| Effects of soil moisture on superficial roots and yield of rice were studied by cutting roots at panicle initiation(PI) and flowering(FL) stage with hybrid cultivars Nei2you6 and Ⅱyou7954 in the field.The results indicated that the yield of Nei2you6 didn't decrease significantly under light water stress,but it was reduced by 15.2% under severe water stress.The yield of Ⅱyou7954 was increased under soil water stress.Nei2you6 was more sensitive than Ⅱyou7954 to soil water stress.The growth of superficial roots was slightly promoted by light water stress,but under severe water stress,the dry weight of superficial roots of Nei2you6 was reduced by 10.5%31.6%,and that of Ⅱyou7954 was reduced by 13%.Under soil water stress,the activity of superficial roots was enhanced.Yield reduction by cutting superficial roots at PI was higher than at FL.Cutting root at PI mainly resulted in the decline of grain number per panicle,and at FL mainly resulted in the decline of spikelet fertility rate. |