Symptoms of programmed cell death in intact and cut flowers of clematis and the effect of a standard preservative on petal senescence in two cultivars differing in flower longevity

Abstract

Clematis is visually a very attractive plant which can be used for cut flowers, provided that proper cultivars are chosen. In this study, the phenomenon of programmed cell death (PCD) was compared in petals of clematis blooming on mother plants in the open field and in cut flowers, in two cultivars with different flower longevity. The dynamics of PCD in petals of field grown plants in the two cultivars were different. In the long flower longevity cultivar the first symptoms of PCD were observed in the flower bud, and in the open flower the process was already advanced. On the other hand, PCD in petals of the short flower longevity cultivar was advanced already in the flower bud. In both cultivars the nuclear degradation started early, but the dynamics were different: in the long flower longevity cultivar 18.6% of the nuclei were degraded in the open flower vs. 68.3% of degraded nuclei already in the flower bud in the short flower longevity cultivar. Senescence processes are intensified in cut flowers. In cut flowers of both cultivars kept in water the process of DNA degradation was much faster than in flowers growing on mother plants. It could be slowed down by the addition of preservatives. The standard preservative of 8-hydroxyquinoline citrate (8-HQC) 200mgL−1 with 2% sucrose prolonged the vase life of cut flowers of both cultivars as compared to water, but organelle degradation in petals was delayed only in the shorter-lived cultivar.