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柑橘根系对Ca~(2+)吸收的区域化通量分析

萧浪涛, 胡笃敬

湖南农业大学基础科学部.湖南,长沙 410128

摘要

对柑橘根系Ca~(2+)吸收的通量分析表明:根系对Ca~(2+)吸收表现出明显的“难进易出”的特点,由细胞质进入环境的单向速率常数K_(co)大大高于由环境进入细胞质的单向速率常数K_(co);根系吸收Ca~(2+)时内流(#phi#_(oc))较小,但外流(#phi#_(co))却相对较大,进入细胞质的绝大部分Ca~(2+)又外流到环境中;根系各区域中Ca~(2+)分布为自由空间>液泡>细胞质,根系吸收Ca~(2+)的净内流(J_(oc)很小,上运速率更小,因此根系吸收的Ca~(2+)只有很小一部分上运到地上部。此外,还根据自由空间中较高的Ca~(2+)含量和钙难被再利用的特点对Ca~(2+)的通量分析方法进行了初步改进。

关键词： 柑橘; 钙; 吸收; 运输; 通量分析

Compartmentation and flux analysis of Ca~(2+) in citrus root

Xiao Langtao, Hu Dujing

Department of Basic Sciences,Hunan Agricultural University.Changsha 410128,Hunan

Abstract

The compartmental analysis method for Ca~(2+) was improved according to the high Ca~(2+) content in free space and its reuse ability in citrus (Citrus unshiu Marc.) root, The results showed a high efflux rate and a low influx rate of citrus root for Ca~(2+) uptake. The unidirectional rate constant of Ca~(2+) from cytoplasm to environment (K_(co)) was much higher than that (K_(oc)) was much higher than that (K_(oc)) in the opposite direction(table 2). Most of the Ca~(2+) enter the cytoplasm soon return to the envitonment. It was found that the distribution of Ca~(2+) in citrus root is in the following order: free space (33.135#mu#mol/L)>vacuole(20.157 #mu#mol/L)>cytoplasm (1.029 #mu#mol/L) (table 1). The net influx (J_(oc) of Ca~(2+) into the citrus root was very low (0.097 #mu#mol g~(-1) FW h~(-1)). The upward transport rate was even lower (0.015 #mu#mol g~(-1) FW h~(-1)), which was only 15.46% of the influx, indicating that only a tiny amount of the Ca~(2+) absorbed by the root was transported to the upper parts of the plant.

Key words: Citrus;Calcium;Uptake;Transport;Fluxanalysis

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引用本文：

萧浪涛, 胡笃敬. 柑橘根系对Ca~(2+)吸收的区域化通量分析[J]. 生理学报 1997; 49 (3): .

Xiao Langtao, Hu Dujing. Compartmentation and flux analysis of Ca~(2+) in citrus root. Acta Physiol Sin 1997; 49 (3): (in Chinese with English abstract).