Studies On Phsiological Metabolism Of Arabidopsis Under Exogenous Cadmium And Ethylene

With the rapid development of China, resulting in China’s environmental problem become increasingly serious. Soil heavy metal pollution is more serious environmental pollution a badly impact on human health and agricultural production. In this study, we used model plant Arabidopsis thaliana as materials, studied seed germination, seedling morphology and biomass, antioxidant capacity, H2O2, MDA content and the Cd content and related gene expression on Arabidopsis seedlings, and exogenous ethylene on Arabidopsis morphological and physiological impact on the basis of the Cd stress. We intensively studied the relationship between ethylene and plant resistance to heavy metal stress and in order to improve crop yields, improve the ability of crop to resist to heavy metal stress, reform the heavy pollution soil to provide a theoretical basis.In this paper, the mains results were as follows:1. When the plant were treated Cd alone, the seed germination and seedling root length elongation increased under low concentrations of Cd, however, under high concentrations of Cd they decreased. The seedling biomass and leaf chlorophyll content reduced under Cd treatment; Under Cd stress we applied different concentrations of ethylene on Arabidopsis had a significant inhibitory effect on seed germination, root length, biomass and chlorophyll.2. When the plant were treated Cd alone, the seedlings root apical had strong oxidative stress, and this stress and Cd concentration showed a positive correlation. The CAT, APX, POD and SOD activity in leaves showed decrease under Cd treatment, compared with the control. GR activity was decreased and then increased with the increase of Cd concentration; Under Cd stress we applied different concentrations of ethylene on seedlings, the CAT, APX, POD activity showed a significant growth, while SOD and GR activity decreased, compared with the seedling under Cd stress.3. With the increase of Cd concentration, the content of MDA in leaves and roots of Arabidopsis seedling increased gradually, and had high consistency trend. It was consistent with H2O2content trend in Arabidopsis seedling leaves; Under Cd stress the higher ethylene concentrations could reduced H2O2content in Arabidopsis seedlings. Under Cd stress we applied different concentrations of ethylene on seedlings, the MDA content decreased, easing the membrane lipid peroxidation injury caused by Cd stress on plants.4. When the plant were treated Cd alone, the Cd content in the aerial parts and roots of Arabidopsis seedlings and atatm3, atpdr8gene expression level increased. This increase with Cd concentration was positively correlated. Translocation factor of aerial parts presented decrease and the increase with the Cd concentration increasing; Under Cd stress the low concentration of ethylene could increase the Cd content, but higher concentration of ethylene reduced the Cd content of Arabidopsis seedlings. Ethylene could reduce the Cd translocation factor of Arabidopsis seedlings. Low concentrations of ACC treatment such as2uM, the atatm3and atpdr8gene expression were decreased, and this result was corresponded with Cd translocation factor.5. Under different concentrations of Cd treatment, aco2, acs2and ein3gene expression of Arabidopsis seedlings showed a significant change. The synthesis and signal of ethylene gene expressions were strongest when the seedlings were under60μM Cd treatment; Under Cd stress ethylene synthesis and signal transduction gene regulated by exogenous ethylene and this regulation was positive. They all showed that ethylene involved in plant responses to Cd stress in order to maintain plant normal growth and development.