Drought events are expected to become more frequent with climate change. To predict the effect of plant emissions on air quality and potential feedback effects on climate, the study of biogenic volatile organic compound emissions under stress is of great importance. Trees can often be subject to a combination of abiotic stresses, for example due to drought or ozone. Even though there is a large body of knowledge on individual stress factors, the effects of combined stressors are not much explored. This study aimed to investigate changes of biogenic volatile organic compound emissions and physiological parameters in Quercus robur L. during moderate to severe drought in combination with ozone stress. Results show that isoprene emissions decreased while monoterpene and sesquiterpene emissions increased during the progression of drought. We exposed plants with daily ozone concentrations of 100 ppb for 1 h for 7 d, which resulted in faster stomatal closure (e.g., a mean value of −31.3 % at an average stem water potential of −1 MPa), partially mitigating drought stress effects. Evidence of this was found in enhanced green leaf volatiles in trees without ozone fumigation, indicating cellular damage. In addition we observed an enhancement in (C₈H₈O₃)H⁺ emissions likely corresponding to methyl-salicylate in trees with ozone treatment. Individual plant stress factors are not necessarily additive, and atmospheric models should implement stress feedback loops to study regional-scale effects.

中文翻译：

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臭氧和干旱胁迫对栎栎生物挥发性有机化合物排放的综合影响 。

干旱事件预计将随着气候变化而更加频繁。为了预测植物排放物对空气质量的影响以及对气候的潜在反馈影响，研究胁迫下生物源性挥发性有机化合物的排放非常重要。树木通常会遭受非生物胁迫的综合作用，例如由于干旱或臭氧。尽管对单个压力因素有大量的知识，但对联合压力源的影响却没有太多探讨。本研究旨在调查栎属生物中挥发性有机化合物的排放量和生理参数的变化。 L.在中度至重度干旱下，再加上臭氧胁迫。结果表明，干旱过程中异戊二烯排放减少，而单萜和倍半萜排放增加。我们暴露与100ppb的每日臭氧浓度植物1个小时7 d，这导致更快的气孔关闭（例如，的平均值- 31.3％在平均茎水势- 1兆帕），部分缓解干旱应力效应。在没有臭氧熏蒸的树木中增加的绿叶挥发物中发现了这种证据，表明细胞受到损害。此外，我们观察到（C ₈ H ₈ O ₃）H ⁺的增强臭氧处理后树木中可能对应的水杨酸甲酯排放量。各个植物的压力因素不一定是相加的，大气模型应实施应力反馈回路以研究区域尺度的影响。