中文摘要：

为更多了解青藏高原＂黑土滩＂退化草地植被特点,通过对青藏高原黄河源区典型＂黑土滩＂退化草地范围内的66种草地植物种子大小、形态等特征进行统计分析。测量了植物种子百粒重、种子长、宽和厚度,计算了种子单粒重、种子体积和种子形状变异系数,并对种子单粒重、体积、形状变异系数、长、宽、厚、长/宽、长/厚、宽/厚进行相关性分析。结果表明：种子各性状都存在不同程度的变异,体积变异范围最大（0.000003~81.97mm~3）。相关分析表明种子单粒重与厚度、形状变异系数与厚度、种子体积与长/厚间都存在较显著的正相关（P〈0.01）。有60种植物种子是小粒种子（种子单粒重小于3 mg）;有35种植物种子是小粒且近圆球形的种子（形状变异系数小于0.090）。总结认为,该区内的这35种植物种子可能易于形成持久土壤种子库。＂黑土滩＂草地中以小粒植物种子为主的主要原因是黄河源区独特的自然环境选择的结果。

英文摘要：

The seed size and shape of 66 plant species in the degraded grassland of＂black soil land＂were analyzed in the source region of Yellow River to provide the basic data for farther studying the characteristics of degraded grassland vegetation in the＂black soil land＂of Qinghai-Tibet Plateau.The hundred grain mass of plant seed,seed length,width and thickness were measured,the single seed mass,seed size and the variation coefficient of seed shape were calculated.And the correlation among seed mass,volume,shape,the variation coefficient,the length,width,thickness,length/width,length/thickness and the width/thickness were analyzed.The results showed that the characteristics of seeds had different degrees of variation.The volume had the largest variation range（0.000003 to 81.97mm~3）.Correlation analyses showed that the single seed mass and thickness,shape variation coefficient and thickness,volume and length/thickness had significant positive correlation（P 0.01）.The 60 plant seeds belonged to small seed（single seed mass less than 3mg）;The 35 plant seeds were the small seeds and nearly round shape（coefficient of variation less than 0.090）.It is concluded that the 35 plant seeds may be easy to form a persistent soil seed bank.The selection of unique natural environment in the source region of Yellow River is the main reason why the most of seeds are small seeds in＂Black soil land＂degraded grassland.