Abstract: A newly-developed super-high-yielding hybrid rice Liangyoupeijiu and a traditional hybrid rice Shanyou 63(as control) were used to study the effects of low night temperature on leaves,mainly by measuring their lipid peroxidation and fatty acid composition of thylakoid membranes with two treatment temperatures 10°C and 25℃.In Shanyou 63,chlorophyll content in rice leaves was decreased obviously with the duration at low temperature, whereas it did not decrease statistically in Liangyoupeijiu.For both of the two hybrids,the contents of 16:0 and 18:0 components at 10℃ were significantly decreased,but there were no marked changes when treated at 25℃,and the contents of both 16:0 and 18:0 components in Liangyoupeijiu were higher than those in Shanyou 63.The contents of 18:1,18:2 and 18:3 component were increased statistically in both of the two hybrids,but those treated at 25℃ increased smoothly.And the content of 18:3 component increased less than that of 18:2.The IUFA(index of unsaturated fatty acid) of fatty acid was increased in the two hybrids,being lower in Liangyoupeijiu than in Shanyou 63.MDA content of the two hybrids showed a similar changing pattern to O2-· content,but the MDA content in Liangyoupeijiu was not increased statistically.The results indicated that,Liangyoupeijiu may be not sensitive to low temperature,and it may have strong chilling-resistance at the seedling stage.Under the chilling conditions,there was a close relationship between IUFA and lipid peroxidation,and both of them were associated with cold adaptation in rice,which suggested that the IUFA may be an indicator of chilling-resistance.The changes in fatty acid composition and protection system on membranes were the key factor of cold adaptation,especially the latter.

Key words: rice(Oryza sativa), low temperature, thylakoid, fatty acid, lipid peroxidation, cold tolerance

摘要： 以高产杂交稻组合两优培九和常规杂交稻汕优63为材料，设10℃低温和25℃常温对照两个处理，研究了夜间低温对幼苗类囊体膜膜脂过氧化和脂肪酸组分的影响。低温处理后，两个组合叶片的叶绿素含量明显下降，但两优培九下降幅度较小。两个组合的低温处理组脂肪酸组分中的16:0和18:0含量下降，常温对照组的下降幅度较小；而低温处理组脂肪酸组分中的18:1、18:2和18:3含量均上升。脂肪酸的不饱和度均呈上升趋势，但两优培九不饱和度整体上比汕优63小。低温处理下，两个组合的MDA和超氧阴离子含量都呈上升趋势，但两优培九MDA含量上升幅度远远比汕优63小。由结果可知，两优培九在苗期对低温不敏感，抗冷性较强。夜间低温引起叶片的类囊体膜膜脂过氧化加剧，脂肪酸不饱和度上升，这两方面的变化有着密切的关系，且都与杂交稻的冷适应发展有紧密的联系。

关键词: 水稻, 低温, 类囊体, 脂肪酸, 膜脂过氧化, 耐冷性