【摘要】 【目的】为探究新型赤霉素抑制剂二氢赤霉素（2HGA₅）对不同增密条件下小麦碳氮积累和籽粒灌浆的影响。【方法】以国审小麦品种“蜀麦133”为试验材料，分别在250万株/hm²（常规密度，D1）、300万株/hm²（增密20%,D2）、350万株/hm²（增密40%,D3）、400万株/hm²（增密60%,D4）4个密度下，喷施100 mg/L二氢赤霉素（P2）和200 mg/L二氢赤霉素（P3），并分别喷施清水（P0）、200 mg/L多效唑-甲哌鎓混合剂（P1）为对照。【结果】增密提高了小麦群体氮素与干物质积累，但不利于小麦叶、穗蔗糖积累及穗部发育。喷施二氢赤霉素能提高小麦叶片可溶性糖含量，加强氮素吸收与利用。P2和P3处理使各种植密度下开花期叶片蔗糖、叶片可溶性糖含量、成熟期籽粒氮素积累量、氮素吸收效率、籽粒氮素生产效率、氮收获指数和干物质积累量，较P0分别提高了26.0%和41.5%、11.5%和20.7%、17.9%和24.3%、10.4%和20.5%、10.2和22.7%、3.5%和4.2%、10%和15.5%；较P1分别有-2.7%和+11.0%、-5.8%和+2.3%、-2.0%和+3.2%、-1.6%和+7.3%、-1.2%和+9.7%、+2.5%和+1.3%、-0.3%和+4.6%的变幅。二氢赤霉素对籽粒灌浆有一定的抑制作用，P2、P3的最大灌浆速率、平均灌浆速率、灌浆持续时间和千粒重，较P0分别降低了2.9%和0.9%、4.4%和4.4%、2.7%和5.7%、6.1%和8.5；较P1分别有+1.1%和+3.3%、+0.2%和+0.2%、-1.8%和+4.9%、-0.8%和-3.4%的变幅。同时，二氢赤霉素能显著增加穗粒数。与P0处理相比，P2、P3穗粒数分别增加6.6%和11.1%。【结论】增密配施二氢赤霉素能有效减轻增密对小麦穗部发育的不利影响，利于氮素吸收与利用，促进碳水化合物的积累，提高干物质积累量，增加穗粒数，缓解籽粒灌浆负效应，综合表现为产量上升。更多还原

【Abstract】 【Objective】 This study investigated the effects of a novel gibberellin inhibitor, 16,17-dihydro-gibberellin A₅（ 2 HGA₅）, on carbon and nitrogen accumulation and grain filling in wheat under different planting densities, using the cultivar "Shumai 133". 【Method】 A split-plot design was adopted with planting density as the main plot factor（2.5×10 6 plants/hm²（D1）, 3×10 6 plants/hm²（D2）, 3.5×106 plants/hm²（ D3）, and 4×106 plants/hm²（ D4）） and chemical regulator treatment as the sub-plot factor, including water control（P0）, 200 mg/L paclobutrazol and mepiquat chloride mixture（P1）, 100 mg/L 2 HGA₅（P2）, and 200 mg/L 2 HGA₅（ P3）.【 Result】Increasing planting density enhanced nitrogen and dry matter accumulation but reduced sucrose accumulation in leaves and panicles and inhibited panicle development. Foliar application of 2 HGA5 significantly increased leaf soluble sugar content and improved nitrogen uptake and utilization. Compared to P0, P2 and P3 treatments increased leaf sucrose content at anthesis by 26.0% and 41.5%, soluble sugar content by 11.5% and 20.7%, grain nitrogen accumulation by 17.9% and 24.3%, nitrogen uptake efficiency by 10.4% and 20.5%, grain nitrogen production efficiency by 10.2% and 22.7%, nitrogen harvest index by 3.5% and 4.2%, and dry matter accumulation at maturity by 10.0% and 15.5%, respectively. When compared to P1, the same parameters changed by-2.7% to +11.0%,-5.8% to +2.3%,-2.0% to +3.2%,-1.6% to +7.3%,-1.2% to +9.7%, +2.5% to +1.3%, and-0.3% to +4.6%, respectively. Although the maximum filling rate, mean filling rate, filling duration, and 1 000-grain weight under P2 and P3 decreased by 2.9% and 0.9%, 4.4% and 4.4%, 2.7% and 5.7%, and 6.1% and 8.5% compared to P0, these traits showed improvements of +1.1% to +3.3%, +0.2% to +0.2%,-1.8% to +4.9%, and-0.8% to-3.4% relative to P1. Additionally, 2 HGA₅ application significantly increased grains per spikelet by 6.6% and 11.1% under P2 and P3 compared to P0. 【Conclusion】 Under high planting densities, foliar application of 2 HGA₅ effectively enhances nitrogen utilization, carbohydrate accumulation, and dry matter content in wheat. It also increases grains per spikelet, mitigating the adverse effects of high density on grain filling and ultimately improving final yield.更多还原