Effect of gibberellic acid on length and number of epidermal cells in petioles of strawberry.

Abstract

INCREASE in height is perhaps the most widely observed effect of gibberellic acid on plants. This is mainly due to longer internodes, and not to a larger number of nodes. The increased length of an internode has been variously ascribed to increases in numbers of cells, increases in length of cells and to both. Stowe and Yamaki1, reviewing earlier (especially Japanese) work, conclude that “cell elongation in most cases seems to predominate as the result of gibberellin application”. Since then Greulach and Haesloop2 could find no significant increase in size of cell when the lengths of internodes of Phaseolus vulgaris were increased by a mean of 2.28-fold by the application of gibberellic acid. They concluded that cell division had been promoted. Further information is clearly desirable. In the strawberry plant, height is determined mainly by the length of the leaf petioles. The results presented in this communication show that increases in length of petiole brought about by the application of gibberellic acid involve increases both in the number and the length of cells in the epidermis.