Benzyladenine reversal of abscisic Acid inhibition of growth and RNA synthesis in germinating bean axes.

The effect of benzyladenine on growth, ATP pool size and specific radioactivity, and the rate and amount of RNA synthesis in aseptically cultured axes of Phaseolus vulgaris during the first 24 hours of germination were measured in experiments where the duration of benzyladenine application and its concentration were varied. Maximum promotion of growth (25%) occurs at 10(-5)m benzyladenine. Maximum promotion of RNA synthesis (44%) occurs at 10(-5)m benzyladenine. Benzyladenine has little effect on the size or specific radioactivity of the ATP pool. Benzyladenine can completely counteract abscisic acid inhibition of growth and RNA synthesis, and these reversals are measurable in 2 hours. GA(1) and GA(3) do not promote growth or counteract abscisic acid inhibition of growth in germinating bean axes in these experiments.