Abstract: The physiological characteristics of root and flag leaf in two hybrid rice, Honglianyou 6 and Liangyou 1193, after flowering stage under different irrigation patterns were studied. Root density and activity were higher under controlled damp irrigation than those of submerged irrigation. Chlorophyll contents in flag leaf under controlled damp irrigation were not different at flowering stage, but distinctly higher at mature stage compared with that under submerged irrigation. Net photosynthetic rate of flag leaf under controlled damp irrigation also significantly higher than that of submerged irrigation at reproductive stage. Compared with submerged irrigation, two hybrid rice combinations had higher community growth rate(CGR) and relative growth rate(RGR), and obtained higher grain yield under controlled damp irrigation. The higher yield might result from enhancement of the dry matter accumulation favorable to the grain development at reproductive stage under controlled damp irrigation.

Key words: hybrid rice, irrigation pattern, root, photosynthetic rate, physiological characteristics

摘要： 对杂交水稻组合红莲优6和两优1193在淹水灌溉和湿润灌溉两种灌溉模式下生育后期的根系和光合生理特性进行了比较分析。结果显示，湿润灌溉增大了水稻根系密度，提高了根系活力，相关分析显示根系密度与根系活力呈正相关(r1=0.66, r2=0.68)。齐穗期剑叶叶绿素含量处理间差异不显著，但成熟期湿润灌溉显著高于淹水灌溉，推测湿润灌溉有利于剑叶功能期的延长和光合速率的提高。湿润灌溉条件下，群体生长率和相对生长率均显著高于淹水灌溉，表明湿润灌溉有利于水稻生殖生长期的干物质积累。上述结果可能是湿灌处理条件下水稻单位面积的产量极显著高于淹灌处理的主要原因。

关键词: 杂交水稻, 灌溉模式, 根系, 光合速率, 生理特性