短穗兔耳草生物量分配格局对高寒草甸营养库衰退的响应

在青海省三江源腹地，选择由于草地利用方式不同而形成的3个具有不同养分资源与植物群落特征的高寒草地，进行了短穗兔耳草（Lagotis brachystachya）生物量在各无性系的分配特性研究，以了解其对土壤营养库衰退的响应方式。结果表明，土壤养分状况对短穗兔耳草生物量在不同无性系构件间的投资也有影响，在土壤养分资源较丰富样地，短穗兔耳草对基株根茎生物量的投资最大，而对基株和分株叶片生物量投资最小；相反的趋势出现在土壤养分贫瘠的样地；但在土样养分中等的条件下，短穗兔耳草对匍匐茎的生物量投资最大，而在养分资源较贫瘠或丰富的样地又趋于减小。短穗兔耳草生物量分配格局随生境养分资源变化而改变，这是克隆植物有效适应生境变化的重要生态对策之一。

Responses of biomass allocation of Lagotis brachystachya to degradation of soil nutrition bank in alpine meadow

In order to understand responses of biomass allocation of Lagotis brachystachya to degradation of soil nutrition bank in high-cold meadow,three plots with differences in nutritional composition of soil and in vegetable community characteristics caused by different utilizing methods of grassland were selected to investigate the biomass allocation of L.brachystachya in clonal plants in the source region of the Yangtze and Yellow Rivers.The results indicated that the biomass allocation of L.brachystachya to each clonal component was affected by soil nutrient resource heterogeneity obviously.L.brachystachya allocated more biomass to the roots of genet,while less biomass was gained in the leaves of genet and ramet under richer soil nutritional resource.The contrary trend was found under poorer soil nutrient resource.However,under moderate soil nutrient resource level,L.brachystachya tended to allocate the highest biomass to stolons,but the lowest in both richer and poorer soil nutrient condition.The pattern of biomass allocation varied with the change of soil nutrient resource,which was one of the ecological strategies that clonal plants exploited soil resource heterogeneous distribution effectively.