Changes in the Hormonal Status of Young Bolls and Their Abscission Zones in Relation to Boll Retention

Abstract

An experiment was conducted to test the hypothesis that a nutritional stress (shortage of photosynthate) affects the hormonal balance in bolls and their abscission zones. It did. The concentration of indoleacetic acid (IAA) in abscission zones of young bolls decreased and boll shedding increased as competition for photosynthate increased. Water deficit also decreased the IAA content of young bolls and their abscission zones, but greatly increased the concentration of abscisic acid (ABA) a hormone that may increase boll shedding.