Effects of silicon application on growth improvement and oxidative stress reduction rice plants grown under Zn deficiency

Zinc is essential micronutrient in plants that its deficiency is widespread in Iran. Effects of silicon on alleviation of deficiency or toxicity of some minerals have been reported. In order to evaluation of effects of silicon on mitigation of Zn deficiency on rice plants, experiments carried out in growth chamber or outdoor. Plants cultivated in hydroponics culture with two levels of Zn treatments including 1 and 10 µgL-1 Zn and two levels of Si including 0, 1. 5 mM. The results indicated that weights, lengths and shoot to root ratios of plants decreased Zn deficiency compared to controls; however, Si application increased weights, lengths and shoot to root ratios of plants in Zn-deficient treatment. Zn deficiency to decrease of Zn accumulation in plant led to increase of H2O2 level and lipid peroxidation and decrease of chlorophyll and soluble proteins in plants. On the contrary, Si application increased Zn accumulation in Zn - deficient plants وreduction of H2O2 level following Si application in plants grown under Zn deficiency may indicated decrease of oxidative stress in plants too. As a results, chlorophyll b, carotenoids and xanthophylls, soluble proteins increased in shoot of Zn-deficient plants due to Si nutrition. The Si nutrition increased poly phenol oxidase activity in roots that probably led to increase of lignin in Zn - deficient plants. The results indicated Si application could reduce oxidative stress, chlorophyll and soluble protein depletion of plants grown under Zn deficiency by increase of Zn content that led to better growth of rice plant.