【目的】探讨桂两优2号在水分胁迫及复水下的生理效应、产量及其构成,明确桂两优2号的水分胁迫阈值,为桂两优2号的节水灌溉提供理论指导。【方法】采用盆栽试验,对桂两优2号在孕穗期和灌浆期设正常灌溉(CK)和4个水分胁迫处理,即土壤含水量分别为饱和含水量90%~100%(T1)、80%~90%(T2)、70%~80%(T3)、60%~70%(T4)。在水分胁迫处理后15 d和复水后10 d采样测定生理指标,成熟期测定产量。【结果】相对于CK,桂两优2号在孕穗期受不同程度水分胁迫15 d后,水稻叶片丙二醛、可溶性蛋白、可溶性糖及叶绿素相对含量(SPDA值)均不断提高,其中以T4处理最高,分别为7.53μmol/gFW、36.55 mg/gFW、11.30 mg/gFW和39.08,极显著提高21.84%、57.00%、61.20%和20.36%,而以T1处理最低;复水10 d后,T2处理丙二醛、T3处理的可溶性蛋白和可溶性糖及T4处理的叶绿素相对含量增幅最大,分别极显著提高16.09%、54.23%、33.96%和11.31%;两个时期均以T2处理的叶片脯氨酸最高。在灌浆期受不同程度水分胁迫15 d后,叶片丙二醛和叶绿素相对含量呈先升高后下降的变化趋势,其中以T2处理最高;可溶性蛋白和可溶性糖则不断上升且以T4处理最高;复水10 d后,叶片丙二醛、叶绿素相对含量、可溶性蛋白和可溶性糖均呈先升高后下降的变化趋势,其中T1处理稍高于CK但均低于其他处理;两个时期的叶片脯氨酸随着胁迫程度加强而不断降低。在孕穗期和灌浆期进行水分胁迫后,T1处理的产量及其构成因素综合表现最好,产量较CK分别增加18.15%和10.92%,而其他处理的产量构成因素综合表现均不如对照。【结论】轻微水分胁迫可提高桂两优2号的抗旱能力并在复水后可获得较好的补偿效应;桂两优2号在孕穗期对水分胁迫的敏感性高于灌浆期。 【Objective】 The objective of this study was to investigate the physiological effects, yield and composition of Guiliangyou No.2 under water stress and rewatering. The water stress threshold of Guiliangyou 2 was clarified to provide theoretical guidance for water saving irrigation of Gui Liangyou 2. 【Method】 The pot experiment was conducted to study the effects of normal irrigation (CK) and four water stress treatments at the booting and filling stages of Guiliangyou No.2, that is, the soil water content was 90% ~ 100% (T1) of saturated water, 80% -90% (T2), 70% -80% (T3), 60% -70% (T4). The physiological indexes were measured 15 days after the water stress treatment and 10 days after the rewatering, and the yield was measured at the mature stage. 【Result】 Compared with CK, the contents of malondialdehyde (MDA), soluble protein, soluble sugar and relative chlorophyll (SPDA) in rice leaves of Guiliangyou No.2 were increased 15 days after booting at different degrees of water stress. Among them, T4 The highest treatment was 7.53μmol / gFW, 36.55 mg / gFW, 11.30 mg / gFW and 39.08, which were significantly increased by 21.84%, 57.00%, 61.20% and 20.36% The relative contents of MDA, T3 and soluble sugar and T4 increased significantly by 16.09%, 54.23%, 33.96% and 11.31%, respectively. The contents of MDA, The highest acid. The content of MDA and chlorophyll in the leaves tended to increase at first and then decrease after 15 days of water stress at the grain filling stage, of which the highest was treated with T2; the soluble protein and soluble sugar increased continuously and reached the highest with T4; The content of malondialdehyde, chlorophyll, soluble protein and soluble sugar in leaves tended to increase first and then decrease after rehydration for 10 days, of which T1 was slightly higher than CK but lower than those of other treatments; Proline decreases with increasing levels of stress. After water stress at booting stage and grain filling stage, the yield and its components of T1 treatment were the best, the yield was increased by 18.15% and 10.92% respectively compared with CK, while the yield performance of other treatments were not as good as the control. 【Conclusion】 Slight water stress can improve the drought tolerance of Guiliangyou 2 and obtain better compensation effect after rewatering. Guiliangyou 2 is more sensitive to water stress at booting stage than filling stage.