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  • Author or Editor: A. M. Kofranek x
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Abstract

Natural daylengths in summer at 38°N latitude are partially inductive for Chrysanthemum morifolium, Ramat. cvs. Albatross and Escapade. This is indicated by the number of nodes to the terminal bud in natural daylength compared to a night break treatment. One week of short days (SD) is enough to fully satisfy induction of the terminal bud as expressed by the number of nodes to flower. Three to four weeks SD are ample for the development of high quality flowers equal to those grown under continuous SD; there was no significant delay in flowering.

Open Access
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Abstract

The mineral nutrient requirements of geranium, Pelargonium hortorum, cv. ‘Irene’, were studied. Plants were grown in solution culture containing varying quantities of N, P, K, Mg, and Ca, or deficient in S, B, Fe, Mn, Cu, or Zn. Deficiency symptoms of the elements listed are described. The mineral levels in leaves which first show deficiency were found to be at approximate incipient deficiency: N, 2.40%; P, 0.28%; K, 0.62%; Ca, 0.77%; Mg, 0.14%; S, 0.12%; B, 18 ppm; Fe, 60 ppm; Cu, 5.5 ppm; Zn, 6 ppm; and Mn, 9 ppm. Additional useful analytical data are presented.

Open Access

Abstract

Poinsettia (Euphorbia pulcherrima, Willd. cv. Annette Hegg Dark Red) plants were subjected to various preharvest cultural treatments with the several effects on harvest and postharvest parameters determined. Termination of injector fertilization at 0, 1, 2 or 4 weeks before harvest or the application of a soil fungicidal drench at harvest did not consistently alter plant height, bract diameter, anthesis date, fresh and dry weight, fruit set, foliar or cyathium abscission, foliar chlorosis, bract shriveling, and Botrytis-infected bracts. However, plants maintained under relatively high light and warm conditions exhibited smaller bracts, were shorter and had 8 fold increase in Botrytis-infected bracts at harvest (compared to ones averaging 2°C lower temperature and 50% light reduction). The high light-warmly grown plants were generally inferior as measured by increased foliar abacission and chlorosis, premature death of cyathia, and increased numbers of bract abnormalities; cyathium abscission was delayed 3.5 days as compared to the lower light-cooler grown plants.

Open Access

Abstract

Direct coating of flowers of carnation (Dianthus caryophyllus L. cv White Sim) with Ag ions by spraying or momentarily dipping flower heads with AgNO3 (50-100 ppm) extended cut flower longevity and counteracted the enhancing effect of ethephon on senescence. Treating stems and leaves similarly had little or no effect. Stem base treatment with 1000 ppm was much less effective than treating the flower directly. Maximum efficiency of the AgNO3 spray was obtained when a period of 2 hours elapsed between the AgNO3 treatment and exposure to ethephon. In spite of the great extension in longevity, silver spray has limited practical use since it causes petal spotting.

Open Access

Abstract

Sleeved poinsettia plants (Euphorbia pulcherrima, Willd. cvs. Annette Hegg Supreme and Annette Hegg Dark Red) stored best at 10°C. Lower temperatures (2-7°C) induced chilling damages as manifested mainly by bract blueing. Higher temperatures (up to 16°) resulted in increased leaf petiole epinasty and bract drooping. The bract blueing and leaf petiole epinasty disorders became worse as storage duration increased from 2 to 10 days, while bract drooping decreased during this same period. Plants sleeved and stored in paper were generally of higher quality upon removal than those sleeved and stored in plastic. Under relatively static conditions (15m/minute air speed), poinsettias froze at about −4°. Sleeving poinsettias delayed low-temperature damage. The injury of sleeved poinsettias was related to temperature, air speed, and exposure time which can be estimated by: time to injury (minutes) = 3.94 × chill factor (°C) + 61.9.

Open Access

Abstract

A 200 ppm solution of Physan-20 [Active ingredients: n-alkyl (60% C14, 30% C16, 5% C12, 5% C18) dimethyl benzyl ammonium chlorides, 10%; n-alkyl (68% C12, 32% C14) dimethyl ethylbenzyl ammonium chlorides, 10%; inert ingredients, 80%.] was as effective in opening buds of ‘Perfecta’ gypsophila as was a 25 ppm silver nitrate solution when combined with sucrose. Sucrose (10%) was more effective in a short time period than 5% in combination with Physan-20. The minimum time in the solution for producing high quality blooms was 4 days. Physan-20, a quaternary ammonium compound, effectively opened gypsophila buds in tap water moderately high in salts, bicarbonates and nitrates. Physan-20 offers an effective alternate to silver nitrate for opening gypsophila without deionized water.

Open Access

Abstract

Flowers of different cultivars of rose (Rosa hybrida L.) vary in their sensitivity to bent-neck after cutting with ‘Cara Mia’ the most sensitive, and ‘Samantha’ the most resistant of the cultivars tested. Bent-neck is influenced by several factors: water loss by leaves, differences in water uptake ability of the stem, and the ability of the bloom to absorb water from other plant organs on the flower shoot.

Open Access

Abstract

Hydrocooling, forced air cooling, and hydrocooling plus forced air cooling techniques reduced the 7/8 mass mean cooling time of packaged potted chrysanthemums (Chrysanthemum morifolium Ramat.) by 57, 43, and 70%, respectively, compared to cooling under normal refrigeration. Mass mean 7/8 cooling time for plants in boxes with 0, 1 or 5 sides exposed to normal air movement in refrigerated storage was 49, 21 and 10 hours, respectively. Plants hydrocooled and stored at 2°C for 0, 5, or 10 days had equal postharvest longevity upon removal compared to plants cooled to 2°C in 60 hours and subsequently stored for the same periods. Plants stored at 22°C displayed equal postharvest longevity after 5 days of storage but were inferior after 10 days storage compared to rapidly cooled plants. Reasons for determining plants inferior varied according to cultivar.

Open Access

Abstract

Immersing stems of carnation flowers (Dianthus caryophyllus L. cv. White Sim) in solutions containing a silver thiosulfate complex prepared by combining silver nitrate with sodium thiosulfate (molar ratio 1:4) doubled their vase life (from 5 to more than 10 days). The effect could be achieved by treating stems with solutions containing as little as 1.0 mM Ag with a pulse as short as 10 minutes. Silver uptake estimations indicated that a minimum of 0.5 μmol Ag was required per stem for maximum vase life and that more than 5 μmol Ag per stem was toxic.

Open Access

Abstract

The longevity and quality of flowers experimentally shipped from California to Maryland by refrigerated trucks for 4–5 days were comparable with or better than simulated air-shipped flowers when properly handled. Flowers shipped by air are usually not refrigerated in transit. Best results with ‘White Sim’ carnations (Dianthus caryophyllus L.), ‘Albatross’ standard chrysanthemums (Chrysanthemum morifolium Ramat) and ‘Cara Mia’ roses (Rosa hybrida L.) were obtained when flowers were pretreated after harvest with a chemical solution for 16 hours, precooled prior to shipment and shipped in insulated boxes. Preshipment pulsing of carnations and chrysanthemums increased longevity and bloom diameter. Pulsing of ‘Cara Mia’ roses extended longevity and prevented “bent neck.” Chrysanthemums and roses benefited from ice in the box even with good refrigeration but carnations did not. Carnations and chrysanthemums cut at a tight bud stage suffered much less than open blooms from heat stress conditions during handling of flowers.

Open Access