Effects of Zn Stress on Zn Accumulation and Anti-Oxidant Enzymes Activity in Four Varieties of Ryegrass

We investigated the influence of different content of Zn2+ (0, 2, 4, 8, 16 mmol*kg-1) on plant growth, activities of peroxidase (POD) and superoxide dismutase (SOD), free proline content and Zn accumulation in four varieties of ryegrass (Loliurn perenne L.) by pot culture experiment. The results showed that plant biomass increased at the ranges of 0-2 (Tuoya), 0-4(Yeying), 0-8 mmol*kg-1 (Airuisi and Taide), respectively, and then decreased under excess Zn. The activities of POD, SOD and proline content in shoots decreased firstly, and then increased with the increase of Zn content. The plant biomass, activities of POD and SOD in Taide were evidently higher than in the other three varieties. Root tolerance index (RTI) and Zn transport ratio from root to shoot (S/R) in Taide were exceed 1.0. The maximum of Zn content was 583.9 mg/kg ( at 16 mmol*kg-1) in Taide's shoot.