Due to climate change, multiple heat events are expected to be an additional limiting factor that will adversely affect wheat production. The study aimed to analyze the physiological response to heat stress in four winter wheat cultivars at different physiological stages under greenhouse conditions during 2019. The net photosynthetic rate, stomatal conductance, chlorophyll index, maximum quantum efficiency of photosystem II, fructose, glucose and sucrose content, grain yield per plant, grain weight and number of grains per plant were analyzed in wheat cultivars under short periods of heat stress at anthesis and mid-grain filling, and combined stress at anthesis and mid-grain filling. The results of the study indicated that heat stress modified the photosynthesis-related and grain yield–related traits. Moreover, heat stress caused a decrease of sucrose content, while fructose and glucose content increased. Heat stress had more pronounced effects on the photosynthetic parameters and grain yield during grain filling than during anthesis. A significant variation observed among cultivar responses to the negative impact of heat stress highlighted the fact that cultivars Pobeda and Gladius were more tolerant than Renesansa and Simonida. Different cultivar reactions to heat stress during anthesis and grain filling indicated the need to conduct further studies with wheat cultivars of different origin in order to identify additional sources of tolerance.

中文翻译：

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开花期和灌浆期高温对冬小麦品种生理特性的影响

由于气候变化，预计多次高温事件将成为对小麦生产产生不利影响的额外限制因素。本研究旨在分析4个冬小麦品种2019年在温室条件下不同生理阶段对热胁迫的生理响应。净光合速率、气孔导度、叶绿素指数、光系统II最大量子效率、果糖、葡萄糖和蔗糖含量, 分析了小麦品种在开花期和灌浆中期以及开花中期灌浆联合胁迫下的单株产量、单株粒重和单株粒数。研究结果表明，热应激改变了光合作用相关和谷物产量相关的性状。而且，热应激导致蔗糖含量减少，而果糖和葡萄糖含量增加。与开花期相比，热胁迫对灌浆期的光合参数和籽粒产量的影响更为显着。在品种对热应激负面影响的反应中观察到的显着差异突出表明，品种 Pobeda 和 Gladius 比 Renesansa 和 Simonida 更耐受。不同品种对开花期和灌浆期热胁迫的反应表明需要对不同来源的小麦品种进行进一步研究，以确定其他耐受性来源。在品种对热应激负面影响的反应中观察到的显着差异突出表明，品种 Pobeda 和 Gladius 比 Renesansa 和 Simonida 更耐受。不同品种对开花期和灌浆期热胁迫的反应表明需要对不同来源的小麦品种进行进一步研究，以确定其他耐受性来源。在品种对热应激负面影响的反应中观察到的显着差异突出表明，品种 Pobeda 和 Gladius 比 Renesansa 和 Simonida 更耐受。不同品种对开花期和灌浆期热胁迫的反应表明需要对不同来源的小麦品种进行进一步研究，以确定其他耐受性来源。