Studies on salt tolerance mechanisms in halophytes

在不同浓度和不同种类盐的水中培养中，培养了一种海岸盐生植物——三棱藓属（Atriplex gmelini）的幼苗。与NaCl浓度较高或较低的植株相比，NaCl浓度为50mM的植株的干重产量最高。在基础培养液中添加50mM KCl、25mM <Na_2SO_4>或25mM <K_2SO_4>也对生长有相同的促进作用。然而，较高浓度的钾盐，如钠盐，会造成。在NaCl或KCl浓度为250 mM时，KCl的处理效果优于钠盐。在250 mM NaCl或KCl浓度下，KCl处理植株的钠钾浓度高于NaCl处理植株。这种现象可能是由于缺乏维持钾的内部浓度的控制系统，当钠盐供应时，这种控制系统可以运作。通过原生质体从盐生植物三棱叶中分离出液泡。，在添加250 mM NaCl的培养液中生长。通过降低介质渗透压和添加0.5 mM浓度的洗涤剂（合成的胆酸衍生物CHAPS）诱导原生质体裂解，并通过连续稀释和浮选纯化所得液泡。分离液泡中钠（569 mM）和氯（260 mM）的含量与原生质体中记录的钠（582 mM）和氯（254 mM）几乎相同，表明液泡是盐生植物叶片中盐的主要吸收部位。原生质体中甜菜碱的浓度约为16 mM，而液泡中甜菜碱的浓度仅为0.24 mM，说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.