The interactive effects of drought and herbivory on ecophysiology of trees In: Combined Stresses in Plants
The interactive effects of drought and herbivory on ecophysiology of trees In: Combined Stresses in Plants
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干旱和食草对树木生态生理学的相互作用影响：植物中的组合胁迫
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发表时间：
2015
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通讯作者：
Sheel Bansal
中科院分区：
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作者：
Sheel Bansal
无论是干旱还是草食都会对树木的生长、生理和生存产生严重的负面影响。当这两种压力源同时发生时，它们对采油树性能的累积影响通常被认为是协同的，即比基于单一压力源的简单累加效应的预期更大。已经发表的关于干旱或草食影响的研究有数千篇，但很少有人测试了它们对树木性能的综合影响的假设。干旱影响了一些减少碳吸收的生理过程，而草食则引发了一些碳昂贵的防御机制。鉴于随着气候变化，干旱事件和草食事件（如虫害暴发）的发生频率和强度预计都将增加，研究这些综合压力因素对树木性能的影响对于预测未来森林健康和生产力至关重要。在一项考虑了这两种压力源的研究中，与假设相反，总体综合影响是拮抗的，因为干旱压力的影响主导了树木的生长和生理，从而超过了食草性的影响。然而，当考虑各胁迫源的相对强度时，在某些植物性状上观察到协同效应。因此，干旱和草食联合胁迫的影响具有性状特异性、强度依赖性和不可预测性。
Independently, either drought or herbivory can have severe, negative impacts on growth, physiology, and survival of trees. When these two stressors occur simultaneously, their cumulative impact on tree performance is often assumed to be synergistic, i.e., greater than expected based on simple additive effects from either stressor alone. There are thousands of published studies on the effects of drought or herbivory, yet very few have tested the assumptions of their combined impacts on tree performance. Drought affects several physiological processes that reduce carbon assimilation, while herbivory elicits a number of carbon-expensive defense mechanisms. Given that both drought events and herbivory (e.g., insect outbreaks) are expected to occur with increased frequency and intensity with climate change, research on the effects from these combined stressors on tree performance is critical for predicting future forest health and productivity. In a study that did consider both stressors, the overall combined impacts were, contrary to assumptions, antagonistic because the effect of drought stress dominated tree growth and physiology, thus outweighing the effects from herbivory. Nevertheless, synergistic effects were observed on some plant traits when the relative intensities of each stressor were considered. Consequently, the impacts from combined drought and herbivory were trait-specific, intensity-dependent, and unpredictable from the effects of single stressors.