杭州西溪湿地植物植硅体产生及其影响因素

Phytolith production in wetland plants of the Hangzhou Xixi Wetlands ecosystem

在浙江杭州西溪湿地选取18种植物,运用微波消解和Walkley-Black消解相结合的方法,研究了湿地生态系统中不同植物植硅体质量分数及其产生通量变化特征,为沼泽湿地生态系统植硅体碳汇调控提供科学依据。研究结果表明:①18种植物植硅体质量分数有较大的差异(P<0.05),其中蒲苇Cortaderia selloana(7.69%),狗尾草Setaria viridis(7.56%),三数马唐Digitaria ternata(6.88%)和芦苇Phragmites australis(6.60%)等植硅体质量分数较高,槐叶萍Salvinia natans(1.28%),美人蕉Canna indica(1.01%)和凤眼莲Halerpestes cymbalaria(1.11%)植硅体质量分数较低。②湿地植物植硅体与其二氧化硅质量分数有较强的正相关性。在湿地生态系统中,选择一种高植硅体质量分数和高生产力的植物芦苇Phragmites australis栽植,对提高地上植物植硅体的产生通量有重要的作用。③在西溪沼泽湿地生态系统中,地上植物植硅体产生通量为4.48～129.92 g.m-2.a-1,植硅体封闭碳的产生通量为0.16～1.03 g.m-2.a-1,植硅体封闭碳的总产生速率为8.29 t.a-1。

Phytoliths,also referred to as plant opal,are silicified features that form as a result of biomineralization within plants and plays an important role in terrestrial biogeochemical cycles of carbon and silicon.This study selected 18 different plant species at the Xixi Wetlands in Zhejiang Province,to determine the phytolith content and its production flux using microwave,Walkley-Black digestion,and a correlation analysis.The main purpose of this study is to provide scientific reference for understanding the role of phytoliths in biogeochemical cycles of silicon and carbon.Results showed strong variation in phytolith content among the 18 plants：Cortaderia selloana（7.7%）,Setaria viridis（7.6%）,Digitaria ternata（6.9%）,and Phragmites australis（6.6%）were higher than Salvinia natans（1.3%）,Halerpestes cymbalaria（1.1%）,and Canna indica L.（1.0%）.A positive correlation between phytolith content and total SiO2 in the 18 plants（R2=0.663 3,P＆lt;0.01）was also found.Phytolith production flux was 4.48-129.92 g·m-2·a-1;phytolith sequestration of atmospheric CO2 was 0.16-1.03 g·m-2·a-1;and the phytolith sequestration rate of atmospheric CO2 was 8.29 t·a-1.So,it is very important to improve the flux of aboveground plant phytolith production in wetlands ecosystems by selecting a plant with high-phytolith（silicon）content and high-ANPP（aboveground net primary production）yields for the plant Phragmites australis