Impacts of silicon nutrition on growth and nutrient status of rice plants grown under varying zinc regimes

This study has evaluated the effects of Si application on the vegetative and reproductive growth and organ-specific mineral content of rice plants under different Zn supplies. Zinc deficiency (1 A mu g L-1 Zn) significantly decreased vegetative and reproductive growth. These decreases were accompanied by declined Zn and increased Fe contents. Zinc supply up to 50 A mu g L-1 resulted in greater growth, yield and higher tissue (including seed) Zn as well as K+, Ca2+ and B contents of rice plants. Excess Zn (above 50 A mu g L-1) resulted in retarded growth and reduction in P and K+ contents without any significant effects on seed Zn content. Irrespective of Zn treatments, Si application improved all vegetative and reproductive growth parameters. Silicon application increased Zn as well as Ca2+, K+, P and B contents in plants supplied up to 50 A mu g L-1 Zn. In plants supplied with excess Zn, silicon declined Zn content of roots and shoots, while increased plant K+ and Fe contents. Zn supply up to 50 A mu g L-1 promoted the yield and Zn content of seeds. The beneficial effects of silicon nutrition on vegetative and reproductive growth of rice plants supplied up to 50 A mu g L-1 Zn may be related to increased Zn as well as Ca2+, K+, P and B contents of plants. Positive effects of Si in plants supplied with 100 A mu g L-1 Zn might be attributed to reduced Zn and increased K+ and Fe contents.