Abstract: In order to study the biological effects of exogenous selenium on tomatoes in substrate cultivation conditions, sodium selenium was used as the selenium source, and the selenium concentrations were set to 0 (CK), 0.25, 0.50, 1.00, 2.50, 5.00, 10.00, 20.00, 40.00 and 80.00 μmol ·L^-1, respectively. Effects of exogenous selenium on tomato biomass, yield, quality, selenium accumulation, transport and accumulation of other mineral elements in various organs were studied. The results indicated that the above-ground dry matter content of 0.25, 1.00 and 5.00 μmol·L^-1 treatments were higher than other treatments, and below-ground dry matter content of 1.00 and 5.00 μmol·L^-1 treatments were lower than that of 0.50 μmol·L^-1 treatment and higher than that of 0.25 μmol·L^-1 treatment. Contents of vitamin C (V_C) and soluble sugar of 40.00 μmol·L^-1 treatment were the highest, and nitrate content of 40.00 μmol·L^-1 treatment was second to 80.00 μmol·L^-1 treatment. Contents of V_C, soluble sugar and nitrate of 0.25 and 5.00 μmol·L^-1 treatments were second to the 40.00 μmol·L^-1 treatment. Nitrate content of 0.50 μmol·L^-1 treatment increased by 21.52% compared with control group. Except 20.00 μmol·L^-1 treatment, sugar-acid ratio of other treatments were higher than that of CK. Yield of 5.00 μmol·L^-1 treatment was significantly higher than those of other treatments. However, the yields became lower than CK when the concentration of Se was higher than 10.00 μmol·L^-1. Selenium application promoted the accumulation and transport of selenium in tomato organs. Selenium accumulation in fruits increased exponentially with the increase of exogenous selenium concentration. Leaves of tomato exhibited the strongest capacity of selenium transport while fruits had the weakest. Contents of N and Ca in tomato of 5.00 μmol·L^-1 treatment were significantly higher than those of other treatments, which increased by 10.75% and 295.20% respectively compared with CK. Content of P in tomato of 1.00、2.50、5.00 and 10.00 μmol·L^-1 treatments were significantly higher than those of other treatments. Selenium application promoted the absorption of Mg (except 10.00 μmol·L^-1 treatment) and iron (except 20.00 μmol·L^-1 treatment). Appropriate selenium concentration could increase plant dry matter content, improve quality, increase yield and promote mineral element absorption. In the production of selenium-enriched tomatoes, we suggested to apply the concentration of 5.00 μmol·L^-1 selenium to increase the yield and quality.

Key words: tomato, selenium, biomass, mineral element, yield