Cytokinins in cut carnation flowers. II. Relationship between endogenous ethylene and cytokinin levels in the petals

Abstract

Tentative identification using HPLC and RIA techniques indicated the presence of zeatin-0-glucoside, zeatin, ribosylzeatin, dihydrozeatin, iso-pentenyladenine and isopentenyladenosine in the petals of carnation flowers. Dihydrozeatin is apparently responsible for most of the biological activity.Within the petals most activity was detected in the basal parts which also senesced much slower than the upper parts of the petals. Treatment with AOA extended petal longevity and reduced ethylene production. This was associated with higher cytokinin-like activity in the basal parts of the petals.These higher levels of cytokinins were not observed in the petals of ACC treated flowers or in the detached control flowers. It is suggested that cytokinin transport and/or metabolism may play an important role in regulating ethylene production in cut carnations.

Shoot Regeneration and Agrobacterium-Mediated Transformation of Carnation

“…zeatin and dihydrozeatin have been shown to extend the longevity (Мог et al, 1983;Van Staden et al, 1987;Bossé and Van Staden, 1989), although the results were inconsistent. When very low concentrations of BA were supplied to the vase solution, senescence was even stimulated (Woodson and Brandt, 1991).…”

Effects of 6-benzylaminopurine treatments on the longevity of harvested Grevillea 'Sylvia' inflorescences

“…In contrast, dip application evidently provided sufficient BA onto flowers to increase their inflorescence longevity in vases. Cytokinins reportedly move within flowers, such as from receptacle van Staden et al 1990) or petal base sources (van Staden et al 1987). As BA applied as dips delayed senescence in G. 'Sylvia', it would be of interest to determine whether carnation senescence could also be altered by BA dip-treatment (cf.…”

“…Cytokinin action in plant tissue is dependent upon the type of cytokinin, internal translocation of cytokinins and regulation by other plant growth regulators, such as ethylene and auxin (Mor et al 1983;Cook et al 1985;van Staden et al 1987van Staden et al , 1990. One type of cytokinin occurs naturally in plants and includes zeatin, dihydrozeatin, and isopentenyl adenine.…”

“…Dihydrozeatin is reported to be the most effective cytokinin in prolonging carnation vase life (van Staden et al 1987(van Staden et al , 1990van Staden and Bossè 1989;Bichara and van Staden 1993). BA also delayed carnation senescence (Cook et al 1985).…”

“…Cook et al (1985) found suppression of ethylene production by intact carnation 'Peterson Red' flowers, the stems of which had been placed in a vase solution of 0.02 mM BA, 5% (w/v) sucrose and 300 mg L -1 8-hydroxyquinoline citrate. Van Staden et al (1987) obtained a delay in senescence of carnation 'White Sim' by treatment with the anti-ethylene agent aminooxyacetic acid (AOA). Treated flowers had higher concentrations of cytokinins at their base and lower rates of ethylene production than non-treated flowers.…”