| Root Morphology and Zn^2＋ Uptake Kinetics of the Zn Hyperaccumulator of Sedum alfredii Hance |
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| 作者姓名： | Ting-Qiang LI Xiao-E YANG Zhen-Li HE Jin-Yan YANG |
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| 作者单位： | [1]Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, Zhejiang University, Huajiachi Campus, Hangzhou 310029, China; [2]University of Florida, Indian River Research and Education Center, Fort Pierce, Florida 34945, USA |
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| 基金项目： | Supported by the State Key Basic Research and Development Plan of China （2002CB410804） and the National Natural Science Foundationof China （20277035）. |
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| 摘 要： | Root morphology and Zn^2＋ uptake kinetics of the hyperaccumulating ecotype （HE） and nonhyperaccumulating ecotype （NHE） of Sedum alfredii Hance were investigated using hydroponic methods and the radiotracer flux technique. The results indicate that root length, root surface area, and root volume of NHE decreased significantly with increasing Zn^2＋ concentration in growth media, whereas the root growth of HE was not adversely affected, and was even promoted, by 500μmol/L Zn^2＋. The concentrations of Zn^2＋ in both ecotypes of S. alfredii were positively correlated with root length, root surface area and root volumes, but no such correlation was found for root diameter. The uptake kinetics for ^65Zn^2＋ in roots of both ecotypes of S. alfredii were characterized by a rapid linear phase during the first 6 h and a slower linear phase during the subsequent period of investigation. The concentration-dependent uptake kinetics of the two ecotypes of S. alfredii could be characterized by the Michaelis-Menten equation, with the Vmax for ^65Zn^2＋ influx being threefold greater in HE compared with NHE, indicating that enhanced absorption into the root was one of the mechanisms involved in Zn hyperaccumulation. A significantly larger Vmax value suggested that there was a higher density of Zn transporters per unit membrane area in HE roots.
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| 关 键 词： | 根形态 锌元素 景天属植物 元素聚集 放射性示踪剂 |
| 收稿时间： | 2004-09-10 |
| 修稿时间： | 2004-09-102005-03-23 |
Root Morphology and Zn2+ Uptake Kinetics of the Zn Hyperaccumulator of Sedum alfredii Hance |
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| Authors: | Ting-Qiang LI Xiao-E YANG Zhen-Li HE Jin-Yan YANG |
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| Institution: | Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, Zhejiang University;, Huajiachi Campus, Hangzhou 310029, China; University of Florida, Indian River Research and Education Center;, Fort Pierce, Florida 34945, USA |
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| Abstract: | Abstract: Root morphology and Zn2+ uptake kinetics of the hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) of Sedum alfredii Hance were investigated using hydroponic methods and the radiotracer flux technique. The results indicate that root length, root surface area, and root volume of NHE decreased significantly with increasing Zn2+ concentration in growth media, whereas the root growth of HE was not adversely affected, and was even promoted, by 500 μmol/L Zn2+. The concentrations of Zn2+ in both ecotypes of S. alfredii were positively correlated with root length, root surface area and root volumes, but no such correlation was found for root diameter. The uptake kinetics for 65Zn2+ in roots of both ecotypes of S. alfredii were characterized by a rapid linear phase during the first 6 h and a slower linear phase during the subsequent period of investigation. The concentration-dependent uptake kinetics of the two ecotypes of S. alfredii could be characterized by the Michaelis-Menten equation, with the Vmax for 65Zn2+ influx being threefold greater in HE compared with NHE, indicating that enhanced absorption into the root was one of the mechanisms involved in Zn hyperaccumulation. A significantly larger Vmax value suggested that there was a higher density of Zn transporters per unit membrane area in HE roots.
(Managing editor: Ping HE) |
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| Keywords: | phytoremediation Sedum alfredii translocation uptake kinetics zinc (Zn) |
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