水稻各生育期不同土壤水势对产量的影响

 用张力计监测并依此严格控制试验盆钵的土水势，研究水稻中熟品种（组合）汕优63和盐粳2号各生育期低土壤水势对产量形成的影响。其结果为：出穗前各生育期对低土壤水势反应的敏感顺序为，分蘖盛期 > 生殖细胞形成期 > 枝梗分化期 > 分蘖末期 > 花粉粒充实期，在分蘖盛期与生殖细胞形成期土水势长期低于-0.025MPa，则明显减产;结实期间对低土壤水势反应最敏感的时期为籽粒灌浆初期，籽粒灌浆末期较低的土水势( > -0.016MPa)有促进籽粒灌浆的倾向；减数分裂期，随土水势的下降，颖花退化率提高，产量线性减低，土水势对产量的影响与土壤质地(砂壤、中壤)无互作效应。

EFFECT OF LOW SOIL WATER POTENTIAL ON RICE YIELD

The effects of low soil water potential during different stages on the yields of two rice cultivars (Shanyou 63 and Yanjing 2) were studied when soil water potential was rigorously examined with soil water tensiometer. The main results were as follows.The orders of the growth stages before heading for the sensitivity to soil water deficient were: Peak tillering stage, Generative cell formating stage, Rachis-branch differentiating stage, Late tillering stage and Pollen mother cell formation stage in both cultivars. When soil water potential was lower than -0.025MPa during peak tillering stage and generative cell formation stage, yield decreased obviously.The most sensitive stage to soil water stress during grain-filling period was early grain-filling stage.It seems that relatively low soil potential at late grain-filling stage could improve grain-filling.The increasing of percentage of degenerated spikelets and decreasing of yield were linear with soil water potential at reduction divsion stage.No significant interaction between soil water potential and soil texture (sandy loam and middle loam) on yield has been found.