across a subalpine forest series,including shrub,deciduous broad-leaved forest,broadleaf-conifer mixed forest,middle-age coniferous forest and mature coniferous forest,which located at southeast of Tibetan Plateau.The results showed that SOC stock ranged from 9.8 to29.9 kg·m^(-2),and exhibited a hump-shaped response pattern across the forest successional series.The highest and lowest SOC stock was observed in the mixed forest and shrub forest,respectively.The SOC stock had no significant relationships with soil temperature and litter stock,but was positively correlated with wood debris stock.Meanwhile,the average percentages of polysaccharides,lignins,aromatics and aliphatics based on FTIR spectroscopy were 79.89%,0.94%,18.87%and 0.29%,respectively.Furthermore,the percentage of polysaccharides exhibited an increasing pattern across the forest successional series except for the sudden decreasing in the mixed forest,while the proportions of lignins,aromatics and aliphatics exhibited a decreasing pattern across the forest successional series except for the sudden increasing in the mixed forest.Consequently,the humification indices(HIs)were highest in the mixed forest compared to the other four successional stages,which means that the SOC quality in mixed forest was worse than other successional stages.In addition,the SOC stock,recalcitrant fractions and HIs decreased with increasing soil depth,while the polysaccharides exhibited an increasing pattern.These findings demonstrate that the mixed forest had higher SOC stock and worse SOC quality than other successional stages.The high proportion of SOC stock(66%at depth of 20-100 cm)and better SOC quality(lower HIs)indicate that deep soil have tremendous potential to store SOC and needs more attention under global chan ge.

The DUF579 proteins GhIRX15s regulate cotton fiber development by interacting with proteins involved in xylan synthesis

Cotton provides the most abundant natural fiber for the textile industry.The mature cotton fiber largely consists of secondary cell walls with the highest proportion of cellulose and a small amount of hemicellulose and lignin.To dissect the roles of hemicellulosic polysaccharides during fiber development,four IRREGULAR XYLEM 15(IRX15)genes,GhIRX15-1/-2/-3/-4,were functionally characterized in cotton.These genes encode DUF579 domain-containing proteins,which are homologs of AtIRX15 involved in xylan biosynthesis.The four GhIRX15 genes were predominantly expressed during fiber secondary wall thickening,and the encoded proteins were localized to the Golgi apparatus.Each GhIRX15 gene could restore the xylan deficient phenotype in the Arabidopsis irx15irx15l double mutant.Silencing of GhIRX15s in cotton resulted in shorter mature fibers with a thinner cell wall and reduced cellulose content as compared to the wild type.Intriguingly,GhIRX15-2 and GhIRX15-4 formed homodimers and heterodimers.In addition,the GhIRX15s showed physical interaction with glycosyltransferases GhGT43C,GhGT47A and GhGT47B,which are responsible for synthesis of the xylan backbone and reducing end sequence.Moreover,the GhIRX15s can form heterocomplexes with enzymes involved in xylan modification and side chain synthesis,such as GhGUX1/2,GhGXM1/2 and GhTBL1.These findings suggest that GhIRX15s participate in fiber xylan biosynthesis and modulate fiber development via forming large multiprotein complexes.

The genome of Chinese flowering cherry(Cerasus serrulata)provides new insights into Cerasus species

Cerasus serrulata is a flowering cherry germplasm resource for ornamental purposes.In this work,we present a de novo chromosome-scale genome assembly of C.serrulata by the use of Nanopore and Hi-C sequencing technologies.The assembled C.serrulata genome is 265.40 Mb across 304 contigs and 67 scaffolds,with a contig N50 of 1.56 Mb and a scaffold N50 of 31.12 Mb.It contains 29,094 coding genes,27,611(94.90%)of which are annotated in at least one functional database.Synteny analysis indicated that C.serrulata and C.avium have 333 syntenic blocks composed of 14,072 genes.Blocks on chromosome 01 of C.serrulata are distributed on all chromosomes of C.avium,implying that chromosome 01 is the most ancient or active of the chromosomes.The comparative genomic analysis confirmed that C.serrulata has 740 expanded gene families,1031 contracted gene families,and 228 rapidly evolving gene families.By the use of 656 single-copy orthologs,a phylogenetic tree composed of 10 species was constructed.The present C.serrulata species diverged from Prunus yedoensis~17.34 million years ago(Mya),while the divergence of C.serrulata and C.avium was estimated to have occurred∼21.44 Mya.In addition,a total of 148 MADS-box family gene members were identified in C.serrulata,accompanying the loss of the AGL32 subfamily and the expansion of the SVP subfamily.The MYB and WRKY gene families comprising 372 and 66 genes could be divided into seven and eight subfamilies in C.serrulata,respectively,based on clustering analysis.Nine hundred forty-one plant disease-resistance genes(R-genes)were detected by searching C.serrulata within the PRGdb.This research provides high-quality genomic information about C.serrulata as well as insights into the evolutionary history of Cerasus species.

Carbon nanotubes loaded with vanadium oxide for reduction NO with NH_3 at low temperature

The catalytic activity of carbon nanotubes-supported vanadium oxide(V_2O_5/CNTs) catalysts in the selective catalytic reduction(SCR) of NO with NH_3 at low temperatures(<250℃) was investigated.The effects of V_2O_5loading,reaction temperature,and presence of SO_2 on the SCR activity were evaluated.The results show that V_2O_5/CNTs catalysts exhibit high activity for NO reduction with NH_3 at low-temperatures.The catalysts also show very high stability in the presence of SO_2.More interestingly,their activities are significantly promoted instead of being poisoned by SO_2.The promoting effect of SO_2 is distinctly associated with V_2O_5 loading,particularly maximized at low V_2O_5 loading,which indicated the role of CNTs support in this effect.The promoting effect of SO_2 at low temperatures suggests that V_2O_5/CNTs catalysts are promising catalytic materials for low-temperature SCR reactions.

Adaptive genetic diversity of dominant species contributes to species co-existence and community assembly

The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.

How Physical Disturbance and Nitrogen Addition Affect the Soil Carbon Decomposition?

The decomposition of soil organic carbon(SOC)plays a critical role in regulating atmospheric CO_(2)concentrations and climate dynamics.However,the mechanisms and factors controlling SOC decomposition are still not fully understood.Here,we conducted a 60 days incubation experiment to test the effects of physical disturbance and nitrogen(N)addition on SOC decomposition.N addition increased the concentration of NO3-by 51%in the soil,but had little effect on the concentration of NH4+.N addition inhibited SOC decomposition,but such an effect differed between disturbed and undisturbed soils.In disturbed and undisturbed soils,application of N decreased SOC decomposition by 37%and 15%,respectively.One possible explanation is that extra N input suppressed microbial N mining and/or increased the stability of soil organic matter by promoting the formation of soil aggregates and incorporating part of the inorganic N into organic matter,and consequently decreased microbial mineralization of soil organic matter.Physical disturbance intensified the inhibition of N on SOC decomposition,likely because physical disturbance allowed the added N to be better exposed to soil microbes and consequently increased the availability of added N.We conclude that physical disturbance and N play important roles in modulating the stability of SOC.

Effects of physiological integration on defense strategies against herbivory by the clonal plant Alternanthera philoxeroides

Aims The plant-herbivore interaction is one of the most fundamental inter-actions in nature.Plants are sessile organisms,and consequently rely on particular strategies to avoid or reduce the negative impact of herbivory.Here,we aimed to determine the defense strategies against insect herbivores in the creeping invasive plant Alternanthera philoxeroides.Methods We tested the defense response of A.philoxeroides to herbivory by a leaf-feeding specialist insect Agasicles hygrophila and a pol-yphagous sap-feeding insect Planococcus minor.We also tested the mechanisms triggering defense responses of A.philoxeroides by including treatments of artificial leaf removal and jasmonic acid application.Furthermore,we examined the effect of physiological integration on these defense strategies.Important Findings The combination of artificial leaf removal and jasmonic acid appli-cation produced a similar effect to that of leaf-feeding by the real herbivore.Physiological integration influenced the defense strat-egies of A.philoxeroides against herbivores,and increased biomass allocation to aboveground parts in its apical ramets damaged by real herbivores.Our study highlights the importance of physio-logical integration and modular plasticity for understanding the consequences of herbivory in clonal plants.

Increased precipitation magnifies the effects of N addition on performance of invasive plants in subtropical native communities

Nitrogen(N)deposition,precipitation and their interaction affect plant invasions in temperate ecosystems with limiting N and water resources,but whether and how they affect plant invasions in subtropical native communities with abundant N and precipitation remains unclear.We constructed in situ artificial communities with 12 common native plant species in a subtropical system and introduced four common invasive plant species and their native counterparts to these communities.We compared plant growth and establishment of introduced invasive species and native counterparts in communities exposed to ambient(CK),N addition(N+),increased precipitation(P+)and N addition plus increased precipitation(P+N+).We also investigated the density and aboveground biomass of communities under such conditions.P+alone did not enhance the performance of invasive species or native counterparts.N+enhanced only the aboveground biomass and relative density of invasive species.P+N+enhanced the growth and establishment performance of both invasive species and native counterparts.Most growth and establishment parameters of invasive species were greater than those of native counterparts under N+,P+and P+N+conditions.The density and aboveground biomass of native communities established by invasive species were significantly lower than those of native communities established by native counterparts under P+N+conditions.These results suggest that P+may magnify the effects of N+on performance of invasive species in subtropical native communities where N and water are often abundant,which may help to understand the effect of global change on plant invasion in subtropical ecosystems.

Effects of clonal integration and nitrogen supply on responses of a clonal plant to short-term herbivory

Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in the ability of clonal plants to tolerate biotic stress such as herbivory.Methods We grew clonal fragments of an invasive clonal plant Alternanthera philoxeroides,each consisting of an apical part(relatively young)and a basal part(relatively old),at two levels(low and high)of soil nitrogen(N).For each fragment,the apical part was subjected to either no herbivory or herbivory for 2 weeks by a specialist insect,Agasicles hygrophila,and was either connected with or discon-nected from the basal part not subjected to herbivory.Important Findings Herbivory in the apical part severely reduced leaf growth(leaf mass,leaf number or leaf area)and ramet production of both apical and basal parts,and increased root to shoot ratio of the apical part.Irrespective of herbivory and soil N,stem connection between the apical and the basal part decreased root to shoot ratio of the ap-ical part,but did not change its growth measures.Meanwhile,con-nection increased stem N concentration of the apical part growing under high-N supply and decreased stem carbon(C)concentration of the apical part under low-N supply.By contrast,connection in-creased root to shoot ratio of the basal part,but reduced its leaf and ramet production.Connection also increased leaf and stem C concentrations of the basal part under low-N supply.Thus,clonal integration can be beneficial for the early development of young A.philoxeroides ramets,but not for their local adaptation to herbivory damage by A.hygrophila.

Adaptive plasticity in response to light and nutrient availability in the clonal plant Duchesnea indica

Phenotypic plasticity enables plants to buffer against environmental stresses and match their phenotypes to local conditions.However,consistent conclusive evidence for adaptive plasticity has only been obtained for a few traits.More studies on a wider variety of plant functional traits and environmental factors are still needed to further understand the adaptive significance of plasticity.We grew 21 genotypes of the stoloniferous clonal plant Duchesnea indica under different light and nutrient conditions,and used selection gradient analyses to test the adaptive value(benefits)of morphological and physiological plasticity responding to variation in light and nutrient availability.Plants grown in shade exhibited lower values for fitness measures(fruit number,ramet number and biomass),shortened thinner internode length and decreased adult leaf chlorophyll content,but higher petiole length,specific leaf area and old leaf chlorophyll content,than plants grown without shade.Plants grown in the low nutrient condition had shorter petiole length,thicker and smaller leaf area,lower chlorophyll content,but higher fruit number and root:shoot ratio than plants grown under the high nutrient condition.Selection gradient analyses revealed that plasticity of petiole length and old leaf chlorophyll content in response to light variation was adaptive,and plasticity of old and adult leaf chlorophyll content in response to nutrient variation was adaptive.Therefore,the adaptive value of plasticity in different traits depends on the specific ecological context.Our findings contribute to understanding the adaptive significance of phenotypic plasticity of clonal plants in response to environmental variation.

Holotrichones A and B,potent anti-leukemic lindenane-type sesquiterpene trimers with unprecedented complex carbon skeletons from a rare Chloranthus species

Two lindenane-type sesquiterpene(LDS)trimers with unprecedented carbon skeletons,holotrichones A(1)and B(2),were obtained from the whole plant of Chloranthus holostegius var.trichoneurus by a ultra performance liquid chromatography-photodiode array detector-mass spectrometry(UPLC-PDA-MS)-guided isolation strategy.Compound 1 represents the first LDS trimer incorporating a unique 3/5/6/6-fused framework,in which a lindenane-type monomer and the 2-methylbutyryl substituent of an LDS dimer is bridged by a six-membered ring system.Compound 2 is the first hetero-trimer fused by an LDS dimer with a p-benzoquinone-meroterpenoid,featuring an unusual 3/5/6/6/3/5/6/6/6 nonacyclic system fused by the sesquiterpenoid unit and a 2-geranyl-6-methyl-2,5-cyclohexadien-1,4-dione moiety.In compound 2,the dimeric LDS moiety is equipped with a rare oxaspiro[4.5]decane system.Their structures,including absolute configurations,were established by spectroscopic methods,GIAO NMR calculations and DP4+probability analyses,electronic circular dichroism(ECD)calculations,and single-crystal X-ray diffraction analysis.The plausible biogenetic pathway speculation indicated that hetero-and homo-DielsAlder additions may dominate the formation of these highly fused polycyclic frameworks.Both compounds 1 and 2 induced the human acute myeloid leukemia MV-4–11 cell death via apoptosis induction,which deserves further investigation on this new chemical class of LDS oligomers for their anti-leukemic potential.

Relationships between Genetic Diversity of Vascular Plant Species and Climate Factors

Genetic diversity is crucial for plants to respond to global climate change,and exploring relationships between genetic diversity and climatic factors may help predict how global climate change will shape the genetic diversity of plants in the future.So far,however,the extent and magnitude of the impact of climatic factors on the genetic diversity of plants has not been clarified.We collected data from 68published papers on two widely used measures of genetic diversity of populations (average expected heterozygosity (He)and average observed heterozygosity (Ho))and on localities of populations of 79vascular plants,and extracted data on 19 climatic factors from WorldClim.We then explored the relationships between measures of genetic diversity and climatic factors using linear regressions.He of plant populations was significantly correlated with climatic factors in 58.7%(44)of the 75 species that used He as a measure of genetic diversity,and Ho was correlated with climatic factors in 65.1% (41)of the 63 species that used this genetic diversity measure.In general,Mean Temperature of Wettest Quarter, Precipitation Seasonality,Precipitation of Driest Quarter and Temperature Seasonality played a vital role in shaping He,and Ho was mostly correlated with Precipitation of Warmest Quarter,Mean Temperature of Wettest Quarter, Precipitation of Driest Quarter and Precipitation of Driest Month.Also,the proportion of the significant correlations between genetic diversity of populations and climatic factors was higher for woody than for herbaceous species, and different climatic factors played different roles in shaping genetic diversity of these two growth forms.Our results suggest that climate may play an important role in shaping genetic diversity of plant populations,that climatic change in the future may alter genetic diversity of plants,and that genetic diversity of different plant forms may respond to climatic change differently.

Construction of cytomegalovirus promoter-driven gene expression system in Laodelphax striatellus

The small brown planthopper(SBPH,Laodelphax striatellus)is a significant rice pest,responsible for transmitting rice stripe virus(RSV)in a persistent and propagative manner.RSV is one of the most detrimental rice viruses,causing rice stripe disease,which results in considerable loss of rice grain yield.While RNA interference and gene knockout techniques have enabled gene downregulation in SBPH,no system currently exists for the overexpression of endogenous or exogenous genes.Consequently,the development of a protein expression system for SBPH is imperative to serve as a technical foundation for pest control and gene function investigations.This study aimed to construct an expression vector using the promoter of the constitutive-expressed tubulin gene of SBPH,and promoter of human cytomegalovirus(CMV).Fluorescence experiments demonstrated that both tubulin and CMV promoter could drive green fluorescent protein(GFP)expression in SBPH,and could also facilitate the expression of a nucleocapsid protein(NP)-GFP fusion protein containing viral NP with comparable efficiency.Through expression vector optimization,we have identified that the 3 tandem CMV promoters display a significantly higher promoter activity compared with both the 2 tandem CMV promoters and the single CMV promoter.In addition,the incorporation of Star polycation nanoparticles significantly enhanced the expression efficiency in SBPH.These results provide a promising technical platform for investigating gene functions in SBPH.

地下芽植物芽库密度响应环境干扰的Meta分析

地下芽库是地下芽植物地下储存器官产生的无性繁殖体的集合,是地下芽植物繁殖的主要方式。地下芽库密度反映了地下芽植物群落的潜在更新能力。然而,不同的扰动和生境类型对地下芽库密度的影响尚缺乏全面的了解;此外,不同类型地下芽库对不同扰动类型的响应是否存在差异也不明确。本研究通过Meta分析系统收集了环境扰动对地下芽库密度影响的相关文献,计算了不同扰动和生境类型对各地下芽库类型密度影响的累计效应值。结果发现,由于地下芽库对扰动的响应存在相反或波动的特征,整体上环境扰动对地下芽库密度的影响较小,而干旱对芽库密度具有负效应。总体而言,环境扰动降低了根状茎芽的密度,但增加了分蘖芽的密度。环境扰动降低了湿地中的地下芽库密度,但在其它生境类型中并未发现显著影响。因此,地下芽植物的芽库对扰动有着很强的抗性和弹性,地下芽库的密度变化取决于扰动的类型、分布的生境和受扰动的芽库类型。

气候变化预计会减少东亚地区豚草的生物防治效果

外来入侵植物对入侵地的生态系统与社会经济可造成严重的威胁。如何控制入侵植物对自然资源的危害,向人类提出了极大的挑战。利用原产地的专食性天敌来控制入侵植物已被广泛证明是一种经济、可持续的生物防治手段。在全球气候变暖的背景下,生物防治研究的关键问题是全面了解物种的潜在分布区和传播范围,进而优化入侵植物的生物防治方案。本研究利用生物地理模型,通过预测两种生物防治昆虫和它们的组合在东亚地区的适宜分布区,预测豚草(Ambrosia artemisiifolia)的生物防治区域。豚草原产北美,目前已经入侵全球多个国家和地区。20世纪末,豚草条纹叶甲(Ophraella communa)和豚草卷蛾(Epiblema strenuana)作为豚草的生物防治昆虫从原产地引入到东亚地区。本研究旨在探讨如下问题:(1)在豚草的适宜生长分布区内,有多少区域也同样适宜其两种天敌的生存?(2)在目前和未来的气候背景下,有多少区域适宜豚草生长但是不适宜它的两种天敌生长?(3)在这些适宜豚草生长却不适宜两种昆虫天敌生长的区域内,需要选择哪些特定的生物型进行投放?为此,我们基于入侵植物和两种生物防治昆虫的全球分布记录及其分布点的重要生物气候因子,同时模拟了入侵植物及其两种生物防治天敌在东亚地区的分布范围。排序技术被用来探索气候因子对每个物种的限制作用,同时也用来检验豚草在北美和东亚地区的生态位重叠和相似性。结果表明,在当前和未来的气候背景下,相较于豚草卷蛾,豚草条纹叶甲与豚草的地理分布范围更加吻合(当前气候:40.3%vs.21.6%,未来气候:29.8%vs.20.3%)。气候变化可能会导致两种生物防治天敌(尤其是豚草条纹叶甲)的地理分布与豚草的地理分布的重叠区域减少(42.9%vs.29.9%)。本研究同时提出了温度和降水等气候因子可用于为特殊区域(生物防治天敌未覆盖的豚草分布区)筛选生物防治天敌的相应株系。

Effects of latitude and soil microbes on the resistance of invasive Solidago canadensis to its co-evolved insect herbivore Corythucha marmorata

There is an increasing likelihood that invasive plants are again exposed to their co-evolved specialist herbivores in the non-native range.However,whether there is a latitudinal pattern associated with the resistance of an invasive plant to its co-evolved herbivores and how soil microbes affect resistance has been little explored.We hypothesized that the resistance of invasive Solidago canadensis to its co-evolved insect herbivore Corythucha marmorata could increase with latitude,and that local rhizosphere microbes could facilitate invasive plants to become resistant to their co-evolved herbivores.We conducted a field survey and a greenhouse experiment to examine whether there was a latitudinal pattern in the abundance of C.marmorata and in the damage it caused to S.canadensis in China.We tested whether local rhizosphere microbes of invasive plants can promote the resistance of S.canadensis to C.marmorata herbivory.In the field survey,both density of C.marmorata and damage level of S.canadensis were positively correlated with latitude,and with S.canadensis plant growth,indicating a latitudinal pattern in the resistance of S.canadensis to C.marmorata.However,in the greenhouse experiment,S.canadensis from different latitudes did not suffer significantly from different levels of damage from C.marmorata.Additionally,the damage level of S.canadensis was lower when rhizosphere soil and rhizomes originated from field S.canadensis with same damage level than with different damage levels.This result indicates that local rhizosphere soil microbes promote the adaptation of S.canadensis to resistance of C.marmorata.

Trans-generational effects in the clonal invader Alternanthera philoxeroides

Aims Recent studies have revealed heritable phenotypic plasticity through vegetative generations.In this sense,changes in gene regulation induced by the environment,such as DNA methylation(i.e.epigenetic changes),can result in reversible plastic responses being transferred to the offspring generations.This trans-generational plasticity is expected to be especially relevant in clonal plants,since reduction of sexual reproduction can decrease the potential for adaptation through genetic variation.Many of the most aggressive plant invaders are clonal,and clonality has been suggested as key to explain plant invasiveness.Here we aim to determine whether trans-generational effects occur in the clonal invader Alternanthera philoxeroides,and whether such effects differ between populations from native and non-native ranges.Methods In a common garden experiment,parent plants of A.philoxeroides from populations collected in Brazil(native range)and Iberian Peninsula(non-native range)were grown in high and low soil nutrient conditions,and offspring plants were transplanted to control conditions with high nutrients.To test the potential role of DNA methylation on trans-generational plasticity,half of the parent plants were treated with the demethylating agent,5-azacytidine.Important Findings Trans-generational effects were observed both in populations from the native and the non-native ranges.Interestingly,trans-generational effects occurred on growth variables(number of ramets,stem mass,root mass and total mass)in the population from the native range,but on biomass partitioning in the population from the non-native range.Trans-generational effects of the population from the native range may be explained by a‘silver-spoon’effect,whereas those of the population from the non-native range could be explained by epigenetic transmission due to DNA methylation.Our study highlights the importance of trans-generational effects on the growth of a clonal plant,which could help to understand the mechanisms underlying expansion success of many clonal plants.

Engineering phosphorus-containing lignin for epoxy biocomposites with enhanced thermal stability,fire retardancy and mechanical properties

Fabricating a high-performing thermoset using bio-based flame retardant is critical for the sustain-able development of engineering materials with superior fire safety and robust mechanical properties.Herein,the epoxy(EP)composites with the industrial requirements are manufactured with a novel high-efficient,lignin-based flame retardant named DAL-x,which is fabricated by grafting 9,10-dihydro-9-oxa-10-phosphaze-10-oxide(DOPO)onto lignin.The resulting DAL-x/EP composite exhibits excellent flame retardancy with a desirable UL-94 V-0 rating and a satisfactory limiting oxygen index(LOI)of 29.8%due to the appropriate phosphorus content of DAL-x with adjustable molecular chain structure.More-over,the DAL-x/EP composite shows an unexpected improvement in the elastic modulus(∼36%)and well-preserved strength and ductility compared with those of pure EP.This work offers a feasible strat-egy for creating efficient bio-based flame retardants utilizing industrial waste lignin and preparing high-performance EP composites that meet the demanding requirement of fire retardancy in industries,con-tributing to the circular economy and sustainability.