青藏高原东缘草地植物种子大小的海拔变异及其与繁殖策略和生物性状的关联

Within plant functional traits, seed size is critically important for it influencing many life history processes such as reproduction, dispersal, seedling survival and establishment as well as plants’ competition and restoration strategies in different environmental conditions. This project will be carried out on temperate, subalpine, and alpine grasslands of the eastern Qinghai-Tibet Plateau, where 12 altitudinal gradients (200 m interval) will be set and 51 grassland plant species selected for the study. In each site, we will investigate seed size and its related traits, i.e. individual plant and its reproductive part size, infructescence number, fruit size, fruit yield, seed number per fruit and intrinsic properties (life form, dispersal mode and pollination type), for each selected species. Based on these investigations, we will evaluate altitudinal gradients in intra-specific seed size variations and their connections with plants’ reproductive strategies (including reproductive biomass allocation and seed size/number trade-off). Moreover, at the between-species level, we will test the influences of species’ intrinsic properties on altitudinal patterns of intra-specific seed size variations as well as their relationships with plants’ reproductive strategies. From the project, we try to reveal the general patterns about seed size variation of grassland plant species and the mechanism of intrinsic factors’ influence on the variation, and also to provide useful scientific bases for the evolutionary and adaptive strategies of mountain plant species.

种子大小影响植物繁殖、扩散、幼苗存活和建植等多个生活史过程和在不同环境中的竞争和恢复对策，是植物响应环境变化的关键特征。本项目拟在青藏高原东缘沿海拔梯度多点布样，通过对典型草地植物种子大小及其相关特征（植株及其繁殖部分大小、果实及果序数、每果种子数及相关物种属性）的测量，在种群水平上研究海拔梯度上种子大小变异式样及其与植株个体大小和植物繁殖策略（繁殖分配和种子大小/数量权衡）的关联，在物种水平上分析植物的物种属性（生活型、果实扩散形式和传粉方式）对海拔梯度上种内种子大小变异式样及其与植物繁殖策略间关联方式的影响，从而揭示该地区草地植物种子大小的变异规律及其内在适应机制，并为阐明山地地区植物分布与适应策略提供可参考的科学依据。

本项目主要研究种子大小在海拔梯度上的变异式样以及该式样与植物繁殖策略和植株大小间的关系以及其进化和适应表现，同时，依据种子大小在特定群落内的适应能力，分析种子大小对群落构建和演替的影响；另外，依据不同种子萌发特征及其营养元素含量分析种子大小与种子生理化学特征的联系及其对种子萌发策略的影响。整体上，项目实施三年来，已按期完成所有工作内容，成果突出，超过预期目标，截止2019年底，已发表论文11篇，其中SCI论文7篇，含一区文章1篇，三区文章2篇，和四区文章4篇，总影响因子14.44（依2018年CI），中文核心文章4篇。此外，学术会议、国内外交流和人才培养也达到或超过预期目标。同时，后续仍有一些研究成果预计在未来的1-2年内陆续发表。