Post‐Flowering High Temperature and Drought Stress Impair Wheat Yield via Physiological and Molecular Disruption of Source‐Sink Dynamics and Starch Metabolism

作者：Qiao Li, Yangchun Ye, Demei Wang, Yanjie Wang, Min Zhang, Ruiqi Ma, Lingxin Zhang, Ruiguo Cai, Zhao GuangCai, Xuhong Chang, Xuze Liu · 发表于：Plant Cell & Environment · 年份：2025 · DOI：10.1111/pce.70039 · 被引用次数：7 · 研究领域：Plant responses to elevated CO2、Crop Yield and Soil Fertility、Plant Water Relations and Carbon Dynamics

Enhancing wheat resilience to concurrent high-temperature (HT) and drought stress (DS) is critical for sustainable agriculture under climate change. However, the physiological and molecular mechanisms underlying their combined effects (DHS) remain poorly understood. Here, a 3-year field study evaluated post-flowering HT, DS and DHS impacts on two wheat cultivars, Zhongmai 36 (ZM36) and Jimai 22 (JM22). Yield losses under HT, DS and DHS averaged 16.9%, 15.3% and 31.7%, respectively, with DHS exhibiting supra-additive effects. Stressors reduced net photosynthetic rate (Pn), PSII efficiency (Fv/Fm) and proton conductivity (gH+/vH+) in flag leaves, leading to 18.1% lower sucrose and 42.4% reduced post-flowering photosynthetic accumulation under DHS. Furthermore, vascular bundle number and area in rachis decreased by 23.8% and 12.9% (ZM36) and 14.3% and 20.3% (JM22) under DHS, impairing sucrose transport. Transcriptomic analysis revealed downregulation of starch biosynthesis genes (AGPase, SS and GBSS) and upregulation of starch degradation genes (ISA3, BAMY2) under DHS, creating a metabolic 'sink trap'. Collectively, these multi-level findings elucidate the hierarchical disruption of source-sink coordination under combined stresses and provide actionable targets for breeding climate-resilient wheat. SUMMARY STATEMENT: Field study revealed post-flowering combined heat and drought stress caused supra-additive yield loss in wheat by impairing source-sink coordination and altering st...