Data from: A shift from phenol to silica-based leaf defenses during long-term soil and ecosystem development

The resource availability hypothesis predicts that plants adapted to infertile soils have high levels of anti-herbivore leaf defenses. This hypothesis has been mostly explored for secondary metabolites such as phenolics, while it remains underexplored for silica-based defenses. We determined leaf concentrations of total phenols and silicon (Si) in plants growing along the 2-million-year Jurien Bay chronosequence, exhibiting an extreme gradient of soil fertility. We found that nitrogen (N) limitation on young soils led to a greater expression of phenol-based defenses, whereas old, phosphorus (P)-impoverished soils favored silica-based defenses. Both defense types were negatively correlated at the community and individual species level. Our results suggest a tradeoff among these two leaf defense strategies based on the strength and type of nutrient limitation, thereby opening up new perspectives for the resource availability hypothesis and plant defense research. This study also highlights the importance of silica-based defenses under low P supply.

资源可用性假说（resource availability hypothesis）预测，适应贫瘠土壤的植物会演化出高水平的抗草食动物叶片防御策略。该假说的相关研究大多聚焦于酚类等次生代谢物，而基于硅的防御策略仍未得到充分探索。我们对沿200万年朱里恩湾时间序列（Jurien Bay chronosequence）生长的植物开展了研究，该序列的土壤肥力呈现极端梯度差异，并测定了这些植物的叶片总酚与硅（Si）含量。研究发现，年轻土壤上的氮（N）限制会促使植物更多表达酚类防御策略，而古老且磷（P）匮乏的土壤则更有利于硅基防御策略的演化。两种防御类型在群落及物种种级上均呈负相关。我们的研究结果表明，这两种叶片防御策略之间存在基于养分限制强度与类型的权衡关系，从而为资源可用性假说及植物防御研究开辟了全新视角。本研究同时凸显了低磷供应条件下硅基防御的重要性。