中文摘要：

本文研究了喀斯特石面常见植物反叶扭口藓（Barbula fallax Hedw.）在干旱胁迫下活性氧代谢的变化。结果显示：早期干旱超氧化酶歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性以及类胡萝卜素（Car）活性逐渐升高,胁迫后期活性下降;超氧阴离子（O-2.）、丙二醛（MDA）和可溶性蛋白含量呈现出先升后降的趋势;质膜相对透性呈现出＂抛物线＂的变化。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;后期反叶扭口藓依然保持较强的自由基清除能力,具有极强的耐旱能力。

英文摘要：

In this research we studied the antioxidant protection mechanism of B.fallax in rock desertification of Karst areas under the conditions of drought stress simulated by PEG-6000.The result showed that the contents of B.fallax superoxide dismutase,catalase,peroxidase activity and carotenoids（Car） content increased in the early period of treatment,and declined late.When osmotic stress intensified,the B.fallax superoxide anion（O-2）,malondialdehyde（MDA） and soluble protein content exhibited the trend from going up and then slow down.As for the relative permeability of membrane were shown a parabola trend of.Therefore,the increases of early O-2and other reactive oxygen species（ROS） in drought stress might induce enzymatic scavenging system to start up clearance of ROS,which would be a synergistic reaction to resist drought.The B.fallax remained strong free radical scavenging capacity,leading to very strong resistant ability to drought.