不同生育时期干旱胁迫对水稻产量与碾米品质的影响

以粳稻品种农大3号为材料，利用盆栽的方式人工控制土壤水分(水势)，研究了不同生育时期干旱胁迫对水稻产量及碾米品质的影响。各时期干旱均导致产量下降，其敏感程度依次为：孕穗中期（抽穗前11~20 d）>孕穗后期（抽穗前1~10 d）>分蘖中期（移栽后11~20 d）>孕穗前期（抽穗前21~30 d）>分蘖初期（移栽后1~10 d）>分蘖后期（移栽后21~30 d）>乳熟期（抽穗后31~40 d）>抽穗开花期（抽穗后1~10 d）>灌浆期（抽穗后21~30 d）>蜡熟期（抽穗后41~50 d）。抽穗前干旱胁迫的敏感时期主要是孕穗中期、孕穗后期和分蘖中期。抽穗后，抽穗到乳熟期均较蜡熟期对干旱敏感，但对土壤水分变化较抽穗前迟钝。抽穗前干旱胁迫对糙米率和精米率影响最大的时期为孕穗中期，其次为孕穗后期。灌浆期到蜡熟期干旱胁迫，糙米率和精米率明显下降，抽穗后11~40 d干旱胁迫对整精米率的影响最大，其次为抽穗前1~20 d，其他时期干旱虽对整精米率有一定影响，但影响较小。

Effects of Drought Stress at Different Growth Stages on Grain Yield and Milling Quality of Rice

The effects of soil drought stress(soil water potential,SWP)on grain yield and milling quality of rice were investigated using Nongda 3,a japonica variety,as material through a pot experiment under artificially-controlled soil water potential with a tension-meter.The result indicated that the yield decreased when SWP was reduced to-75 kPa at different growth stages.The sensitivity degree ranked as follows:mid-booting stage(11-20 d before heading)> late booting stage(1-10 d before heading)> mid-tillering stage(11-20 d after transplanting)>early booting stage(21-30 d before heading)> early tillering stage(1-10 d after transplanting)> late tillering stage(21-30 d after transplanting)> milky stage(31-40 d after heading)>heading stage(1-10 d after heading)> filling stage(21-30 d after heading)> wax ripening stage(41-50 d after heading).The sensitive periods to drought before heading were at mid-booting,late booting and mid-tillering stages,and after heading,it was more sensitive from heading to milky stage than at wax ripening stage,but less sensitive than before heading.Mid-booting stage was the most crucial stage affecting brown and milled rice rates,followed by late booting stage.Meanwhile,11-40 d after heading and 1-20 d before heading were the sensitive stages when drought stress might greatly influence head rice rate,although drought stress at other stages also affected head rice rate.