Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: J.A. Reinert x
Clear All Modify Search

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.

Open Access

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.

Open Access

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.

Open Access

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.

Open Access

One hundred sixteen rose (Rosa spp.) cultivars were evaluated under minimal input conditions in north-central Texas for 3 years. Plant quality data included overall plant performance, number of flowers, percentage of bloom coverage, final vigor, and survival. Disease ratings for black spot (Diplocarpon rosae), petal blight (Alternaria alternata), powdery mildew (Sphaerotheca pannosa), and aphid (Myzus spp.) infestations were previously reported. Of the original 116 cultivars, 25 had 50% or higher mortality during the trial. Own-root cultivars performed significantly better than the grafted cultivars and had significantly better survival (P = 0.001). As a class, the Polyantha cultivars exhibited the best overall performance, mean bloom percentage, final vigor and survival, while cultivars in the Hybrid Tea class had the worst performance in all measures. Foliar nutrient content, bloom number, and mean percentage of bloom were not good predictors of overall performance. Of the diseases monitored, black spot was the most severe and was closely correlated to overall performance and final vigor, but was not the only factor determining overall performance. The top five cultivars in mean overall performance were RADrazz (Knock Out™), Caldwell Pink, Sea Foam, Perle d'Or, and The Fairy, in descending order.

Full access

Abstract

Four cultivars of bean (Phaseolus vulgaris L.), with different sensitivities to ozone (O3), were exposed to chronic doses of O3 for 7 hr/day in early and late-season studies. Plants were pot-cultured in open-top field chambers. Greater than ambient O3 doses were applied by supplementing the O3 present in nonfiltered air with additional O3 at a constant rate for 7 hr/day. Cultivar sensitivity, as determined using an acute exposure screening protocol, was maintained in both studies. Regression of yield against O3 concentrations showed that ‘BBL-254’ and ‘BBL-290’ were more sensitive to O3 than were ‘BBL-274’ and ‘Dwarf Horticultural’. Results suggest that the acute screen used can predict the relative yield response of cultivars grown under field conditions when very sensitive and very resistant cultivars are compared. The results support the contention that bean germplasm has traits for resistance to O3 at current levels of O3, but that resistance is lost with increasing O3 concentration. Predicted relative yield suppression at a 7 hr/day seasonal mean of 0.04 to 0.06 ppm (the common ambient range in eastern United States) was 2% to 4% for the two resistant cultivars and 10% to 26% for the two sensitive cultivars.

Open Access

Abstract

Ozone (O3) is the most damaging air pollutant affecting agricultural crops in the United States and bean is one of the most O3-sensitive crop species. More than 2000 plant introductions of Phaseolus vulgaris L. were evaluated for sensitivity to O3 by exposing bean plants to 0.6 ppm O3 for 2 hours under controlled environmental conditions; 54 insensitive and 67 highly sensitive plant introductions were identified based on foliar injury symptoms.

Open Access