NaHSO3对盐胁迫下小麦幼苗氮同化酶及脯氨酸含量的影响

以普通小麦(Triticum aestivumL.)为材料,研究了NaHSO3对不同盐度胁迫下小麦幼苗氮素同化酶和脯氨酸含量的调节。结果表明,盐胁迫降低了叶片中硝酸还原酸(NR)的活性,加入NaHSO3之后,NR活性表现出进一步的降低。谷氨酰胺合成酶(GS)在低浓度盐胁迫下活性增加,在高浓度盐胁迫下活性降低;NaHSO3加入时,即便在低盐浓度下GS活性也降低。依赖于NADH的谷氨酸脱氢酶(NADH-GDH)和依赖于NADP的异柠檬酸脱氢酶(NADP-ICDH)的变化趋势一致,在盐胁迫下它们的活性都明显增加;NaHSO3加入促进了它们活性的进一步增加,尤其对NADH-GDH活性的促进更为明显。游离脯氨酸在高浓度盐胁迫下大量积累,在低浓度盐胁迫下含量增加不明显;NaHSO3促进了盐胁迫下脯氨酸的积累,提示了NaHSO3促进了盐胁迫下小麦幼苗碳氮营养元素的贮存。

Effects of NaHSO3 on Nitrogen Assimilation Enzymes and Proline Accumulation of Wheat Seedlings Exposed to Salinity

Effects of NaHSO_3 on nitrogen assimilation enzymes and proline accumulation under salinity were investigated using ordinary wheat cultivar(Triticum aestivum L.) as materials.The results showed that leaf nitrate reductase(NR) activity was decreased by salinity and further decreased by addition of NaHSO_3.Glutamine synthetase(GS) activity was enhanced by low salinity and depressed by high salinity.NaHSO_3 significantly decreased GS activity in leaves of wheat plants exposed to salinity,resulting in the disappearing of GS activity induced by low salinity.The activities of dependence-NADH glutamate dehydrogenase(NADH-GDH) and dependence-NADP isocitrate dehydrogenase(NADP-ICDH) in(leaves) increased under salinity and further increased by NaHSO_3,especially for NADH-GDH activity.Free proline content was obviously increased by high salinity.NaHSO_3-induced increase in proline content under salinity was found.This indicated that NaHSO_3 might improve the reserve of carbon and nitrogen in wheat plants under salt stress.