Herbivores disrupt clinal variation in plant responses to water limitation
Herbivores disrupt clinal variation in plant responses to water limitation
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DOI：
10.1111/1365-2745.14237
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发表时间：
2023-12
影响因子：
5.5
通讯作者：
Aramee C. Diethelm;M. Reichelt;E. G. Pringle
中科院分区：
文献类型：
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作者：
Aramee C. Diethelm;M. Reichelt;E. G. Pringle
植物性状（包括次生代谢产物）的可塑性对植物在逆境条件下的生存和竞争力至关重要。植物有效应对组合胁迫的能力可能会受到生物化学途径、资源可用性和进化历史中的串扰的影响，但这种反应仍然未得到充分研究。特别是，我们知道的很少种内变化，以应对组合的压力，或这种变化是否与压力历史的一个给定的人口。在这里，我们调查的后果相结合的水和植食性压力的植物性状，包括相对生长速度，叶形态和各种措施的植物化学，使用一个共同的花园的萝草。为了研究植物性状平均值和可塑性如何依赖于环境胁迫的历史，从美国大盆地的干旱梯度中收集了实验用种子。然后，我们进行了析因实验交叉水分限制与草食动物。植物通过增加吸收紫外线的次生代谢物的均匀性来单独响应水分限制，通过增加代谢物的丰富性来单独响应草食动物。然而，经历水和植食性胁迫的植物表现出与良好灌溉的对照植物相似的植物化学多样性。这种缺乏可塑性的植物化学多样性的植物经历组合压力与相对生长率的降低。叶化学平均值和可塑性表现出与种源水分亏缺相对应的倾斜变化。紫外线吸收代谢物的总浓度随着种子来源中水分可用性的增加而降低，这是由更高浓度的黄酮醇糖苷驱动的，这些黄酮醇糖苷被假设为抗氧化剂，来自干燥地区的植物。植物来源于干燥的网站表现出更高的可塑性，响应水的限制，增加植物化学的均匀性，黄酮醇糖苷的浓度，但同时草食动物抑制植物响应水的限制，无论种子来源。合成.这些结果表明，气候历史可以影响种内植物化学可塑性，这可能会赋予耐受水分限制，但同时发生的食草动物破坏这种模式。全球变化正在增加压力组合的频率和强度，因此了解种内对组合压力的反应对于预测植物种群的持久性至关重要。
Plasticity in plant traits, including secondary metabolites, is critical to plant survival and competitiveness under stressful conditions. The ability of a plant to respond effectively to combined stressors can be impacted by crosstalk in biochemical pathways, resource availability and evolutionary history, but such responses remain underexplored. In particular, we know little about intraspecific variation in response to combined stressors or whether such variation is associated with the stress history of a given population. Here, we investigated the consequences of combined water and herbivory stress for plant traits, including relative growth rate, leaf morphology and various measures of phytochemistry, using a common garden of Asclepias fascicularis milkweeds. To examine how plant trait means and plasticities depend on the history of environmental stress, seeds for the experiment were collected from across a gradient of aridity in the Great Basin, United States. We then conducted a factorial experiment crossing water limitation with herbivory. Plants responded to water limitation alone by increasing the evenness of UV‐absorbent secondary metabolites and to herbivory alone by increasing the richness of metabolites. However, plants that experienced combined water and herbivory stress exhibited similar phytochemical diversity to well‐watered control plants. This lack of plasticity in phytochemical diversity in plants experiencing combined stressors was associated with a reduction in relative growth rates. Leaf chemistry means and plasticities exhibited clinal variation corresponding to seed source water deficits. The total concentration of UV‐absorbent metabolites decreased with increasing water availability among seed sources, driven by higher concentrations of flavonol glycosides, which are hypothesized to act as antioxidants, among plants from drier sites. Plants sourced from drier sites exhibited higher plasticity in flavonol glycoside concentrations in response to water limitation, which increased phytochemical evenness, but simultaneous herbivory dampened plant responses to water limitation irrespective of seed source. Synthesis. These results suggest that climatic history can affect intraspecific phytochemical plasticity, which may confer tolerance to water limitation, but that co‐occurring herbivory disrupts such patterns. Global change is increasing the frequency and intensity of stress combinations, such that understanding intraspecific responses to combined stressors is critical for predicting the persistence of plant populations.