高寒草甸退化对短穗兔耳草克隆生长特征的影响

以调查统计和比较样地法研究了江河源区高寒草甸退化对典型匍匐茎植物短穗兔耳草克隆生长特征的影响。结果表明,退化草甸的植物群落结构、功能以及土壤特征发生了明显地变化,继而对短穗兔耳草无性系的克隆生长行为和形态特性产生了影响。高寒草甸退化后短穗兔耳草的匍匐茎有所增多,分支强度加大。退化草甸内短穗兔耳草的基株高度小于未退化草甸,根长大于未退化草甸,基株的叶片数目间没有明显差别。退化草甸内短穗兔耳草的分株高度显著小于未退化草甸,分株叶数明显多于未退化草甸,而根长尽管大于未退化草甸,但差异不显著。短穗兔耳草匍匐茎长度在未退化草甸内明显大于退化草甸,匍匐茎茎生叶数和匍匐茎粗度也在未退化草甸大于退化草甸。短穗兔耳草在未退化草甸用于克隆繁殖的能量投资比例高于退化草甸,其中未退化草甸内短穗兔耳草基株的干重比例略低于退化草甸,分株和匍匐茎的干重比例高于退化草甸。高寒草甸退化对短穗兔耳草克隆生长特征的这些影响,是其对高寒草甸退化导致的资源和生境差异的反应,也是对资源利用达到的最合理状态,是一种选择适应的结果。

Effects of alpine meadow degradation on clonal growth characteristics of Lagotis brachystachya

This paper studied the effects of alpine meadow degradation in the source region of Yangtze and Yellow Rivers on the clonal growth characteristics of typical stolon plant Lagotis brachystachya.The results showed that on degraded alpine meadow,the stolon number and branching intensity of L.brachystachya increased,and the genet and ramet were lower but their roots were longer than those on the non-degraded alpine meadow.No significant difference was observed in genet leaf number,but the ramet leaf number on degraded alpine meadow was significantly more than that on non-degraded alpine meadow.The stolon length,diameter,and leaf number of L.brachystachya were larger on non-degraded than on degraded alpine meadow,and the energy allocatgion of L.brachystachya for clonal reproduction was more on non-degraded than on degraded alpine meadow.The dry mass proportion of genet was less on non-degraded alpine meadow than on degraded alpine meadow,while that of ramet and stolon was in adverse.All of these were the responses of L.brachystachya to the variations of habitat caused by alpine meadow degradation,and the most reasonable status of this plant for its resources utilization and habitat adaptation.