EFFECT OF GIBBERELLIC-ACID AND INDOLE-3-ACETIC-ACID ON GROWTH AND DIFFERENTIATION OF CULTURED EAR INFLORESCENCES OF MAIZE (ZEA-MAYS L)

In order to explore the involvement of gibberellins and auxins in the development of maize ears, immature ear inflorescences were cultured in defined liquid media containing different concentrations of gibberellic acid (GA3) and indole-3-acetic acid (IAA). The overall growth of the youngest ear promordia (5.1-10.0 mm long) was inhibited by higher concentrations of GA3. A negative relationship between growth and increasing GA3 concentration was demonstrated for young ear primordia. Growth of large ears (10.1-15.0 mm long), however, was stimulated slightly by increasing concentrations of GA3. Expert at the lower concentrations of GA3, female flowers overwhelmingly predominated. Growth of older meristems (10.1-15.0 and 15.1-20.0 mm long) was inhibited at higher concentrations of IAA. IAA promoted the maturation of female flowers in the developing ears but to a less consistent degree than GA3. © 1990.