Ion Transport in Plant Cells
Ion Transport in Plant Cells
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植物细胞中的离子传输
DOI：
10.1098/rstb.1971.0099
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发表时间：
1971
期刊：
影响因子：
--
通讯作者：
E. Macrobbie
中科院分区：
文献类型：
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作者：
E. Macrobbie
关于植物细胞和组织中离子转运的研究主要关注细胞的性质而不是细胞层的性质，并且证据总体上反对跨相当于动物上皮的细胞层的不对称离子转运的重要作用。结构上专门用于运输的细胞，表面积大幅增加，似乎单独或以小组形式出现，但不组织成紧密堆积的层;它们被称为转移细胞，Gunning和Pate（1969）在各种情况下进行了描述。在细胞水平上，离子运输在巨型藻类细胞中表现得最好，但在高等植物中情况可能很相似。在半透明丽藻中，质膜上的哇巴因敏感性ATP依赖性钠钾交换泵维持细胞的高K/Na，并且通过（氯化物+阳离子）泵的净盐吸收来实现高内部渗透压，也在质膜上。氯离子和阳离子之间的连接似乎更可能是化学的而不是产电的。该泵可由膜氧化还原系统供能，但不是ATP供能的。氯最初进入细胞的机制似乎也控制示踪剂氯在细胞质和液泡之间的分布，因为进入和转移到液泡的两个过程是非常密切相关的。液泡转移的动力学与盐在质膜的胞饮进入一致，胞饮小泡与内质网融合，由此形成新的液泡。放电到液泡的过程似乎是量化的，但这种观察的机制和意义还不清楚。
Work on ion transport in plant cells and tissues is largely concerned with the properties of cells rather than of cell layers, and the evidence is on the whole against an important role for asymmetric ion transport across cell layers equivalent to animal epithelia. Cells structurally specialized for transport, having a large increase in surface area, seem to occur singly or in small groups, but not to be organized into closely packed layers; they are known as transfer cells and were described in a wide variety of situations by Gunning & Pate (1969). At the cell level, ion transport is best characterized in giant algal cells, but the situation may well be similar in higher plants. In Nitella translucens an ouabain-sensitive ATP-dependent sodium-potassium exchange pump at the plasmalemma maintains the high K/Na of the cell, and the high internal osmotic pressure is achieved by net salt uptake by a (chloride + cations) pump, also at the plasmalemma. The linkage between chloride and cations seems more likely to be chemical than electrogenic. This pump may be energized by a membrane redox system, but is not ATP-powered. The mechanism for initial entry of chloride to the cell seems also to control the distribution of tracer chloride between cytoplasm and vacuole, since the two processes of entry and transfer to the vacuole are very closely linked. The kinetics of vacuolar transfer are consistent with a pinocytotic entry of salt at the plasmalemma, fusion ofpinocytotic vesicles with the endoplasmic reticulum, from which new vacuole is formed. The process of discharge to the vacuole seems to be quantized, but the mechanism and significance of this observation are not understood.