Short‐term exposure to silicon rapidly enhances plant resistance to herbivory

Silicon (Si) can adversely affect insect herbivores, particularly in plants that evolved the ability to accumulate large quantities of Si. Very rapid herbivore-induced accumulation Si has recently been demonstrated, but level protection against herbivory this affords remains unknown. Brachypodium distachyon, a model hyperaccumulating grass, was exposed chewing herbivore, Helicoverpa armigera, and grown under three conditions: supplied over 34 d (+Si), not (−Si), or once began (−Si → +Si). We evaluated effectiveness each treatment at reducing herbivore performance measured Si-based defenses phenolics (another form defense often reduced by Si). Although concentrations remained lower, within 72 h exposure Si, −Si +Si were as resistant plants. Both treatments damage growth, increased mandible wear compared −Si. After 6 h, filled cell density plants, 24 reached similar densities although decreased only occurred demonstrate with short-term rapidly antiherbivore effectively long-term exposure.