【作者】 赵明；

【导师】 颜宏；

【作者基本信息】 东北师范大学 ， 植物学， 2018， 硕士

【摘要】 种子萌发是种子植物生活史的起始阶段,它影响着植物种群的延续。种子萌发不仅受到外界环境因素的影响,也与其自身功能性状密切相关。由于种子的性状特征在一定程度上既反应了植物物种原有的稳定遗传信息,又受到环境因素的影响,因此种子功能性状对萌发的影响研究受到越来越多学者的关注。以往关于松嫩草原植物种子萌发的研究主要集中于盐碱胁迫、温度、光照对种子萌发的影响,有关草原植物种子性状特征与萌发的关系研究缺少信息。本研究从种子形态特征、传播方式、休眠类型、贮藏物质等功能性状方面来探究不同植物的种子萌发对策,并揭示了不同内含物类型的种子萌发过程中贮藏物质动员情况。本研究以98个草原植物种子为实验材料,研究种子相关性状:种子质量、体积、传播方式、休眠类型以及萌发率;以虎尾草(Chloris virgata Sw.)、地肤(Kochia scoparia L.)、胡枝子(Lespedeza hedysaroides Turcz.)、斜茎黄耆(Astragalus adsurgens Pall.)、益母草(Leonurus Artemisia Laur.)和香青兰(Dracocephalum moldavica Linn.)为实验材料,测定干种子中的贮藏物质(淀粉、蛋白质、脂肪)以及萌发过程中的物质动员(淀粉、脂肪、可溶性糖、可溶性蛋白)。研究结果表明:1.种子功能性状特征:松嫩草原98个物种种子的质量和体积有4-5个数量级的变化范围,55.1%物种的种子质量小于1g,产生小种子的物种主要以菊科和禾本科植物为主,大种子主要以豆科植物为主;绝大部分物种的休眠方式为生理休眠,传播类型以重力传播为主。说明该草原物种以小种子为主,并且物种的休眠类型和传播方式与其所处的生存环境相适应。2.种子功能性状特征与萌发的关系:本实验研究的物种中有一半比例的物种萌发率达到50%以上;种子质量与萌发率呈显著负相关关系(p<0.05),但是种子的体积以及休眠类型与萌发没有显著的相关性;种子传播方式显著影响种子的萌发。从我们的研究结果看,在种子的功能性状中,种子质量和传播方式对萌发的影响更大。3.种子贮藏物质与萌发的关系:成熟后的种子中蛋白、淀粉和脂肪含量与种子萌发没有显著的相关性,但在萌发过程中可溶性糖和可溶性蛋白的含量与萌发速率呈正相关关系,即不同物种在相同萌发阶段可溶性糖或可溶性蛋白含量越高,萌发速率越快;从吸胀阶段到早期幼苗阶段,六个物种种子内可溶性蛋白、淀粉和脂肪的利用大致相同,即可溶性蛋白呈显著降低趋势,脂肪变化不显著,淀粉呈降低趋势。我们的结果与栽培的草种和豆类植物相比,在种子萌发时,蛋白和脂肪的利用是不同的,相同科属和相同生活型的物种对淀粉的降解程度和可溶性糖的利用模式是不同的。更多还原

【Abstract】 Seed germination is the beginning of the life history for seed plants,which affects plant population continuation.Seed germination was not only affected by environmental factors,but also by seed functional traits.See traits reflects the original stable genetic information of plants and effects of environmental factors,therefore the effects of seed functional traits on germination has been widely attended by researchers.The previous study mainly focus on the effects of saline-alkaline stress,temperature and light on seed germination of plants in Songnen grassland.The information of the effects of seed functional traits on germination is lacked.In our study,we investigated the strategies of seed germination from morphological characters,dispersal model,dormancy type and seed reserves and reveals the seed reserve mobilization during germination for the grassland species.Our study determined seed traits(seed mass,seed volume,dispersal model,dormancy type,germination percentage)of 98 grassland species.Six species(Chloris virgata,Kochia scoparia,Lespedeza hedysaroides,Astragalus adsurgens,Leonurus artemisia and Dracocephalum moldavica)with different seed reserve type were selected to measure contents of starch,protein and fat in dry seeds and seed reserve(starch,fat,soluble sugar,soluble protein)mobilization during germination.The results showed that:1.The characteristics of seed functional traits: the change of seed mass and volume have 4-5 orders of magnitude for the 98 species in Songnen grassland.The seed mass of 55.1% species was less than 1 g.Small-seeded species mainly belonged to Asteraceae and Poaceae and large-seeded species mainly belonged to Fabaceae.The dormant type of most species was physiological dormancy and barochorous was the main dispersal model.The results illustrate that most species in Songnen grassland produce small seeds and the dispersal model and dormancy type of plants are suitable to their living environments.2.The relationship between seed functional traits and germination: the germination percentage of half of the species were more than 50%.Seed mass was negatively correlated with germination percentage(p < 0.05).Seed volume and dormancy type were not significantly correlated with germination percentage.Seed dispersal model was significantly correlated with germination.From our results,seed mass and dispersal model have more effects than other seed functional traits on germination.3.The relationship between seed reserves and germination: starch,protein and fat in dry seeds were not significantly correlated with germination percentage,but soluble sugar and protein contents were positively significantly correlated with germination rate for the six species.The higher soluble sugar and soluble protein content were,the faster germination rate for the different species in the same germination stage.The utilization of soluble protein,starch and fat is roughly same for the six species,Soluble protein contents is significantly reduced,Fat contents is no significant changes and starch contents showed a decreasing trend from imbibition to the early seedling stage.Our results for protein and fat utilization differ from those obtained for cultivated grasses and legumes during germination.The patterns of starch degradation and soluble sugar utilization from imbibition to the early seedling stage varied for species in the same family and with the same kind of life cycle.更多还原