Factors Controlling the Retardation of Chlorophyll Degradation during Senescence of Detached Statice (Limonium sinuatum) Flower Stalks

Abstract

Summary Detachment of green, flowering Limonium sinuatum flower stalks stimulated chlorophyll degradation. The loss of chlorophyll, which is regarded as a marker process of senescence, was accelerated when flower stalks were kept in the dark. Exposure of sections of the stalk to continuous white light or to brief red irradiations inhibited chlorophyll degradation. The effectiveness of the brief red i rradiations was similar to that of continuous white light, and could be completely reversed if each red irradiation was followed by a brief far-red irradiation. It is concluded that phytochrome is present in the flower stalks and mediates the retardation of flower stem senescence by light. Treatment of excised flower stalks with cytokinin (BAP) or gibberellin (GA3) significantly retarded the destruction of chlorophyll which occurred in the dark.