Light and temperature are two primary environmental factors for plant growth and development. The response of plants to multiple stresses of high light intensity and heat stress are complex. The priming effects of high light and heat stress on improving heat tolerance of plants need to be further illuminated. This study aimed to explain the effect of high light intensity, high temperature and their combination on tomato and clarify the response of tomato to heat stress after priming. Tomato plants were treated under control, high light, heat stress and the combination for the first-round treatments, followed by recurring heat stress as the second-round treatments. For the first-round treatments, the net photosynthetic rate (PN) of the plants at individual high light and individual high temperature on day four significantly increased and decreased, respectively, as compared with control. Combined stress caused significant reduction in Fv/Fm (maximum quantum efficiency of photosystem II) and chlorophyll content as well as increase in carotenoids and carbohydrates content. No significant difference in the PN was observed in tomato with and without priming; however, heat priming did improve the heat avoidance ability by increasing evaporation and decreasing leaf temperature. Overall, the high light affected the physiological response of tomatoes at heat stress. The tomato plants developed their defense systems including chlorophyll loss and synthesis of carotenoids to protect themselves from multiple stresses. Our work provided new insights into the understanding of plants response to high light and heat stress.

中文翻译：

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高光和热胁迫的结合在番茄中引发了复杂的反应，并在热启动后更好地冷却了叶片。

光照和温度是植物生长发育的两个主要环境因素。植物对高光强度和热胁迫的多种胁迫的响应是复杂的。需要进一步阐明高光和热胁迫对提高植物耐热性的引发作用。这项研究旨在解释高光强度，高温及其组合对番茄的影响，并阐明番茄在引发后对热胁迫的响应。番茄植株在控制，强光，热胁迫和第一轮处理的组合下进行处理，然后在第二轮处理中反复出现热应激。对于第一轮处理，在第四天的个别强光和高温下，植物的净光合速率（PN）显着增加和减少，与对照相比。联合胁迫导致Fv / Fm（光系统II的最大量子效率）和叶绿素含量显着降低，以及类胡萝卜素和碳水化合物含量增加。在有和没有引发的番茄中，PN值均无显着差异。然而，热启动确实通过增加蒸发和降低叶片温度来提高避热能力。总体而言，强光影响了番茄在热胁迫下的生理反应。番茄植物开发了其防御系统，包括叶绿素损失和类胡萝卜素合成，以保护自己免受多种胁迫。我们的工作为了解植物对强光和高温胁迫的反应提供了新的见解。联合胁迫导致Fv / Fm（光系统II的最大量子效率）和叶绿素含量显着降低，以及类胡萝卜素和碳水化合物含量增加。在有和没有引发的番茄中，PN值均无显着差异。然而，热启动确实通过增加蒸发和降低叶片温度来提高避热能力。总体而言，强光影响了番茄在热胁迫下的生理反应。番茄植物开发了其防御系统，包括叶绿素损失和类胡萝卜素合成，以保护自己免受多种胁迫。我们的工作为了解植物对强光和高温胁迫的反应提供了新的见解。联合胁迫导致Fv / Fm（光系统II的最大量子效率）和叶绿素含量显着降低，以及类胡萝卜素和碳水化合物含量增加。在有和没有引发的番茄中，PN值均无显着差异。然而，热启动确实通过增加蒸发和降低叶片温度来提高避热能力。总体而言，强光影响了番茄在热胁迫下的生理反应。番茄植物开发了其防御系统，包括叶绿素损失和类胡萝卜素合成，以保护自己免受多种胁迫。我们的工作为了解植物对强光和高温胁迫的反应提供了新的见解。