K/Na selectivity at the plasmalemma of cortical root cells and preferential release of sodium to the xylem vessels in roots of Atriplex hortensis
K/Na selectivity at the plasmalemma of cortical root cells and preferential release of sodium to the xylem vessels in roots of Atriplex hortensis
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滨藜根皮层根细胞质膜的 K/Na 选择性和钠优先释放到木质部导管
DOI：
10.1111/j.1399-3054.1983.tb05735.x
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Wolf Dieter Jesehke
中科院分区：
文献类型：
--
作者：
W. Stelter;Wolf Dieter Jesehke
Using excised roots of Atriplex hortensis L., cv. Gelbe Gartenmelde, the uptake, accumulation and xylem transport of K+ and Na+ have been measured. Influx as well as xylem transport proved to discriminate little between K+ and Na+, when considered in relation to the external solution. Both K+ and Na+ inhibited the uptake and xylem transport of each other to about the same degree. Measurements of intracel-lular Na+ fluxes by means of compartment analysis indicated that the low degree of K/Na discrimination during uptake was due to low influx selectivity. Moreover, K+/Na+ exchange at the plasmalemma was not very efficient in Atriplex roots. In order to establish the basis of the low K/Na discrimination in xylem transport, the rates of K+ and Na+ transport were related to the cytoplasmic K+ and Na+ concentrations to yield the selectivity ratio of transport, S(transport) = (ϕcx(K) × [Na+]c)/(ϕcx(Na) × [K+]c). Under all conditions this ratio was far below one indicating that Na+ was favoured during xylem release in excised roots of Atriplex at low external concentrations. The implications of this discrimination in favour of Na+ are discussed with respect to salt tolerance of A. hortensis.
