Shennan C, Hunt R, Macrobbie E A C
Botany School, Downing Street, Cambridge CB2 3EA, U.K.
Plant Cell Environ. 1987 Jan;10(1):67-74. doi: 10.1111/j.1365-3040.1987.tb02081.x.
Measurements of tissue ion contents (Na, K and Cl) were carried out at frequent intervals on plants of Aster tripolium L. grown at a range of salinities for 36 d. Aster tripolium behaved as a typical halophyte showing high levels of inorganic ion accumulation even at low salinities. As salinity increased Na replaced K to a large extent in the shoot but root K was unaffected up to 500 mol m external NaCl. Shoot (Na + K) concentration on a tissue water basis was maintained constant in all treatments throughout the experiment, whereas shoot (Na + K) on a dry weight basis showed marked fluctuations in some treatments. An increase in (Na + K) per gram dry weight was, however, accompanied by a parallel increase in fresh weight: dry weight (FW : DW) ratio. Transport of (Na + K) to the shoot per unit root weight changed during the experiment in the manner expected, given the observed changes in shoot relative growth rate and FW : DW to result in a constant shoot (Na + K) concentration on a water basis. Chloride was the major balancing anion in the shoot at high salinity, but never accounted for more than 38% of the (Na + K) found in the root tissue. At all salinities (Na + K) salts accounted for the majority of the measured shoot sap osmotic potential. The interactions between salinity, growth, ion transport and osmotic adjustment are discussed.
对生长在一系列盐度环境下36天的海生紫菀植株，定期测量其组织离子含量（钠、钾和氯）。海生紫菀表现为典型的盐生植物，即使在低盐度下也能积累高水平的无机离子。随着盐度增加，地上部的钠在很大程度上取代了钾，但在外部氯化钠浓度达500 mol m时，根部钾含量未受影响。在整个实验过程中，所有处理基于组织水的地上部（钠+钾）浓度保持恒定，而基于干重的地上部（钠+钾）在某些处理中出现明显波动。然而，每克干重中（钠+钾）的增加伴随着鲜重：干重（FW:DW）比值的相应增加。鉴于地上部相对生长速率和FW:DW的观察变化，单位根重向地上部运输的（钠+钾）在实验过程中的变化符合预期，从而使基于水的地上部（钠+钾）浓度保持恒定。在高盐度下，氯是地上部主要的平衡阴离子，但在根组织中其含量从未超过所测（钠+钾）的38%。在所有盐度下，（钠+钾）盐占所测地上部汁液渗透势的大部分。本文讨论了盐度、生长、离子运输和渗透调节之间的相互作用。
