三江平原湿地典型植物群落氮的积累与分配

采用野外采样和室内分析结合的方法,研究了三江平原湿地典型植物群落氮的积累与分配特征。结果表明,小叶章（Calamagrostics angustifolia）、乌拉苔草（Carex meyeriana）和毛苔草（Carex lasiocarpa）群落地上器官氮含量不存在显著差异,根的氮含量存在显著差异,枯落物的氮含量表现为乌拉苔草群落〉小叶章群落〉毛苔草群落（p〈0.01）。小叶章、乌拉苔草和毛苔草群落不同部分的氮积累量和积累速率（VN）季节变化明显,三者地上器官、枯落物的氮积累量和VN表现为乌拉苔草群落〉小叶章群落〉毛苔草群落;三者根的氮积累量表现为小叶章群落〉毛苔草群落〉乌拉苔草群落,VN表现为毛苔草群落〉小叶章群落〉乌拉苔草群落。小叶章、乌拉苔草和毛苔草群落不同部分的氮分配比在各时期差异明显,根是重要的氮储库,其分配比高达（87.76±2.55）%、（79.84±7.53）%和（89.25±5.49）%;地上部分的氮分配比均以叶最高,茎较低;地上与地下的氮分配比呈相反变化规律,反映了其在氮供给方面的密切联系。

Nitrogen accumulation and allocation patterns of typical plant communities in Sanjiang Plain wetland

This paper studied the nitrogen accumulation and allocation patterns of three typical plant communities in Sanjiang Plain wetland. The results showed that the nitrogen content was not significant different in aboveground plant organs but different significantly in roots among Calamagrostics angustifolia, Carex meyeriana, and Carex lasiocarpa communities. The nitrogen content in litter among the three community types showed a significant decrease： Carex meyeriana〉 Calamagrostics angustifolia〉 Carex lasiocarpa. The seasonal changes of nitrogen accumulation amount and accumulation rate in different plant organs and litter were obvious in Calamagrostics angustifolia, Carex meyeriana ~ Carex lasiocarpa communities. The nitrogen accumulation amount and accumulation rate of aboveground plant organs and litter among the three plant community types showed a decrease： Carex meyeriana〉Calamagrostics angustifolia〉Carex lasiocarpa. The nitrogen accumulation amount of root among the three plant community types showed a decrease： Calamagrostics angustifolia〉Carex lasiocarpa〉Carex meyeriana, and the nitrogen accumulation rate showed a different order： Carex lasiocarpa〉Calamagrostics angustifolia〉Carex meyeriana. The nitrogen allocation ratio was different significantly among the three community types within the growth season. Root proved to be the main nitrogen storage of plant, the nitrogen allocation ratio in Calamagrostics angustifolia, Carex meyeriana, and Carex lasiocarpa communities were （ 87.76±2.55 ） %, （ 79.84±7.53 ） % and （ 89.25±5.49 ） % respectively. The nitrogen allocation ratio is higher in leaf than stem in the three community types. The change patterns of the nitrogen allocation ratio of aboveground and belowground parts were just in adverse, which reflected the osculation contact in nitrogen supplement aspect.