The postharvest quality of regal pelargoniums [Pelargonium × domesticum 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-1 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.
Phytophthora parasitica was transmitted within 6 weeks from vinca (Catharanthus roseus) plants growing in infested potting mix, on the drain end of ebb-and-flow benches, to plants in noninfested potting mix. Transmission of Phytophthora was very low when potting mix was not pasteurized. When potting mix was steam pasteurized, infection of plants, disease incidence, and severity increased with time and decreased with distance from plants in infested pots. The cultivar Pretty in Pink was more susceptible to infection by P. parasitica than cv. Peppermint Cooler, allowing more rapid and severe disease development as well as pathogen dissemination and transmission. Pot spacing did not significantly affect transmission of P. parasitica on an ebb-and-flow bench.
Shoot tips from in vitro cultures of Veronica spicata L. ‘Red Fox’ were grown on modified Woody Plant Medium containing one of 3 cytokinins or cytokinin plus NAA. Of the 3 cytokinins tested (BA, kinetin, and 2iP), BA was the most effective stimulator of axillary shoot growth. The greatest number of shoots greater than or equal to 5 mm in length was produced on medium containing 8 μM BA plus 0.01 μM NAA, whereas medium containing 2 μM BA plus 0.01 μM NAA produced the greatest number of shoots greater than or equal to 10 mm. Shoots were rooted and established at an 80% rate in a soilless medium under high humidity. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); 1-naphthaleneacetic acid (NAA).
Tissue-cultured plugs of Nandina domestica Thunb. `Hat-hour Dwarf' and `San Gabriel' were grown in 1.5-liter pots under 30%, 47%, or 62% shade. After 20 weeks, plants were moved to a simulated consumer environment (SCE) maintained at 21C, ≈60% relative humidity, and a 12-hour photoperiod with an irradiance of 7 μmol·m -2·s-1. Final quality ratings (after 35 weeks in the SCE) for both cultivars were good, but the plant quality of `San Gabriel' declined more quickly than that of `Harbour Dwarf'. Final quality rating of `Harbour Dwarf' grown under the highest percentage of shade was higher than that of plants grown under 30% or 47% shade; production shade percentages had no influence on the final quality rating of `San Gabriel'. Plants (of both cultivars) grown in 0.6-liter (11-cm-diameter) pots were test-marketed through six supermarket floral departments and captured 16% of total 10- to 11-cm-size foliage plant sales. Sixty percent of consumers indicated the plant's “newness” as the primary consideration for its purchase. These two N. domestica cultivars could be marketed successfully as interior foliage plants.
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