Combined Effect of 6-Benzylaminopurine, Gibberellic Acid, and 3- Indoleacetic Acid on the Expansion of Isolated Pumpkin Cotyledons

Abstract

The effect of 6-benzylaminopurine, gibberellin, and 3-indoleacetic acid, used separately or in combinations, on the expansion of isolated pumpkin cotyledons has been studied. All three types of phytohormones can promote the expansion of isolated cotyledons. The resulting effect depends on the concentration of the particular phytohormone and on its quantitative ratio with the other phytohormones. The optimum combinations of phytohormones introduced externally varied according to the seed. The stimulating effect on the expansion of cotyledons is evidently exerted by those phytohormones which are present in the seeds in minimum amounts. An analysis of the concentration curves of the phytohormone effect indicates that they are not interchangeable as regards their influence on the expansion of isolated pumpkin cotyledons.