Search Results
Abstract
The sensitivity of 26 cultivars of tomato (Lycopersicon esculentum Mill.) were compared at 2 concentrations of SO2 in specially designed exposure greenhouses. Cultivars studied included fresh market, processing, and specialty types. Insensitive and sensitive cultivars were identified by assessment of acute SO2-induced foliar necrosis. Cultivars found to be insensitive to SO2 included: ‘Ace’, ‘Bonanza’, ‘Heinz 1350’, ‘Tarquinia Tondino’, and ‘VF 145-B 7879’. Cultivars found to be sensitive to SO2 included: ‘Bellarina’, ‘Chico IIP, ‘Flora-Dade’, ‘Red Cherry Large’, ‘SubArctic Delight’, and ‘Vetomold’.
Two-year-old seedlings of red maple (Acer rubrum L.) were fumigated with SO2 (0.0, 0.5, 2.0, and 4.0 ppm) 8 hours daily for two 3-day periods spaced 3 days apart. Response to acute SO2 stress was determined by measuring changes in ethylene biosynthesis and membrane permeability. Ethylene evolution was a useful indicator of the onset of SO2 stress in red maple, but was not a particularly good indicator of the degree of stress. Membrane permeability was not as sensitive to the initial stages of SO2 stress, and significant changes in permeability were noted only at higher concentrations of this pollutant (> 2.0 ppm).
Abstract
Mechanically harvested fruit of the strawberry (Fragaria × ananassa Duch.) cv. Veeglow destined for processing can be stored at 1°C in bulk bins for 4 to 6 days if room-cooled, and for 6 to 8 days if forced-air cooled promptly after harvest, without appreciable loss due to rot development or of quality of processed product. Yields of puree from fresh fruit mechanically harvested on day 8 of the storage trial were lower than for fruit that had been forced-air cooled and stored at 0° for 8 days. Sulfur dioxide fumigation immediately after cooling reduced losses due to rot and lowered mold counts, particularly when the fruit was room cooled.
Abstract
Potted plants of ‘Merit’ tomato (Lycopersicon esculentum Mill.) were grown from seed to maturity in controlled-environment chambers and exposed to charcoal-filtered air or 288-314 μgm-3 (0.11-0.12 ppm) SO2 during weeks 1-5, 6-10, or 1-10 beginning about one week after transplanting. Red ripe fruit harvested from plants exposed to SO2 exhibited a slight but significant decrease in ascorbic acid expressed on a dry-weight basis. SO2 induced significantly greater levels of foliar sulfur, but did not increase sulfur content of the fruit. Exposure of plants to SO2 did not affect fruit yield or quality factors including soluble solids, total solids, or ascorbic acid on fresh-weight basis. A multiple regression model revealed low but significant R2 values, indicating a weak and indirect, yet significant, association between plant sulfur content and fruit ascorbic acid.
Abstract
Early-season ‘Perlette’, ‘Cardinal’, ‘Flame Seedless’, and ‘Thompson Seedless’ table grapes (Vitis vinifera L.) were fumigated at 21°C with methyl bromide (MB) at 32 g m−3 for 3.5 hours, SO2 (0.5% for 0.5 hours), or the 2 fumigants in sequence. Quality evaluations were made following holding at 2.5° for 6 days and again after an additional 2 days at 21°. SO2 fumigation reduced the percentage of rotten berries and the combination of SO2 and MB reduced the amount of bunch rot (Rhizopus rot). SO2 slightly bleached the color of the dark-pigmented grapes. Bromine residues in MB-fumigated and untreated grapes averaged 10.8 and 1.4 ppm, respectively.
Watermelon, Citrullus lanatus (Thunb.) Matsum & Nakai cv. Sugar Baby, were grown in the field as a fall crop in open-top chambers (OTC) in southwestern Indiana with either charcoal-filtered (CF) or nonfiltered (NF) air. Ozone and sulfur dioxide were continuously monitored in OTC and ambient air. There was a significant decrease in marketable yield by weight (19.9%, P = 0.05), percentage of marketable fruit by number (20.8%, P = 0.10), and total yield by weight (21.5%, P = 0.05) from plants grown in the NF air treatment compared with those grown in CF air. Ozone-induced foliar injury was significantly greater on plants grown under NF conditions. Ambient concentrations of 03 in southwestern Indiana caused foliar injury (P = 0.10) and significant yield loss to a fall crop of watermelons.
Abstract
Tuber initiation on rooted potato cuttings has been shown to be favored by shortened photoperiods (2). The objective of this study was to characterize the initiation and growth of tubers on plants in growth chambers and to establish an appropriate covariate for tuber mass measurements. Preliminary data on the effects of sulphur dioxide and nitrogen dioxide on tuber growth are also described.
Fruit of table grape cvs. Black Monukka, Flame Seedless, Thompson Seedless and Himrod were fumigated with 2, 4 and 6 Deccodione tablets for 30 minutes in a fumigation chamber. Fruit was brought to the cold rooms and stored at 32 F and high relative humidity for upto 10 weeks. Decay control index, freshness of stems and bleaching around the capstem were recorded at 2, 4, 6, 8 and 10 weeks of storage. Size of the smoke particles was determined using an electrical aerosol analyzer.
Fruit was kept in good condition by fumigation with 6 smoke tablets upto 10 weeks. Lower doses failed to control the decay. No bleaching around the capstems commonly associated with sulfur dioxide fumigation was noticed. Majority of the smoke particles were between 0.18 and 0.32 micrometers. Fumigation with Deccodione tablets could be a viable alternative to sulfur dioxide fumigation.
Fruit of Vitis vinifera cvs. Flame Seedless, Thompson Seedless and Black Monukka were fumigated with 4, 6 and 8 Deccodione Smoke Tables (DST) for 30 minutes. Fruit was stored at 32 F and high relative humidity. Decay control index, freshness of stems and bleaching around the capstem were recorded at 4, 8, 12 and 16 weeks of storage. Size of the aerosol particles was determined using an electrical aerosol analyzer. Fruit was analysed for Deccodione residues.
Lower rates of the fungicide gave unsatisfactory decay control. Eight DSTs successfully controlled decay upto a period of 14 weeks. There was no bleaching of pigments commonly associated with sulfur dioxide fumigation. Majority of the aerosol particles were between 0.18 and 0.32 micrometers. Deccodione residues on the fruit were within the acceptable limits established for Deccodione. There was no perceptible difference in taste between treated and control fruit. This method of decay control could provide a viable alternative to sulfur dioxide fumigation.
Refrigerated fresh-cut fruit and vegetables are the most rapidly expanding area in produce sales. Shelf life for minimally processed produce depends on natural product senescence or spoilage organism decay. Shelf life limits, near-aseptic cutting facilities, refrigerated transportation, and refrigerated storage make it possible to ship precut cantaloupe coast to coast on a year-round basis. Thorough cantaloupe surface disinfection reduces potential spoilage organisms and harmful pathogens. We compared using vapor hydrogen peroxide and sulfur dioxide to the current practice of hypochlorite (HOCL) washing to reduce cantaloupe microbial load. After treatment, cantaloupe were stored in unsealed polyethylene bags at 2.2°C for 4 weeks. The HOCL treated fruit were scrubbed and soaked for 5 minutes in a commercial HOCL solution. After 4 weeks, the HOCL washed fruit had reduced visible molds compared to controls. Cantaloupes fumigated for 60 minutes with 5000 or 10,000 ppm sulfur dioxide developed sunken lesions but no significant decay after 4 weeks storage. Cantaloupes, treated 60 minutes with 3 mg·L–1 volume vapor hydrogen peroxide, did not show injury or significant decay after 4 weeks storage. Sulfur dioxide and vapor hydrogen peroxide show promise as alternatives to HOCL.