喀斯特石生穗枝赤齿藓抗氧化防御系统对干旱胁迫的响应

Responses of antioxidant defense system of Erythrodoutium juluceum to drought stress in rocky desertification of karst areas

为科学选择石漠化环境恢复治理的植物材料和深入了解岩生植物的耐旱机制,以喀斯特石生穗枝赤齿藓(Erythrodoutium juluceum)为实验材料,研究了干旱胁迫对其抗氧化酶防御系统的影响。结果表明:超氧化酶歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性,超氧阴离子(O-2·)、丙二醛(MDA)含量呈现出先升后降的趋势;类胡萝卜素(Car)含量一直升高,质膜相对透性呈现出"抛物线"的变化趋势,可溶性蛋白含量波动变化。因此,干旱胁迫早期由于O-2·等活性氧的增加而启动活性氧清除系统进行清除,是抵御干旱的一种协同反应;后期穗枝赤齿藓依然保持较强的自由基清除能力,具有极强的耐旱能力。所以在长期的进化过程中,喀斯特石生藓类形成具有适合干旱变化的系列生理和代谢机制,通过形态上的变化来降低水分的散失,通过生理上的调整来应付环境的恶劣变化,这对于在石漠化地区揭示苔藓植物的抗逆机制,利用苔藓植物的先锋拓荒作用治理石漠化生态环境以及对退化生态系统进行人工恢复治理具有重要价值。

The research focuses on the antioxidant defense system of E .juluceum by PEG-6000 simulated drought stress conditions.The contents of E .juluceum superoxide dismutase dismutase （SOD）,catalase （CAT）,peroxidase （POD）activity,superoxide anion （O-2·）and malondialdehyde （MDA）content increased,and at late declined.The carotenoids （Car）content always increasing.As for the relative permeability of membrane,E .juluceum were shown a trend of the parabola and increased in varying degrees, and the soluble protein content in variation of fluctuate.Therefore,the increases in drought stress early O-2· and other reactive oxygen species （ROS）induce en-zymatic and non-enzymatic scavenging system to start to clear ROS.Keep the radical scavenging ability and strong a-bility of drought tolerance.So,in the long process of evolution,karst epilithic mosses formed with a series of physio-logical changes and metabolic mechanism for drought,through the change in morphology to reduce water loss,bad by changes in physiological regulation to cope with the environment,which for the mechanism of resistance to reveal the bryophytes inrocky desertification area,the use of pioneer the pioneering role of bryophytes in rocky desertifica-tion control and ecological environment have important value of artificialrestoration of degraded ecosystem.