夜间低温胁迫对番茄叶片活性氧代谢及AsA-GSH循环的影响

以番茄品种‘辽园多丽’为试材,利用人工气候室模拟设施生产中的夜间低温胁迫环境,研究9℃和6℃夜低温对番茄叶片活性氧代谢和AsA-GSH循环的影响。结果显示:9℃和6℃夜间低温胁迫3～9d可诱导番茄叶片中超氧阴离子(O2.-)产生速率、过氧化氢(H2O2)和丙二醛(MDA)含量上升;抑制过氧化物酶(POD)、过氧化氢酶(CAT)的活性,增加超氧化物歧化酶(SOD)和AsA-GSH循环中抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、谷胱甘肽还原酶(GR)的活性,并提高还原型抗坏血酸(AsA)、还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)的含量。研究表明,在夜间低温胁迫过程中,增加的番茄叶片中SOD活性和AsA-GSH循环清除活性氧的能力并未与氧还原的速率一致,从而导致番茄叶片中活性氧的累积,使细胞膜系统受到一定破坏,在6℃处理的植物中尤为明显。

Active Oxygen Metabolism and Ascorbate-Glutathione Cycle of Tomato Leaves under Low Nocturnal Temperature

The effect of low nocturnal temperature at 9℃ and 6℃ simulated by climate chambers on the active oxygen metabolism and Ascorbate-Glutathione cycle of tomato leaves was studied.The results showed that low nocturnal temperature treatment increased O-·2 production rate,H2O2,malondialdehyde(MDA) contents;inhibited peroxidase(POD),catalase(CAT) activities;and improved superoxide dismutase(SOD),ascorbate peroxidase(APX),dehydroascorbate reductase(DHAR),glutathione reductase(GR) activities as well as reduced-ascorbate(AsA),reduced-glutathione(GSH),oxidized-glutathione(GSSG) contents.It indicated that the enhanced SOD activity and scavenging activity of Ascorbate-Glutathione cycle did not keep pace with the rate of oxygen reduction since increased O-·2,H2O2 and MDA levels were observed throughout the experiment,especially in 6℃ treated plants.