植物在硅生物地球化学循环过程中的作用  

Roles of plants in biogeochemical cycling of silicon

作　　者：汪秀芳[1] 陈圣宾[2] 宋爱琴[1] 叶文[1] 李振基[1] 

机构地区：[1]厦门大学生命科学学院,福建厦门361005 [2]中国科学院植物研究所,北京100093

出　　处：《生态学杂志》2007年第4期595-600,共6页Chinese Journal of Ecology

基　　金：福建省自然科学基金资助项目(C0310004)

摘　　要：硅是地球上重要的矿质元素,在许多生物地球化学过程中起着重要作用。传统认为硅的循环主要受岩石风化、矿物溶解和水体沉积的影响。实际上,植物在硅的生物地球化学循环中起着重要作用。植物体本身就是一个相当大的硅库,它们能以无定型硅(SiO2.nH2O)的形式积累硅,称作生物硅(BSi)、植硅石或蛋白石。陆地植物每年以BSi的形式固定约1.68×109～5.60×109t的硅,通过枯枝落叶返回到土壤中的BSi有92.5%被植物再吸收,7.5%进入土壤库。陆地植物从土壤BSi库吸收的硅量远超过从岩石风化释放吸收的硅量,植物-土壤内循环的有效性强烈地影响着陆地生态系统中的硅向河流和海洋的输送。在海洋中,硅藻通过吸收、溶解和沉积在很大程度上影响着海洋里的硅循环,硅藻每年固定的硅约为5.60×109～7.84×109t,同样,在向海底沉积的过程中,97%的BSi重新被硅藻吸收,每年只有1.43×108～2.55×108t(约3%)沉积到海底。可见,植物在陆地生态系统和水生生态系统硅的循环中均起着非常重要的作用,研究硅的全球生物地球化学循环时必须考虑到植物的作用。Silicon is an important mineral element on the earth, because of its crucial role m many biogeochemical processes. Traditionally, silicon cycling is thought to be mainly controlled by rock weathering, subsequent mineral dissolution, and final aggradation in waters. Actually, plants react on the biogeochemical cycling of silicon. A great pool of silicon is contained as the accumulations of amorphous silica （ SiO2 · nH2O） in living plant tissues, known as biogenic silica （BSi） , phytolith or opal. The annual fixation of BSi by terrestrial plants ranges from 1.68 × 10^9 to 5.60 × 10^9 t. After decomposition, about 92. 5% of the BSi from litterfall is absorbed by plants again, and the rest 7.5% remains in soil. Because the silicon absorbed by plants from soil BSi pool is far more than that released by weathering, plant-soil internal cycling can greatly affect the dissolved silicate fluxes from terrestrial ecosystem to rivers and oceans. The annual fixation of BSi by diatom in ocean is from 5.60 × 10^9 to 7.84 × 10^9 t, about 97% of which is absorbed by diatom again before reaching seabed, and only 1.43 × 10^8-2.55 × 10^8 t （ about 3% ） is buried in sediment yearly. In this way, diatom plays an important role in the aquatic cycling of silicon. In conclusion, plants are very irnportant in both terrestrial and aquatic biogeochemical cycling of silicon, and thus, the effects of plants must be considered in the study of global biogeochemical cycling of silicon.

关 键 词：硅 植物 硅藻 生物硅(BSi) 生物地球化学循环 

分 类 号：Q948[生物学—植物学]