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

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

Variability in seed traits and genetic divergence in a clonal seed orchard of Dalbergia sissoo Roxb.

The variations in seed and pod traits, genetic superiority and genetic divergence were evaluated for a Clonal Seed Orchard （CSO） of Dalbergia sissoo Roxb. at Bithmera, India consisting of 20 clones from different agro-climatic conditions of four northern states （Uttar Pradesh, Uttarakhand, Haryana and Rajasthan）. The seeds and pods of various clones in the orchard exhibited significant variability in size, weight and other characters. Significant positive correlations were observed between seed length and seed width （p〈0.05）, seed length and sccd thickness （p〈0.01）, seed length and seed weight （p〈0.01）, seed thickness and seed weight （p〈0.01）, seed length and germination value （p〈0.05）. The ge- netic parameters for seed and pod traits also showed a wide range of variations in the orchard. Heritability values were found to be over 50 percent for most of ~e seed and pod traits. Seed weight, seed length and seed thickness showed high heritability values coupled with maximum genetic gain for these characters. Ward＇s minimum variance dendrogram of clones of D. sissoo showed three distinct clusters; cluster I was the largest with 12 better clones whereas cluster 2 and 3 consisting of seven moderate clones and one poor clone, respectively. Mean cluster values showed sufficient variation among the clusters for seed weight, germina- tion value and seed length. The possible hybridization between best clones of cluster I to the disease resistant clone of cluster 2 （resistant against deadly Gandoderma lucidum root rot disease of D. sissoo） is also suggested for further breeding programmes of the species. The deploy- ment of clone 194 （better performed and disease resistant） is also rec- ommended in future plantation programmes of D. sissoo in northern India.

Effects of wind speed,underlying surface,and seed morphological traits on the secondary seed dispersal in the Tengger Desert,China

The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key role.Based on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert,China,we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its stability.Our results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed(TWS).The TWS of Caragana korshinskii was the highest among the 11 plant species,whereas that of Echinops gmelinii was the lowest.Seed morphological traits and underlying surface could generally explain the TWS.During the secondary seed dispersal processes,the proportions of seeds that did not disperse(no dispersal)and only dispersed over short distance(short-distance dispersal within the wind tunnel test section)were significantly higher than those of seeds that were buried(including lost seeds)and dispersed over long distance(long-distance dispersal beyond the wind tunnel test section).Compared with other habitats,the mobile dunes were the most difficult places for secondary seed dispersal.Buried seeds were the easiest to be found in the semi-fixed sand dunes,whereas fixed sand dunes were the best sites for seeds that dispersed over long distance.The results of linear mixed models showed that after controlling the dispersal distance,smaller and rounder seeds dispersed farther.Shape index and wind speed were the two significant influencing factors on the burial of seeds.The explanatory power of wind speed,underlying surface,and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance,implying that the processes and mechanisms of burial and long-distance dispersal are more complex.In summary,most seeds in the study area either did not move,were buried,or dispersed over short distance,promoting local vegetation regeneration.

Index selection on seed traits under direct,cytoplasmic and maternal effects in multiple environments

Crop seeds are important sources of protein, oil, and carbohydrates for food, animal feeds, and industrial products. Recently, much attention has been paid to quality and functional properties of crop seeds. However, seed traits possess some distinct genetic characteristics in comparison with plant traits, which increase the difficulty of genetically improving these traits. In this study, diallel analysis for seed models with genotype by environment interaction （GE） effect was applied to estimate the variance-covariance components of seed traits. Mixed linear model approaches were used to estimate the genetic covariances between pair-wise seed and plant traits. The breeding values （BV） were divided into two categories for the seed models. The first category of BV was defined as the combination of direct additive, cytoplasmic, and maternal additive effects, which should be utilized for selecting stable cultivars over multi-environments. The three genetic effects, together with their GE interaction, were included in the second category of BV for selecting special lines to be grown in specific ecosystems. Accordingly, two types of selection indices for seed traits, i.e., general selection index and interaction selection index, were developed and constructed on the first and the second category BV, respectively. These proposed selection indices can be applied to solve the difficult task of simultaneously improving multiple seed traits in various environments. Data of crop seeds with regard to four seed traits and four yield traits based on the modified diallel crosses in Upland cotton （Gossypium hirsutum L.） were used as an example for demonstrating the proposed methodology.

Seed traits and taxonomic relationships determine the occurrence of mutualisms versus seed predation in a tropical forest rodent and seed dispersal system

Although many studies have been carried out on plant-animal mutualistic assemblages,the roles of function­al traits and taxonomy in determining both whether interactions involve mutualisms or predation and the struc­ture of such assemblages are unclear.We used semi-natural enclosures to quantitatively assess the interaction strengths between seeds of 8 sympatric tree species and 4 rodent species in a tropical forest in Xishuangban­na,Yunnan,Southwest China.We found 2 clusters of species in the seed-rodent network represented by 2 gen­era in the Fagaceae(Castanopsis,Lithocarpus).Compared to seeds of 3 Castanopsis species,seeds with heavy weight,hard coat or caloric content(including 3 Lithocarpus species)were eaten less and more frequently hoarded by rodents.In turn,hoarded seeds showed less predation and more mutualism with rodents.Our results suggest that seed traits significantly affected the hoarding behavior of rodents,and,consequently,the occurrence of mutualisms and predation as well as assemblage structure in the plant-animal seed dispersal system.Taxo­nomically-related species with similar seed traits as functional groups belong to the same substructures in the assemblage.Our results indicate that both seed traits and taxonomic relationships may simplify thinking about seed dispersal systems by helping to elucidate whether interactions are likely to be dominated by predation or mutualism.

Seed traits and rodent community interact to determine seed fate:evidence from both enclosure and field experiments

Animal-mediated seed dispersal is an important ecological process in which a strong mutualism between animals and plants can arise.However,few studies have examined how a community of potential seed dispersers interacts with sympatric seed trees.We employed a series of experiments in the Qinling Mountains in both semi-natural enclosure and the field to assess the interactions among 3 sympatric rodent species and 3 Fagaceae tree seeds.Seed traits all showed similar tannin levels but markedly different physical traits and nutritional contents.We found that seeds with heavy weight,thick coat,and high nutritional contents were less likely to be eaten in situ but more often to be eaten after dispersal or hoarded by rodents.These results support both the handling time hypothesis and the high nutrition hypothesis.Surprisingly,we also found that rodents,maybe,preferred to consume seeds with low levels of crude fiber in situ,and to harvest and hoard those with high levels of crude fiber for later consumption.The sympatric rodent species,Cansumys canus,the largest rodent in our study,harvested and hoarded more Quercus variabilis seeds with high physical and nutritional traits,while Apodemus draco,the smallest rodent,harvested more Q.serrata seeds with low physical and nutritional traits,and Niviventer confucianus harvested and hoarded more Q.aliena seeds with medium physical and nutritional traits.Our study demonstrates that different seed traits play different roles in influencing the seed fate and the shaping of mutualism and predation interactions within a community of rodent species.

The effects of seed detectability and seed traits on hoarding preference of two rodent species

Seed traits play an important role in affecting seed preference and hoarding behaviors of small rodents.Despite greatly affected by seed traits,seed detectability of competitors represents pilfering risks and may also modify seed hoarding preference of animals.However,whether seed traits and seed detectability show consistent effects on seed hoarding preference of animals remain largely unknown.Here,we explored how seed traits and seed detectability correlate with seed hoarding preference of Leopoldamys edwardsi and Apodemus chevrieri in a subtropical forest.Despite the effects of seed coat thickness and caloric value on hoarding preference of L.edwardsi,we detected no significant effects of other seed traits on hording preference of the 2 rodent species.There was no correlation between larder-hoarding preference and inter-or intra-specific seed detectability of L.edwardsi;however,seed detectability of L.edwardsi was negatively correlated with its own scatter-hoarding preference.Although scatter-hoarding preference of A.chevrieri was not correlated with inter-and intra-specific seed detectability,larder-hoarding preference of A.chevrieri was positively correlated with intra-specific seed detectability.Our study may provide evidence that intra-specific seed detectability rather than seed traits and inter-specific pilfering risks play an important role in modifying seed hoarding preference of rodents.

Bird functional traits affect seed dispersal patterns of China's endangered trees across different disturbed habitats

Background: The most dominant global threat to natural forests and their biodiversity is land-cover change, which has negative impacts on both species persistence and ecosystem functions. Land-cover change could alter animal behaviour and disrupt seed dispersal mutualisms. However, its effects on the role of bird functional traits in seed dispersal are not well studied.Methods: In the present study, we assessed the contributions of bird functional traits(behavioural traits: food habit, foraging pattern, foraging frequency, and habitat specialisation; morphological traits: weight, body length, wing length, and tail length) to both seed removal patterns and seed dispersal distances of an endangered and native tree species, Chinese yew(Taxus chinensis), in farmland, patchy habitat, and natural habitat, of southeast China.Results: We found that the ability of T. chinensis trees to form seed dispersal mutualisms with local birds varied across the different disturbed habitats. As a consequence of these mutualisms, more seeds were removed by birds from the patchy habitat than from the other two habitats. The number of seeds removed increased with bird foraging frequency. Moreover, the dispersal distance from the three habitats differed, and the longest dispersal distances were observed at both the patchy habitat and the farmland site. Seed dispersal distance increased with bird tail and wing length.Conclusions: Our results highlight the importance of bird functional traits in the seed dispersal patterns of endangered trees across disturbed forest habitats, which should be considered for tree conservation and management.

Identification of Quantitative Trait Loci Controlling Seed Physical and Nutrient Traits in Cotton

Cotton(Gossypium spp.) is the leading fiber crop,and an important source of the important edible oil and protein meals in the world.Complex genetics and strong environmental effects hinder

Identi cation of seed heat tolerance and its correlation with agronomic traits in Brassica napus L.

To better understand the effect of high temperature on seed viability, artificial aging treatments were implemented on 472 accessions of rapeseed (Brassica napus L.) by constant high temperature at 70℃for 8h. Results showed a remarkable impact of constant heat on seed germination. After heat treatment, considerable variation was found in seed germinability, some genotypes even lost the ability to germinate. The effect of accelerated aging was highly significant. Germination parameters varied among ecotypes. Seed viability varied with different origin, and was significantly and positively correlated with seed yield per plant and dry weight of aboveground parts per plant among 14 agronomic traits. Germination traits were positively correlated with oil contents.

烯效唑对扁穗雀麦生长发育和种子产量品质的影响

探究烯效唑对扁穗雀麦生长发育和种子产量品质的影响,为其种子增产提质提供科学依据。以‘江夏’扁穗雀麦为试验材料,采取随机区组设计,在拔节期喷施不同浓度烯效唑(0、50、90、130 mg/kg),研究植株生长、种子产量和萌发特性。结果表明:烯效唑降低了植株高度,提高了抗倒伏能力。除50 mg/kg的烯效唑对生殖枝数有显著增加外(P<0.05),其余处理对植株第二节长、茎粗、分蘖数和生殖枝数影响差异不显著。喷施不同浓度烯效唑,扁穗雀麦的小穗数/生殖枝、种子数和种子产量均表现为增加,但只有50 mg/kg处理下各指标差异达显著水平(P<0.05)。90 mg/kg烯效唑处理可显著增加扁穗雀麦种子活力指数(P<0.05),但所有处理对千粒重、发芽率和发芽指数影响较小。各指标相关性分析发现,植株高度与倒伏率、分蘖数和生殖枝数极显著正相关(P<0.01);种子产量和生殖枝数显著正相关(P<0.05)。喷施50 mg/kg烯效唑,扁穗雀麦种子产量最高,达1508.31 kg/hm^(2),较对照增加13.63%,差异显著(P<0.05)。

种衣剂防治小麦茎基腐病效果的评价

茎基腐病已成为黄淮小麦主产区最具破坏性的土传病害之一,对我国粮食安全供给构成严重威胁。目前抗茎基腐病主栽品种稀少,生产上主要依赖于化学农药措施。药剂拌种可以有效防治茎基腐病。综合评价现有的种衣剂对小麦茎基腐病的防治及增产效果,以期为合理用药提供依据。采取高感茎基腐病小麦品种郑麦1354为研究对象,播种前种子包衣晾干,利用高致病力茎基腐病菌株PY20-20培养小米菌谷,连续2个小麦生长季利用进行人工接种病圃,包衣种子和接种菌谷等重量混合播种,分别于小麦拔节期和乳熟期记载处理小区植株发病情况,调查9种种衣剂处理后不同生育期的病情指数(disease index,DI),成熟收获后测定小区实际产量,结合小麦产量相关性状,比较种衣剂防病增产作用。结果表明:种衣剂处理后拔节期茎基腐病DI值均小于1.0,显著小于空白对照(5.07),防治效果为85.09%~100%,其中33 g·L^(-1)咯菌·噻虫胺、9%苯甲·吡虫啉和35 g·L^(-1)精甲霜灵·咯菌腈的防效达到为97%~100%。在乳熟期,种衣剂处理后茎基腐病DI平均值低于15,显著小于空白对照(81.55),其中35 g·L^(-1)精甲霜灵·咯菌腈和9%苯甲·吡虫啉防效较好,平均防效分别达到92%和95%,而且分别增产39.62%和36.31%。综合而言,采用种衣剂35 g·L^(-1)精甲霜灵·咯菌腈和9%苯甲·吡虫啉防治小麦茎基腐病效果好且增产效果显著,具有较好的应用前景。

基于种实表型性状和SSR标记的杉木2代种子园遗传多样性分析

【目的】从表型和分子2个角度评估江西信丰县国家杉木良种基地杉木2代种子园的遗传多样性,明确种子园的遗传背景,为后期种子园的改良(去劣疏伐)、重建(亲本选择与配置)等提供依据,同时为开展杂交育种提供遗传信息。【方法】以江西信丰杉木2代种子园内51个建园无性系为研究对象,通过分析8个种实表型性状掌握种子园不同无性系间种实性状的差异,同时利用SSR标记从DNA水平进行遗传多样性评估。【结果】供试51个无性系在种实表型性状和DNA水平上均存在明显的变异和较丰富的遗传多样性。8个表型性状变异系数为10.53%~37.04%,其中球果和种子的平均变异系数分别为18.99%和14.01%,种子的变异系数较小,表明种子的稳定性要比球果的高;种实性状的Shannon-Weaver多样性信息指数平均为2.060,表明种实性状的多样性较丰富。在DNA水平,14个SSR标记在51个无性系中共扩增出68个等位位点,平均Shannon’s信息指数、平均Nei’s遗传多样性指数、平均观测杂合度和平均期望杂合度分别为0.925、0.506、0.486和0.511,表明信丰杉木2代种子园遗传多样性较丰富。基于种实表型性状和SSR标记均可将51个无性系分为两大类群,但两者的具体聚类结果存在较大差异,Mantel检验显示种实性状与SSR标记之间不存在相关性(r=0.064,P=0.870>0.05)。【结论】信丰杉木2代种子园遗传多样性较丰富,具有再选择空间和改良潜力。

基于Seed Identification软件的棉籽机器视觉快速精选

为了研究Seed Identification软件在棉花种子加工工艺和精选参数选择上应用的可行性,以鲁棉28酸脱绒棉籽为材料,通过扫描仪获取400粒棉籽的PNG图像,利用Seed Identification软件快速提取图像中棉籽的RGB、Lab、HSB、灰度、长度、宽度和投影面积等物理指标,通过卷纸发芽获得每颗幼苗鲜质量作为种子的活力指标,种子物理指标与种子活力的相关性分析表明:幼苗鲜质量与R、S、B(HSB)、b、宽度、长度、投影面积的相关系数均达到0.05显著水平。按R<90、S≤18、B(HSB)≤36、b≤4、宽度>4 mm、长度>7.2 mm、投影面积≥25 mm2对种子进行精选,发芽率可由原来的89%分别提高到96.1%、95.1%、95.1%、95.3%、93.1%、93.5%、94.4%,获选率分别为96.6%、99.2%、98.9%、97.8%、98.6%、97%、94.7%。验证试验将种子按以上指标精选后,发芽率分别为95.1%、95.1%、94.8%、94.8%、94.4%、94.4%、94.8%。该研究为基于机器视觉技术对脱绒棉种实施快速、有效精选提供了理论依据。

巴青垂穗披碱草种子产量与农艺性状相关性分析

垂穗披碱草(Elymus nutans)既是优质牧草,也是生态修复的先锋植物。巴青垂穗披碱草是西藏第1个野生牧草驯化品种,为提高巴青垂穗披碱草种子产量,明确巴青垂穗披碱草种子产量与农艺性状的关系,本研究以3个种子产量指标与7个农艺性状指标为研究对象,采用主成分分析、典型相关分析以及逐步回归法分析了巴青垂穗披碱草种子产量与农艺性状的关系。结果表明:单株穗数和单株产量与分蘖数、平均旗叶长呈极显著正相关关系(P<0.01);综合农艺性状指标变量V1和V2,分蘖数和株高结构系数相对较大,可见分蘖数与株高是决定垂穗披碱草种子产量的主要因子。基于逐步回归法分析发现单株产量与单株穗数、平均穗粒数极显著相关(P<0.01);平均穗粒数与单株穗数、种子长度、平均拔节数、株高、平均旗叶长显著相关(P<0.05);单株穗数与种子长度、芒长、平均拔节数显著相关(P<0.05)。因此或可通过增加旗叶长来增加单株穗数与单株产量,进而提高巴青垂穗披碱草种子产量。

不同种源花榈木种子表型性状变异分析

以浙江杭州、湖南长沙等8个种源地的花榈木种子为研究对象,采用方差分析、聚类分析和相关分析等方法对其种子的表型性状进行分析比较,以探究花榈木种子表型性状在种源水平上的变异规律。结果表明:(1)8个种源花榈木的种子长度、宽度、千粒重和种形指数的平均值分别为9.39 mm、7.58 mm、250.23 g和1.24,且在不同种源间存在极显著差异(P<0.01),变异系数分别为6.78%、8.01%、10.24%、7.99%;(2)花榈木种子4个表型性状之间无显著的相关性,但种子宽度与种源地的年均气温有显著正相关关系;千粒重与年日照时数显著正相关,随年日照时数的增长有不断增大的趋势;(3)聚类分析将花榈木种源划分为五大类,由不同类群种源的地理位置可知花榈木种子表型性状的变异具有地域性和随机性。

Variation in cone and seed characters in blue pine (Pinus wallichiana) across natural distribution in western Himalayas

We analyzed 17 seed sources （seed stands） ofPinus wallichiana for variations present in cone and seed characters, scattered over natural distribution in north-west Himalayan states （Uttarakhand and Himachal Pradesh） of India. The significant variations were observed in cone weight, cone length, cone width, seed length, seed width, seed weight, seed germination, radicle length, and plumule length among different seed sources of the species. Significant positive correlation between seed weight, cone weight and cone width showed that seed weight in the species depend more on the cone size. Seed germination was also positively correlated with seed weight, cone weight and radicle length in the study. The estimates of variability with regard to genetic parameters for seed weight, seed germination, cone length, cone width, cone weight showed wide range of variation in the study. Seed weight showed high heritability values coupled with maximum genetic gain. Traits with such values indicate presence of good amount of heritable additive components and are under strong genetic control. The findings of the study revealed that seed sources expressed both phenotypic and genotypic differences in the seed and cone traits which might be due to the differences in genetic make up of various seed sources and environmental factors i,e. genotypic and environmental interaction, The study suggests that the seed weight should be given the top priority for the further improvement of this species.

Variability in cone,seed and seedling characteristics of Pinus kesiya Royle ex.Gordon

Investigations were made to determine the nature and extent of variations present for 10 morphological characters of cone,seed and seedlings of 17 plus trees（PTs）of Pinus kesiya growing in eastern Himalayas（Meghalaya state） of India.The significant variations has been observed in cone weight,cone length,cone diameter,seed length,seed diameter,seed weight,number of seeds per cone,seed germination,seedling height and seedling collar diameter among different PTs of the species.Significant positive correlation（p ／ 0.01） between seed weight,cone length and cone diameter showed that seed weight in P.kesiya depend more on the cone size.Seed germination is found positively correlated（p ／ 0.01） with seed weight,seed diameter,cone size and number of seeds per cone in the study.Among geographical factors,latitude and altitude are found positively correlated（p ／ 0.05） with cone weight and seed diameter,respectively.The genetic parameters for seed,cone and seedlings of PTs of P.kesiya also showed a wide range of variability in terms of variance,coefficient of variability,broad sense heritability,genetic advance and genetic gain.Seed weight,seeds per cone and seedling diameter showed high heritability values（[75） coupled with maximum genetic gain.Traits with such values indicate the presence of good amount of heritable additive components and are under strong genetic control.The findings of the study revealed that PTs expressed both phenotypic and genotypic differences in the seed,cone and seedling characters,which may be attributed to the differences in genetic makeup of various PTs and environmental factors i.e.genotypic and environmental interaction.The presence of high variability in P.kesiya PTs for different characters provide further opportunities to improve the population in subsequent generations so as to establish this species as an important timber tree to be grown on less fertile and degraded soils in its distributional ranges.

芥菜型油菜AHK家族成员的全基因组鉴定及调控粒质量性状的初步探索

为探究芥菜型油菜AHK家族蛋白的结构特征及其与粒质量性状相关的调控功能,采用生物信息学方法对芥菜型油菜AHK家族成员进行了全基因组鉴定、理化性质、系统发育树、蛋白结构、启动子顺式元件和不同组织表达谱等分析。结果表明,在芥菜型油菜基因组中共鉴定到19条BjAHK蛋白序列,系统发育树分析将BjAHK家族成员分为了4个分支,即G1(BjAHK2~BjAHK4)、G2(BjAHK5)、G3(BjAHK1)和G4(BjCKI1)。功能结构域研究发现,BjAHK家族成员具有6个核心基序(Motif1~Motif6),与HisKA、HATPase_c和REC保守结构域相对应,其中BjAHK1~BjAHK4和BjCKI1蛋白的N端含有较为保守的跨膜结构域,可能与其跨膜作用功能有关。不同组织表达谱研究发现,细胞分裂素受体蛋白基因(BjAHK2~BjAHK4)为泛表达基因,且在根组织中表达量最高。结合已有的芥菜型油菜粒质量性状转录组数据,成功挖掘出4个可能参与粒质量性状调控的基因BjA07.AHK3、BjB03.AHK3、BjA10.AHK5和BjB05.AHK5。其中,BjA07.AHK3和BjB03.AHK3可能正向调控种子发育,而BjA10.AHK5和BjB05.AHK5则负向调控。结合BjAHK基因家族分析和转录组测序结果,推测BjAHK3和BjAHK5基因在调控芥菜型油菜种子发育方面发挥重要功能。