Effects of nutrient solutions supplemented with sodium selenite on the selenium enriched effect of Lettuce in hydroponics

With Italian lettuce（ Lactuca ativa L. var. ramosa Hort.）， the effect of nutrient solutions supplemented with 0.25， 0.5， 1.0 and 2.0 mg/L different concentrations of sodium selenite on the selenium enriched effect of lettuce in hydroponics was studied. The results showed that supplying sodium selenite to the nutrient solutions with the final concentration of 0.5 mg/L significantly increased contents of organic selenium 10 times of the control， the plant height by 25.9%， vitamin C content by 20.4% and total phenolics by 29.5% compared with the control in lettuce leaves. There was no significant effect on the single plant weight， content of chlorophyll， protein and cellulose. supplying sodium selenite with the final concentration of 2.0 mg/L significantly inhibited the plant growth by 48%， but increasing the total phenol sharply by 215.2% compared with the control in lettuce leaves.