Phytolith production in wetland plants of the Hangzhou Xixi Wetlands ecosystem

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＜0.01）was also found. Phytolith production flux was 4.48-129.92 gm-2a-1；phytolith sequestration of atmospheric CO2 was 0.16-1.03 gm-2a-1；and the phytolith sequestration rate of atmospheric CO2 was 8.29 ta-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.［Ch，1 fig. 1 tab. 35 ref.］