低温胁迫对草莓叶片SOD和AsA-GSH循环酶系统的影响

Effect of Low Temperature Stress on Activities of SOD and Enzymes of Ascorbate-Glutathione Cycle

以草莓试管苗为试材,研究低温胁迫对草莓离体叶片抗坏血酸、脱氢抗坏血酸含量和SOD以及抗坏血酸—谷胱甘肽(AsA-GSH)循环中4种酶活性的影响。结果表明,低温胁迫导致超氧化物歧化酶、抗坏血酸过氧化物酶和单脱氢抗坏血酸还原酶活性上升,脱氢抗坏血酸还原酶和谷胱甘肽还原酶活性下降;同时使还原态抗坏血酸含量下降而脱氢抗坏血酸含量上升。随着低温处理时间延长,过多活性氧不能被防御体系有效清除,植物受到伤害。试验结果还表明,抗坏血酸过氧化物酶具有较强的氧化还原抗坏血酸的能力,单脱氢抗坏血酸还原酶是AsA-GSH循环再生抗坏血酸的主要酶。

To investigate the effect of low temperature stress on ascorbate content, activities of its relative oxidative enzymes and superoxide dismutase （SOD）, the ascorbate and dehydroascorbate content and activities of SOD and four enzymes involved in the ascorbate-glutathione cycle （ AsA - GSH cycle） in strawberry were studied. The results showed that under low temperature stress the activities of SOD, ascorbate peroxidase （APX） and monodehydroascorbate reductase （MDAR） increased, while the acitivities of dehydroascorbate reductase （DHAR） and glutathione reductase （GR） decreased. Meanwhile, low temperature stress induced decrease in ascorbate （AsA） content and increase in dehydroascorbate （DHA） content. When low temperature stress continued, more reactive oxygen species （ROS） were produced and could not be removed efficiently by defense system. The results also indicated that APX had a strong ability to oxidize AsA and MDAR was a main enzyme to regenerate AsA in AsA- GSH cycle.