植硅体化学组成研究进展

现代植物植硅体化学组成研究有利于揭示植硅体的化学组成与细胞形态、植物种类及植物生长环境之间的关系,认识植硅体形成机制、植物分类及生态意义。植硅体化学组成测试方法多种多样,主要涉及植硅体化学元素组成及Si、O和C元素同位素组成测定,研究表明植硅体主要含二氧化硅和水,封闭有少量的有机成分及多种矿质元素。在植硅体封闭有机成分存在形式,部分元素的形成、迁移等循环机理,稳定碳同位素组成、分布及其生态指示意义以及^14C测年研究等方面取得一定认识。植物种类、组织部位、细胞微环境以及植物生长的环境因子能够影响植硅体的化学组成。植硅体化学组成研究对植硅体形成机制及碳、硅等元素循环具有重要意义,植硅体部分化学元素、植硅体稳定同位素组成及^14C测年具有较好的古环境及考古研究潜力。现代植物植硅体化学组成及其与环境因子的关系,以及植硅体电子探针微区研究有待于进一步深入开展。

ADVANCE OF STUDY ON CHEMICAL COMPOSITION OF PHYTOLITH

The study on chemical compositions of modern plant phytoliths is helpful to reveal the relationships between the chemical composition of phytoliths and cell morphology,plant species and plant growth environment,and to understand the mechanism of phytolith formation,plant classification and ecological significance.The measurement technologies and methods of phytolith chemical composition are various and involved in major chemical elements and isotopic compositions of Si,O and C.The test results showed SiO2 and H2O form the basis of phytolith,few organic components and various inorganic mineral elements are occluded in phytolith.Some achievements were got on the existing form of organic components,the cycle(deposition,migration)mechanism of some elements occluded in phytolith,the compositions and distributions of carbon isotope in phytolith and their ecological indicative significance,and 14C age of phytolith.The chemical compositions of phytoliths are influenced by plant species and plant tissue parts,the cellular micro-environment which phytoliths are deposited,and by plant growing conditions.The study of phytolith chemical composition is significant to understand the mechanisms of phytolith,and the natural cycle of Si,C and other elements related to phytolith.Some chemical elements,stable isotope compositions of phytoliths,and ^14C age of phytolith are potential stools for paleoenvironmental reconstruction and archaeological research.The investigation of chemical compositions of phytoliths from modern plants and their relationship with environmental conditions which phytoliths formed,and the electron probe microanalysis(EPMA)of phytoliths are necessary to be further developed.