Abstract: This study investigates an underground biomass variation of Poa pratensis var.anceps Gaud.cv.Qinghai over a six-year period.Further,it reveals intraspecies competition characteristics of rhizome plants and provides basic data for both species adaptation and an ecological balance system maintaining.Results showed the highest underground biomass in 0～5 cm,but concentrated in 0～20 cm.Vertical distribution of underground biomass appeared as "T" shape.Seasonal variation of underground biomass in two years showed a single-peak.Underground biomass increased most quickly during the first two years,peaked in four years,then declined.The first year presented a phase of adjustment while the second and third years showed logarithmic period.The fourth and fifth years exhibit a stationary phase,followed by a decline after six years.Root density,root area and root specific surface area of four years were higher than that of six years.The model of underground biomass is y=e^{7.355-1.939/t}.

Key words: Poa pratensis var.anceps Gaud.cv.Qinghai, Root System, Spatial and temporal distribution, Population, Develop strategy

摘要： 通过研究青海扁茎早熟禾(Poa pratensis var.anceps Gaud.cv.Qinghai)地下生物量6年来的时空变化特征,揭示根茎植物种内竞争,并为青海扁茎早熟禾在物种适应特征、维护生态系统平衡等方面提供基础数据。结果表明:青海扁茎早熟禾的地下生物量垂直分布为"T"型,以0~5 cm层地下生物量最高,地下生物量主要集中在0~20 cm。地下生物量在第2年为单峰季节变化,毛根地下生物量、根茎地下生物量、根颈地下生物量和总地下生物量均以第2年增长最快,第4年达到最大值之后略有降低。根系变化可分为4个时期:第1年为调整期,第2年和第3年为对数期,第4年和第5年均为稳定期,第6年之后为衰亡期。第4年的根生物量、根密度、根比面积和根比表面积均大于第6年,说明第6年根系已经有逐渐衰老的趋势。地下生物量时序变化最符合S曲线模型,其表达式为:y=e^{7.355-1.939/t};地下生物量垂直变化最符合逆变换曲线,表达式为:y=-92.167+2773/x。

关键词: 青海扁茎早熟禾, 根系, 时空分布, 种群, 发展策略