Abstract
Abscission of flowers of Geraldton wax (Chamelaucium uncinatum Schau., Myrtaceae) exposed to ethylene was prevented by pulsing with silver thiosulfate. Both a short pulse (15 min, 4.0 mm Ag+) at 25°C and an overnight pulse (0.5 mm Ag+) at 2° were effective treatments. Silver thiosulfate did not improve the vase-life of flowers held in air. Gamma irradiation (60Co source), an insect control measure, resulted in a reduction in vase-life; even at doses as low as 0.05 kGy. Vase-life of Geraldton wax flowers was not affected by prior storage for up to 2 weeks at 0° to 2°. Iprodione pretreatment (1 g·liter−1, 30-sec dip) for Botrytis cinerea Pers. control improved the vase-life of flowers stored for 2 weeks. A preservative solution containing sucrose (1% to 3% w/v) and 8-hydroxyquinoline sulfate (200 mg·liter−1) increased the vase-life of Geraldton wax flowers. Higher sucrose levels (>5% w/v) may cause desiccation of foliage and excessive nectar secretion from floral nectaries. Chemical name used: 3-(3,5-dichlorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide (iprodione).
In an effort to reduce chemical usage to prolong postharvest keeping time of cut flowers, a cross was made between a long-lived (vase life, 10.9 days) inbred line of Antirrhinum majus and a short-lived (vase life, 5.0 days) inbred line. The F1 hybrid was backcrossed to the short-lived parent. Sixty plants of the BC1 generation were carried on through three generations of selfing by single-seed descent. Eight replications each of 60 BC1S3 families, the parents, and the F1 hybrid were grown in the greenhouse, harvested with 40-cm stems when five florets opened, and placed in distilled water for vase life evaluation. Stems were discarded when 50% of the florets on a spike wilted, browned, or dried. Three families proved not significantly different from the long-lived inbred parent. Results indicate that inbred backcross breeding shows potential to increase the postharvest keeping time of short-lived Antirrhinum majus inbred lines.
To improve the ability to discriminate between Asiatic hybrid lilies (Lilium L.) with regard to cut flower longevity in breeding trials, sources creating nongenetic variation during the preharvest, harvest, or postharvest phases were identified. The bulb stock origin (grower) and evaluation temperature caused only small nongenetic variation in individual flower longevity. In contrast, the developmental stage of floral buds, when cut, produced significant nongenetic variation in flower longevity. This variation could be reduced by delaying harvest. An evaluation temperature of 17 °C was optimal to discriminate between longevity levels compared to 14 and 20 °C. Flower deformation due to withering of the petals was an improved criterion for the termination of flower longevity and was preferred instead of loss of turgor of the petals. Standard conditions for screening and selecting Asiatic hybrid lilies for individual flower longevity after cutting are proposed.
Abstract
Physiological changes accompanying anthurium flower (Anthurium andraenum Andre) senescence were monitored. Silver pulse treatment of flower stems was used to modify the senescence process. Florets on the spadix continued to open for 5-10 days after harvest. In both treated and untreated flowers, respiration rate was low until senescence began 8 days after harvest. The rate of increase in respiration of silver treated flowers was half that of the controls. Ethylene production remained low throughout the postharvest life of the flowers. Ten days from harvest spathe color began to change from red to blue with no significant changes in the ratios of the anthocyanins. There was a simultaneous change in tissue pH, from 5.2 to 5.6. Tissue organic acids remained constant during senescence. There was a significant increase in spathe tissue ammonium ion due, apparently, to protein breakdown which probably caused the increase in tissue pH. The concentration of tissue phenolics increased during senescence and could have intensified the color change by copigmentation. Flower senescence apparently was not due to a shortage of carbohydrates, though tissue starch levels did decline by about 25%. The ratio of free sugars in the stem, spathe and spadix remained constant with a slight decline in concentration during postharvest life. Senescence probably was caused by water stress due to stem plugging of undetermined nature. Silver-pulsing of the stem reduced the amount of plugging and therefore reduced the rate of change of all the senescence processes.
Abstract
Hybrid lisianthus [Eustoma grandiflora (Raf.) Shinn.] was evaluated as cut flower and flowering pot plants. Lisianthus is a day neutral summer blooming plant blooming earlier at high growing temperatures (18°/26°C night/day) than at low temperatures. It is a slow growing plant, requiring about 5 to 6 months from sowing to flowering. Forcing period is about 2 months. Three color variants are available: blue, pink, and white. Only the blue and white are suitable as cut flowers. About 3 cut flower stems are produced per plant in the 1st harvesting cycle, and retaining the plant for a 2nd crop is considered uneconomical. Keeping quality of the cut flowers can be improved by pulsing for 24 hr with a solution containing 5% to 10% sugar, and desirable blue and pink pot plants were obtained by spraying with butanedioic mono-2.2-dimethylhydrazide (daminozide, B-Nine). The white cultivar did not respond to daminozide but did respond to soil application of a-cyclopropyl-a-(p-methyoxyphenyl)-5-pyrimedine methyl (ancymidol). Flowering pot plants should be grown in the greenhouse until about half of the flower buds on the plants open, since buds do not develop properly under home conditions.
Evaluation of leaf stomatal numbers and postharvest water loss indicate these are important factors in Antirrhinum majus (snapdragon) cut flower postharvest longevity (PHL). Cut flowers with 9 days longer PHL had 53% fewer leaf stomata. Long PHL is associated with an early reduction in transpiration followed by low steady transpiration. Short-lived genotypes had a linear transpiration pattern over the period of PHL indicating poor stomatal control of water loss. Short-lived genotypes had 22% to 33% reductions in fourth quarter transpiration while long-lived genotypes had 2% to 8% reductions. In addition, short-lived genotypes had higher average fourth quarter cut flower weight losses compared to long-lived genotypes. Further investigation of stomatal numbers and functioning relative to PHL may provide breeders a rapid and nondestructive indirect selection method for PHL.
Aqueous solution (2%) of sucrose, glucose, fructose, or maltose delayed bloom wilting and foliage yellowing of cut chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura] caused by gamma irradiation at 750 Gy. Solutions of silver thiosulfate, sodium dodecylbenzenesulfonate, polyoxyethylene lauryl ether, potassium sorbate, mannitol, sorbitol, glycerol, 6-benzylamino purine, and gibberellin did not reduce irradiation damage. Holding chrysanthemum cut flowers in a sucrose solution before and during irradiation did not influence the vase life, but holding the cut flowers in a sucrose solution following irradiation prolonged the vase life. The results suggest that sugars reduce radiation-induced physiological deterioration of chrysanthemums.
Abstract
Cut flowers of rose (Rosa hybrida L. cv. Samantha) exhibited a longer vase life when opened in solutions containing cobaltous ion (Co2+). The extended vase life in response to Co2+ was related to 1) an increased water uptake into the cut flower, 2) an improved water balance during opening, 3) a delay in loss of fresh weight, and 4) a prevention of the occurrence of bent-neck. A concentration of 1.5 mm Co2+ gave maximum beneficial effects without injury to the cut flower, while a 2.0 mm concentration induced some toxic symptoms on leaves.
Postharvest treatments designed to enhance the vase life of cut Gloriosa rothschildiana flowers were tested. Vase life was significantly extended by the germicides 8-HQC (250 mg·liter-1), DICA (50 mg·liter-1), and Physan-20 (50 mg·liter-1). Germicides acted primarily by improving solution uptake. Sucrose, either as a continuous treatment (of 2% or 5% w/v), or as a 24-hour pulse (20%), significantly enhanced vase life, primarily by enhancing the development of immature buds and delaying senescence in open flowers. Flowers stored at 1C developed signs of chilling injury within 3 days, but chilling symptoms were not displayed in stems stored at 10C for 10 days. Flowers were not affected when exposed to 50 μl ethylene/liter for 24 hours. Transport and short-term storage in sealed, air-filled bags to protect the flowers from physical damage resulted in some atmosphere modification within the bags. Fungal growth occurred when flowers were kept in air-tilled bags for more than 6 days, resulting in a reduction in vase life. Chemical names used: 8-hydroxyquinoline citrate (8-HQC); sodium dichloroisocyanuric acid (DICA); n-alkyl dimethyl ethylbenzyl ammonium chloride (Phyrsan-20).
Ebenus cretica, Leguminosae, is a perennial bush endemic to the island of Crete, and produces attractive pinky red or purple flowers on 15-cm long racemes. To study the possibility of its use as a cut flower, cut inflorescences on 40-cm-long spikes were taken from plants grown outdoors in the farm of the Technological Educati Institute and used to determine the postharvest characteristics of Ebenus flowers. Without any postharvest treatments, the inflorescences held in water had an average life of about 7 days. A solution of 100 ppm 8-hydroxyquinone sulfate (HQS) in DI water, supplemented with 5% Ca(NO)3 increased vase life for 2 days and improved the water potential without affecting transpiration, whereas the addition of 2% or 5% sucrose decreased vase life by 1 or 2 days respectively. Pulsing with 0.2 mm STS for 2 h improved flower quality and vase life. Addition of 6-BAP (2 ppm) or GA3 (3 ppm) in the preservative solution did not affect flower quality or vase life compared to control. These results indicate that inflorescences of Ebenus cretica may be used as cut flowers; however, further research is required to determine their sensitivity to ethylene as well as its storage capabilities.