Considerations for evaluating flower abscission in potted plants with multiple inflorescences-Plectranthus as a case study

The ability to protect plants and flowers from the adverse affects of ethylene and sub-optimal transport conditions relies on a thorough understanding of the environmental triggers and subsequent downstream physiological and molecular processes that result in senescence or abscission. Characterising abscission is the essential starting point in this process. In this study we explore additional measures of abscission that provide insight into differential abscission patterns where open flowers or unopened buds are preferentially shed. We examine equations relating to the proportion of open or unopened flowers shed, as well as those that are available for abscission using simulated data. To test these equations, two varieties of potted Plectranthus were subjected to continuous darkness or placed under fluorescent lights. After 96 h, abscission data was calculated using equations. Cultivar P000603 was found to preferentially shed open flowers in both conditions, as indicated by differences in the number of open flowers abscised as a proportion of the total available for abscission. Cultivar P010509 shed open and unopened flowers at similar proportions. These additional measures of abscission enlarge our understanding of this intricate process by providing a more comprehensive and thorough approach to evaluate abscission.