Episodes of prolonged drought coupled with heat waves (i.e., drought and heat combination) can have a devastating impact on agricultural production and crop yield. It is therefore not surprising that improving tolerance to drought and heat combination has been a major goal for breeders and biotech companies. Although much is known about the physiological and molecular responses of vegetative tissues to a combination of drought and heat stress, less is known about the impact of this stress combination on yield and different yield components. Here, we used a meta-analysis approach to synthesize results from over 120 published case studies of crop responses to combined drought and heat stress. Our findings reveal that drought and heat stress combination significantly impacts yield by decreasing harvest index, shortening the life cycle of crops, and altering seed number, size and composition. Furthermore, these impacts are more severe when the stress combination is applied during the reproductive stage of plants. We further identify differences in how legumes and cereals respond to the stress combination and reveal that utilizing C3 or C4 metabolism may not provide an advantage to plants during stress combinations. Taken together our study highlights a need to focus future studies, as well as breeding efforts, on crop responses to drought and heat combination at the reproductive stage of different crop species. This article is protected by copyright. All rights reserved.

中文翻译：

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干旱和热应激组合对作物产量和产量构成影响的荟萃分析

长时间的干旱加上热浪（即干旱和高温的结合）会对农业生产和作物产量产生破坏性影响。因此，提高对干旱和高温组合的耐受性一直是育种者和生物技术公司的主要目标也就不足为奇了。尽管人们对营养组织对干旱和热胁迫组合的生理和分子反应知之甚少，但对这种胁迫组合对产量和不同产量组成部分的影响知之甚少。在这里，我们使用荟萃分析方法综合了 120 多个已发表的作物对干旱和热应激联合反应案例研究的结果。我们的研究结果表明，干旱和热应激的组合通过降低收获指数、缩短作物的生命周期来显着影响产量，并改变种子数量、大小和组成。此外，当在植物生殖阶段施加胁迫组合时，这些影响更为严重。我们进一步确定豆类和谷物对胁迫组合的反应方式的差异，并揭示在胁迫组合期间利用 C3 或 C4 代谢可能不会为植物提供优势。综上所述，我们的研究强调需要将未来的研究和育种工作重点放在不同作物物种生殖阶段对干旱和高温组合的作物反应上。本文受版权保护。版权所有。我们进一步确定豆类和谷物对胁迫组合的反应方式的差异，并揭示在胁迫组合期间利用 C3 或 C4 代谢可能不会为植物提供优势。综上所述，我们的研究强调需要将未来的研究和育种工作重点放在不同作物物种生殖阶段对干旱和高温组合的作物反应上。本文受版权保护。版权所有。我们进一步确定豆类和谷物对胁迫组合的反应方式的差异，并揭示在胁迫组合期间利用 C3 或 C4 代谢可能不会为植物提供优势。综上所述，我们的研究强调需要将未来的研究和育种工作重点放在不同作物物种生殖阶段对干旱和高温组合的作物反应上。本文受版权保护。版权所有。