Abstract: Malonaldehyde(MDA) content,proline content, superoxide dismutase(SOD) activity and relative permeability of plasma membrane were measured in seedlings of rice variety Guibao 8 and its low potassium tolerant mutant progeny under 20% PEG 6000-simulated drought stress. MDA content,proline content and relative permeability of plasma membrane in rice seedling increased rapidly after drough stress, and MDA,proline levels were much higher in Guibao 8 than those in its mutants.SOD activity in rice seedling firstly increased and then rapidly dropped after drough stress and it was always higher in the mutant progeny than that in Guibao 8. These results suggested that the drought resistance of the mutant progeny was stronger than that of Guibao 8.Correlation analysis showed that there were significantly positive correlations between proline content, and MDA content,and relative permeability of plasma membrane in rice, however,proline content was negatively related to SOD activity to a certain extent.

Key words: rice, drought stress, low potassium tolerance, drought resistance, malonaldehyde, superoxide dismutase, proline, membrane permeability

摘要： 以早稻品种瑰宝8号及其耐低钾变异后代为材料，用20%PEG6000模拟干旱胁迫，测定丙二醛（MDA）含量、脯氨酸（Pro）含量、超氧化物歧化酶（SOD）活性及质膜相对透性。模拟干旱胁迫后，MDA、Pro含量和质膜相对透性呈急剧上升的趋势，瑰宝8号中的MDA、Pro含量显著高于它的变异后代；SOD活性先迅速上升后急剧下降，变异后代的SOD活性始终高于瑰宝8号。相关性分析表明，Pro含量与MDA含量和质膜相对透性呈显著正相关，而与SOD活性呈一定程度的负相关。

关键词: 水稻, 干旱胁迫, 耐低钾性, 抗旱性, 丙二醛, 超氧化物歧化酶, 脯氨酸, 质膜透性