Studies on salt tolerance mechanisms in halophytes

以滨海盐生植物滨藜(Atriplex gmelini C.A.Mey)为材料，在不同盐分浓度和种类的水培条件下，对其幼苗进行了培养。与接受较高或较低浓度盐分的植株相比，接受50 mM氯化钠营养的植株干重产量最高。在基础培养液中添加50 mM KCl25 mM+Na_2SO4+GT或25 mM+Lt+K_2SO4+GT也有同样的促进作用。然而，更高浓度的钾盐，如比钠盐。在浓度为250 mM的氯化钠或氯化钾的加入量下，氯化钾处理的效果优于钠盐。当添加250 mM的氯化钠或氯化钾时，氯化钾处理的植株表现出比氯化钠处理的植株更高的钠钾浓度。这种现象可能归因于缺乏维持体内钾浓度的控制系统，当供应钠盐时，钾可以运行。通过原生质体从盐生植物滨藜的叶片中分离出真空分子，该植物生长在添加250 mM氯化钠的培养液中。通过降低介质渗透压和添加0.5 mM的合成胆酸盐衍生物CHAPS的去污剂来诱导原生质体裂解，并通过连续稀释和浮选来纯化所产生的空泡。分离液泡的钠(569 MM)和氯(260 MM)浓度与原生质体(分别为582 mM和254 mM)的浓度基本相同，表明液泡是盐生植物叶片中氯化钠的主要封存部位。甜菜碱在原生质体中的浓度约为16 mM，而在液泡中的浓度仅为0.24 mM，表明甜菜碱以相容溶质的形式积累在细胞质中。

Seedlings of a coastal halophyte, Atriplex gmelini C.A.Mey were grown in water culture with varying concentrations and species of salts. Plants receiving nutrients supplemented with 50mM NaCl gave the maximum dry weight yield compared with those receiving the higher or the lower concentrations of NaCl. Addition of 50mM KCl, 25mM <Na_2SO_4> , or 25mM <K_2SO_4> to the basal culture solution also stimulated the growth to the same extent. However, higher concentrations of potassium salts, such as than sodium salts did. At a concentration of 250 mM NaCl or KCl addition, the KCl-treated than sodium salts did. At a concentration of 250 mM NaCl or KCl addition, the KCl-treated plants showed a higher sodium plus potassium concentration than the NaCl-treated plants. This phenomenum may be ascribed to the lack of control systems for the maintenance of the internal concentration of potassium, which can operate when sodium salts are supplied.Vacuoles were isolated via protoplasts from the leaves of a halophyte Atriplex gmelini C.A.Mey., grown in culture solution supplemented with 250 mM NaCl. Lysis of the protoplasts was induced by lowering the medium osmolarity and adding a detergent, a synthesized cholate derivative, CHAPS, at a concentration of 0.5 mM and the resulting vacuoles were purified by successive dilution and floatation. Isolated vacuoles contained almost the same concentration of sodium (569 mM) and chloride (260 mM) as recorded in protoplasts (582 mM and 254 mM, respectively), suggesting that the vacuoles are the major sequestration site of NaCl in leaves of halophytes. Betaine concentration in the protoplasts was about 16 mM, while that in vacuoles was only about 0.24 mM, indicating that betaine is accumulated in the cytoplasm as compatible solute.