1. Brakke, M. K., andL. G. Nickell: Secretion of an enzyme from intact cells of a higher plant tumor. Ann. Biol.31, 215–224 (1955).
2. Burström, H.: Studies on the carbohydrate nutrition of roots. Ann. agric. Coll. Sweden9, 264–284 (1941).
3. Constabel, F.: Zur Amylasesekretion pflanzlicher Gewebekulturen. Naturwissenschaften47, 17–18 (1960).
4. Dormer, K. J., andH. E. Street: The carbohydrate nutrition of tomato roots. Ann. Botany13, 199–217 (1949).
5. Gautheret, R. J.: La culture des tissus végétaux. Paris: Masson & Cie. 1959.