Combined enhanced UV‐B radiation and drought may induce different morphological and physiological alterations in plants than either abiotic stress alone. We evaluated morphology, biomass, and primary and secondary metabolism changes in seedlings of two common bean cultivars, IAC Imperador (drought‐resistant) and IAC Milênio. To test the hypothesis that cultivars responded differently to combined stresses in a controlled environment, seedlings of the examined been cultivars were exposed to UV‐B and/or drought treatments for three weeks. The cultivars behaved differently, especially to the drought treatment, suggesting that they use different mechanisms to cope with unfavorable environmental conditions. IAC Imperador showed a stronger protective response, modifying wax composition and primary metabolism, and improving its resistance to UV‐B radiation. For IAC Imperador, the accumulation of cuticular wax and alkane was higher under combined stress but production of primary alcohols was reduced, suggesting a possible fatty acyl switch. Root/shoot length and biomass ratios increased in both cultivars, particularly for the combined stress, indicating a common plant response. We show that these two bean cultivars responded more strongly to UV‐B and combined stress than drought alone as evident in changes to their chemistry and biology. This shows the importance of investigating plant morphological and physiological responses to combined stress.

中文翻译：

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UV-B 和干旱胁迫影响两种菜豆品种（豆科）的生长和细胞化合物

与单独的非生物胁迫相比，增强的 UV-B 辐射和干旱相结合可能会引起植物不同的形态和生理变化。我们评估了两种常见豆类品种 IAC Imperador（抗旱）和 IAC Milênio 幼苗的形态、生物量以及初级和次级代谢变化。为了验证品种在受控环境中对复合胁迫的反应不同的假设，被检查品种的幼苗暴露于 UV-B 和/或干旱处理三周。品种表现不同，特别是对干旱处理，表明它们使用不同的机制来应对不利的环境条件。IAC Imperador 表现出更强的保护反应，改变蜡成分和初级代谢，并提高其对 UV-B 辐射的抵抗力。对于 IAC Imperador，在联合压力下，角质层蜡和烷烃的积累较高，但伯醇的产生减少，表明可能发生了脂肪酰基转换。两个品种的根/枝条长度和生物量比率都增加了，特别是对于组合胁迫，表明植物的共同反应。我们表明，这两个豆类品种对 UV-B 和联合胁迫的反应比单独的干旱更强烈，这在它们的化学和生物学变化中很明显。这表明研究植物形态和生理对复合胁迫的反应的重要性。两个品种的根/枝条长度和生物量比率都增加了，特别是对于组合胁迫，表明植物的共同反应。我们表明，这两个豆类品种对 UV-B 和联合胁迫的反应比单独的干旱更强烈，这在它们的化学和生物学变化中很明显。这表明研究植物形态和生理对复合胁迫的反应的重要性。两个品种的根/枝条长度和生物量比率都增加了，特别是对于组合胁迫，表明植物的共同反应。我们表明，这两个豆类品种对 UV-B 和联合胁迫的反应比单独的干旱更强烈，这在它们的化学和生物学变化中很明显。这表明研究植物对复合胁迫的形态和生理反应的重要性。