Abstract: Low concentration of selenium enhanced, but high concentration inhibited the growth of tomato seedlings, the higher the concentration of selenium, the more the inhibition of the growth was. Selenium was absorbed quickly by roots, and conveyed to the other organs. With prolonged time, the degree of increase in the distribution of total selenium content in the plants was in the orders of roots>leaves>stems. From lower to upper the distribution of selenium in the leaves increased progressively. At the flowering and bearing stage, the orders of selenium distribution were roots>fruits>stems>leaves. Only a part of selenium in the plants existed at the state of inorganic selenium, and most changed into organic selenium, and the majority of it was in the form of selenoproteins. 90.89% of its selenoproteins was found in the fruits which was more than that of the other organs of plants. Sulfur starvation enhenced the absorption and transportation of selenium from roots,accelerated the distribution of selenium in the leaves ,and increased the organic selenium content in the roots ,stems and fruits.

Key words: omato, Selenium, Sulfur starvation