Control of Abscission in Cotton Boll Explants with Plant Regulators

Abstract

Summary Efficacy of four plant regulators (each used at two doses i. e. 0.025 and 0.25 mM) applied singly or in combination with abscission accelerator — abscisic acid either distally or proximally or direct to the abscission zone of 1 and 3 day old cotton (Gossypium hirsutum L.) boll explants was studied under controlled laboratory conditions. Naphthalene acetic acid and ascorbic acid each applied either distally or direct to the abscission zone significantly reduced the abscission in explants and these were ineffective or resulted in promotion in abscission when applied proximally. Ascorbic acid used at higher concentration (0.5 mM) promoted explant abscission. All the gibberellic acid treatments promoted abscission. Distal and proximal kinetin treatments enhanced and promoted abscission but applied direct to the abscission zone reduced explant abscission. Ascorbic acid and naphthalene acetic acid each applied along with abscisic acid could erase significantly the promotive effect of abscisic acid on abscission. Kinetin also showed such counteraction when applied along with abscisic acid at the abscission zone. Data suggest ascorbic acid to be playing a regulatory role in the process of abscission.