Regulation of Petal Abscission in Pelargonium × domesticum

Abstract

<jats:p>The postharvest quality of regal pelargoniums <jats:italic>[Pelargonium</jats:italic> × <jats:italic>domesticum</jats:italic> L. H. Bailey] is limited by petal abscission. Cultivars that have diverse postharvest longevities were selected to study ethylene sensitivity and endogenous ethylene production. Petals of both intact and detached inflorescences abscised in response to low dosages of exogenous ethylene (0.5 μl·liter<jats:sup>-1</jats:sup> for 1 hour). Ethylene sensitivity varied among cultivars and increased with floret age. Silver thiosulfate reduced ethylene sensitivity and often extended floret longevity beyond that of the controls. A climacteric-like rise in endogenous ethylene production occurred in excised gynoecia (including the receptacle) as floret age increased from 1 to 12 days postanthesis. Ethylene production increased a few days earlier and achieved a higher maximum rate in `Parisienne' than in `Virginia'; `Parisienne' also abscised petals earlier. Relatively low levels of endogenous ethylene may regulate petal abscission, since inflorescences were very sensitive to exogenous ethylene, and increased endogenous ethylene production preceded petal abscission.</jats:p>

Ethylene responsiveness changes in Pelargonium×domesticum florets

“…We have shown previously that ethylene production by the gynoecium/receptacle tissue increased between 6 and 12 days after anthesis (Deneke et al 1990). Therefore, increases in both ethylene production and ethylene responsiveness preceded natural abscission, which was 50% complete at 21 days after anthesis (Deneke et al 1990). This developmental pattern is consistent with the view of ethylene as the natural regulator of abscission in P. x domesticum florets (Deneke et a).…”

Floral Development and Flower Longevity in Rhipsalidopsis and Schlumbergera (Cactaceae)

“…Thus, selection of Rhipsalidopsis and Schlumbergera cultivars with increased flower longevity is feasible. Genotypic differences in flower longevity have been reported in several other floricultural crops, including Dianthus caryophyllus (Wu et al, 1991), Gerbera hybrida (De Jong and Garretsen, 1985;Harding et al, 1981), Pelargonium ×domesticum (Deneke et al, 1990;Evensen and Olson, 1992), and Tulipa (Van Eijk and Eikelboom, 1976). The physiological or genetic basis for diversity within Rhipsalidopsis and Schlumbergera for flower longevity needs to be determined Literature Cited Boyle, T.H.…”

Genetic Variation in Ethylene Responsiveness of Regal Pelargonium

“…Regal pelargonium is classified as one of the ornamental species most sensitive to ethylene (Deneke et al, 1990;Woltering, 1987). All of the regal pelargonium genotypes that we examined responded to ethylene, however, ethylene responsiveness varied signifi cantly among genotypes.…”

“…Flowers of the Geraniaceae are particularly sensitive to ethylene, and species within this family consistently demonstrated petal abscission in response to applied ethylene (van Doorn, 2001;Woltering and van Doorn, 1988). The postproduction quality of regal pelargonium, a fl owering potted plant with extraordinary aesthetic characteristics, is limited by rapid petal abscission within 1 to 2.5 h after treatment with as little as 1 μL·L -1 ethylene (Deneke et al, 1990;Olson and Evensen, 1990). In the absence of exogenous ethylene treatment, petal abscission results from a combination of ethylene synthesis by fl oral parts and increasing ethylene responsiveness during fl ower development (Deneke et al, 1990;Evensen, 1991).…”

“…The postproduction quality of regal pelargonium, a fl owering potted plant with extraordinary aesthetic characteristics, is limited by rapid petal abscission within 1 to 2.5 h after treatment with as little as 1 μL·L -1 ethylene (Deneke et al, 1990;Olson and Evensen, 1990). In the absence of exogenous ethylene treatment, petal abscission results from a combination of ethylene synthesis by fl oral parts and increasing ethylene responsiveness during fl ower development (Deneke et al, 1990;Evensen, 1991). In diploid zonal geraniums (P. ×hortorum L.H.…”