Climate warming and plant biomechanical defences: Silicon addition contributes to herbivore suppression in a pasture grass

摘要: Plants, notably the Poaceae, often accumulate large amounts of silicon (Si) from soil. Si has multiple functional roles, particularly for alleviating abiotic and biotic stresses (e.g., defence against herbivores). Recent evidence suggests that environmental change, including temperature changes, can diminish accumulation which could affect functions such as herbivore defence. Using a field warming experiment, we grew pasture grass (Phalaris aquatica) was either supplemented or untreated with (+Si −Si, respectively) under ambient elevated (+2.8°C above ambient) air temperatures. We quantified soil water, plant growth rates, accumulation, leaf biomechanical properties in situ relative rates herbivorous global insect pest (Helicoverpa armigera). supplementation promoted shoot root biomass by c. 48% 61%, respectively temperatures, but these gains were not apparent warmed conditions. Warmer temperatures reduced uptake −Si plants 17%, potentially due to lower levels water content plots. supplementation, however, increased leaves 24% plots restoring those seen enhanced leaves, this only statistically significant temperatures; +Si required 42% more force fracture 30% tougher at midrib than plants. The H. armigera declined 56% when feeding on while caused trend towards declining warmer conditions, significant. conclude climate may mitigate beneficial effects Phalaris aquatica short term, reducing uptake. While be restored Si‐enhanced defences fully A plain language summary is available article.