低温强光下水稻类囊体膜脂不饱和度和叶黄素循环组分的变化

为了阐明籼稻、粳稻对低温强光敏感性的差异，着重研究了低温强光下水稻类囊体膜脂不饱和度与紫黄质脱环氧化酶（VDE）活性的变化。随着低温强光处理时间的延长，类囊体膜脂不饱和脂肪酸含量降低、饱和脂肪酸含量增加，因而膜脂不饱和指数(IUFA)下降。同时，叶黄素循环的关键酶——VDE活性降低，叶黄素循环组分中紫黄质（V）含量增加，而单环氧玉米黄质（A）和玉米黄质（Z）的含量减少，表现为(A+Z)/(A+Z+V)比值下降。Arrhenius分析证明，VDE对低温和膜脂不饱和度都敏感。相关分析表明，类囊体IUFA分别与VDE活性、(A+Z)/(A+Z+V)和D1蛋白量呈显著的正相关。与粳稻9516相比，籼稻汕优63类囊体膜的IUFA较低，低温下类囊体膜脂流动性和稳定性较差， VDE活性和(A+Z)/(A+Z+V)比值较低。

Changes in Unsaturation of Thylakoid Membrane Lipids and Xanthophyll Cycle Components in Rice (Oryza sativa) under Chilling and Strong Light

To explore the differences in sensitivities to chilling and strong light between indica and japonica rice, changes in unsaturation of thylakoid membrane lipids and the activity of violaxanthin deepoxidase (VDE) in flag leaves were studied under chilling (day/night temperatures of 11±1℃/10±1℃) and strong light (1050 μmol / m² · s). The contents of unsaturated fatty acids of thylakoid membrane lipids decreased and the saturated fatty acids increased with chilling and strong light treated time delaying, as a result, the index of unsaturation of fatty acid (IUFA) reduced. Also, the activities of VDE, a key enzyme of xanthophyll cycle, reduced. The content of violaxanthin (V) increased, and the contents of antheraxanthin (A) and zeaxanthin (Z) decreased consequently, the ratio of (A+Z)/(A+Z+V) decreased corresponsively. Arrhenius analysis showed that VDE was sensitive to both chilling and unsaturation level of thylakoid membrane lipids. Correlation analysis showed that there were distinctly positive relationships between IUFA of thylakoid membrane lipids and the activity of VDE, (A+Z)/(A+Z+V) ratio, D₁ protein content, respectively. Lower IUFA value, less fluidity and stability of thylakoid membrane lipids, lower VDE activity and (A+Z)/(A+Z+V) ratio were found in indica rice Shanyou 63 than in japonica rice 9516 under chilling and strong light.