Sim-type carnation flowers (Dianthus caryophyllus L., cv. Elliot's White) continuously treated with 50 mM or 100 mM 3-amino-1,2,4-triazole (amitrole) and held in the dark at 18°C did not exhibit a respiratory climacteric relative to dH2O-treated controls. No morphological changes symptomatic of floral senescence appeared in treated flowers until 12-15 days post-harvest. Other triazoles were not effective in prolonging senescence. Amitrole appears to inhibit ethylene biosynthesis by blocking the enzyme-mediated conversion of S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylate. Ethylene action appears to be progressively inhibited in that flowers held in treatment solution for 2 d or less responded to application of 10 uL/L exogenous ethylene whereas flowers held 10 d or longer exhibited no response. Electrophoretic resolution of total crude extracts evidenced protein synthesis as well as degradation. Western analysis and total activity assays showed an amitrole concentration-specific inhibition of catalase activity.
A floral preservative solution containing iso-ascorbic acid, 100 ppm, sucrose, 4%, and 8-hydroxyquinoline sulfate, 50 ppm, extended cut rose life and was equal to other preservative formulations for carnations and snapdragons. Biochemical and other changes in rose petals resulting from the use of this preservative solution are described.
Regardless of their maturity at harvest, the vase life of cut inflorescences of the hybrid Limonium `Fantasia' placed in deionized water was 4 to 5 days. A vase solution containing Physan (a quaternary ammonium disinfectant solution) at 200 μl·liter–1 and 20 g sucrose/liter not only prolonged the longevity of individual florets but also promoted bud opening so that the vase life of cut inflorescences extended to 17 days. Pulse treatment with 100 g sucrose/liter in combination with Physan at 200 μl·liter–1 for 12 hours partially substituted for a continuous supply of sucrose. Including 30 mg gibberellic acid/liter in the vase solution was without benefit.
Optimum pruning height for cut foliage production was investigated for 3-year-old trees of Eucalyptus globulus Labill. Trees cut at a height of 1.0 m above ground level had most stems resprouting from the trunk, but a pruning height of 0.5 m produced the longest stems. Postharvest trials were conducted to assess the vase life of cut stems, and the effect of pulsing and simulated transportation on vase life. Holding solutions containing 1% or 2% sucrose and 8-HQC at 200 mg·L–1 significantly increased vase life of E. globulus and E. cinerea F. Muell. ex Benth. over the control, but pulsing E. cinerea in 1%, 5%, or 10% sucrose plus 8-HQC for 2 hours at 24 °C or 24 hours at 3 °C had no effect. In simulated transport trials, pulsing overnight in 1% or 5% sucrose plus 8-HQC at 3 °C followed by 1 week dry storage at 3 °C had no effect on the vase life of cut stems of E. sideroxylon Cunn. ex Wools., E. platypus Hook., E. spathulata Hook., E. cladocalyx F. Muell. E. platypus, or E. spathulata E. sargentii Maiden, but a 5% sucrose pulse plus 8-HQC significantly increased the vase life of E. spathulata E. platypus. A long pulse at low temperature (24 hours/3 °C) followed by 1 week dry storage was more effective than a short pulse at high temperature (2 hours/24 °C) for E. albida Maiden & Blakely stems and no sucrose was more effective than 1% or 5%. Thus, a pruning height of 0.5 or 1.0 m was optimum for cut foliage production of E. globulus, and a 2% sucrose holding solution extended vase life. There was no advantage of sucrose pulsing to extend vase life, or to improve vase life following dry storage, except for the hybrid E. spathulata E. platypus. Chemical name used: 8-hydroxyquinoline citrate (8-HQC).
Splitting and out-rolling of the stem bases in cut flowers of Hippeastrum Xhybridum was prevented by a 1-day-pulse treatment with 0.125 m sucrose. Pulsing also slightly increased vase life and promoted the opening of all the flower buds on the stem.
Big Bend bluebonnet (Lupinus havardii Wats.) is native to a narrow geographic range in southwestern Texas and produces attractive blue inflorescences (racemes) that may be used as cut flowers. Several crops were produced in the greenhouse to determine postharvest-characteristics of the cut inflorescences. Without any postharvest conditioning treatments, the inflorescences held in water had an average vase life of about 7 days. During this period, an average of 13 flowers abscised per inflorescence. When preconditioned for 4 hours in 40 to 160 mg·liter−1 silver thiosulfate (STS), vase life increased to 10 to 12 days and fewer than three flowers abscised per inflorescence. A commercial floral preservative (Oasis) had no effect on flower abscission or vase life of STS-treated inflorescences. Flower abscission and vase life were the same whether STS-treated inflorescences were placed in floral foam moistened with water or in water alone. Storing STS-preconditioned inflorescences in water at 5C for 72 hours did not affect flower abscission or vase life compared to the unstored control. Dry postharvest storage at 5C for 72 hours caused noticeable wilting, but, on dehydration, these inflorescences still had a vase life of about 8 days. Postharvest characteristics of pink-and white-flowered breeding lines were the same as for the blue-flowered line. These results indicate that cut inflorescences of L. havardii have desirable postharvest qualities and can be stored for up to 72 hours without seriously limiting vase life.
The effects of pH, osmolarity, and oxygen content on solution uptake by cut flowers of Rosa hybrida L. cvs. Cara Mia and White Satin were investigated. Solution uptake was increased at low pH (below 3) while high pH (above 6) inhibited uptake; both effects were amplified with time. Solution uptake was altered by the composition of the buffer. Maximum vase life was achieved with pH 5 solutions. The rates of uptake of various floral chemicals correlated well with the pH values. Mannitol and high concentration of sucrose significantly inhibited total solution uptake but potassium chloride did not inhibit uptake. Deoxygenated solutions were taken up 45% more rapidly during the first 2 hours, but oxygen content had no significant effect on total uptake after 72 hours. High rates of solution uptake do not seem to be required for extension of cut rose vase life.
The respiration of cut flowers of gerbera (Gerbera jamesonii H. Bolus ex Hook.f. `Vesuvio') and sunflower (Helianthus annuus L.) increased exponentially with increasing storage temperature. Poststorage vase life and negatively gravitropic bending of the neck of the flowers were both strongly affected by simulated transport at higher temperatures. Vase life and stem bending after dry storage showed highly significant linear relationships (negative and positive, respectively) with the rate of respiration during storage. The data indicate the importance of maintaining temperatures close to the freezing point during commercial handling and transport of these important commercial cut-flower crops for maximum vase life.
Leaf yellowing of Alstroemeria hybrida L. `Rio' and `Jacqueline', as measured by sphere spectrocolorimetry, was significantly delayed in vase life studies when the ends of cut stems were immersed in solutions of BAP or GA3 immediately following harvest. When BAP or GA3 was used alone at 50 mg·liter-1, foliage color and color intensity did not diminish during 14 days of storage in tap water. BAP and GA3 also showed interaction effects on leaf color, but little was gained by using combinations of chemicals. Chemical names used: 6N-benzylaminopurine (BAP); gibberellin (GA3).
Four spunbonded crop covers were evaluated for use with and without irrigation for cold protection of leatherleaf fern [Rumohra adiantiformis (Forst.) Ching]. Heavier and less porous covers provided the most protection when used without over-the-crop irrigation. However, differences in cover weight and porosity did not affect temperatures under covers when over-the-crop irrigation was applied. Damage to immature fronds was decreased by 75% to 99% when the covers were used alone and by 98% to 99% when the covers were used with over-the-crop irrigation. Covers had no effect on frond vase life.