NaCl对水稻谷氨酸合酶和谷氨酸脱氢酶的胁迫作用
EFFECT OF NaCl STRESS ON GLUTAMATE SYNTHASE AND GLUTAMATE DEHYDROGENASE OF RICE PLANTS
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摘要: 在NaCl的胁迫下, 水稻幼苗根和叶的谷氨酸合酶和谷氨酸脱氢酶的活性随着营养液中的NaCl浓度的升高而降低;游离NH4+在叶中积累, 在根中未见明显变化。与根相比, 叶对NaCl的胁迫作用更为敏感。叶的NADH-GOGAT和NADH-GDH活性在NaCl胁迫下降低的程度明显大于根。无论是否有NaCl存在, 根的NADH-GDH活性明显高于叶。GS/GDH比值分析提示, 在对照下, 根中的NH4+的同化以GS-GOGAT途径为主;而在NaCl胁迫下, GS-GOGAT途径明显削弱, GDH途径在NH4+的同化中的作用明显加强。无论是否有NaCl的存在, 叶的NH4+同化途径都是以GS-GOGAT为主。Abstract: Glutamate synthase(GOGAT) and glutamate dehydrogenase(GDH) activity in the roots and leaves of rice seedlings were decreased under NaCl stress.H4+ level in leaves was increased significantly due to NaCl stress, but the content of H4+ in roots was not altered obviously, irrespective of NaCl treatment.As compared with root, leaf was more sensitive to NaCl stress.The reduction of the activity of NADH GOGATand NADH GDHin leaves was more than that in roots.Whether NaCl was added or not to the nutrient solution, NADH GDHactivity of roots was much higher than that of leaves.Analysis for GS GDHratio showed that GS GOGATcycle was main pathway of ammonium assimilation in the control plant roots, but under NaCl stress, GDHpathway was strengthened obviously.Irrespective of NaCl treatment, GS/GOGATcycle was main pathway in leaves.