中文摘要：

依据2006～2008冬季的自然雪被分布状况,在青藏高原东缘的高寒草甸中设置3条样带（即深雪、中雪和浅雪）。在2009年的生长季,在3个雪梯度样带中,分别测定了2种优势植物圆穗蓼（Polygonum macrophyllum）和黑褐穗苔草（Carexatrofusca subsp.Minor）生物量和碳氮营养积累及分配的动态特征。结果表明,深雪能够促进圆穗蓼和黑褐穗苔草生物量和碳氮养分的积累,可能使它们产生的凋落物数量更多且质量更好。深雪更有利于圆穗蓼（非禾本科草本植物）根系生物量、碳氮养分的积累;深雪不仅同时促进黑褐穗苔草（禾本科植物）地上部分和根系生物量、碳氮积累,而且还使其种子产量增加和质量提高,潜在地增强了黑褐穗苔草种子的繁殖能力,可能使得黑褐穗苔草的种间竞争能力增强。可以预见,未来季节性雪被的变化,必定会引起青藏高原东缘高寒草甸的初级生物量及其结构、植物群落物种组成等均发生相应变化。

英文摘要：

Based on the natural snow distribution,an experiment comparing three snow regimes of different snow depths and durations at an altitude of 4,100 m in the Minshan Range on the eastern Tibetan Plateau were conducted.These three snow regimes included a shallow and short duration snowpack（SS）,a moderate snow depth and medium duration snowpack（MS）,as well as a deep and long duration snowpack（DS）.The results showed that deep snowcover promoted the biomass,carbon and nitrogen contents accumulation of Polygonum macrophyllum and Carex atrofusca and made the quantity and quality of their litter better.Moreover,the pattern on the accumulation and distribution of carbon and nitrogen in these two plants had some differences.Deep snowcover only promoted the roots growth and the accumulation of carbon and nitrogen contents in P.macrophyllum（forb）,whereas it enhanced the aboveground and belowground biomass,carbon and nitrogen contents of C.atrofusca（graminoid）.Deep snowcover enhanced the seed biomass,carbon and nitrogen contents of C.atrofusca,which might be a positive effect on seed reproduction ability.Thus,it was speculated that increased snow depth might enhance the competition of C.atrofusca and ultimately lead to the change in primary production and its structure,species component of vegetation community in the alpine meadow in eastern Tibetan Plateau.