| 植物中硅矿化作用的硅同位素示踪研究 |
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| 关键词:silicon isotope rice bamboo silica mineralization global geochemical cycle |
| 基金项目:国家自然科学基金项目(40473011)和国家973项目(2007CB815601) |
| 作者 | 单位 | E-mail | | 丁悌平 | 中国地质科学院矿产资源研究所, 北京 100037；国土资源部同位素地质重点实验室, 北京 100037 | tding@cags.net.cn | | 田世红 | 中国地质科学院矿产资源研究所, 北京 100037；国土资源部同位素地质重点实验室, 北京 100037 | | | 孙立 | 浙江大学资源环境学院, 浙江杭州 310029 | | | 马国瑞 | 浙江大学资源环境学院, 浙江杭州 310029 | | | 周剑雄 | 中国地质科学院矿产资源研究所, 北京 100037 | | | 吴良欢 | 浙江大学资源环境学院, 浙江杭州 310029 | | | 万德芳 | 中国地质科学院矿产资源研究所, 北京 100037；国土资源部同位素地质重点实验室, 北京 100037 | | | 水茂兴 | 浙江大学资源环境学院, 浙江杭州 310029 | | | 王成玉 | 中国地质科学院矿产资源研究所, 北京 100037 | | | 陈振宇 | 中国地质科学院矿产资源研究所, 北京 100037 | | | 高建飞 | 中国地质科学院矿产资源研究所, 北京 100037 | |
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| Study on Silicon Isotope Tracing for Silica Mineralization in Plants |
| A systematic investigation on contents, morphology, distribution and silicon isotope compositions of silica was undertaken the first time on field grown rice plants and bamboos, as well as on laboratory grown rice plants. It was found that the SiO2 contents in rice plant increased generally from roots, through stem and leaves, to husks, but decreased drastically from husks to grains. Similarly the silica contents in bamboo plant increased also from stem, through branch, to leaves, although decreased slightly from root to stem. The silica was found to occur exclusively in the endodermis cells in the roots of rice and bamboo, but mainly in epidermal cells in their aerial parts (stem, branch, leaves and husks). Large and systematic silicon isotope fractionation was observed among different organs of individual plant of rice and bamboo. The ??30Si value of rice organs decreased from roots to stem, and then increased through leaves, husks and grains. Similarly the ??30Si values of bamboo organs decreased from roots to stem, but then increased from stem, through branch, to leaves. This kind of silicon isotope variation might be caused by isotope fractionation in a Rayleigh process when SiO2 precipitated in stem, branches, leaves and husks gradually from plant fluid. The Si isotope fractionation factor between dissolved Si and precipitated Si is inferred to be 0.9981 in bamboo plant and 0.9996 in rice plant. Another biochemical silicon isotope fractionation was also observed in process of silicon uptake by roots of rice and bamboo from soil solution. The silicon isotope fractionation factor between plant and growth solution is inferred to be 0.9988 for bamboo and 0.9989 for rice. Based on above observations, it can be inferred that: a) Monosilicic acid is the major silicon-bearing component taken up by roots of rice and bamboo; b) Passive uptake of silicon is important for these plants; c) Evapo-rate-transpiration may be the major mechanism for the transportation and precipitation of silicon in these plants. The quantitative data obtained in this study provide us a solid base for understanding the mechanisms of silicon absorption, transportation and precipitation in plants and the role of plant growth in the continental Si cycle. |
| DING Ti-ping,TIAN Shi-hong,SUN Li,MA Guo-rui,ZHOU Jian-xiong,WU Liang-huan,WAN De-fang,SHUI Mao-xing,WANG Cheng-yu,CHEN Zhen-yu,GAO Jian-fei.2009.Study on Silicon Isotope Tracing for Silica Mineralization in Plants[J].Acta Geoscientica Sinica,30(2):129-142. |
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