Abstract:

Exogenous silicon (Si) application has been proved to be an effective approach to boost pathological resistance in rice, yet the response mechanism of rice stress defense system to exogenous Si is still lacking in-depth investigation. To study the effects of Si on rice growth, yield, and resistance under blast stress, pot experiments were carried out under the condition of artificial inoculation of blast fungus. The plant height, number of panicles, panicle length, aboveground biomass, and thousand-grain weight were measured. The MDA content and the activities of defense-related enzymes (PPO, CAT, SOD, and POD) in panicles were analyzed. The results showed that the disease index was decreased by 44.47% with Si application. The PPO, CAT, and SOD activities in panicles were significantly increased, the POD activity and MDA content were decreased, and the oxidative stress induced by the rice blast was alleviated. Si remarkably increased the plant height, boosted its vigor, and inhibited the infestation and spread of the blast fungus. Finally, the dry matter weight of the shoot was increased, and the yield was increased by 61.2% compared with that of the infected group. Therefore, Si could effectively enhance rice blast resistance, increase plant vigor, and effectively reduce plant damage by participating in the plant physiological metabolism process.

Key words: rice, rice blast, exogenous silicon, oxidative stress