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  • Author or Editor: Yoram Mor x
  • Journal of the American Society for Horticultural Science x
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Abstract

Three cultivars of Chrysanthemum × morifolium Ramat. were grown as pot plants in a greenhouse at either normal (15.6°C minimum) night temperature (NNT). or at lower (5.0° minimum and 7.1° average) night temperature (LNT) during the period of flower development. The leaf area index was kept at or above the critical for both groups following original pot-to-pot spacing by a gradual increase in spacing to the final commercial spacing. The LNT plants took longer to become salable plants. Increased spacing for the LNT plants purposely proceeded more slowly, resulting in less average space being occupied per day, so that the total bench space cost per pot was essentially the same for the LNT and NNT plants. Under the above conditions, it was found that dry weight gain per pot at LNT was as great as or greater than at NNT. The quality of the plants, which were harvested when commercially salable, was satisfactory at both LNT and NNT for ‘Mandarin’ and ‘Yellow Mandalay’. The quality of ‘Tip’ was poor at both LNT and NNT. The accumulation of dry matter as a function of photosynthetically active radiation was more efficient at LNT than at NNT.

Open Access

Abstract

Senescence of sweet pea (Lathyrus odoratus L.) flowers was associated with a climacteric rise in ethylene (C2H4) production. Pretreatment for 8 min with 4 mM silver thiosulfate (STS) doubled the vase life of the flowers and enhanced opening of buds on the spike. An overnight pulse at 20°C with 4% sucrose also promoted bud opening. A combined STS and sucrose treatment improved flower quality by promoting bud opening of spikes cut with tight florets, and by delaying floret senescence and abscission in both fresh and stored flowers. Aminooxyacetic acid (AOA) was less effective than STS in extending the vase life of sweet peas.

Open Access

Abstract

The presence of very low concentrations of ethylene had dramatic effects on the opening of cut flowers of rose (Rosa hybrida L.). Depending on cultivar, the rate of opening was unaffected (e.g., ‘Gold Rush’), accelerated (e.g., ‘Sterling Silver’), or inhibited (e.g., ‘Lovely Girl’). The K m for the inhibition of opening of ‘Lovely Girl’ by ethylene was 4 ppb. Flowers of some cultivars (e.g., ‘Royalty’) had an abnormal shape when opened in the presence of ethylene. The effects of exogenous ethylene could be overcome by pretreatment of the flowers with 0.5 μmol silver thiosulfate per stem. No phytotoxicity was observed in flowers treated with 2 μmol per stem. Examination of the kinetics of the ethylene/Ag+ interaction in inhibition of opening of ‘Lovely Girl’ flowers indicated that the Ag+/ethylene interaction was competitive.

Open Access

Abstract

A range of postharvest treatments was applied to cut flowers of the Lily of the Niie, Agapanthus orientalis Hoffmanns cvs, Mooreanus (blue) and Albidus (white), in an effort to improve flower bud opening, vase life, and to reduce floret abscission. Basal treatment of partially opened flowers (2 to 5 florets open) with solutions containing 10–20% sucrose and a bactericide improved bud opening. A 60% to 120% increase in vase life and a substantial reduction in bud abscission (to 20% of the control) was obtained by treating the flowers with the anionic silver-thiosulfate complex (STS) as a basal “pulse” (4 mm Ag+, 3 hr), and spraying the inflorescence with 30 ppm naphthalene acetic acid (NAA) prior to the sucrose pulse. These treatments also were effective in flowers subjected to short-term cold storage (4 days at 1°C).

Open Access