【目的】明确盐−旱复合胁迫对水稻籽粒灌浆特性的影响及其与产量形成的关系。【方法】以江苏滨海盐碱地主栽的粳稻品种南粳9108为试材，设置盐胁迫与干旱胁迫组合处理，盐胁迫设置无盐(Non-salinity, NS, 盐浓度0%)和高盐(High-salinity stress, HS, 盐浓度0.3%)处理；干旱胁迫于拔节期至抽穗期设置浅水层灌溉(Well-watered, WW)、中度干旱(Moderate drought, MD)和重度干旱(Severe drought, SD)。【结果】与无胁迫相比，1）单一盐胁迫、单一干旱胁迫和盐−旱复合胁迫后产量分别下降36.8%、13.7%~30.0%和60.3%~107.1%(两年平均值)。2）单一盐、单一干旱和盐−旱复合胁迫下单位面积穗数、每穗粒数、结实率和千粒重均较低，且以盐−旱复合胁迫下的降幅更大；水稻穗长、穗部强、弱势粒的结实率和千粒重亦呈类似趋势。3）单一盐、单一干旱和盐−旱复合胁迫显著降低了抽穗期和成熟期干物质量及抽穗期至成熟期干物质积累量、抽穗后20 d和40 d叶片光合速率和SPAD值，盐−旱复合胁迫下的降幅高于单一盐和单一干旱胁迫。4）单一盐、单一干旱和盐−旱复合胁迫下强、弱势粒的最大灌浆速率和平均灌浆速率均较低，强势粒达最大灌浆速率的时间和有效灌浆天数则呈增加趋势，弱势粒达最大灌浆速率的时间和有效灌浆天数差异则较小。单一盐、单一干旱和盐−旱复合胁迫下灌浆前、中、后期的天数较高，灌浆速率和灌浆量则较低。5）单一盐、单一干旱和盐−旱复合胁迫处理降低了籽粒中淀粉合成关键酶活性，尤其是AGPase和GBSS酶活性。【结论】本研究表明，单一盐、单一干旱胁迫和盐−旱复合胁迫下水稻强、弱势粒灌浆速率和淀粉合成关键酶活性显著下降，弱化强、弱势粒充实性状，且以盐−旱复合胁迫下降幅更大。盐−旱复合胁迫对籽粒强、弱势粒灌浆速率和灌浆量以及产量的抑制效应高于单一盐和单一干旱胁迫。

【Objective】This study aims to investigate the effects of combined salinity-drought stress on rice grain-filling characteristics and its relationship with yield formation.【Method】The study was conducted with conventional japonica rice cultivar Nanjing 9108, which is widely cultivated in the coastal saline soil of Jiangsu Province, China. The experimental design consisted of factorial combinations of salinity and drought stresses: salinity stress induded non-salinity (NS, salt concentration 0%) and high-salinity stress (HS, salt concentration 0.3%); while drought regimes comprised well-watered (WW), moderate drought (MD), and severe drought (SD) treatments from jointing stage to heading stage.【Result】Compared with non-stress, 1) the yield reduction under salinity stress, drought stress, and combined salinity-drought stress was 36.8%, 13.7%−30.0%, and 60.3%−107.1%, respectively (two-year average). 2) the number of panicles per unit area, grains per panicle, seed setting rate, and the thousand-grain weight were all lower under single salinity stress, single drought stress, and combined salinity-drought stress, and the reduction was greater under combined salinity-drought stress; the panicle length, and grain weight and seed setting rate of superior and inferior grains showed a similar trend. 3) single salinity stress, single drought stress, and combined salinity-drought stress significantly reduced dry matter weight at jointing and heading and the accumulation of dry matter weight from heading to maturity, as well as leaf photosynthetic rate and SPAD value at 20 and 40 days after heading; the reductions under combined salinity-drought stress were greater than those under single salinity and single drought stress. 4) the maximum grain-filling rate and the mean grain-filling rate of superior and inferior grains were lower under single salinity stress, single drought stress, and combined salinity-drought stress, while the time to reach the maximum grain-filling rate and the effective grain-filling period of superior grains showed an increasing trend, and the differences in the time to reach the maximum grain-filling rate and the effective grain-filling period of inferior grains were smaller. The number of days in the early, middle, and late periods were greater under single salinity stress, single drought stress, and combined salinity-drought stress, while lower for the mean grain-filling rate and grain-filling amount. 5) single salinity stress, single drought stress, and combined salinity-drought stress treatments reduced the activities of key starch synthesis enzymes in grains, especially for AGPase and GBSS enzymes.【Conclusion】This study demonstrats that the grain-filling rate and key starch synthesis enzyme activities of superior and inferior grains decreased significantly and the grain-filling characteristics of superior and inferior grains were deteriorated under single salinity stress, single drought stress, and especially combined salinity-drought stress. The inhibitory effects of combined salinity-drought stress on the grain-filling rate, grain-filling amount of superior and inferior grains, and grain yield were greater than single salinity and drought stress.