Peng Changlian, Lin Zhifang, Lin Guizhu, Chen Shaowei
College of Life Science, South China Normal University, Guangzhou 510631, China.
Sci China C Life Sci. 2006 Dec;49(6):543-51. doi: 10.1007/s11427-006-2022-1.
In the leaf of rice (Oryza sativa L.) cultivar Yunnan purple rice, the anthocyanins with an obvious absorption peak at 530nm were distributed in the cells of upper and lower epidermis, bulliform tissue and bristle. The maximal photosynthetic oxygen evolution rate and chlorophyll content in flag leaves were 28% and 23%, respectively, more than the common green leaf rice cultivar Chijiaoruanzhan. Higher chlorophyll content is probably one of the physiological adaptations for enhancing light harvesting capacity of the antenna in photosystems in this cyanic leaves species. Upon the photooxidation of leaf segments mediated by methyl viologen in weak light for 3 days, the distinct bleaching of anthocyanins in purple rice was associated with the reduction of scavenging ability to DPPH * free radical ability and the increase in membrane leakage rate. But almost no changes in contents of flavonoids and total phenolics were observed. Chlorophyll fluorescence parameters Fv/Fo, qP and phi(PSII) decreased with the increase in NPQ and DES of xanthophylls cycle after photooxidation treatment. Green rice leaves showed more decrease in DPPH * scavenging rate and more increase in cell membrane leakage rate but showed a trace of anthocyanins during photooxidation. It is suggested that anthocyanin may be a beneficial and primary antioxidant in sun cyanic rice leaves against oxidative stress induced by environmental adversity. And photooxidation could induce different changing patterns of anthocyanins between the tested purple and green rice leaves.
在水稻（Oryza sativa L.）品种云南紫稻的叶片中，在530nm处有明显吸收峰的花青素分布于上下表皮细胞、泡状组织和刚毛中。剑叶的最大光合放氧速率和叶绿素含量分别比普通绿叶水稻品种赤角软占高28%和23%。较高的叶绿素含量可能是该蓝叶物种增强光合系统中天线捕光能力的生理适应之一。在弱光下用甲基紫精介导叶片片段光氧化3天后，紫稻中花青素明显褪色，同时对DPPH自由基的清除能力降低，膜渗漏率增加。但类黄酮和总酚含量几乎没有变化。光氧化处理后，叶绿素荧光参数Fv/Fo、qP和phi(PSII)随叶黄素循环的NPQ和DES增加而降低。绿叶水稻叶片在光氧化过程中DPPH清除率下降更多，细胞膜渗漏率增加更多，但花青素含量仅微量变化。这表明花青素可能是阳生蓝叶水稻叶片中抵御环境逆境诱导的氧化应激的一种有益且主要的抗氧化剂。并且光氧化可诱导受试紫叶和绿叶水稻叶片中花青素呈现不同的变化模式。
