Fig. 8

Three strategies are involved in Si enhancement of plant tolerance to high temperatures (43 ± 0.5 °C). In strategy I, Si enhances the antioxidant enzyme activity by both upregulating the expression of antioxidant enzyme genes and reducing the decrease of MDA and O₂⁻ caused by Reactive Oxygen Species (ROS). In strategy II, Si activates the heat shock proteins and drought tolerance genes such as SlDREB2 and SlMAPK1. In strategy III, Si downregulates stress-related hormones, such as ABA and SA