Additive and non-additive responses of seedlings to simulated herbivory and drought data

Drought is a global threat, increasing in severity and frequency throughout tropical ecosystems. Although plants often face drought in conjunction with biotic stressors, such as herbivory or disease, experimental studies infrequently test the simultaneous effects of drought and biotic stress. Because multiple simultaneous stressors may have non-additive and complex effects on plant performance, it is difficult to predict plant responses to multiple threats from research examining one stress at a time. Using an experimental approach in the greenhouse, we investigated potential non-additivity in seedling growth and survival to simulated drought and herbivory across a phylogenetically diverse pool of ten Hawaiian plant species. Overall, seedlings showed limited tolerance, defined as similar growth and survival in stressed compared to control (non-stressed) plants, to simulated herbivory and drought, with the combined effects of both stressors to be generally additive and negative across sp...

干旱是一种全球性威胁，在热带生态系统中其严重程度与发生频率正不断加剧。尽管植物常同时遭遇干旱与生物胁迫因子（biotic stressors），诸如植食胁迫（herbivory）或病害，但现有实验研究极少同时检测干旱与生物胁迫的联合效应。由于同时施加的多重胁迫可能对植物表现产生非加性效应（non-additive effects）与复杂影响，仅通过单一胁迫的相关研究，难以预测植物对多种威胁的响应模式。本研究采用温室实验方法，针对由10个系统发育多样性丰富的夏威夷植物物种组成的类群，探究了模拟干旱与植食胁迫对幼苗生长及存活的潜在非加性效应。总体而言，幼苗对模拟植食胁迫与干旱的耐受能力有限——耐受能力的定义为：胁迫组与对照（非胁迫）植株的生长及存活水平无显著差异——且两种胁迫的联合效应在多数物种中整体呈现加性效应（additive effects）的负面影响，相关研究结果暂未完全呈现。