渗透胁迫对直叶灰藓活性氧代谢的影响

Effect of Osmotic Stress on Reactive Oxygen Species Metabolis-m of Hypnum vaucheri Lesq.

用不同浓度的PEG-6000溶液处理直叶灰藓,研究渗透胁迫处理对其活性氧代谢的影响.实验结果表明,不同强度的渗透胁迫处理引起直叶灰藓超氧阴离子(O2-.)的含量增加,导致膜脂过氧化,生成丙二醛(MDA),使膜透性增加.在不同强度的渗透胁迫下,直叶灰藓保护酶超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性先下降,随后又升高,其活性与超氧阴离子含量呈极显著负相关(P<0.01).抗氧化剂抗坏血酸(AsA)和还原型谷胱甘肽(GSH)的含量在低胁迫强度下增加,当胁迫强度超过-1.0 MPa时其含量下降,抗坏血酸含量与超氧阴离子含量呈极显著正相关(R=0.935),并与保护酶协同作用.这说明直叶灰藓与其他高等植物一样具有完善的抗氧化系统,其较强的维持活性氧代谢平衡的能力是直叶灰藓对干旱环境的适应性生理机制之一.

A study of the effect of osmotic stress on reactive oxygen species metabolism has been carried out by using Hypnum vaucheri Lesq.treated with different concentrative PEG-6000 solution.The experiment results showed that the treatment with different degrees osmotic stress causes the increase of superoxide anion radical concentration,peroxidation of the membrane lip,and the increase of the malondialdehyde（MDA） concentration and membrane penetration.Under the different degrees osmotic stress,the protective enzymes superoxide dismutase（SOD）,peroxidase（POD） and catalase（CAT） activity of Hypnum vaucheri Lesq.decreased at first and then increased.Its activity had an extremely remarkable negative correlation with the content of superoxide anion radical（O-·2）（P0.01）.In contrast,antioxidants ascobicacid（AsA） and glutathione（GSH） content increased at a low degree stress,but their content decreased when the stress degree was over-1.0 Mpa.Meanwhile,the content of AsA had an extremely remarkable positive relativity with the content of superoxide anion radical（R=0.935）,and it cooperated with protective enzymes.These experiment results indicated that Hypnum vaucheri Lesq.had a complete antioxidant system similar as advanced plants,and the capacity of maintaining reactive oxygen species metabolism dynamic balance is one of the physiological adaptable mechanisms to the desert environment.