不同耐盐性水稻幼苗根氨同化酶对盐胁迫的反应

在盐胁迫下,检测了耐盐性不同的水稻(Oryza sativa L.)品种根部氨同化酶及其相关参数的变化.结果表明,根的可溶性蛋白、谷氨酰胺合成酶(GS)及依赖于NADH的谷氨酸合酶(NADH-GOGAT)活性在高盐浓度下不同程度地降低,其影响大小依次为早花二号(盐敏感品种)、金珠一号(正常栽培品种)、津稻779(耐盐品种),与其耐盐性相一致.在盐胁迫条件下,在耐盐性较高的水稻品种中,GS和GOGAT活性比盐敏感品种高,NH4 浓度维持在较低的水平.Native-PAGE和活性染色结果表明,GSrb更容易受到外界环境的影响.在高浓度盐的胁迫下,早花二号、金珠一号的依赖于NADH的谷氨酸脱氢酶(AADH-GDH)活性都有较显著的升高,津稻779却无明显的变化,这和NH4 含量的变化相一致.盐不同程度地导致可溶性糖(TSS)在金珠一号和津稻779根部积累,而在早花2号的根部,可溶性糖的水平则随盐浓度的不同而表现出不同的变化.在所检测的品种中,脯氨酸的含量均有不同程度的升高,但在高盐浓度下,盐敏感品种的含量较低.这些结果提示,不同的水稻品种对盐胁迫的敏感程度与该品种GS以及GOGAT活性的高低有关.

Effect of Salt Stress on Ammonium Assimilation Enzymes of the Roots of Rice (Oryza sativa) Cultivars Differing in Salinity Resistance

Effects of NaCl-stress on ammonia assimilation enzymes and the related parameters were determined in the roots of three rice (Oryza sativa L.) cultivars differing in salt tolerance. The results showed that the activities of glutamine synthetase (GS) and NADH-dependent glutamate synthase (NADH-GOGAT), as well as the levels of soluble protein decreased under high concentration salt. The influence extent was in accordance with Zao-hua 2 (salt-sensitive), Jin-zhu 1 (normal cultivar) and Jin-dao 779 (salt-resistant), which was consistent with their salt-tolerance. Nevertheless, under the stress of high salt concentration, NADH-dependent glutamate dehydrogenase (NADH-GDH) activity of Zao-hua 2 and Jin-zhu 1 was induced significantly, but that of Jin-dao 779 did not increase remarkably. The salt stress led to the accumulation of total soluble sugar (TSS) in the root of Jin-zhu 1 and Jin-dao 779 in different degree. The level of TSS in Zao-hua 2 changed with different NaCl concentrations. Among the cultivars observed, content of proline increased in different degree, but under high salt concentrations, it had a more marked rise in the roots of salt-sensitive cultivars.