Storey R, Jones R G
Department of Biochemistry and Soil Science, University College of North Wales, Bangor, Gwynedd, Wales.
Plant Physiol. 1979 Jan;63(1):156-62. doi: 10.1104/pp.63.1.156.
The growth and tissue water, K(+), Na(+), Cl(-), proline and glycinebetaine contents of the shoots and roots of two Chenopodiaceae, Atriplex spongiosa and Suaeda monoica have been measured over a range of external NaCl salinities. Both species showed some fresh weight response to low salinity mainly due to increased succulence. S. monoica showed both a greater increase in succulence (at low salinities) and tolerance of high salinities than A. spongiosa. Both species had high affinities for Na(+) and maintained constant but low shoot K(+) contents with increasing salinity. These trends were more marked with S. monoica in which Na(+) stimulated the accumulation of K(+) in roots. An association between high leaf Na(+) accumulation, high osmotic pressure, succulence, and a positive growth response at low salinities was noted. Proline accumulation was observed in shoot tissues with suboptimal water contents. High glycinebetaine contents were found in the shoots of both species. These correlated closely with the sap osmotic pressure and it is suggested that glycinebetaine is the major cytoplasmic osmoticum (with K(+) salts) in these species at high salinities. Na(+) salts may be preferentially utilized as vacuolar osmotica.
在一系列外部NaCl盐度条件下，对藜科的两种植物——海绵状滨藜（Atriplex spongiosa）和单盐蓬（Suaeda monoica）地上部和根部的生长、组织含水量、钾（K⁺）、钠（Na⁺）、氯（Cl⁻）、脯氨酸和甘氨酸甜菜碱含量进行了测定。两种植物对低盐度都表现出一定的鲜重响应，这主要是由于肉质化增加所致。单盐蓬在低盐度时肉质化增加幅度更大，并且比海绵状滨藜更耐高盐度。两种植物对Na⁺都有较高的亲和力，随着盐度增加，地上部K⁺含量保持恒定但较低。这些趋势在单盐蓬中更为明显，其中Na⁺刺激了根部K⁺的积累。在低盐度下，观察到高叶片Na⁺积累、高渗透压、肉质化与正向生长响应之间存在关联。在含水量次优的地上部组织中观察到脯氨酸积累。在两种植物的地上部都发现了高含量的甘氨酸甜菜碱。这些与汁液渗透压密切相关，表明在高盐度下，甘氨酸甜菜碱是这些物种中的主要细胞质渗透剂（与K⁺盐一起）。Na⁺盐可能优先用作液泡渗透剂。
