The frequency and severity of heat waves are expected to increase in the near future, with a significant impact on physiological functions and yield of crop plants. In this study, we assessed the residual post-heat stress effects on photosynthetic responses of six diverse winter wheat (Triticum sp.) genotypes, differing in country of origin, taxonomy and ploidy (tetraploids vs. hexaploids). After 5 days of elevated temperatures (up to 38 °C), the photosynthetic parameters recorded on the first day of recovery (R1) as well as after the next 4–5 days of the recovery (R2) were compared to those of the control plants (C) grown under moderate temperatures. Based on the values of CO₂ assimilation rate (A) and the maximum rates of carboxylation (V_Cmax) in R1, we identified that the hexaploid (HEX) and tetraploid (TET) species clearly differed in the strength of their response to heat stress. Next, the analyses of gas exchange, simultaneous measurements of PSI and PSII photochemistry and the measurements of electrochromic bandshift (ECS) have consistently shown that photosynthetic and photoprotective functions in leaves of TET genotypes were almost fully recovered in R2, whereas the recovery of photosynthetic and photoprotective functions in the HEX group in R2 was still rather low. A poor recovery was associated with an overly reduced acceptor side of photosystem I as well as high values of the electric membrane potential (Δψ component of the proton motive force, pmf) in the chloroplast. On the other hand, a good recovery of photosynthetic capacity and photoprotective functions was clearly associated with an enhanced ΔpH component of the pmf, thus demonstrating a key role of efficient regulation of proton transport to ensure buildup of the transthylakoid proton gradient needed for photosynthesis restoration after high-temperature episodes.

预计在不久的将来，热浪的频率和严重程度将会增加，对农作物的生理功能和产量产生重大影响。在这项研究中，我们评估了残余热应激对六种不同冬小麦 ( Triticum sp.) 基因型的光合反应的影响，这些基因型在原产国、分类学和倍性（四倍体与六倍体）方面有所不同。在温度升高 5 天（最高 38 °C）后，将恢复第一天（R1）以及恢复后 4-5 天（R2）记录的光合参数与对照进行比较植物 ( C ) 在中等温度下生长。基于CO ₂同化率（A) 和 R1 中的最大羧化率 ( V _Cmax )，我们发现六倍体 (HEX) 和四倍体 (TET) 物种对热应激的反应强度明显不同。接下来，气体交换分析、PSI 和 PSII 光化学的同时测量以及电致变色带移 (ECS) 的测量一致表明，TET 基因型叶片的光合和光保护功能在 R2 中几乎完全恢复，而光合和光合和光保护功能的恢复R2 中 HEX 组的光保护功能仍然相当低。恢复不良与光系统 I 的受体侧过度减少以及电膜电位的高值（质子动力的 Δψ 分量，pmf) 在叶绿体中。另一方面，光合能力和光保护功能的良好恢复明显与pmf的 ΔpH 成分增强有关，因此证明了有效调节质子转运以确保建立光合作用恢复后所需的跨类囊体质子梯度的关键作用。高温发作。