【目的】 明确外源海藻糖对大穗型粳稻籽粒灌浆结实的影响。【方法】 以大穗型粳稻品系W1844为试验材料，在孕穗末期叶面喷施浓度分别为0、15、30、50、70、100 mmol/L的海藻糖，分别标记为T₀、T₁₅、T₃₀、T₅₀、T₇₀、T₁₀₀。研究不同浓度海藻糖对大穗型粳稻W1844光合特性、茎鞘物质积累与转运、籽粒灌浆特性和产量的影响。【结果】 1）喷施不同浓度海藻糖均能提高水稻产量，以T₅₀处理的水稻产量最高。与T₀相比，T₅₀处理下的产量平均增加7.71%，强势粒的结实率与千粒重分别提高4.36%和5.92%，弱势粒的结实率与千粒重分别提高11.98%和10.01%。由此可见，海藻糖对弱势粒灌浆结实的改善效果更好。2）海藻糖处理改变了籽粒灌浆特性。与T₀相比，T₅₀处理下强、弱势粒达到最大灌浆速率的时间分别缩短了3.70 d与3.93 d；灌浆前期强、弱势粒的平均灌浆速率分别提高了16.57%、28.03%；灌浆中期强、弱势粒平均灌浆速率分别提高了20.74%、24.54%。此外，T₅₀处理下，强、弱势粒达到最大灌浆速率时的粒重分别比T₀增加了6.74%和7.36%。3）海藻糖处理显著提高水稻剑叶的光合特性。T₅₀处理下水稻叶片的净光合速率、气孔导度和蒸腾速率分别比T₀平均提高了31.08%、42.58%和10.42%。4）海藻糖处理促进了抽穗期茎鞘非结构性碳水化合物(NSC)的积累与转运。与T₀处理相比，T₅₀处理下抽穗期茎鞘NSC含量平均增加11.63%，茎鞘物质转运量平均提升28.52%，且对籽粒贡献率增加18.18%。这可能是由于茎鞘蔗糖转运基因OsSUT2、OsSUT4和OsSUT5上调表达，促进了茎鞘的物质转运。【结论】 外源海藻糖可有效地改善大穗型粳稻的灌浆结实，这可能是由于海藻糖处理能提高剑叶净光合速率，上调蔗糖转运基因的表达，促进茎鞘NSC的积累与转运，从而加快了强、弱势粒的灌浆，提高了其结实率和粒重。在本研究条件下，50 mmol/L海藻糖处理对大穗型水稻W1844籽粒灌浆结实的改善效果最好。

【Objective】 It is very important to clarify the effect of exogenous trehalose on grain filling and seed setting of large-panicle japonica rice. 【Method】 The effects of different concentrations of trehalose on photosynthetic characteristics, dry matter accumulation and translocation of stems and sheath, grain filling characteristics and yield of large-panicle japonica rice W1844 were investigated by foliar spraying of various concentrations of trehalose (T₀, T₁₅, T₃₀, T₅₀, T₇₀ and T₁₀₀, 0, 15, 30, 50, 70, 100mmol/L, respectively) at the end of booting stage. 【Result】 1) Trehalose exposure increased grain yield, and the highest yield was obtained under T₅₀ treatment. Compared with T₀, the yield under T₅₀ treatment increased by 7.71% on average, and the yield and thousand grain weight of superior spikelets increased by 4.36% and 5.92%, respectively, while the yield and thousand grain weight of inferior spikelets increased by 11.98% and 10.01%, respectively. Trehalose had a better effect on the improvement of grain filling and seed-setting of the inferior spikelets. 2) Trehalose treatment changed the grain filling characteristics. Compared with T₀, the time to the maximum filling rate of superior and inferior spikelets was shortened by 3.70 and 3.93 d under T₅₀ treatment; the average filling rates of superior and inferior spikelets were increased by 16.57% and 28.03% in the early stage of filling; the average filling rates of superior and inferior spikelets were increased by 20.74% and 24.54% in the middle of grain filling. In addition, compared with T₀, the grain weight of superior and inferior spikelets at maximum filling rate increased by 6.74% and 7.36%, respectively. The net photosynthetic rate, stomatal conductance and transpiration rate of rice leaves under T₅₀ treatment increased by 31.08%, 42.58% and 10.42% on average, respectively as compared with T₀. 4) Trehalose treatment promoted the accumulation and translocation of non-structural carbohydrates (NSC) in stem and sheath during the heading stage. Compared with T₀, the NSC content in stem and sheath at the heading stage increased by 11.63% on average under T₅₀ treatment, and the translocation of dry matter in stems and sheaths increased by 28.52% on average, and the contribution rate to seeds increased by 18.18%. This might be due to the up-regulated expression level of sucrose transporter genes OsSUT2, OsSUT4 and OsSUT5 in stems and sheaths, which promoted dry matter transport in stems and sheaths.【Conclusion】 Exogenous trehalose could effectively improve grain filling and seed setting of large-panicle japonica rice, which might be due to the fact that trehalose treatment could increase the net photosynthetic rate of flag leaf, up-regulate the expression of sucrose transporter genes, and promote the accumulation and translocation of NSC in the stems and sheaths, thus increasing the grain filling rate, seed-setting rate and grain weight of superior and inferior grains. Under the present experimental conditions, 50 mmol/L is the most effective in improving grain filling and seed setting in large-panicle rice W1844.