Effects of selenium on the growth and nutrient absorption of pakchoi

Effects of selenium on the growth and nutrient absorption in pakchoi(Brassica campestris ssp. chinensis L.)were studied. The results showed that the plant growth was promoted at lower selenite concentration, while it was inhibited at higher selenite concentration. The contents of soluble sugar and reducing sugar in shoots of pakchoi were increased, while those of the sucrose and starch were decreased. The content of cellulose was increased at lower selenite concentrations, but decreased at higher selenite concentrations. The content of protein was decreased at the treatment (Se1.0 mg/L ), but it was increased gradually with the increase of selenite concentration in the solution. The content of total free amino acids was higher than control. The contents of N, Ca, Mg, Mn, Zn in shoots of pakchoi treated with selenite were increased, while those of P, K, S were decreased. Compared to the control, the contents of N, S in roots of plant were increased while those of P、Ca、Mg、Fe、Mn、Zn were decreased at the treatment, but the K content was hardly affected . The content of selenium in either shoots or roots of the plant was positively correlated with the selenite concentration in the solution. Most of the selenium form in plant was organic selenium and the organic selenium invert rates were above 80 percent in all treatments.