Stress Oxidative Evaluation on SiK®-Supplemented Castanea sativa Mill. Plants Growing Under High Temperature

The protective effect of silicon (Si) against environmental stress has been observed in many crops. The objective of this work was to evaluate the impact of SiK® (potassium silicate) fertilization on the resilience capacity of chestnut plants growing under high air temperature conditions and their recovery capacity after a turnover to adequate temperatures. Castanea sativa plants were supplied with 0 mM, 5 mM, 7.5 mM, and 10 mM SiK® and exposed sequentially to 25 °C, 32 °C, and 25 °C for 1 month each. Data suggested that silicon are involved in increasing the heat tolerance of chestnut plants by reducing the oxidative damage and improving the antioxidant enzymes and metabolites. Under heat stress (32 °C), there was an increase in the catalase, ascorbate peroxidase, and peroxidase activities, as well as in the phenol content of supplemented plants, which consequently reduced the electrolyte leakage, lipid peroxidation, and hydrogen peroxide content. Additionally, a lower proline content was measured inside the leaves’ tissues of Si-treated plants. Besides the resilience against heat stress, after exposure to 32 °C, the recovery was also quick.