滇西北高原纳帕海湿地湖滨带优势植物凋落物分解特征研究

A study on lakeside dominant plants litter decomposition characteristics in Napahai plateau wetland in northwest Yunnan

选取滇西北高原纳帕海湿地湖滨带优势植物茭草(Zizania caducifolia)、水葱(Scirpus tabernaemontani)和刘氏荸荠(Heleocharis liouana)作为研究对象,采用网袋法对凋落物的分解动态进行研究,并分析了凋落物的初始化学组成。结果表明:3种凋落物都表现出随时间进程残留率有逐渐减少的趋势,但残留率并不与时间呈线性相关。水葱凋落物残留率(70.5%)显著高于茭草(56%)和刘氏荸荠(52.5%)(P﹤0.05),茭草与刘氏荸荠凋落物残留率无显著差异。不同凋落物分解速率存在差异。刘氏荸荠分解速率最大、茭草其次、水葱最小,平均分解速率常数k值分别为0.067、0.062和0.039。3种凋落物在不同时段分解速率存在差异,凋落物的分解与温度的关系非常密切,随着温度升高,分解速率加快,且呈线性增长。此外,3种凋落物在C、N组成上也存在显著差异,但没有发现凋落物分解速率与凋落物本身C、N、C/N间的密切关系。

Lakeside dominant plants, Zizania caducifolia, Scirpus tabernaemontani and Heleocharis liouana, in Napahai plateau wetland in northwest Yunnan were chosen as research objectives. The decomposition dynamics was studied by litterbag method, and initial chemical components of litters were also analyzed. The results showed that the retention rate of the three litters was reduced with decrease of time, while the retention rate was not correlated with time. The retention rate of Scirpus tabernaemontani （70.5%） was obviously higher than that of Zizania caducifolia （56%） and Heleocharis liouana （52.5%）（P〈0.05）, while the latter two had no significant difference in retention rate. The decomposition rates differed in each community litter. Heleocharis liouana had the fastest decomposition rate, followed by Zizania caducifolia and then Scirpus tabernaemontanL with k, the average decomposition ration constant, 0.067, 0.062 and 0.039 respectively. The three litters had different decomposition rates in different periods, and the decomposition was closely related to temperature, which was increased with increase of temperature, showing a linear increase. In addition, the three litters were significantly different in C, N components, while there was no evidence showing that the decomposition rate was closely related to the initial C, N and C/N.