Allium Root Tips Research Articles

THE INFLUENCE OF CERTAIN DUCTLESS GLAND SUBSTANCES ON THE GROWTH OF PLANT TISSUES

1. Growth of root-tips of Allium is retarded by the presence in their fluid nutrient environment of thyroid gland material. Retardation is approximately in direct proportion to the amount of thyroid substance present.2. The presence of thyroid materials in the nutrient fluid in which Allium is sprouting does not modify the growth of the early leaves.3. Iodine, used as KI, in amounts equivalent to that in thyroid substances provoking marked modifications of growth, has no appreciable effect on growing root-tips.4. Pituitary substances up to two grains of the desiccated gland, and supra-renal substances up to one grain of the desiccated gland in 120 c.c. of nutritive solution have no effect on the growing root-tips of Allium.5. While no general conclusion can be based on experiments limited to a single form, the indication is that thyroid constituents may influence the rôle of protoplasmic action in cells other than those of animal tissues.