Search Results
Abstract
American ginseng (Panax quinquefolius L.), was injured by exposure to 20 pphm ozone and/or 50 pphm (v/v) sulfur dioxide for 6 hr daily for 4 days. Ozone induced upper surface leaflet stippling along the veins and interveinaily, and sulfur dioxide induced mild chlorosis to irregular necrotic areas. Ginseng was less sensitive to ozone and as sensitive to sulfur dioxide as ‘Cherry Belle’ radish (Raphanus sativus L.) and ‘Bel W-3’ tobacco (Nicotiana tabacum L.).
Abstract
Crosses and subsequent segregation between inbred lines of ‘National Pickling cucumber (Cucumis satirus L.) resistant to acute exposure to sulfur dioxide, and the sensitive ‘Chipper‘ cucumber indicated that resistance was dominant and may be controlled by a single gene.
Abstract
Eight cultivars of poinsettia, Euphorbia pulcherrima Willd. ex Klotzsch., were exposed to sulfur dioxide under controlled-environment conditions. A new cultivar, ‘Ruff & Reddy’, showed the most overall tolerance while ‘Rudolph’ and ‘Mikkel Blaze’ were least tolerant. The bracts of ‘Annette Hegg’ were injured most by sulfur dioxide, whereas the bracts of ‘Ruff & Reddy’ and ‘Eckespoint C-1’ were not visibly injured at the dosage levels tested. The wide range in tolerance to SO2 among the 8 different genotypes indicates a potential for breeding and selection of tolerant cultivars.
Clusters of four varieties of table grapes were packed in TKV lugs and fumigated with 4, 6, or 8 Deccodione Smoke Tables (DST) for a period of 30 minutes in a fumigation chamber. After fumigation, inoculum of Botrytis cineraria was placed among the berries in the clusters in predetermined locations. Fruit was stored at 0C and high relative humidity for up to 16 weeks. Fruit was examined at 4, 8, 12, and 16 weeks of storage. Decay control index, freshness of stems, and bleaching of pigments around the capstem was recorded at each evaluation time. Size of aerosol particles was determined. Satisfactory control of decay was obtained with 8 DSTs. Lower doses failed to give satisfactory decay control. Bleaching of capstems typically seen with sulfur dioxide fumigation was not noticed with DST fumigation.
Abstract
A single 4 hour exposure of shore juniper, Juniperus conferta Parl., to 0.3 ppm O3, alone or in combination with 0.15 ppm nitrogen dioxide and/or sulfur dioxide, produced a significant number of small (<3 mm), elongate, tan foliar lesions 2 to 4 days after exposure. The injury symptoms were not identical to those associated with shore juniper decline.
Abstract
Two-year-old containerized seedlings of American sycamore (Platanus occidentals L.) were treated with maleic hydrazide (MH) before, after, or in the absence of sulfur dioxide (S02) fumigation. Exposure to S02 did not reduce the effectiveness of MH in controlling regrowth of this species. A strong negative linear trend was observed between SO2 concentration and sprout growth, either with or without MH treatment. In all instances, exposure to 1.0 ppm S02 resulted in high levels of phytotoxicity.
Abstract
Excised shoots of 10 shade tree species were exposed for 6 hours to 40 pphm (vv−1) sulfur dioxide (SO2), 40 pphm nitrogen dioxide (NO2), or 25 pphm ozone (O3) separately or in mixture. Sorption rates were generally greater in coniferous than in deciduous shoots and higher for SO2 than NO2. Adsorption on leaf surfaces was greater than absorption through stomates for 4 of 5 species in which the 2 forms of sorption could be separated, while sorption from single gases was similar to that from mixed gases for these species. For the 5 species in which transpiration continued in darkness, sorption from the mixture was consistently less than from single gases.
Abstract
Thirty-nine cultivars of marigold (Tagetes spp.) were exposed to sulfur dioxide to determine their relative sensitivity. Flowering plants were fumigated at 1 ppm SO2 for 4 hours or at 2 ppm SO2 for 2 hours. The average foliar injury for all leaves on individual plants ranged from 42.3% for ‘Crackerjack Mix’ at 2 ppm SO2 to 0.0% for ‘Cupid Yellow’ at 1 ppm SO2. Foliar necrosis appeared as a gray to white marginal and/or interveinal scorch 1 day after exposure. There was a tendency for interveinal necrosis to be near the midvein. The extra-floral nectaries which line the leaf margins of marigold were scorched in 15 of the 39 cultivars. This injury may be of diagnostic value. Sepals were very sensitive to SO2. Sepal injury appeared as a pinpoint scorch and as tip burn, and was apparent in some cultivars when no foliar injury occurred.
Abstract
Eight lines (2 cultivars and 6 selections) of Euvitis grapes in 1982 were stored for 4, 6, 7, and 8 weeks at 0° ± 0.5°C without sulfur dioxide (SO2) generators and for 4, 8, 12, 16, and 20 weeks with SO2 generators in 5.7-liter telescoping, corrugated cardboard shipping containers with polyethylene liners. Grapes stored without SO2 were of poorer appearance after 4 weeks than those stored with SO2 after 8 weeks. After 16 weeks of storage with SO2, 4 of the 8 lines still had appearance ratings similar to those before storage. Overall, good flavor was maintained over 7 weeks without SO2 and over 12 weeks with SO2. During 8 weeks of storage without SO2, 6 of the 8 lines developed 23% to 60% decay. In contrast, 6 of the 8 lines stored with SO2 for 16 weeks developed 3% or less decay. SO2 injury (percentage by number) ranged from 0% to 59% but was judged to be objectionable in flavor or appearance in only 2 instances. All lines stored well for 12 weeks with SO2. Of the 8 lines, ‘Suffolk Red’ was judged to be outstanding. After 20 weeks of storage with SO2, ratings of its appearance and flavor were equal to those before storage; decay was only 3.5%.
immediately after harvest with sulfur dioxide gas followed by additional sulfur dioxide application during storage using either direct gas treatment or fumigation through continuous-release sulfur dioxide (SO 2 ) -generating pads. However, the concentration of