TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liege, Gembloux, Belgium.
Institut de Recherche en Biologie Végétale, Université de Montréal, 4101 Sherbrooke Est, Montréal, QC H1X 2B2, Canada.
Ecol Lett. 2021 May;24(5):984-995. doi: 10.1111/ele.13713. Epub 2021 Mar 11.
The resource availability hypothesis predicts that plants adapted to infertile soils have high levels of anti-herbivore leaf defences. This hypothesis has been mostly explored for secondary metabolites such as phenolics, whereas it remains underexplored for silica-based defences. 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 defences, whereas old, phosphorus (P)-impoverished soils favoured silica-based defences. Both defence types were negatively correlated at the community and individual species level. Our results suggest a trade-off among these two leaf defence strategies based on the strength and type of nutrient limitation, thereby opening up new perspectives for the resource availability hypothesis and plant defence research. This study also highlights the importance of silica-based defences under low P supply.
资源可用性假说预测，适应贫瘠土壤的植物具有高水平的抗草食性叶片防御。这一假说主要针对次生代谢物（如酚类）进行了探讨，而对于基于硅的防御机制则研究较少。我们测定了在 Jurien Bay 年龄序列中生长的植物的叶片总酚和硅（Si）浓度，该序列展示了土壤肥力的极端梯度。我们发现，年轻土壤中的氮（N）限制导致基于酚类的防御反应更为强烈，而年老、磷（P）贫化的土壤则有利于基于硅的防御。这两种防御类型在群落和个别物种水平上呈负相关。我们的研究结果表明，基于养分限制的强弱和类型，这两种叶片防御策略之间存在权衡，从而为资源可用性假说和植物防御研究开辟了新的视角。本研究还强调了在低磷供应下基于硅的防御的重要性。
