Effects of Cadmium Stress on the Growth and Physiological Characteristics of Flue-cured Tobacco

Effects of cadmium with different concentrations on the growth and activated oxygen-scavenging system of flue-cured tobacco were studied with water culture experiment.The results showed that the growth of tobacco plant was restrained under the cadmium stress,the shoot biomass and root biomass of tobacco declined with the increasing of cadmium stress intensity and the restraining effect became more evidence under higher Cd levels.Low concentration of Cd(8 mg·kg-1) had a promoting effect on levels of the chlorophyll a,chlorophyll b,chlorophyll a+b,carotenoid and activated oxygen-scavenging system,while high concentration of Cd(16 mg·kg-1) had the opposite effect.The correlation analysis of each physiological index and Cd concentration indicated that the Cd concentration showed significantly negative correlation with the root biomass,and very significantly negative correlation with chlorophyll a,chlorophyll b,chlorophyll a+b,carotenoid,SOD and POD activities,while,the very significantly positive correlation was observed between Cd concentration and the content of MDA.The content of MDA was the most sensitive physiological index affecting the growth of flue-cured tobacco under Cd stress.