Cytokinins in cut carnation flowers. IX. Transport and metabolism of iso-pentenyladenine and the effect of its derivatives on flower longevity

Abstract

Of the four 2iP derivatives applied to cut carnations 2iP, IPA and IPAMP delayed the rate of flower senescence but did not delay longevity . 2iP9G was the least effective . ['H]2iP was rapidly transported to all flower components . The receptacular tissue apparently plays a major role in the distribution of the applied cytokinin to the rest of the flower parts . Over and above possible interconversion between 2iP, IPA and IPAMP the applied [' H]2iP was also converted to 2iP9G, Ade, Ado, tZ and DHZ . The presence of Ade indicates the involvement of cytokinin oxidase-type enzymes while the presence of tZ and DHZ indicates a degree of hydroxylation . These latter steps may contribute to the efficiency of 2iP in the system .

Endogenous cytokinins in rose petals and the effect of exogenously applied cytokinins on flower senescence

“…Interconversions between the cytokinins, such as transhydroxylation of 2iP-type cytokinins to Z-type cytokinins common in higher plants [9], may occur during rose flower development. This was observed by Van Staden and co-workers [19] in carnation flowers during vase-life.…”

An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

“…4C), suggesting that different pathways may function in CTK accumulation in rose petals as a consequence of tRNA degradation. In carnation flower, among iso-pentenyladenine derivatives, iPA was most abundant during flower senescence, and application of iPA delayed the onset of flower senescence (van Staden et al, 1990). It suggests that iPA may play an important role in flower senescence.…”

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).…”