土壤水分状况对水稻表层根系和产量的影响

Effects of soil moisture on superficial roots and yield of rice

以内2优6号和Ⅱ优7954为材料，研究了不同土壤水分状况对水稻表层根系生长和活力及表层根系对产量的影响。结果表明：内2优6号在轻度水分胁迫下产量与对照无显著差异，在重度水分胁迫下产量下降15．2％。水分胁迫使Ⅱ优7954产量提高。内2优6号对水分胁迫较Ⅱ优7954敏感。轻度水分胁迫对表层根系干重没有显著影响，在重度水分胁迫下，内2优6号表层根系干重下降10．5％～31．6％，Ⅱ优7954下降13％。然而，在土壤水分胁迫下，表层根系活力提高。穗分化期切根对产量的影响大于开花期，穗分化期切根主要影响每穗粒数，而开花期的切根主要影响结实率。

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 Ⅱ you7954 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 Ⅱ you7954 was increased under soil water stress. Nei2you6 was more sensitive than Ⅱ you7954 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 Ⅱ you7954 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.