不同生育时期干旱胁迫对水稻产量与碾米品质的影响

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

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11～20d)>孕穗后期(抽穗前1～10d)>分蘖中期(移栽后11～20d)>孕穗前期(抽穗前21～30d)>分蘖初期(移栽后1～10d)>分蘖后期(移栽后21～30d)>乳熟期(抽穗后31～40d)>抽穗开花期(抽穗后1～10d)>灌浆期(抽穗后21～30d)>蜡熟期(抽穗后41～50d)。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11～40d干旱胁迫对整精米率的影响最大,其次为抽穗前1～20d,其他时期干旱虽对整精米率有一定影响,但影响较小。

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 midtillering 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.