Cultivation of Excised Root Tips and Stem Tips Under Sterile Conditions

A simple method of growing the isolated meristematic tissue of higher plants, excised root tips and stem tips, under sterile conditions is described. 2. The excised root tips of peas, corn, and cotton make considerable growth in the dark in solution cultures containing mineral salts and glucose or levulose. 3. The excised root tips of peas, corn, and cotton make little growth in the dark in solution cultures containing mineral salts and lacking carbohydrate. 4. The growth of the isolated root tips of peas, corn, and cotton is markedly greater in solution cultures containing glucose than in those containing levulose. 5. The excised roots of corn respond normally to gravity when grown on agar containing mineral salts and glucose. 6. The isolated shoot tips of peas and corn make considerable growth in the dark in sterile solution cultures containing mineral salts and glucose or levulose, but little in the absence of carbohydrates. 7. The excised shoot tips of corn and peas grown in sugar solutions remain chlorotic, and those of peas show the stem elongation and small leaf development characteristic of plants grown in the dark. 8. When the excised root tips of corn are grown for ten days or two weeks in the dark in a solution culture containing glucose and mineral salts, and the tip is then cut off and transferred to a fresh solution of the same type, the amount of growth in the second period is less than that in the first, and ceases in the third period.