Senescence Factor & Abscission of Coleus Leaves

Abstract

Sections cut from the petioles of naturally senescent (i.e., old, faded in color, and ready to abscise at a touch) leaves of Coleus blumei. Speeded the abscission of younger debladed petioles on explants. The activity was of the same order of magnitude as that reported by Osborne from senescent petioles of other species. However, no such abscission accelerating activity was found in non-senescent petioles of various defined developmental stages. The results provide evidence against the hypothesis that the previously reported steady decline in auxin activity from progressively more aged Coleus leaves is due to a steady increase in such senescence factor activity.