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

Effects of NaHSO₃ 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 NaHSO₃.Glutamine synthetase(GS) activity was enhanced by low salinity and depressed by high salinity.NaHSO₃ 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 NaHSO₃,especially for NADH-GDH activity.Free proline content was obviously increased by high salinity.NaHSO₃-induced increase in proline content under salinity was found.This indicated that NaHSO₃ might improve the reserve of carbon and nitrogen in wheat plants under salt stress.