The response of a radiation-induced dwarf bean mutant to gibberellic acid

Abstract

To test the growth response to gibberellic acid (GA) a dwarf mutant induced in bean by gamma irradiation was used. This dwarf mutant is controlled by a simple recessive gene and is characterized by very long shoots and smaller, darker colored leaves than the corresponding parts in normal plants. Weekly applications of aqueous solutions of GA from 1 to 32 ppm were able to convert the dwarf mutant to a normal phenotype. It appears that this dwarf is a GA-deficient mutant. The action of this dwarfing gene is thought to be to completely or partially obstruct the biosynthesis of PA, the production of a GA-like substance necessary for normal growth.