Abscission zones: cellular interfaces for the programmed separation of organs

Abscission zones are specialized sites where plants shed organs, such as leaves, petals, or fruits, in response to developmental or environmental signals. These zones form at predictable locations and, once activated, undergo structural and physiological changes that detach the organ and seal the exposed area. During crop domestication, plants that retained ripe fruit or seeds were selected, and abscission traits still influence crop yield and quality today. This article reviews the stages of abscission zones development: initiation, competence, separation, and sealing. We combine insights from classic structural and physiological studies with modern genetic and molecular research, focusing on two plant species: Arabidopsis thaliana as a model for floral organ abscission and Solanum lycopersicum as a model for fleshy fruit development. These studies show that abscission is a conserved but flexible developmental process. We conclude by exploring how these findings are being applied to improve abscission traits in modern agriculture.