不同灌水方式对水稻结实期一些生理性状和产量的影响

选用抗旱性不同的杂交水稻冈优527、D优363和汕优63，研究了旱种、湿润灌溉、“湿润灌溉（前期）+浅水灌溉（孕穗期）+干湿交替灌溉（抽穗至成熟期）”灌溉（简称C处理）和淹水灌溉4种灌水方式下，水稻结实期光合特征、渗透调节物质及保护性酶活性等生理性状变化和产量表现。结果表明，在C处理和湿润灌溉两种灌水方式下，剑叶的叶绿素含量高，叶片衰老缓慢，具有较高的净光合速率，且有利于可溶性糖和游离氨基酸等渗透调节物质的主动积累和保护性酶CAT、POD活性的提高，维持了细胞正常的代谢。而旱种下水稻剑叶叶绿素含量低，衰老快，净光合速率和气孔导度降低，渗透调节物质和保护性酶的变化水平对水分胁迫程度极为敏感。产量以C处理最高，湿润灌溉次之，旱种降低了产量构成各项因素，从而减产。试验表明，水稻叶片光合作用、渗透调节物质及保护性酶活性的变化幅度和产量与品种的抗旱性密切相关。

Effects of Different Irrigation Regimes on Some Physiology Characteristics and Grain Yield in Paddy Rice during Grain Filling

Draught and irrigation regime have been attracted more and more attention because of limited water resources in China.Rice is one of the main stable food crops in the world, and may suffer serious water stress during its growth period. Grain yield under different irrigation regimes during grain filling, and its physiological mechanism are unclear. So the experiments were carried out using three hybrid rice of Gangyou 527, D you 363, and Shanyou 63 in potted and farmland experiments to investigate the effects of four irrigation regimes dry cultivation (DC), damp irrigation (DI), the treatment C that controlled damp irrigation before booting stage, shallow irrigation at booting stage, wetting-drying alternation irrigation from heading stage to mature stage, and submerged irrigation (SI)] on photosynthetic rate, osmotic regulators, antioxidant enzyme activities, and grain yield. The results indicated that the treatment C and DI had high chlorophyll content in flag leaf, with slow senescence of flag leaf and high photosynthetic rate (P_n) of flag leaf. Both the treatment C and DI promoted the accumulation of soluble sugar content, amino acids content, and proline content, etc., and enhanced the catalase (CAT) and peroxidase (POD) activities, which maintains the natural metabolism of cells. However, compared with submerged irrigation, changes of these substances were sensitive to water stress of DC. It was showed that grain yield of the treatment C was the highest. Grain yield and its components were significantly higher under DI than under SI, but the potential of enhancing grain yield was slightly weaker under DI than under the treatment C. Decreases of grain yield and its components were obviously less than those of the treatment C. These results suggested that photosynthetic rate, osmotic regulators content antioxidant enzyme activities, and grain yield are correlated significantly to drought resistance of rice cultivars.