低氧胁迫下γ-氨基丁酸(GABA)对甜瓜植株活性氧代谢的影响

Effect of Exogenous γ-aminobutyric Acid(GABA) on Reactive Oxygen Species Metabolism of Melon Under Hypoxia Stress

以‘西域一号’甜瓜为试材,采用营养液水培法,研究了外源γ-氨基丁酸(GABA)对低氧胁迫下甜瓜植株根系和叶片活性氧代谢的影响,以期了解外源GABA对甜瓜低氧胁迫伤害缓解的活性氧代谢机制。结果表明:低氧胁迫条件下,甜瓜植株根系和叶片的抗氧化酶如超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性均显著上升,且H2O2含量、O2^-产生速率和丙二醛(MDA)含量也较通气对照显著上升;营养液中添加5 mmol·L^-1 GABA后,根系和叶片中的SOD、POD和CAT活性显著高于低氧胁迫处理,而植株体内O2^-产生速率、H2O2和MDA含量则显著降低。证明外源GABA可通过提高植株体内抗氧化酶活性,降低活性氧的积累,减轻活性氧对于细胞的伤害,从而促进甜瓜的耐低氧能力的提高。

By the method of hydroponic culture,the effects of exogenous γ-aminobutyric acid(GABA) on active oxygen metabolism of roots and leave of ‘Xiyu No.1’ muskmelon under hypoxia stress were studied,in order to elucidate the mechanism of active oxygen metabolism of exogenous GABA in alleviating hypoxic stress injury of Melon.It showed that the activity of SOD,POD and CAT,and H2O2,MDA content and O2^- productive rate of hypoxia stress treatment were all dramatically rised,compared to ventilation control.Exogenous 5 mmol·L^-1 GABA could effectively alleviate the harm of hypoxia stress in roots and leaves of melon.Activities of SOD,POD and CAT of roots and leaves of melon plant dramatically rised,and O2^- productive rate,the contents of H2O2 and MDA dramatically decreased.It suggested that exogenous GABA could increase the resistance of melon plant under hypoxia stress most likely by improvng the activity of antioxidant enzymes in plants and decreasing the accumulation of reactive oxygen species.