水稻产量和构件对持续干旱胁迫的补偿效应初探

 有关干旱胁迫对水稻生长的影响，过去的研究多集中于它的负面作用上，认为水分胁迫必然导致水稻生长发育的障碍和产量降低。现从正面效应的角度探讨水稻对干旱胁迫的补偿性响应。研究结果表明：①轻度水分胁迫不但不会导致水稻减产，产量还比对照增加了3.6%。水稻地上和地下部生长对轻度胁迫也存在明显的补偿效应。轻度水分胁迫显著地促进了水稻茎鞘干物质的转运。虽然轻度胁迫抑制了水稻生育中期的根系生长，但显著地延缓了生长后期水稻根系的衰老。②中度和重度水分胁迫严重地抑制了水稻地上部干物质积累和前、中期根系的生长发育。但在生长后期水稻根系也出现了一定的补偿性生长，根质量、总根长和根系表面积的下降幅度均显著低于对照。然而，由于补偿作用低于水分胁迫带来的损失，水稻产量均显著低于对照。

Compensatory Reponse of Rice Yield and Its Modules to Durative Water Stress

As for the effects of water stress on the rice growth, previous studies paid main attention to its negative effects and concluded normally that water stress would result in rice growth stunt and yield decrease. However, the present studies explored its positive effects from a view of the compensatory effects of rice to water stress. Main results obtained were as follows: ① Low water stress not only did not result in rice yield decrease, but also increased the yield by 3.6%. Compensatory effects were also found in the growth of both shoots and roots of rice. Low water stress significantly increased the matter translocation ratio of rice stem and sheath. Although low water stress treatment inhibited the growth of rice roots at its middle growth stage, it delayed the senescence of rice roots during the late growth period of rice. ② Although both the medium and the heavy water stress inhibited rice dry matter accumulation and roots growth of rice at its early and middle growth stages, the compensatory effects were also found in roots growth at the later growth stage. Namely, the decrement of dry matter, total length and surface area of rice roots of those treatments were significantly lower than that of the control. However, the compensatory effects could not balance the loss at the early and middle growth stages, so that the rice yields under medium and heavy water stresses were all significantly lower than that of control.