【摘要】 为探讨外源γ-氨基丁酸（GABA）对盐胁迫下西伯利亚白刺幼苗伤害缓解效应,研究不同浓度GABA(0～10 mmol·L^-1)对200 mmol·L^-1NaCl胁迫下西伯利亚白刺幼苗生长、生理特性、渗透调节及GABA支路中关键代谢物含量和关键酶活性的影响。结果表明,NaCl胁迫下白刺幼苗生长指标显著下降,丙二醛（MDA）、脯氨酸和可溶性糖含量显著增加,内源GABA含量和谷氨酸脱酸酶（GAD）活性显著上升。外源施加5 mmol·L^-1GABA对NaCl胁迫伤害缓解效应最佳,增加西伯利亚白刺幼苗株高、相对含水量、叶绿素和可溶性蛋白含量,并降低MDA含量、电解质外渗率、可溶性糖和脯氨酸含量;降低GAD活性并增加GABA转氨酶（GABA-T）活性以促进GABA分解代谢进入三羧酸循环（TCA）。上述结果表明,NaCl胁迫对西伯利亚白刺幼苗生长具有一定抑制作用,外源GABA促进西伯利亚白刺幼苗生长,且通过增加内源GABA含量和调节GABA支路中关键酶活性以增强西伯利亚白刺耐盐性。更多还原

【Abstract】 To explore the alleviating effect of exogenous GABA on the injury of Nitralia sibiria Pall.seedlings under salt stress, the influence of different concentrations of GABA(0-10 mmol · L^-1) on the growth, physiological characteristics, osmotic adjustment, the contents of key metabolites and the activities of key enzymes in GABA shunt in N. sibiria seedlings under 200 mmol · L^-1 NaCl stress was investigated. The results showed that the growth parameters of N. sibiria seedlings significantly decreased, the contents of malondialdehyde（MDA）, proline and soluble sugar significantly increased,the content of endogenous GABA and the activity of glutamate decarboxylase（GAD） were notably enhanced under NaCl stress. Exogenous application of 5 mmol · L^-1 GABA showed the best alleviating effect on the injury of N. sibiria seedlings under NaCl stress, plant height, relative water content, and the contents of chlorophyll and soluble protein were elevated. MDA content, electrolyte leakage rate, the contents of soluble sugar and proline decreased. GAD activity reduced while GABA transaminase（GABA-T） activity increased, which promoted GABA catabolism and entered TCA cycle. The above results indicated that NaCl stress inhibited the growth of N. sibiria seedlings. However, exogenous GABA promoted the growth of N. sibiria seedlings, and enhanced the salt tolerance by increasing endogenous GABA content and regulating the activities of key enzymes in GABA shunt.更多还原