[Impacts of Cd and Pb pollution on soil microbes in tobacco root zone and on tobacco leaf quality].

A pot experiment was conducted to study the impacts of Cd and Pb pollution on soil microbes in tobacco root zone and the quality of tobacco leaves. The results indicated that the higher concentrations of Cd and Pb in soil, the less soil microbes in tobacco root zone. When the levels of Cd and Pb were < or = 10 and < or = 300 mg x kg(-1), respectively, the individuals of soil microbes decreased acutely. As for the quality indexes of tobacco leaves, the ratios of reductive sugar/nicotine and total-N/nicotine increased, and the main components became disharmony, which was disadvantage for the fragrance forming of tobacco leaves. The K content in tobacco leaves had a negative correlation with soil Cd and Pb concentrations, but a significantly positive correlation with the quantity of potassium bacteria in root zone under Cd pollution. No significant correlation was observed between the K content in tobacco leaves and the quantity of potassium bacteria in root zone under Pb pollution.