Study On The Effects Of Cadmium On Physiological-ecology Characteristics Of Rape And Cadmium Distribution In Soil-rape System

With the development of industry modernization, urban civilization and agriculture modernization, the release of heavy metals into the environment has been accelerating annually. This study concentrated on the physiological characteristics of rape treated by extrinsic cadmium and cadmium distribution in soil-rape system. The growth and accumulation potential ability of cadmium of rape and food safety evaluation on the rapeseed obtained from the rape grown in the soils polluted by cadmium may be concluded in this article.Through water cultivation, the seed germination and seedling growth of rape treated with cadmium have been studied. The results showed that seed germination rate, germination viability and germination index have been promoted (under5 mg·L^-1) and inhibited (above5 mg·L^-1) when treated by cadmium. The curve estimation showed that the correlation between germination index and cadmium concentration was superiority to the relation of germination rate as well as germination viability and cadmium concentration, respectively. The vigour index, total length, bud length, root length, total weight, bud weight and root weight were inhibited by cadmium. The growth of root was inhibited stronger than the growth of bud. The stepwise regress showed that the inhibition of seedling resulted from the inhibition of root. The conductance of rapeseed as well as the mitosis of the cells in rape seedling root correlated significantly with cadmium concentration (0.603** and -0.571**, respectively). The factor analysis disclosed that root length was more sensitive than other indices. Therefore, root length could be perfectly adapted to monitoring cadmium pollution.The study with pot experiment showed that the fresh weight of rape plant and leaf decreased with increasing cadmium concentration, and the decrease of leaf fresh weight resulted in the decreased of whole plant fresh weight. The permeability of cell membrane and content of MDA increased with increasing cadmium concentration. When the concentration of cadmium was 20 mg·kg^-1, cell membrane permeability and MDA content were increased by 29.68% and 15.19%, respectively, compared with the control, and there was a significant correlation between these two indices. When the cadmium concentration was 5 mg·kg^-1, the contents of Chlorophyll a, b and Chlorophyll a+b reached their peaks, and were23.97%, 33.63% and 26.45% higher...