Cadmium transport in submerged macrophyte Ceratophyllum demersum L. in presence of various metabolic inhibitors and calcium channel blockers

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• 作者：Tripathi ; R.D. ; Rai ; U.N. ; Gupta ; Meetu ; Yunus ; Mohd. ; Chandra ; P.
• 刊名：Chemosphere
• 出版年：1995
• 期刊代码：15_00456535
• 类别：env
• 出版时间：October, 1995
• 卷：31
• 期：7
• 页码：3783-3791
• 文件大小：404 K

摘要

Transport of Cd²⁺ in Ceratophyllum demersum was light dependent process requiring metabolic energy. The extent of Cd influx was linear up to 10 μM external Cd²⁺, however, beyond that plants showed metal uptake plateau after 120 min. Cadmium influx was more in the light than in the dark. Various uncouplers: 2,4-dinitrophenol (DNP), carbonyl cyanide m-chlorophenylhydrazone (CCCP), and ATPase inhibitor N-N′-dicyclohexylcarbomidide (DCCD) limited this process. Cadmium ion and Ca²⁺ were antagonistically decreasing uptake of each other. Cd²⁺ influx followed Michaelis-Menten (Cd²⁺) saturation kinetics with a low value of Km 40.0 μM which increased in the presence of Ca²⁺ (66.66 μM). Verapamil and nifedipine, blockers of voltage dependent calcium channels reduced Ca²⁺ uptake in the plant, however, provoked Cd²⁺ augmentation in both continuous and short Cd²⁺ exposure experiments. Highly significant Cd²⁺ influx provoked by verapamil and nifedipine was possibly due to enhanced diffusion of Cd²⁺ in the dark.