Abstract: To clarify the resistance of a new super hybrid rice (Oryza sativa) Liangyou 122 to chilling temperature at the milky stage, the contents of photosynthetic pigments, the changes of thylakoid membrane fatty acid and the activities of several enzymes in anti-oxidation system were investigated using a traditional hybrid rice Shanyou 63 as control, under the conditions of 25℃/15℃ and 25℃/20℃(day/night temperature). The contents of malondialdehyde(MDA) and superoxide anion (O₂ -·) were increased remarkably, while the activities of superoxide dismutase(SOD) and catalase(CAT) were obviously dropped with the overtime of low temperature and the increased difference in temperature between daytime and night; at the same time, the index of unsaturated fatty acid (IUFA) of both varieties went up. As a result, the photosynthetic rate and the chlorophyll content were decreased obviously, the content of carotenoids increased firstly and then dropped. Of all the characteristics investigated, the changing degree of Liangyou 122 was less than that of Shanyou 63, but in the quantity the former was more than the latter, which meant that Liangyou 122 may have higher resistance to chilling temperature in milky period.

Key words: low temperature, photosynthetic pigments, fatty acid, anti-oxidation system, enzyme activity, super hybrid rice

摘要： 为了阐明新型超级杂交稻两优122在灌浆期间对低温的抗性，以汕优63作对照，在25℃/15℃和25℃/20℃（昼/夜平均温度）两种温度条件下，研究了两个组合的光合色素含量的变化、类囊体膜脂肪酸组分及抗氧化系统部分酶活性的变化。结果表明：低温使水稻的光合速率和叶绿素含量下降，类胡萝卜素含量先上升后下降，随低温处理时间的延长和昼夜温差的加大，膜脂过氧化产物丙二醛和超氧阴离子含量都显著上升，超氧化物歧化酶和过氧化氢酶活性明显下降，同时，两个品种的类囊体膜脂肪酸不饱和指数都有所上升。两优122的所有指标变化幅度都较对照汕优63要小，但在量上都较汕优63高，这可能意味着两优122在灌浆期较汕优63耐低温。

关键词: 低温, 光合色素, 脂肪酸, 抗氧化系统, 酶活性, 超级杂交稻