干旱胁迫下蒭雷草的生理响应

为探讨蒭雷草(Thuarea involuta)在热带珊瑚岛干旱环境下的适应能力，对干旱胁迫下蒭雷草叶片抗逆生理指标的变化进行了研究。结果表明，干旱胁迫初期，叶片的丙二醛(MDA)含量随胁迫程度增加的差异不显著；随胁迫时间的延长，除重度胁迫下先迅速增加后急速下降外，其余处理的变化较小。超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性随干旱胁迫程度增加而升高；随时间延长，SOD活性不断上升，POD活性基本稳定，CAT活性则先下降后上升。除轻度胁迫下可溶性蛋白(SP)含量低于对照外，其余处理均随干旱胁迫程度增加而增加；干旱胁迫下的脯氨酸(Pro)含量随时间延长呈先上升后下降的变化趋势，但在处理第18天时不同胁迫程度间均差异不显著。因此，蒭雷草具有较强的抗旱能力，可用于南海诸岛的人工植物群落构建和植被恢复以营造良好生态环境。

Physiological Response of Thuarea involuta under Drought Stress

Tropical coral islands have adverse natural conditions, and a very fragile vegetation ecosystem. In order to investigate the suitability of Thuarea involuta in arid environment of tropical coral islands, the physiological indexes of stress resistance of leaves were studied. The results showed that there was no significant difference in malondialdehyde (MDA) content of leaves among drought degrees at early stress stage. The MDA content rapidly increased at first and then decreased quickly under severe drought stress, which had little change under other drought treatments. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased with the increment of drought degree. Along the treatment time, SOD activity increased, POD activity was basically stable, and CAT activity decreased first and then increased. The soluble protein (SP) content under light drought stress was lower than that under control, which increased with increment of drought stress. The change in proline (Pro) content increased first and then decreased with the treatment time, but there was no significant difference among stress treatments at 18th day. Therefore, Thuare involuta had strong drought resistance ability and could be used for artificial plant community construction, vegetation restoration and improving environmental conditions of Nansha Islands.