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- High production temperature increases postproduction flower longevity and reduces bud drop of potted, miniature roses ‘Meirutral’ and ‘Meidanclar’Publication . Monteiro, José; Nell, Terril A.; Barrett, J.The effect of two temperature regimes (29 °C day/24 °C night and 24 °C day/18 °C night) and of a 4-hour night interruption, during production, was studied on postproduction flower longevity and bud drop of ‘Meirutral’ and ‘Meidanclar’ potted, miniature roses (Rosa L. sp.). High production temperatures increased postproduction flower longevity and decreased postproduction bud drop. In ‘Meidanclar’, the high production temperature increased incidence of malformed flowers. No effects of night interruption could be shown on either postproduction flower longevity or bud drop.
- Bougainvillea post-production: NAA and STS control of bract abscission is subject to exogenous ethylenePublication . Gago, Custódia; Monteiro, José; Rodrigues, M. H.The effect of NAA (500 mg.L-1 sprayed once at end-of-production), STS (0.4 mM sprayed every 15 days after bracts started to be apparent) and STS+NAA on plants exposed or not to exogenous ethylene (from ethephon), were tested using two completely randomized experiments. At the end-of-production plants were placed for three days under simulated transport conditions (17 +/-1 degreesC, no light) and then, placed under interior conditions (21 +/-1 degreesC and 11 mu mol.m(-2)s(-1) of cool white fluorescent light 12 hr a day). Twice a week, during postproduction (PP) the number of developing (D) bracts as well as the number of completely developed (CD) bracts remaining in the plants were assessed. Among the treatments tested, NAA was enough to reduce CD bract abscission during post-production, abscising at day 32 PP, a maximum of 50% of the bracts, provided that no exogenous ethylene was present. If plants were exposed to exogenous ethylene, then the treatment STS + NAA was needed to reduce bract abscission, abscising at 32 PP a maximum of 58% of CD bracts. At this time, plants treated only with STS had abscised all CD bracts if exposed to ethylene or at least 97% of CD bracts if not exposed to ethylene.
- Exogenous sucrose effects on carbohydrate level, flower respiration and longevity of potted miniature rose (Rosa hybrida) flowers during postproduction.Publication . Monteiro, José; Nell, Terril A.; Barrett, J.The effect of continuous injection of exogenous sucrose on single flower postproduction longevity of attached flowers of potted ‘Meijikatar’ miniature roses was studied. At bud showing color, with sepals starting to unfold, plants were moved to interior conditions and started being continuously injected with a solution of 3% sucrose or distilled water. Carbohydrate levels, flower respiration and single flower longevity were assessed. The method presented some variability in the amounts of solution supplied to the plants. Infusion of exogenous sucrose increased attached miniature rose flower longevity by 1.5 days and also increased flower respiration rate. The higher the uptake rate of sucrose solution the longer the flowers lasted. Exogenously supplied sucrose was consumed by increased respiration and consequently, at day 6 after anthesis, no differences were found in nonstructural carbohydrate levels between water and sucrose treatments. However, stem percent of soluble sugars was higher in the sucrose infused plants, suggesting that exogenous sucrose supply not only served as an extra source of respirable carbohydrates but also released stored carbohydrates to flower respiration. At flower death, leaf soluble sugars and total non-structural carbohydrates were higher in the sucrose infusion treatment and, independently of infusion treatment flower soluble sugars and total non-structural carbohydrates positively correlated with flower longevity.
- Postproduction of potted miniature rose: flower respiration and single flower longevityPublication . Monteiro, José; Nell, Terril A.; Barrett, J.Research was conducted to investigate the relationship between flower respiration and flower longevity as well as to assess the possibility of using miniature rose (Rosa hybrida L.) flower respiration as an indicator of potential flower longevity. Using several miniature rose cultivars as a source of variation, four experiments were conducted throughout the year to study flower respiration and flower longevity under interior conditions. For plants under greenhouse as well as interior conditions, flower respiration was assessed on one flower per plant, from end-of-production (sepals beginning to separate) up to 8 days after anthesis. Interior conditions were 21 ± 1 °C and 50 ± 5% relative humidity with a 12-hour photoperiod of 12 μmol.m–2.s–1 (photosynthetically active radiation). Flower respiration was higher if the plants were produced during spring/summer as compared to fall/winter. ‘Meidanclar’, ‘Schobitet’, and ‘Meilarco’ miniature roses had higher flower respiration rates than ‘Meijikatar’ and ‘Meirutral’. These two cultivars with the lowest respiration rates showed much greater flower longevity if grown during spring/summer as compared to fall/winter. The three cultivars with the higher respiration rates did not show differences in flower longevity between seasons. For plants under greenhouse or interior conditions, flower respiration was negatively correlated with longevity in spring/summer but a positive correlation between these parameters was found in fall/winter. During spring/summer, flower respiration rate appears to be a good indicator of potential metabolic rate, and flowers with low respiration rates last longer.