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Abstract
The response of ‘White Cascade’ and ‘Coral Magic’ petunia (Petunia hybrida Vilm. -Andr.) plants to peroxyactyl nitrate (PAN) was tested 7 days after application of soil drenches of 0, 20, 40, 60, 80, 100, 120 μg benomyl/g drv weight of soil. The susceptible ‘White Cascade’, showed increased sensitivity to 745 μg/m3 PAN for 1.5 hr when soil was treated with benomyl levels of 60 μ/g soil or greater. Enhanced foilar response to PAN was similar at all concentrations of benomyl greater than 60 μ/g soil. Foliage of ‘White Cascade’ petunias treated with concentrations of benomyl below 60 μ/g soil, responded to PAN similarly to plants which were not treated with the fungicide. The PAN sensitivity of the tolerant ‘Coral Magic’ was unaffected by benomyl application.
Abstract
Greenhouse-grown ‘Kennebec’ and ‘Atlantic’ potato (Solanum tuberosum L.) plants were exposed twice-weekly for 5 hours to 380 μg·m−3 (0.2 ppm) NO2 throughout their growing season. NO2 accelerated the rate of leaf abscission and reduced tuber number, weight, and dry matter percentage. NO2 was absorbed by exposed plants, as reflected by an increase in leaf total N content, but did not affect the total glycoalkaloid (tga) status of potato foliage or tubers.
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
Bean plants (Phaseolus vulgaris L. cvs. Provider and Stringless Black Valentine) were exposed to 395 µg/m3 (0.08 ppm) peroxyacetyl nitrate (PAN) for 0.5 hr and subjected to drought stress following exposure. PAN influenced the plant water potential of ΡAN-sensitive ‘Provider’ resulting in visible wilting and reduced soil moisture content. There was no effect of PAN on the water relations of the PAN-tolerant ‘Stringless Black Valentine’.
Abstract
The inheritance of peroxyacetyl nitrate (PAN) resistance in Petunia hybrida Vilm. was studied using the inbred parents of ‘White Cascade’, a susceptible F1 hybrid, and ‘Coral Magic’, a resistant hybrid. In each of 6 experiments, 4-week-old plants of the parents, their reciprocal F1 hybrids, the F2 generation, and reciprocal backcross generations were simultaneously tested for PAN resistance. Plants were exposed to 742 μg/m3 (0.15 ppm) PAN for 1.5 hours in a controlled environment chamber. The percent area of bifacial necrosis was determined for each leaf on a plant and an average was calculated to yield an injury rating. Significant genetic variation was detected in each experiment, but the best fitting genetic model varied among experiments, indicating large genotype by environment interaction. In the experiment with the most severe PAN injury, genes for susceptibility exhibited almost complete dominance to those for resistance and epistatic effects were not significant. In other experiments with lower levels of PAN injury, resistance was partially dominant to susceptibility and one or more epistatic parameters were significant.