Termination of vase life for cut flowers is characterized by wilting associated with an imbalance developing between water uptake through xylem conduits in stems and water loss through stomata and other structures on leaves and other organs. To
Peitao Lü, Xinmin Huang, Hongmei Li, Jiping Liu, Shenggen He, Daryl C. Joyce, and Zhaoqi Zhang
John M. Dole, Frankie L. Fanelli, William C. Fonteno, Beth Harden, and Sylvia M. Blankenship
Optimum postharvest handling procedures were determined for Linaria maroccana `Lace Violet', Trachelium`Jemmy Royal Purple', and Zinnia elegans `Benary's Giant Scarlet' and `Sungold.' A 24-hour 10% or 20% sucrose pulse increased the vase life of Linaria by 2–4 days, resulting in a vase life of 9 days as compared to 5 days for control flowers held in deionized (DI) water. Use of floral foam and cold storage at 1 °C for 1 week decreased vase life. Treatment with either 0.1 or 1.0 ppm ethylene had no effect. The use of a commercial holding solution (Floralife Professional or Chrysal Professional 2 Processing Solution) or 2% or 3% sucrose increased vase life 4–10 days. For cut Trachelium, ethylene caused florets to close entirely or stop opening; 1-MCP and STS prevented these ethylene effects. Stems tolerated 4 days of 1 °C storage, but 1 week or more of storage reduced the 14-day vase life of unstored flowers to 9 days. Stems in 2% or 4% sucrose had a longer vase life compared to DI water. While the use of floral foam was not detrimental when used with sucrose solutions, it reduced vase life when sucrose was not used. Zinnia stems could not be cold stored for 1 week at 1 °C due to loss of turgidity and cold damage. Stems stored dry at 5 °C regained turgidity and averaged a vase life of 14 days; however, petals remained slightly twisted and curled after being in the vase for several days. Treatment with ethylene had no effect. Floral foam reduced vase life to 9–10 days.
Susan S. Han, Abraham H. Halevy, and Michael S. Reid
Vase life of individual flowers of cut brodiaea (Triteleia laxa Benth.) inflorescences ended 4 days after opening. Best vase life was achieved by harvesting inflorescences 1 to 2 days before anthesis of the first flower and holding them in a vase solution containing 2% sucrose and 200 ppm 8-hydroxyquinoline citrate (HQC). Such inflorescences had a display life of 12 days. Decreasing the pH of the vase solution or pulsing inflorescences with 10% sucrose for 16 hours did not increase their longevity. T. laxa flowers pretreated with 10% sucrose overnight could be stored for up to 2 weeks without significant reduction in vase life.
José J.M. van der Meulen-Muisers and Joop C. van Oeveren
Nongenetic variation in cut flower longevity due to plant characteristics was investigated in whole inflorescences and individual flowers of Asiatic hybrid lilies (Lilium L.). To distinguish this variation from genetic variation, plant characteristics of five cultivars were varied by using bulbs of three significantly different weight classes per cultivar. Inflorescence longevity depended on total number of floral buds, number of buds opening and variation in bud length. Variation in individual flower longevity per cultivar appeared to be small, despite a larger number of buds per stem with increasing bulb weight. Plant characteristics caused only small nongenetic variation in individual flower longevity when compared to inflorescence longevity. Therefore, individual flower longevity appears to be the best criterion to discriminate among longevity levels for a lily breeding program.
William J. Martin and Dennis P. Stimart
On-plant floret longevity and cutflower postharvest longevity (PHL) of Antirrhinum majus L., snapdragon, were evaluated using inbreds P1 (16 day PHL) and P2 (6 day PHL), F1 (P1 × P2), F2 (F1 self-pollinated), F2 × F2 (among and within PHL categories: long, 17 to 25 days; middle, 9 days; and short, 2 to 3 days), and F3 families (F2 self-pollinated). F2 on-plant floret longevity and PHL correlated to later generation PHL. Prediction of progeny PHL from F2 × F2 matings appears feasible if genotypic value for PHL of F2 is known. Selection for PHL is best based on evaluation of multiple cutflowers per genotype. Significant additive and dominant genetic variance components contribute to PHL.
G.A. Picchioni, M. Valenzuela-Vazquez, and L.W. Murray
Lupinus havardii Wats. is a promising new specialty cut flower crop, but data on its greenhouse culture and management are limited. Two experiments investigated senescence-delaying activity of preharvest Ca fertilization and postharvest preconditioning with 1-MCP on L. havardii `Texas Sapphire' cut flower stems (racemes). In the first study, Ca (as CaCl2) was added to the nutrient culture solution at concentrations of 0, 2.5, 5.0, and 10.0 mm for 88 days in a greenhouse. Additional CaCl2 supply did not affect the total number of racemes produced per plant, the average number of flowers per raceme, or the retention of individual flowers on cut racemes over a 7-day vase period. However, Ca concentration in cut raceme tissues, ranging from 5.3 to 7.6 mg·g-1 dry weight, increased linearly with increasing Ca concentration in the nutrient solution, which was accompanied by a linear increase in average fresh weight retention per raceme and individual mature flowers (up to 7% above controls) during the 7-day vase period. In the second study under similar plant culture and vase conditions, 1-MCP applied at harvest resulted in an average fresh weight retention increase of 9% above controls during 7 days in the vase. Equivalent levels of desiccation in control racemes (loss in fresh weight retention) were delayed by 1.5 to 3 days in racemes with the highest Ca concentrations and those that had been preconditioned with 1-MCP. In view of the physiological significance of desiccation in cut flower quality loss, preharvest Ca fertilization and postharvest 1-MCP preconditioning may be useful techniques for delaying senescence and maintaining vase quality of cut L. havardii racemes. Chemical name used: 1-methylcyclopropene (1-MCP)
Susan S. Han
Individual 'Stargazer' flowers lasted about 4.5 to 5 days and weighed ≈14 g. Addition of 2% sugar into the vase solution neither affected the longevity nor the size of the flowers but significantly enhanced anthocyanin content and, thus, the intensity of petal color. Defoliation of Oriental lilies, the common practice of retail florists, did not affect the opening, longevity, and size of the open flowers, but did result in lighter-color petals when placed in a solution without sugar. Addition of sugar to the vase solution counteracted the adverse effects of defoliation on petal color. Sugar in the vase solution did not overcome the increased bud blasting and the reduced longevity and size of flowers induced by cold storage. However, it enabled more flowers to open fully, which, without sugar, remained only partially open. Excised bud experiments revealed that bud size of 6.1 cm and 7.0 cm were critical for opening of non-cold-stored and cold-stored buds, respectively. Unlike other cut flower species in which flowers for long-term storage or long-distance transport are harvested at a tighter-bud stage than those intended for the local market, in 'Stargazer', harvesting of stems where the smallest bud is >7.0 cm would be critical in reducing cold-storage-induced bud blasting.
Robert H. Stamps and Richard T. Poole
Effects of repeated applications of preemergence herbicides (alachlor, metolachlor, oxadiazon, and simazine) at 1 ×, 2 ×, and 4 × rates to leatherleaf fern [Rumohra adiantiformis (Forst.) Ching] beds were studied. During the first two years of bed establishment, all herbicides reduced weed coverage compared to commercial practice (hand-weeding 3 times per year), but only simazine and oxadiazon suppressed weed coverage to commercially acceptable levels between hand-weedings. In year 3, when the fern beds had become well-established, all herbicide treatments provided adequate weed suppression. Simazine was phytotoxic to the fern and reduced yield. Metolachlor increased rhizome mortality compared to commercial practice. Herbicide and weed-free treatments had no effect compared to commercial practice on frond fresh and dry weights or postharvest water uptake and longevity of cut fronds. Chemical names used: 2-chloro-N-2,6-diethylphenyl)-N-(methoxymethyl)acetamide (alachlor); 2 chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor); 3-[2,4-dichloro-5-(l-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon); 6-chloro-N, N′-diethyl-1,3,5-triazine-2,4-diamine (simazine).
William J. Martin and Dennis P. Stimart
Narrow-sense heritabilities and genetic correlations of ornamental quality traits of Antirrhinum majus (snapdragon) were evaluated with special reference to cut flower postharvest longevity (PHL). Inbreds P1 (16 days PHL) and P2 (3 days PHL) were hybridized to produce an F1 (P1 × P2) that was self-pollinated to produce an F2 population. The F2 were self-pollinated to produce F3 families and advanced through single-seed descent by self-pollination to the F5 generation. P1, P2, F1, F3, F4, and F5 were evaluated for ornamental quality traits. Quality traits were found to be quantitative and normally distributed. Narrow-sense heritability (h2) estimates were high and consistent across generations examined; PHL h2 ranged from 0.79 to 0.81 ± 0.06. Phenotypic and genotypic correlations revealed underlying physiological and pleiotropic interactions relevant to breeding programs aimed at simultaneous improvement of ornamental quality traits. PHL is inversely related to cut flower strength and days to flower, -0.44 ± 0.04 and -0.43 ± 0.44. Buds at discard is positively correlated to cut flower and plant diameter, cut flower weight and days to flower, 0.77 ± 0.05, 0.58 ± 0.06, 0.71 ± 0.06, and 0.77 ± 0.07, respectively. Gain from selection for quality traits of interest can be rapid.
Jaime A. Weber, William J. Martin, and Dennis P. Stimart
Progeny of 158 F5 × F5 crosses of Antirrhinum majus (snapdragon) selected within and among cut flower postharvest longevity (PHL) categories (long = 12.6-16.8 days, middle = 9.3-12.1 days, and short = 4.8-8.9 days) were evaluated for PHL and quality traits. Results were compared with previous studies involving F2 × F2 progeny, and F3, F4, and F5 inbred lines. Heritability of PHL in F5 × F5 progeny (0.77 ± 0.11) agrees with that of inbred lines (0.79 to 0.81) but is higher than in F2 × F2 progeny (0.41). Therefore, selection for increased PHL should progress more rapidly and predictably through application of inbred lines rather than F2 individuals. Significant differences between F5 × F5 progeny PHL categories confirm PHL is heritable with a significant additive component. Heritabilities of quality traits in A. majus are high, suggesting selection for quality traits should progress without difficulty. Phenotypic and genotypic correlations of PHL with quality traits are not consistently significant across PHL studies in A. majus. Discrepancies between studies suggest most traits may not be correlated to PHL or are subject to strong environmental influence.