Free-ranging yak grazing is a regime specially adapted to high-elevation environments across the Pan-Tibetan Highlands, yet its impacts on alpine birds remain poorly understood. The Chinese Monal(Lophophorus lhuysii) ...Free-ranging yak grazing is a regime specially adapted to high-elevation environments across the Pan-Tibetan Highlands, yet its impacts on alpine birds remain poorly understood. The Chinese Monal(Lophophorus lhuysii) is a rare pheasant species that serves as a representative and umbrella species for alpine meadow ecosystems in the mountains of Southwest China, and has long been regarded as threatened by free-ranging yaks. However, the actual impacts and specific mechanisms through which yak grazing influences Chinese Monal have not been empirically tested. Here, we conducted infrared camera monitoring in alpine meadows within the Wolong National Nature Reserve, Sichuan, China, from 2019 to 2022. We analyzed the effects of free-ranging yaks on habitat occupancy, activity pattern, and population density of the Chinese Monal using multispecies occupancy models, kernel density estimations, avoidance attraction ratios, and random encounter models. We found that interactions with yaks affect monal habitat occupancy in conjunction with other ecological factors. Specifically, the presence of yaks alters monals' occupancy responses to variations in grass cover and elevation, causing monals to use habitats with lower grass cover and elevation more frequently. Additionally, the activity patterns of the Chinese Monal and yaks are significantly different, and the presence of yaks significantly prolongs the time until monals re-occupy the same habitats. As an outcome of the cumulative effects of spatial and temporal avoidance, the population density of the Chinese Monal negatively correlated with increasing grazing intensity. This study provides the first empirical evidence of the negative impacts of free-ranging yaks on the Chinese Monal and elucidates the underlying mechanisms, highlighting great risks to conservation of this vulnerable species. Our findings inform the optimization of grazing management that balances production with conservation. Strict control over yak numbers and grazing areas in critical habitats for Chinese Monal and other threatened species could be a feasible compromise to mitigate these pressures.展开更多
Species boundaries are dynamic and constantly challenged by gene flow.Understanding the strategies different lineages adopt to maintain ecological and genetic distinctiveness requires employing an integrative species ...Species boundaries are dynamic and constantly challenged by gene flow.Understanding the strategies different lineages adopt to maintain ecological and genetic distinctiveness requires employing an integrative species concept that incorporates data from a variety of sources.In this study,we incorporated genetic,ecological,and environmental evidence to assess the extent of speciation or evolutionary divergence within a monophyletic yet dimorphic group(i.e.,clade Leucolirion consisting of six species)within the genus Lilium.This clade consists of two lineages that exhibit unexpectedly distinct perianth appearances:whitish trumpet(funnel form,encompassing four species)and orange recurved(reflex form,including two species),respectively,which are separated by completely different pollination syndromes.Transcriptome-based nuclear and plastome datasets indicate that these two lineages are isolated,with only weak ancient gene flow between them.Within each lineage,several taxa with incomplete isolation have diverged,as indicated by weak genetic structure,strong gene flow,and conflicts between nuclear and chloroplast phylogenies,especially in the trumpet lineage.Although these taxa are not entirely independent,our evidence indicates that they are diverging,with recent gene flow disappearing and multiple isolation strategies emerging,such as differences in flowering time and niche specialization.Taken together,our findings suggest that species divergence and maintenance in Lilium are driven by a combination of adaptive and non-adaptive processes,highlighting the complex interplay of historical climate changes,ecological adaptation,and gene flow in shaping biodiversity within this genus.展开更多
Oysters are of the most economically important bivalves worldwide.It has high nutritional value and is regarded as a good source of proteins,lipids,glycogen,and amino acids.C.gigas and C.angulata are allopatric congen...Oysters are of the most economically important bivalves worldwide.It has high nutritional value and is regarded as a good source of proteins,lipids,glycogen,and amino acids.C.gigas and C.angulata are allopatric congeneric dominant oysters that are widely cultivated in the northern and southern coast of China,and have shown remarkable differentiation in the nutritional content.Interspecific hybridization and backcross of the two species are effective ways to improve the nutritional quality of the oyster.Sixteen progenies were constructed based on a 4×4 diallel crosses among broodstock of C.gigas(G),C.angulata(A)and their hybrids GA(H)and AG(R).The glycogen,fatty acids,and amino acids performance of these progenies were evaluated in 22 months after fertilization.The glycogen content of AA was significantly lower than that of the other 15 progenies(P<0.05),while only the GH progeny was significantly higher than the GG(P<0.05),with a heterosis value of 21.06%.The backcross progenies GR exhibited significantly higher saturated fatty acids,eicosapentaenoic acid(EPA),and polyunsaturated fatty acids(PUFAs)content than those of GG(P<0.05),and did not show significant differences from AA.The AA showed significantly higher content of total amino acids(TAAs)than GG(P<0.05).The AH progeny displayed significantly higher taurine(Tau)content than GG(P<0.05),and the heterosis value was 27.88%.Therefore,the backcross breeding was shown an effective way to improve the glycogen,fatty acids,and TAAs of GG,and the glycogen of AA.This study provided useful information to characterize the benefits of backcrossing in nutritional quality,which will facilitate the production of differentiated products and increase the efficiency of the oyster industry.展开更多
Challenges arise in global viticulture due to low temperatures.To ensure the sustainable and high-quality development of the wine industry,it is essential to breed wine grape varieties that are not only of high qualit...Challenges arise in global viticulture due to low temperatures.To ensure the sustainable and high-quality development of the wine industry,it is essential to breed wine grape varieties that are not only of high quality but also possess cold hardiness.Intraspecific recurrent selection in Vitis vinifera can enhance cold hardiness while maintaining fruit quality.In this study,we used‘Ecolly’as an intermediary grape variety for crossing with‘Cabernet Sauvignon’,‘Marselan’,and‘Dunkelfelder’,including three reciprocal crosses and a total of 1,657 intraspecific hybrids.We characterized the cold hardiness of these intraspecific hybrids and analyzed the genetic aspects of cold hardiness,ultimately identifying excellent strains with cold hardiness.Parameters like mean high-temperature exotherm(mHTE),mean low-temperature exotherm(mLTE),bound/free water ratio,water loss ratio in vitro,frost damage grades,and overall performance displayed partially normal distributions.In intraspecific hybrids,there was a maternal advantage in traits related to bound/free water ratio and water loss ratio.Some hybrid populations exhibited values for mHTE,mLTE,and water loss ratio that were lower than the low parent's values,while bound/free water ratio showed values higher than the high parent's values.Among the 1,657 intraspecific hybrids,52 strains could bud under stress at-18℃,and seven of these strains excelled in three important cold hardiness measures.Our study revealed that cold hardiness in V.vinifera is influenced by multiple genes and is a quantitative trait.Intraspecific hybridization can produce a small number of superior strains with enhanced cold hardiness.展开更多
Pentaploid hybrids produced from crosses between hexaploid and tetraploid wheats combine the genetic variation of both parents.Crossing a synthetic hexaploid wheat LM/AT23 with its AB-genome donor,the durum wheat LM,a...Pentaploid hybrids produced from crosses between hexaploid and tetraploid wheats combine the genetic variation of both parents.Crossing a synthetic hexaploid wheat LM/AT23 with its AB-genome donor,the durum wheat LM,and selfing the pentaploid hybrids to the F7 generation yielded mostly euploid tetraploids and a few hexaploids.Two special derivatives of tetraploid were isolated,including a 4D(4B)substitution line with large panicles and high resistance to stripe rust and a 2DS.2AL translocation line with non-waxy epidermis.The discovery of small D-genome introgressions in the A and B genomes suggested that pentaploidization can be used to induce homoeologous recombination.The introgression of D genome from Aegilops tauschii to the AB genomes might promote the development of super tetraploid wheat with hexaploid biological characteristics(especially stress resistance)and quality functions and the functional study of the introduced chromosomes or fragments.展开更多
Sugarcane is recognized as the fifth largest crop globally,supplying 80%of sugar and 40%of bioenergy production.However,sugarcane genetic research has significantly lagged behind other crops due to its complex genetic...Sugarcane is recognized as the fifth largest crop globally,supplying 80%of sugar and 40%of bioenergy production.However,sugarcane genetic research has significantly lagged behind other crops due to its complex genetic background,high ploidy(8-13×),aneuploidy,limited flowering,and a long growth cycle(more than one year).Cross breeding began in 1887 following the discovery that sugarcane seeds could germinate.Both self-and cross-pollination and selection were conducted by sugarcane breeders,but new cultivars were often eliminated due to disease susceptibility.Within the Saccharum genus,different species possess variable numbers of chromosomes.Wild sugarcane species intercrossed with each other,leading to development of the‘Nobilization’breeding strategy,which significantly improved yield,sucrose,fiber content,and disease resistance,and accelerated genetic improvement of cultivars.In recent years,scientific achievements have also been made in sugarcane genome sequencing,molecular marker development,genetic linkage map construction,localization of quantitative trait locus(QTL),and trait-associated gene identification.This review focuses on the progress in sugarcane genetic research,analyzes the technical difficulties faced,presents opportunities and challenges,and provides guidance and references for future sugarcane genetics research and cultivar breeding.Finally,it offers directions for future on sugarcane genetics.展开更多
Co-flowering species may have evolved strategies to avoid or tolerate the adverse effects of heterospecific pollen deposition.However,the precondition for this evolutionary response is spatialetemporal stability,an as...Co-flowering species may have evolved strategies to avoid or tolerate the adverse effects of heterospecific pollen deposition.However,the precondition for this evolutionary response is spatialetemporal stability,an aspect currently understudied.Here,we examined the spatialetemporal stability in conspecific and heterospecific pollen loads on stigmas across 19 co-flowering species in six sub-alpine meadow communities over four consecutive years.We found that,although conspecific and heterospecific pollen loads,as well as proportions of heterospecific pollen,differed significantly among species,with heterospecific pollen proportion ranging from 0.1%to 41.8%,variation in heterospecific pollen proportion among species was stable across different years and communities.The most important predictor of variation in both conspecific and heterospecific pollen loads,as well as heterospecific pollen proportions,was species identity;furthermore,this factor was independent of phylogenetic relationship.The proportion of heterospecific pollen varied less within species that had high proportions of heterospecific pollen.Furthermore,both the proportion of heterospecific pollen and its coefficient of variation were more strongly driven by heterospecific pollen than by conspecific pollen.Our study suggests that variation in stigmatic pollen load among co-flowering species is spatially and temporally consistent,a precondition for the tolerance-avoidance strategy.This study provides new insights into how different plant species respond to heterospecific pollen deposition.展开更多
Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source.How...Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source.However,delayed sowing is unavoidable in mulch-free cultivation in ecological regions with a short frost-free period.Intercropping with cumin,which has a shorter growth period,served as an effective strategy to improve land use efficiency during the early growth stages of cotton.Therefore,a two-year field experiment was conducted to study the effects of intercropping cumin at the seeding rate of 2.5(ID1),3.85(ID2),and 5.2(ID3)kg・hm−2 on cotton growth,interspecies competition,fiber quality,and water use efficiency(WUE),as well as system economic benefits under subsurface drip irrigation.Monocropping cotton was used as the control(CK)treatment.Results At the initial flowering(IF)stage(the end of the co-growth period of cotton and cumin),cotton plant height in ID2 and ID3 treatments decreased by 5.93%–16.53%and 10.87%–31.11%,respectively,cotton stem diameter by 11.41%–14.25%and 3.37%–26.49%,respectively,and vegetative biomass by 14.46%–30.65%and 22.59%–49.91%,respectively,compared with CK treatment.With the increase in cumin density,the crop growth rate(CGR)and compensation effect in cotton tended to significantly decrease at the IF stage regardless of organs considered.For the non-co-growth period(after harvesting cumin),cotton reproductive organ biomass in ID2 and ID3 treatments increased by 4.09%‒14.61%at the boll opening stage,crop growth rate in reproductive organs by 20.74%and 74.26%from peak boll to boll opening stages compared with CK treatment,due to an enhancement of 19.09%and 49.30%in the compensation effect.Compared with ID1,the aggressivity treated by ID2 and ID3 decreased by 12.82%–46.34%and 17.95%–31.71%,respectively.However,owing to a greater number of green bolls in the upper canopy at the harvest stages in the ID3 treatment,the system production value(closely related to yield)treated by ID2 was 11.69%–16.89%,6.56%–20.02%,and 16.48%–59.83%greater than that of the ID1,ID3,and CK treatments,respectively.This also led to the highest WUE and net profit under the ID2 treatment.Conclusion Intercropping cumin with medium density improved the cotton biomass accumulation characteristics and increased resources such as land and water utilization efficiency and economic benefits through a stronger compensation effect after harvesting cumin under subsurface drip irrigation without mulch.This study not only provides alternatives to residual film pollution in arid cotton fields but also establishes a sustainable agro-ecological-economic planting paradigm by reducing plastic use and enhancing water and fertilizer use efficiency,holding significant implications for advancing resource-efficient agricultural systems.展开更多
To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the dow...To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.展开更多
Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,pr...Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.展开更多
Niche theory predicts that closely related and ecologically similar species with overlapping distribution ranges can coexist through resource partitioning that limits interspecific competition.However,studies examinin...Niche theory predicts that closely related and ecologically similar species with overlapping distribution ranges can coexist through resource partitioning that limits interspecific competition.However,studies examining the mechanisms promoting coexistence of top predators at a large geographical scale are still scant.Here,we describe the foraging ecology of 3 sympatric owl species(Northern long-eared owl[Asio otus],Tawny owl[Strix aluco],Eurasian eagle owl[Bubo bubo])in the Mediterranean Basin.We review 160 studies reporting diet information(212,236 vertebrate preys)and investigate among-species differences in diet metrics(diversity,evenness,prey size,and proportion of mammals)and their variation along geographical and environmental gradients.Moreover,we test whether diet metrics differ in presence or absence of the other predators.All the 3 species mainly rely on small mammals,but they significantly differ in diet metrics.The smallest predator(i.e.,long-eared owl)shows a higher level of specialism on small mammals(highest proportion but lowest diversity of mammals in the diet)compared to the larger ones.In addition,mean prey size significantly increases with predator body size(long-eared owl<tawny owl<eagle owl).Finally,interspecific competition results in an increase of diet diversity and evenness in the long-eared owl,and species’diet also varies in response to environmental factors.The 3 species thus segregate along several dietary niche axes over a large spatial scale and according to both morphological characteristics(i.e.,body size)and environmental variables.Such dietary niche segregation may adaptively buffer interspecific competition costs,ultimately allowing coexistence.展开更多
Variations in host traits that influence their exposure and susceptibility may impact probability of vector-transmitted diseases.Therefore,identifying the predictors of infection probability is necessary to understand...Variations in host traits that influence their exposure and susceptibility may impact probability of vector-transmitted diseases.Therefore,identifying the predictors of infection probability is necessary to understand the risk of disease outbreaks during expanding environmental perturbation.Here,we conducted a large survey based on microscopic examination and molecular analysis of haemosporidian parasite infection in raptors rescued at the Beijing Raptor Rescue Centre.Combining these data with biological and ecological variables of the raptors,we determined predictors that affect the probability of haemosporidian infection using generalized linear mixed models and multimodel inference.Our results showed that infection probability exhibited considerable variation across host species in raptors,and body mass,sex,and evolutionary history played relatively weaker roles in driving infection probability.Instead,activity pattern,age,geographic range size,migration distance,and nest type were important predictors of the probability of haemosporidian infection,and the role of each predictor differed in the three main haemosporidian genera(Plasmodium,Haemoproteus,and Leucocytozoon).This macro-ecological analysis will add to our understanding of host traits that influence the probability of avian haemosporidian infection and will help inform risk of emerging diseases.展开更多
Fossil remains of snakes in Quaternary localities are most often represented by vertebrae.Therefore,it is necessary to carry out a comparative study of the vertebrae of modern species in the areas of interest to ident...Fossil remains of snakes in Quaternary localities are most often represented by vertebrae.Therefore,it is necessary to carry out a comparative study of the vertebrae of modern species in the areas of interest to identify fossil materials.In this study,we examined 52 specimens of viperids(7 specimens of Gloydius intermedius,12 specimens of Gloydius ussuriensis,6 specimens of Gloydius halys,4 specimens of Vipera sakhalinensis,16 specimens of Vipera berus,and 7 specimens of Vipera renardi).The features of the trunk,cervical,cloacal and caudal vertebrae of 6 species from 2 genera are described.The vertebrae of the Viperidae are highly similar across species,with variation along the vertebral column.Nevertheless,they can be distinguished if their exact position within the vertebral column is known.The most important diagnostic feature is the shape of the hypapophysis,especially when identifying the cervical vertebrae.Among other morphological features,it is important to consider the shape of the ventral surface of the vertebra,prezygapophyseal and parapophyseal processes,neurapophysis,and zygapophysis.For the epistropheus,the position of the anterior edge of the neurapophysis in relation to the anterior edge of the neural arch is also significant.The caudal vertebrae bear the greatest resemblance.There is a significant overlap between the ratios of different measurements(indices)in different species.However,if an index is out of the overlapping zone,it is possible to identify a vertebra more or less accurately,especially when considering it in conjunction with other indices and morphological characteristics.展开更多
China is a hotspot of relict plant species that were once widespread throughout the Northern Hemisphere.Recent research has demonstrated that the occurrence of long-term stable refugia in the mountainous regions of ce...China is a hotspot of relict plant species that were once widespread throughout the Northern Hemisphere.Recent research has demonstrated that the occurrence of long-term stable refugia in the mountainous regions of central and south-western China allowed their persistence through the late Neogene climate fluctuations.One of these relict lineages is Dipteronia,an oligotypic tree genus with a fossil record extending to the Paleocene.Here,we investigated the genetic variability,demographic dynamics and diversification patterns of the two currently recognized Dipteronia species(Dipteronia sinensis and D.dyeriana).Molecular data were obtained from 45 populations of Dipteronia by genotyping three cpDNA regions,two single copy nuclear genes and 15 simple sequence repeat loci.The genetic study was combined with niche comparison analyses on the environmental space,ecological niche modeling,and landscape connectivity analysis.We found that the two Dipteronia species have highly diverged both in genetic and ecological terms.Despite the incipient speciation processes that can be observed in D.sinensis,the occurrence of long-term stable refugia and,particularly,a dispersal corridor along Daba Shan-west Qinling,likely ensured its genetic and ecological integrity to date.Our study will not only help us to understand how populations of Dipteronia species responded to the tectonic and climatic changes of the Cenozoic,but also provide insight into how Arcto-Tertiary relict plants in East Asia survived,evolved,and diversified.展开更多
Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerni...Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.展开更多
Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficienc...Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficiency is limited. For this purpose, the embryonic and larval development of reciprocal crosses of Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) were studied under laboratory conditions. The fertilization rate varied from 63.33% to 92%, while the hatching rate ranged from 55.68% to 76% with the highest value in hybrids ♀Cg × ♂Cj. Crosses between ♀Cj × ♂Cj, ♀Cg × ♂Cj and ♀Cj × ♂Cg had embryonic stages similar to those of the pure sib ♀Cg x ♂Cg. All crosses, however, had different timing for the various embryological stages. Hatching occurred at 32 h 15 min and 38 h for ♀Cj × ♂Cj and ♀Cj × ♂Cg, and 23 h and 23 h 30 min, respectively, for ♀Cg × ♂Cg and ♀Cg × ♂Cj. However, both crosses produced viable larvae until the first external feeding. The external morphological features of the larvae were completely formed by the 10th day after hatching. The body forms of the crosses at this time were indistinguishable from the pure sib. This study thus laid the groundwork for further comparative studies on hybrid performance and characterization.展开更多
The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau....The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau. The present study on population distribution, taxonomy, morphology, development andgenetic structure demonstrated that the geographical distribution of these three species was successiveand in gradual change, thus forming a geographical cline which extended from the east to the west of NeiMongol Plateau. With an analysis of climate change over time, it was considered that the formation of thisgeographical cline was a result of plant adaptation to its natural environment.展开更多
We examined the competitive ability of larval toads （Bufo gargarizans ） and frogs （Rana kukunoris ） which co-occur in natural pools in the Jiuzhaigou Nature Reserve. We measured the activity level, growth rate, ma...We examined the competitive ability of larval toads （Bufo gargarizans ） and frogs （Rana kukunoris ） which co-occur in natural pools in the Jiuzhaigou Nature Reserve. We measured the activity level, growth rate, mass at metamorphosis and larval period in a laboratory experiment. Tadpoles of B. gargarizans were significantly more active when food was abundant than scarce, while there was no significant difference in the activity of R. kukunoris tadpoles at different food levels. At low food availability, mass at metamorphosis and growth rate of R. kukunoris were significantly increased in the presence of B. gargarizans, whereas the presence of R. kukunoris had no significant effect on the mass and growth rate of B. gargarizans. In all treatments, the larval period of B. gargarizans at low food availability was the shortest. These results suggest that B. gargarizans can adapt to different food levels by changing their activity rate. At high food level, B. gargarizans increased activity to gain more food. At low food level, B. gargarizans decreased activity and achieved early metamorphosis. However, when food resources were limited, R. kukunoris could gain more food than B.gargarizans .展开更多
Both Brassica juncea（mustard）and B.napus（rapeseed）are allotetraploid species of Brassica.Although these two species have their unique characters,they possess a common A genome and a few homeologous chromosomes bet...Both Brassica juncea（mustard）and B.napus（rapeseed）are allotetraploid species of Brassica.Although these two species have their unique characters,they possess a common A genome and a few homeologous chromosomes between the genomes B and C,which provide the foundation for transfer of superior traits from B.juncea into worldwide cultivated B.napus.The unique characters of B.juncea were summarized,breeding procedure for introgression of superior traits from B.juncea into B.napus by the interspecific crossing proposed,and some recently developed rapeseed germplasm lines with novel traits such as yellow seed and super oil content,restorer of fertility for pol CMS,extreme early maturity,high oleic acid content and short-staure plant briefly introduced in this paper.展开更多
The effects of interspecific competition on the population dynamics of four insect grain Insecp pests （ Sitophilus zeamais, Rhizopertha dominica, Tribolium castaneum and Cryptolestes ferrugineus ） was studied at 30...The effects of interspecific competition on the population dynamics of four insect grain Insecp pests （ Sitophilus zeamais, Rhizopertha dominica, Tribolium castaneum and Cryptolestes ferrugineus ） was studied at 30℃, 75% relative humidity. A regression analysis of the population dynamics was conducted. The results showed that population growth of S. zeamais , R. dominica, T. castaneum and C. ferrugineus was restrained under mixed rearing. Population growth of T. castaneum and C. ferrugineus was remarkably accelerated when they coexisted with S. zeamais or R. dominica, while that of S. zeamais and R. dominica was restrained to some extent. Regression analysis results showed that the population growth potential of S. zeamais was the largest and that of C. ferrugineus was the smallest, and the changing trends of population growth rates were not distinct.展开更多
基金supported by the National Natural Science Foundation of China (32000354)the Natural Science Foundation of Sichuan Province (2022NSFSC0123)+1 种基金the Innovation Team Funds of China West Normal University (KCXTD 2024-5)the Tangjiahe National Nature Reserve Administration Bureau (cxycs [2023]016)。
文摘Free-ranging yak grazing is a regime specially adapted to high-elevation environments across the Pan-Tibetan Highlands, yet its impacts on alpine birds remain poorly understood. The Chinese Monal(Lophophorus lhuysii) is a rare pheasant species that serves as a representative and umbrella species for alpine meadow ecosystems in the mountains of Southwest China, and has long been regarded as threatened by free-ranging yaks. However, the actual impacts and specific mechanisms through which yak grazing influences Chinese Monal have not been empirically tested. Here, we conducted infrared camera monitoring in alpine meadows within the Wolong National Nature Reserve, Sichuan, China, from 2019 to 2022. We analyzed the effects of free-ranging yaks on habitat occupancy, activity pattern, and population density of the Chinese Monal using multispecies occupancy models, kernel density estimations, avoidance attraction ratios, and random encounter models. We found that interactions with yaks affect monal habitat occupancy in conjunction with other ecological factors. Specifically, the presence of yaks alters monals' occupancy responses to variations in grass cover and elevation, causing monals to use habitats with lower grass cover and elevation more frequently. Additionally, the activity patterns of the Chinese Monal and yaks are significantly different, and the presence of yaks significantly prolongs the time until monals re-occupy the same habitats. As an outcome of the cumulative effects of spatial and temporal avoidance, the population density of the Chinese Monal negatively correlated with increasing grazing intensity. This study provides the first empirical evidence of the negative impacts of free-ranging yaks on the Chinese Monal and elucidates the underlying mechanisms, highlighting great risks to conservation of this vulnerable species. Our findings inform the optimization of grazing management that balances production with conservation. Strict control over yak numbers and grazing areas in critical habitats for Chinese Monal and other threatened species could be a feasible compromise to mitigate these pressures.
基金supported by the National Natural Science Foundation of China(NSFC Grant Nos.32171605,31770406)Natural Science Foundation of Sichuan Province(Grant No.2023NSFSC0141)to Y.D.Gao.
文摘Species boundaries are dynamic and constantly challenged by gene flow.Understanding the strategies different lineages adopt to maintain ecological and genetic distinctiveness requires employing an integrative species concept that incorporates data from a variety of sources.In this study,we incorporated genetic,ecological,and environmental evidence to assess the extent of speciation or evolutionary divergence within a monophyletic yet dimorphic group(i.e.,clade Leucolirion consisting of six species)within the genus Lilium.This clade consists of two lineages that exhibit unexpectedly distinct perianth appearances:whitish trumpet(funnel form,encompassing four species)and orange recurved(reflex form,including two species),respectively,which are separated by completely different pollination syndromes.Transcriptome-based nuclear and plastome datasets indicate that these two lineages are isolated,with only weak ancient gene flow between them.Within each lineage,several taxa with incomplete isolation have diverged,as indicated by weak genetic structure,strong gene flow,and conflicts between nuclear and chloroplast phylogenies,especially in the trumpet lineage.Although these taxa are not entirely independent,our evidence indicates that they are diverging,with recent gene flow disappearing and multiple isolation strategies emerging,such as differences in flowering time and niche specialization.Taken together,our findings suggest that species divergence and maintenance in Lilium are driven by a combination of adaptive and non-adaptive processes,highlighting the complex interplay of historical climate changes,ecological adaptation,and gene flow in shaping biodiversity within this genus.
基金Supported by the Key Research and Development Program of Shandong(No.2022LZGC015)the National Key R&D Program of China(No.2022YFD2400304)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA24030105)the Key Technology Research and Industrialization Demonstration Projects of Qingdao(No.22-3-3-hygg-2-hy)the China Agriculture Research System of MOF and MARA(No.CARS-49)。
文摘Oysters are of the most economically important bivalves worldwide.It has high nutritional value and is regarded as a good source of proteins,lipids,glycogen,and amino acids.C.gigas and C.angulata are allopatric congeneric dominant oysters that are widely cultivated in the northern and southern coast of China,and have shown remarkable differentiation in the nutritional content.Interspecific hybridization and backcross of the two species are effective ways to improve the nutritional quality of the oyster.Sixteen progenies were constructed based on a 4×4 diallel crosses among broodstock of C.gigas(G),C.angulata(A)and their hybrids GA(H)and AG(R).The glycogen,fatty acids,and amino acids performance of these progenies were evaluated in 22 months after fertilization.The glycogen content of AA was significantly lower than that of the other 15 progenies(P<0.05),while only the GH progeny was significantly higher than the GG(P<0.05),with a heterosis value of 21.06%.The backcross progenies GR exhibited significantly higher saturated fatty acids,eicosapentaenoic acid(EPA),and polyunsaturated fatty acids(PUFAs)content than those of GG(P<0.05),and did not show significant differences from AA.The AA showed significantly higher content of total amino acids(TAAs)than GG(P<0.05).The AH progeny displayed significantly higher taurine(Tau)content than GG(P<0.05),and the heterosis value was 27.88%.Therefore,the backcross breeding was shown an effective way to improve the glycogen,fatty acids,and TAAs of GG,and the glycogen of AA.This study provided useful information to characterize the benefits of backcrossing in nutritional quality,which will facilitate the production of differentiated products and increase the efficiency of the oyster industry.
基金supported by Project of Ningxia Hui Autonomous Region Key R&D Program(Grant No.NXNYYZ202101)the National Natural Science Foundation of China(Grant No.32360804)+1 种基金Ningxia Science and Technology Department major scientific and technological achievements transformation project(Grant No.2022CJE9007)Ningxia Natural Science Foundation(Grant No.2023AAC03064).
文摘Challenges arise in global viticulture due to low temperatures.To ensure the sustainable and high-quality development of the wine industry,it is essential to breed wine grape varieties that are not only of high quality but also possess cold hardiness.Intraspecific recurrent selection in Vitis vinifera can enhance cold hardiness while maintaining fruit quality.In this study,we used‘Ecolly’as an intermediary grape variety for crossing with‘Cabernet Sauvignon’,‘Marselan’,and‘Dunkelfelder’,including three reciprocal crosses and a total of 1,657 intraspecific hybrids.We characterized the cold hardiness of these intraspecific hybrids and analyzed the genetic aspects of cold hardiness,ultimately identifying excellent strains with cold hardiness.Parameters like mean high-temperature exotherm(mHTE),mean low-temperature exotherm(mLTE),bound/free water ratio,water loss ratio in vitro,frost damage grades,and overall performance displayed partially normal distributions.In intraspecific hybrids,there was a maternal advantage in traits related to bound/free water ratio and water loss ratio.Some hybrid populations exhibited values for mHTE,mLTE,and water loss ratio that were lower than the low parent's values,while bound/free water ratio showed values higher than the high parent's values.Among the 1,657 intraspecific hybrids,52 strains could bud under stress at-18℃,and seven of these strains excelled in three important cold hardiness measures.Our study revealed that cold hardiness in V.vinifera is influenced by multiple genes and is a quantitative trait.Intraspecific hybridization can produce a small number of superior strains with enhanced cold hardiness.
基金funded by the Natural Science Foundation of Sichuan Province for Young Scholars(2024NSFSC1218)the HighLevel Talent Introduction Project of Sichuan Academy of Agricultural Sciences(NKYRCZX2024022)+1 种基金the Accurate Identification Project of Crop Germplasm from Sichuan Provincial Finance Department(1+3 ZYGG001)the Strategic Scientist Studio of Sichuan Academy of Agricultural Sciences.
文摘Pentaploid hybrids produced from crosses between hexaploid and tetraploid wheats combine the genetic variation of both parents.Crossing a synthetic hexaploid wheat LM/AT23 with its AB-genome donor,the durum wheat LM,and selfing the pentaploid hybrids to the F7 generation yielded mostly euploid tetraploids and a few hexaploids.Two special derivatives of tetraploid were isolated,including a 4D(4B)substitution line with large panicles and high resistance to stripe rust and a 2DS.2AL translocation line with non-waxy epidermis.The discovery of small D-genome introgressions in the A and B genomes suggested that pentaploidization can be used to induce homoeologous recombination.The introgression of D genome from Aegilops tauschii to the AB genomes might promote the development of super tetraploid wheat with hexaploid biological characteristics(especially stress resistance)and quality functions and the functional study of the introduced chromosomes or fragments.
基金supported by the National Key Research and Development Program of China(2022YFD2301100)National Natural Science Foundation of China(32272156)+3 种基金Natural Science Foundation of Fujian Province,China(2022J01160)Central Publicinterest Scientific Institution Basal Research Fund(1630052024003,1630052024020)Chinese Academy of Tropical Agricultural Sciences for Science and Technology Innovation Team of National Tropical Agricultural Science Center(CATASCXTD202402)China Agriculture Research System of MOF and MARA(CARS-17).
文摘Sugarcane is recognized as the fifth largest crop globally,supplying 80%of sugar and 40%of bioenergy production.However,sugarcane genetic research has significantly lagged behind other crops due to its complex genetic background,high ploidy(8-13×),aneuploidy,limited flowering,and a long growth cycle(more than one year).Cross breeding began in 1887 following the discovery that sugarcane seeds could germinate.Both self-and cross-pollination and selection were conducted by sugarcane breeders,but new cultivars were often eliminated due to disease susceptibility.Within the Saccharum genus,different species possess variable numbers of chromosomes.Wild sugarcane species intercrossed with each other,leading to development of the‘Nobilization’breeding strategy,which significantly improved yield,sucrose,fiber content,and disease resistance,and accelerated genetic improvement of cultivars.In recent years,scientific achievements have also been made in sugarcane genome sequencing,molecular marker development,genetic linkage map construction,localization of quantitative trait locus(QTL),and trait-associated gene identification.This review focuses on the progress in sugarcane genetic research,analyzes the technical difficulties faced,presents opportunities and challenges,and provides guidance and references for future sugarcane genetics research and cultivar breeding.Finally,it offers directions for future on sugarcane genetics.
基金supported by the National Natural Science Foundation of China(No.32071535 and 32371602)the Key Scientific Research Projects of College and University in Henan Province(No.24ZX001)the Henan Province Foundation for University Key Teacher(No.2020GGJS074).
文摘Co-flowering species may have evolved strategies to avoid or tolerate the adverse effects of heterospecific pollen deposition.However,the precondition for this evolutionary response is spatialetemporal stability,an aspect currently understudied.Here,we examined the spatialetemporal stability in conspecific and heterospecific pollen loads on stigmas across 19 co-flowering species in six sub-alpine meadow communities over four consecutive years.We found that,although conspecific and heterospecific pollen loads,as well as proportions of heterospecific pollen,differed significantly among species,with heterospecific pollen proportion ranging from 0.1%to 41.8%,variation in heterospecific pollen proportion among species was stable across different years and communities.The most important predictor of variation in both conspecific and heterospecific pollen loads,as well as heterospecific pollen proportions,was species identity;furthermore,this factor was independent of phylogenetic relationship.The proportion of heterospecific pollen varied less within species that had high proportions of heterospecific pollen.Furthermore,both the proportion of heterospecific pollen and its coefficient of variation were more strongly driven by heterospecific pollen than by conspecific pollen.Our study suggests that variation in stigmatic pollen load among co-flowering species is spatially and temporally consistent,a precondition for the tolerance-avoidance strategy.This study provides new insights into how different plant species respond to heterospecific pollen deposition.
基金supported by the National Natural Science Foundation of China(31250512).
文摘Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source.However,delayed sowing is unavoidable in mulch-free cultivation in ecological regions with a short frost-free period.Intercropping with cumin,which has a shorter growth period,served as an effective strategy to improve land use efficiency during the early growth stages of cotton.Therefore,a two-year field experiment was conducted to study the effects of intercropping cumin at the seeding rate of 2.5(ID1),3.85(ID2),and 5.2(ID3)kg・hm−2 on cotton growth,interspecies competition,fiber quality,and water use efficiency(WUE),as well as system economic benefits under subsurface drip irrigation.Monocropping cotton was used as the control(CK)treatment.Results At the initial flowering(IF)stage(the end of the co-growth period of cotton and cumin),cotton plant height in ID2 and ID3 treatments decreased by 5.93%–16.53%and 10.87%–31.11%,respectively,cotton stem diameter by 11.41%–14.25%and 3.37%–26.49%,respectively,and vegetative biomass by 14.46%–30.65%and 22.59%–49.91%,respectively,compared with CK treatment.With the increase in cumin density,the crop growth rate(CGR)and compensation effect in cotton tended to significantly decrease at the IF stage regardless of organs considered.For the non-co-growth period(after harvesting cumin),cotton reproductive organ biomass in ID2 and ID3 treatments increased by 4.09%‒14.61%at the boll opening stage,crop growth rate in reproductive organs by 20.74%and 74.26%from peak boll to boll opening stages compared with CK treatment,due to an enhancement of 19.09%and 49.30%in the compensation effect.Compared with ID1,the aggressivity treated by ID2 and ID3 decreased by 12.82%–46.34%and 17.95%–31.71%,respectively.However,owing to a greater number of green bolls in the upper canopy at the harvest stages in the ID3 treatment,the system production value(closely related to yield)treated by ID2 was 11.69%–16.89%,6.56%–20.02%,and 16.48%–59.83%greater than that of the ID1,ID3,and CK treatments,respectively.This also led to the highest WUE and net profit under the ID2 treatment.Conclusion Intercropping cumin with medium density improved the cotton biomass accumulation characteristics and increased resources such as land and water utilization efficiency and economic benefits through a stronger compensation effect after harvesting cumin under subsurface drip irrigation without mulch.This study not only provides alternatives to residual film pollution in arid cotton fields but also establishes a sustainable agro-ecological-economic planting paradigm by reducing plastic use and enhancing water and fertilizer use efficiency,holding significant implications for advancing resource-efficient agricultural systems.
基金Supported by the National Key Scientific Research Project(No.2018YFC1508200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX 23_0714)+1 种基金the China Scholarship Council(No.202206710066)the Construction Project of Wenzhou Hydrology High quality Development Pilot Zone(No.WZSW-GZLFZXXQ-202105)。
文摘To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.
基金supported by the National Natural Science Foundation of China(32071529)the Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station(Z202204)+1 种基金Shanghai Key Lab for Urban Ecological Processes and EcoRestoration(SHUES2020B06,SHUES2021C04)the Fundamental Research Funds for the Central Universities.
文摘Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.
文摘Niche theory predicts that closely related and ecologically similar species with overlapping distribution ranges can coexist through resource partitioning that limits interspecific competition.However,studies examining the mechanisms promoting coexistence of top predators at a large geographical scale are still scant.Here,we describe the foraging ecology of 3 sympatric owl species(Northern long-eared owl[Asio otus],Tawny owl[Strix aluco],Eurasian eagle owl[Bubo bubo])in the Mediterranean Basin.We review 160 studies reporting diet information(212,236 vertebrate preys)and investigate among-species differences in diet metrics(diversity,evenness,prey size,and proportion of mammals)and their variation along geographical and environmental gradients.Moreover,we test whether diet metrics differ in presence or absence of the other predators.All the 3 species mainly rely on small mammals,but they significantly differ in diet metrics.The smallest predator(i.e.,long-eared owl)shows a higher level of specialism on small mammals(highest proportion but lowest diversity of mammals in the diet)compared to the larger ones.In addition,mean prey size significantly increases with predator body size(long-eared owl<tawny owl<eagle owl).Finally,interspecific competition results in an increase of diet diversity and evenness in the long-eared owl,and species’diet also varies in response to environmental factors.The 3 species thus segregate along several dietary niche axes over a large spatial scale and according to both morphological characteristics(i.e.,body size)and environmental variables.Such dietary niche segregation may adaptively buffer interspecific competition costs,ultimately allowing coexistence.
基金funded by the National Natural Science Foundation of China(No.210100191).
文摘Variations in host traits that influence their exposure and susceptibility may impact probability of vector-transmitted diseases.Therefore,identifying the predictors of infection probability is necessary to understand the risk of disease outbreaks during expanding environmental perturbation.Here,we conducted a large survey based on microscopic examination and molecular analysis of haemosporidian parasite infection in raptors rescued at the Beijing Raptor Rescue Centre.Combining these data with biological and ecological variables of the raptors,we determined predictors that affect the probability of haemosporidian infection using generalized linear mixed models and multimodel inference.Our results showed that infection probability exhibited considerable variation across host species in raptors,and body mass,sex,and evolutionary history played relatively weaker roles in driving infection probability.Instead,activity pattern,age,geographic range size,migration distance,and nest type were important predictors of the probability of haemosporidian infection,and the role of each predictor differed in the three main haemosporidian genera(Plasmodium,Haemoproteus,and Leucocytozoon).This macro-ecological analysis will add to our understanding of host traits that influence the probability of avian haemosporidian infection and will help inform risk of emerging diseases.
文摘Fossil remains of snakes in Quaternary localities are most often represented by vertebrae.Therefore,it is necessary to carry out a comparative study of the vertebrae of modern species in the areas of interest to identify fossil materials.In this study,we examined 52 specimens of viperids(7 specimens of Gloydius intermedius,12 specimens of Gloydius ussuriensis,6 specimens of Gloydius halys,4 specimens of Vipera sakhalinensis,16 specimens of Vipera berus,and 7 specimens of Vipera renardi).The features of the trunk,cervical,cloacal and caudal vertebrae of 6 species from 2 genera are described.The vertebrae of the Viperidae are highly similar across species,with variation along the vertebral column.Nevertheless,they can be distinguished if their exact position within the vertebral column is known.The most important diagnostic feature is the shape of the hypapophysis,especially when identifying the cervical vertebrae.Among other morphological features,it is important to consider the shape of the ventral surface of the vertebra,prezygapophyseal and parapophyseal processes,neurapophysis,and zygapophysis.For the epistropheus,the position of the anterior edge of the neurapophysis in relation to the anterior edge of the neural arch is also significant.The caudal vertebrae bear the greatest resemblance.There is a significant overlap between the ratios of different measurements(indices)in different species.However,if an index is out of the overlapping zone,it is possible to identify a vertebra more or less accurately,especially when considering it in conjunction with other indices and morphological characteristics.
基金co-supported by the National Natural Science Foundation of China(Grant No.31470311)the Ph.D.Programs Foundation of the Ministry of Education of China(Grant No.20136101130001).
文摘China is a hotspot of relict plant species that were once widespread throughout the Northern Hemisphere.Recent research has demonstrated that the occurrence of long-term stable refugia in the mountainous regions of central and south-western China allowed their persistence through the late Neogene climate fluctuations.One of these relict lineages is Dipteronia,an oligotypic tree genus with a fossil record extending to the Paleocene.Here,we investigated the genetic variability,demographic dynamics and diversification patterns of the two currently recognized Dipteronia species(Dipteronia sinensis and D.dyeriana).Molecular data were obtained from 45 populations of Dipteronia by genotyping three cpDNA regions,two single copy nuclear genes and 15 simple sequence repeat loci.The genetic study was combined with niche comparison analyses on the environmental space,ecological niche modeling,and landscape connectivity analysis.We found that the two Dipteronia species have highly diverged both in genetic and ecological terms.Despite the incipient speciation processes that can be observed in D.sinensis,the occurrence of long-term stable refugia and,particularly,a dispersal corridor along Daba Shan-west Qinling,likely ensured its genetic and ecological integrity to date.Our study will not only help us to understand how populations of Dipteronia species responded to the tectonic and climatic changes of the Cenozoic,but also provide insight into how Arcto-Tertiary relict plants in East Asia survived,evolved,and diversified.
基金This publication is based upon work from COST Action CLIMO(CA15226) supported by COST (European Cooperation in Science and Technology)the UMBRACLIM project (PID2019-111781RB-I00)funded by the Spanish Ministry for Science and Innovation. Teresa Valor was contracted with a grant“Juan de la Cierva-Formaci on”(FJC2018-036673-I). Z.S. received funds from the grant no. APVV-20-0365 and from project TreeAdapt supported by the MPRV SR. Aitor Ameztegui is supported by a Serra-Húnter fellowship by the Generalitat de Catalunya。
文摘Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.
文摘Establishing intraspecific breeding and hybridization programs and determining genetic variability are two important issues for aquaculture. However, interspecific hybridization to improve growth and feeding efficiency is limited. For this purpose, the embryonic and larval development of reciprocal crosses of Clarias gariepinus (Burchell, 1822) and Clarias jaensis (Boulenger, 1909) were studied under laboratory conditions. The fertilization rate varied from 63.33% to 92%, while the hatching rate ranged from 55.68% to 76% with the highest value in hybrids ♀Cg × ♂Cj. Crosses between ♀Cj × ♂Cj, ♀Cg × ♂Cj and ♀Cj × ♂Cg had embryonic stages similar to those of the pure sib ♀Cg x ♂Cg. All crosses, however, had different timing for the various embryological stages. Hatching occurred at 32 h 15 min and 38 h for ♀Cj × ♂Cj and ♀Cj × ♂Cg, and 23 h and 23 h 30 min, respectively, for ♀Cg × ♂Cg and ♀Cg × ♂Cj. However, both crosses produced viable larvae until the first external feeding. The external morphological features of the larvae were completely formed by the 10th day after hatching. The body forms of the crosses at this time were indistinguishable from the pure sib. This study thus laid the groundwork for further comparative studies on hybrid performance and characterization.
文摘The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau. The present study on population distribution, taxonomy, morphology, development andgenetic structure demonstrated that the geographical distribution of these three species was successiveand in gradual change, thus forming a geographical cline which extended from the east to the west of NeiMongol Plateau. With an analysis of climate change over time, it was considered that the formation of thisgeographical cline was a result of plant adaptation to its natural environment.
文摘We examined the competitive ability of larval toads （Bufo gargarizans ） and frogs （Rana kukunoris ） which co-occur in natural pools in the Jiuzhaigou Nature Reserve. We measured the activity level, growth rate, mass at metamorphosis and larval period in a laboratory experiment. Tadpoles of B. gargarizans were significantly more active when food was abundant than scarce, while there was no significant difference in the activity of R. kukunoris tadpoles at different food levels. At low food availability, mass at metamorphosis and growth rate of R. kukunoris were significantly increased in the presence of B. gargarizans, whereas the presence of R. kukunoris had no significant effect on the mass and growth rate of B. gargarizans. In all treatments, the larval period of B. gargarizans at low food availability was the shortest. These results suggest that B. gargarizans can adapt to different food levels by changing their activity rate. At high food level, B. gargarizans increased activity to gain more food. At low food level, B. gargarizans decreased activity and achieved early metamorphosis. However, when food resources were limited, R. kukunoris could gain more food than B.gargarizans .
文摘Both Brassica juncea（mustard）and B.napus（rapeseed）are allotetraploid species of Brassica.Although these two species have their unique characters,they possess a common A genome and a few homeologous chromosomes between the genomes B and C,which provide the foundation for transfer of superior traits from B.juncea into worldwide cultivated B.napus.The unique characters of B.juncea were summarized,breeding procedure for introgression of superior traits from B.juncea into B.napus by the interspecific crossing proposed,and some recently developed rapeseed germplasm lines with novel traits such as yellow seed and super oil content,restorer of fertility for pol CMS,extreme early maturity,high oleic acid content and short-staure plant briefly introduced in this paper.
基金重庆市科委攻关项目(CSTC,2004A C 1003) 重庆市教委科学技术研究资助项目(KJ030204)~~
文摘The effects of interspecific competition on the population dynamics of four insect grain Insecp pests （ Sitophilus zeamais, Rhizopertha dominica, Tribolium castaneum and Cryptolestes ferrugineus ） was studied at 30℃, 75% relative humidity. A regression analysis of the population dynamics was conducted. The results showed that population growth of S. zeamais , R. dominica, T. castaneum and C. ferrugineus was restrained under mixed rearing. Population growth of T. castaneum and C. ferrugineus was remarkably accelerated when they coexisted with S. zeamais or R. dominica, while that of S. zeamais and R. dominica was restrained to some extent. Regression analysis results showed that the population growth potential of S. zeamais was the largest and that of C. ferrugineus was the smallest, and the changing trends of population growth rates were not distinct.
