Search Results
Abstract
‘Ace’ lilies were grown in soils amended with: dicalcium phosphate; dicalcium phosphate and elevated levels of F, B, or F plus B; superphosphate; and with superphosphate plus B. Not only were symptoms of B injury evident earlier than those of F injury, but B and F toxicity syndromes were readily distinguishable. Plants grown with B had chlorotic and necrotic leaf tips without chlorotic and necrotic basal leaves, and the leaves contained elevated B levels. In B injury, the necrotic area was sharply delineated from live tissue. Plants grown with F on superphosphate had basal leaves that were chlorotic and necrotic, had upper leaves that were chlorotic and necrotic, and contained elevated F levels. Initial symptoms of injury in plants grown in soils amended with dicalcium phosphate and F plus B, with superphosphate plus B, and with dicalcium phosphate plus B were similar, because of the early effect of B. At flowering, plants grown in soils amended with dicalcium phosphate and F plus B, with dicalcium phosphate plus F, with superphosphate, and with superphosphate plus B were severely injured.
Abstract
Dracaena sanderana Hort. Sander ex M. T. Mast and Spathiphyllum ‘Clevelandii’ plants were injured when exposed to 10°C for 1 day or 13° for 2 days. The longer plants were exposed to a given chilling temperature or the lower the chilling temperature, the greater the injury. In Spathiphyllum, injury (leaf wilting or water soaking at the margins) was apparent during or immediately after the cold exposure. Affected leaf margins eventually became necrotic. In Dracaena, symptoms of injury were not apparent immediately but appeared after 3-4 days. Leaf margins eventually became chloratic and necrotic.
Abstract
Geranium seedlings were exposed to various levels of ethylene (0–10 µl/liter air) at 23°C for 2 and 5 days in light. Seedlings held in ethylene for 2 days developed more chlorotic leaves and did not grow as well as seedlings held in air. Seedlings exposed to ethylene for 5 days abscised leaves, whereas those exposed for 2 days did not. Seedlings exposed to ethylene (1 µl/liter air) at 23° for 3 days in dark had more chlorotic leaves and did not grow as well as seedlings exposed to ethylene in light. Seedlings held in air in darkness had more chlorotic leaves than seedlings held in air in light. Seedlings held in air in the laboratory grew as well as seedlings held in the greenhouse. Seedlings exposed to ethylene (1 µl/liter air) for 3 days in dark retained more chlorophyll and had better growth at low temperatures (4.5°, 10°) than those exposed at higher temperatures (15.5°, 23°). Seedlings held in air at all temperatures for 3 days had similar chlorophyll levels and growth patterns. Temperature was negatively correlated with loss of chlorophyll and plant dry weight and positively correlated with number of chlorotic leaves of seedling held in darkness for 7 days.
Abstract
Plants of Philodendron scandens subsp. oxycardium (Schott) Bunt. were exposed to ethylene-air mixtures at various temperatures and levels of light and CO2. Plants held in ethylene (2.5 to 10μl/liter air) abscised leaves and stipules, developed chlorotic foliage, and grew poorly. As the levels and duration of exposure to ethylene increased, the rate of leaf abscission increased. Plants exposed to 5μl ethylene/liter air at 23.5°C for 3 days in light abscised more than 50% of their leaves, whereas plants similarly handled but held in darkness lost 20%. At a given level of ethylene, the lower the temperature the fewer the number of leaves abscised. Plants held at 27° at 10 μl/liter air had total leaf abscission. Plants held in ethylene with 5% CO2 or with lanolin-coated leaves abscised fewer leaves than plants without added CO2 or non-coated leaves.
Abstract
Flowering Kalanchoe blossfeldiana Poelln, exposed to various concentrations of ethylene (0-1 μl/liter of air) at 23.5°C for 2 and 3 days were injured at levels of ethylene greater than 0.5 μl/liter of air for 2 or more days. Ethylene induced leaf abscission and chlorosis, and closed open florets (sleepiness). Sleepy florets failed to re-open. Bud florets were not as severely injured by ethylene as open florets. Bud florets opened when removed from an ethylene environment but their opening was delayed. Florets on plants exposed to 2.5 μ1 ethylene/liter air for 3 days at 6°C were slightly injured. At 2.5 μl ethylene/liter air, severity of injury increased as temperature increased.
Abstract
Plants of ‘Croft’, ‘Ace’ and ‘Nellie White’ grown in F- or Li-amended sand cultures had injured leaves. F-injury on ‘Croft’ developed as a semi-circular necrotic area at the margin of the leaf near its apex. The necrosis enlarged until the entire leaf tip and margin became necrotic. F injury on ‘Ace’ and ‘Nellie White’ varied from the semi-circular necrosis pattern to chlorotic or necrotic leaf margins. Injury affected only lower leaves of ‘Ace’ and ‘Nellie White’ but affected all leaves of ‘Croft’. Li injured leaves of all cultivars but the number and degree of injury were less than those produced by F. Li injury developed as chlorotic leaf margins which eventually became necrotic. In all cultivars Li injury was confined to lower leaves. ‘Croft’ was more sensitive to F and Li than ‘Ace’ or ‘Nellie White’.
‘Ace’ and ‘Nellie White’ were also grown in soil amended with dicalcium phosphate or superphosphate at both low and high lime rates and fertilized with NH4-N or NO3-N nitrogen. Plants grown with dicalcium phosphate with NH4-N or at any lime rate had no leaf injury. Plants grown with superphosphate had injured leaves, particularly at low lime rates with NH4-N. Soil and plant analysis showed a high positive correlation between superphosphate, which contains F, and leaf scorch. Soil-borne F was influenced by source of N fertilizer and lime rate. The pattern of leaf scorch from superphosphate in ‘Nellie White’ and ‘Ace’ was the same as that from NaF.
Abstract
A simulated marketing system was designed to test the effect of light intensity and duration of packaging (conditions similar to those of warehousing, transportation, and retail marketing) on packaged and unpackaged potted ornamental plants. No significant differences were recorded in quality between plants held at 525 and 1600 lux when stored in packages for 14 or 28 days. Six days of darkness did not reduce the time plants could be kept in packages. Packaging duration and plant species were the chief factors affecting the marketability of the plants; the various simulated market conditions had only minor effects. Packaged Pilea cadierei Gagnep. & Guillaum, Philodendron cordatum (Veil.) Kunth, Fittonia verschaffeltii (Lem.) Coem. var. argyroneura (Coem.) Nichols, and Plectranthus australis R. Br. were marketable for 60 days, Gynura aurantiaca (Blume) DC. for 30 days, and Catharanthus roseus L. for 18 days. Plants in sealed packages did not require watering.
Abstract
Twenty gerbera (Gerbera jamesonii H. Bolus, ex Hook f.) cultivars were evaluated for longevity in deionized water (DI), deionized water containing 1 mg fluoride (F)/liter, and deionized water containing 200 mg 8-hydroxyquinoline citrate (8-HQC) + 20 g sucrose (S)/liter. Flowers of different cultivars differed in fluoride sensitivity. Sensitive cultivars developed necrosis on the tips of ray florets within 12 to 24 hr of exposure to fluoridated water, whereas the least-sensitive cultivars were injured within 4 to 6 days. Petal necrosis was the prim ary factor reducing longevity in fluoridetreated flowers. Petal necrosis did not occur on flowers held in DI or 8-HQC + S. The mean postharvest lives of the 20 cultivars held in fluoridated water, DI, and 8-HQC + S were 2.6, 5.3, and 8.3 days, respectively.
Abstract
Excessive temperatures recorded within flower boxes on transcontinental refrigerated trucks were avoided by using an integrated system of preshipment cooling with forced-air, standardized containers and appropriate stacking pattern. The longevity and quality of flowers shipped from California to Florida by refrigerated trucks were comparable to or better than that of air-shipped flowers. Preshipment conditioning treatments did not improve flower longevity of shipped roses, carnations or gladioli. Preconditioning chrysanthemum stems in AgNo3 solution eliminated the need to recut stems after shipment. Carnations and gladioli handled dry lasted as long as conditioned flowers. Floral preservative used on roses and carnations after shipping had a more positive affect on longevity than any other handling treatment.