冬小麦生殖生长早期弱光胁迫下粒数恢复补偿机制研究

气候变化及大气污染形成的雾霾天气引起了光照时数及强度降低，对作物生长发育常造成不利影响。以往研究表明开花前的非生物胁迫（包括弱光）导致小麦花粉败育、穗粒数减少、产量降低。弱光环境下植株同时会做出一系列响应，以减少弱光造成的这种不利影响。我们前期研究工作表明，冬小麦生殖生长早期弱光胁迫后穗的颖壳展开角度增大、分蘖再次萌发成穗，植株粒数下降得以部分恢复补偿、产量下降得以缓解，但其粒数恢复补偿的机制至今少见报道。本研究以4个耐弱光性不同的冬小麦品种为材料，桶栽和大田试验相结合，利用遮荫构建弱光环境，通过显微观察、碳同位素示踪等先进技术，系统开展小麦生殖生长早期不同遮光程度及遮光时间下植株粒数的变化规律、量化再生分蘖与颖壳展开对粒数恢复的作用及品种间差异、分析光-光合作用-光合产物运转-籽粒形成的变化特征、探究分蘖再发成穗的激素调控作用与机理，为弱光逆境下小麦高产提供理论依据。

Smoggy weather caused by climate change and atmospheric pollution result in decreased illumination hours and intensity, which often adversely affect crop growth and development. Previous research has shown that non-biological stress (including weak light) leads to pollen abortion, fewer grains per panicle, and decreased yields. In weak light environments, plants adopt a series of coping strategies to reduce the adverse impacts of weak light. In our previous study, an increased angle of opening of glumes and re-emergence and then spike formation of new tillers were observed in winter wheat following exposure to weak light stress during the early stages of reproductive growth. This resulted in partial recovery and compensation for decreased grain numbers and mitigation of yield losses. However, the mechanisms underlying grain number recovery and compensation have rarely been reported. In the present study, four winter wheat varieties with different levels of tolerance to weak light were used as materials in a combined pot cultivation and field experiment. By constructing a weak light environment through shading with black polyethylene netting and using the technique of 13CO2 stable isotope tracer and microscopical observation, we systematically investigated the variation patterns of grain number in wheat plants subjected to different degrees and durations of shading during the early reproductive growth stages, quantified the effects of new tiller generation and glume opening on grain number recovery and differences among winter wheat varieties, analyzed the variation characteristics of the light-photosynthesis-photosynthate translocation-grain formation process, and explored hormonal regulation and mechanisms of panicle re-emergence from new tillers after shading stress. Our findings provide a theoretical basis for the achievement of high wheat yields in adverse weak light environments.