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Eight Bush Blue Lake type snap bean (Phaseolus vulgaris L.) lines and cultivars with similar genetic backgrounds were container-grown to green-pod maturity in open-top field chambers while being exposed to chronic doses of 03 for 7 hours·day-1 for 42 consecutive days. Treatments included charcoal-filtered air, nonfltered air, and 0.02, 0.04, or 0.08 ppm O3 added to nonfiltered air. Visible injury was estimated during the 2nd week of exposure and compared to the green pod yield data. The presence of four yield response groups, as determined via regression analysis, indicated the presence of variation for 03 sensitivity in the germplasm pool, but all eight lines were O3 - sensitive with yield losses at 03 levels exceeding a 7-hour daily mean of 0.085 ppm. Foliar injury may be a good indicator of general yield loss; however, estimates of visible injury lack the precision necessary to distinguish subtle differences among a collection of O3-sensitive snap bean lines.
Abstract
Seedlings of ‘Fantastic’, ‘Homestead 24’, ‘Walter’ and ‘Heinz 1439’ tomato (Lycopersicon esculentum Mill.) were exposed to ozone 6 times between the 2nd and 5th week after emergence. Early total, marketable, and U.S. No. 1 yield were reduced when plants were exposed to 40 pphm ozone for 2 hours for all cultivars, except for ‘Walter’ in one trial. Early marketable yield of the most sensitive cultivar, ‘Fantastic’, was reduced an average of 14.7 metric tons/ha per year at 40 pphm ozone for 2 hours. Effect on early yield of 10 pphm ozone for 8 hours and 40 pphm for 1 hour was influenced by cultivar and year. Early yield was affected more by ozone concentration than by dose. Season marketable yield was unaffected by early acute ozone fumigation except for ‘Homestead 24’ at 40 pphm ozone for 2 hours in 1976. Fruit quality and fruit weight were not appreciably influenced by acute ozone exposure.
Abstract
Six cultures of Lycopersicon esculentum Mill. were exposed to 3 doses of ozone (O3) at 3 ages. Cultivars exposed to O3 at 2 weeks age ranked differently in sensitivity based on foliar injury than cultivars exposed at 4 and 6 weeks. Cultivars were more sensitive to O3 at 4 than at 6 weeks but sensitivity rankings based on foliar injury were similar. The highest O3 dose significantly inhibited the growth of all cultivars, except ‘Heinz 1439’ at 6 weeks. Cultivar rankings based on average percent change in growth from control plants were more similar at 4 and 6 weeks compared with 2 weeks.
Abstract
Twelve cultivars of Elatior begonia (Begonia X hiemalis Fotsch.) were exposed to O3 at 25 and 50 pphm. The ‘Schwabenland’ group, ‘Whisper ‘O’ Pink’, and ‘Improved Krefeld Orange’ were the most sensitive, whereas ‘Ballerina’, ‘Mikkell Limelight’, and ‘Turo’ were the least sensitive. ‘Rennaisance’, ‘Heirloom’ ‘Nixe’, and ‘Fantasy’ were intermediate in sensitivity. The dry weight of foliage (stems plus leaves) of 9 cultivars exposed to O3 was significantly less than that of control plants. Ozone at 25 and 50 pphm inhibited flower growth (including peduncles) and development in 4 and 8 of the 12 cultivars, respectively. Differences in flower weight ranged from 43 to 105% of the control at 25 pphm and from 25 to 98% of the control at 50 pphm, depending on cultivar.
Abstract
Eight cultivars of azalea were tested for sensitivity to 0.25 ppm of nitrogen dioxide (NO2), sulfur dioxide (SO2) and ozone (O3), alone and in mixture. Sixty-eight days after pruning, the 1 yr-old liner plants were exposed to the pollutants for 6, 3-hr fumigations over a 4 week period. Cultivars demonstrated a range of sensitivity (tolerant to moderately sensitive) based on both visible injury and growth. Neither NO2 nor SO2 (alone and in combination) induced foliar injury on any of the cultivars. Ozone and mixtures of O3 with NO2 and/or SO2 induced small amounts of injury (10% or less) to foliage of ‘Pink Gumpo’, ‘Mme. Pericat’ and ‘Red Wing’. ‘Red Luann’, ‘Glacier’, and ‘Hershey Red’, sustained >10% foliar injury from mixture treatments containing O3. No significant interactions among NO2, SO2, and O3 were detected by measurements of plant weight. The pollutants did not change the weight of leaves or stems of ‘Pink Gumpo’ and ‘Mme. Pericat’. Significant weight loss occurred in leaves or stems from exposure of ‘Hershey Red’, ‘Red Luann’, and ‘Red Wing’ to treatments containing O3 and from exposure of ’Mrs. G. G. Gerbing’, ‘Glacier’, and ‘Red Luann’ to treatments containing SO2.
Abstract
Radish (Raphanus sativus L. cv. Cherry Belle) and marigold (Tagetes patula L. cv. King Tut) were exposed 3 times (every other day), for 3 hours each time to NO2, SO2, and O3, alone and in mixture at 0.3 ppm of each pollutant. Plants were exposed to the pollutant treatments at 3 ages. Radish was most sensitive to O3 at 19–23 days from seeding. The response of marigold to the individual pollutants was not dependent on plant age. Pollutant treatments containing O3 reduced radish root (hypocotyl) dry weight 48% per plant compared with plants exposed to treatments without O3. Interactions of NO2, SO2, and O3 on weight changes in marigold were significant. Sulfur dioxide, alone, reduced the dry weight of the marigold flower and roots, but the inhibitory effect of SO2 was reversed in the presence of NO2 or O3.
Abstract
The effect of SO2 (0.5 ppm) and O3 (0.25 ppm) were tested alone and in combination using 5 cultivars of Elatior begonia (Begonia × hiemalis Fotsch). ‘Schwabenland Red’ and ‘Whisper ‘0’ Pink’ were the most sensitive to O3 based on foliage and flower weight. ‘Fantasy’ was the most sensitive to SO2 and flower production was significantly reduced without visible injury at 0.5 ppm SO2. The only significant (SO2 × O3) interaction occurred with flower weight of ‘Schwabenland Red’, where the combined effect of the 2 pollutants was less than expected from the linear additive model.
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
Foliage of field-grown muskmelon (Cucumis melo L. var. reticulatus Ser.) is susceptible to injury induced by ambient concentrations of ozone. Foliar injury symptoms consisted of interveinal chlorosis of the adaxial surface of the leaf tissue followed by bleaching of the foliage and necrosis. Fully mature leaves were affected more than younger leaves. Controlled fumigations of muskmelon plants with known concentrations of ozone produced foliar symptoms identical to those observed in the field. A differential cultivar response to ozone is reported and potentially tolerant genotypes are identified.
Abstract
Foliage of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] is susceptible to injury induced by ambient concentrations of ozone. Injury symptoms consisted of a premature chlorotic mottle of leaf tissue, followed by stippling and bleaching of the foliage, and necrosis. Older, more mature leaves were more affected than younger leaves. There was a differential cultivar response to ozone, which identified potential insensitive genotypes.