毛竹林生态系统植硅体的分布及其影响因素

在浙江省临安市青山、安吉县船坝、新昌县巧英和新昌县大市聚等4个地点选取毛竹Phyllostachys edulis竹叶及林地土壤,运用微波消解及Walkley-Black方法,研究不同岩性土壤上发育的同一竹龄毛竹竹叶和同一岩性土壤上发育的不同竹龄毛竹竹叶中植硅体的产生和分布规律,为毛竹林植硅体碳汇调控提供科学参考。结果表明:①毛竹竹叶中植硅体质量分数为50.8~99.1 g·kg-1,基本上是由上部到下部递减,在不同岩性间的差异表现为花岗岩>花岗闪长岩>玄武岩>页岩。②毛竹竹叶中植硅体的产生通量变化范围为154.9~605.9 kg·hm-2·a-1,在不同岩性间的差异表现为花岗岩>花岗闪长岩>玄武岩>页岩。③若按目前全国毛竹林面积3.3×106hm2,植硅体产生通量209.5~420.2 kg·hm-2·a-1以及植硅体中碳含量(3±1)%计算,那么中国毛竹林通过叶植硅体约可以固定二氧化碳(76.1~152.5)×106kg·a-1。

Phytolith distribution and carbon sequestration in China with Phyllostachys edulis

Phytoliths, the opals of amorphous silica, are deposited in the cell wall, cell lumen, and intercellular spaces during the growth of plants, especially gramineous plants. To provide references for regulation of phytolith carbon sinks, the phytolith distribution in Phyllostachys edulis bamboo from Qingshan, Chuanba, Qiaoying, and Dashiju in Zhejiang Province, with different ages on the same lithology and with the same age on different lithologies （granite, granodiorite, basalt, and shale） was studied by sampling surface soils （500.0 g for each sample）and bamboo leaves （150.0 g for each sample） with three replicates and using the phytolith extraction method of microwave and Walkley-Black digestion. Results showed that the range of phytolith content in Phyllostachys edulis was 50.8－99.1 g·kg^－1 and decreased from top to bottom of the leaf; it also decreased in the order: granite ＞ granodiorite ＞ basalt ＞ shale. The phytolith production flux in Ph. edulis for different lithologies was 154.9－605.9 kg·hm^－2·a^－1 and decreased in the following order: granite ＞ granodiorite ＞ basalt ＞ shale. Assuming a phytolith production flux in Ph. edulis of 209.5－420.2 kg·hm^－2·a^－1, the potential phytolith production rate in China was estimated to be 0.7－1.4 Tg·a^－1. Thus, using the current distribution area of Ph. edulis in China （3.3 ×10⁶ hm²） and the PhytOC content in phytoliths （3±1）%, （76.1－152.5）×10⁶ kg·a^-1 CO₂ could be sequestered from phytoliths. ［Ch, 3 fig. 3 tab. 34 ref.］