Stomatal Conductance, Fleck Injury, and Growth of Tobacco Cultivars Varying in Ozone Tolerance

Importance of Moisture on Stomatal Behavior Of Plants Subjected to Ozone

“…5 Although the CVresistant cultivar, Consolidated L, in the present study differed from the ones used in the previous study, in a dry atmosphere the stomatal resistance of the Os-resistant line was consistently higher in all leaves than the stomatal resistance of the O 3 -susceptible line. However, the result depended on the atmospheric humidity at which the ozonations were performed; in the moist atmosphere the O 3 -resistant and O 3 -sensitive lines had similar stomatal resistances before ozonation.…”

“…3 " 5 We have demonstrated that stomatal behavior in the presence of O3 depends on plant hydration, atmospheric humidity, and the species or cultivar under study. The stomata of water stressed, but nonwilted bean plants, were more sensitive to the presence of O3 in the chamber than were those of well watered plants; the stomata of the stressed plant closed quickly when exposed to the pollutant.…”

“…Indeed, the closure of stomata was the basis of resistance to O 3 injury in resistant cultivars of onions, 4 and a possible basis of resistance in selections of tobacco. 5 Stomata open and close in response to turgor changes in the guard cells. Large leaf-water deficits, created by the loss of water from the leaf exceeding the supply to the leaf, induce turgor loss by the guard cells and cause stomatal closure.…”

Leaf Diffusion Resistance Responses of Three Petunia Cultivars to Ozone and/or Sulfur Dioxide

“…7 Differences in stomatal conductance between tobacco cultivars were not sufficient to account entirely for differences in 03-induced fleck injury. 8 Differences in sensitivity to SO2 among Cucurbitaceae species and cultivars were due to the relative rates of absorption of the gas. 9 Atmospheric humidity during exposure to pollutants has affected the response of stomata.…”

Economic measurement of environment damages

“…This study concluded that: (I) plants grown on deep sandy soils and showing drought stress symptoms exhibit less injury from air pollution than plants grown on sandy loam or silt loam soils; (2) reductions in yield, average price, and value of the cured tob~cco are associated with increases in weather fleck intensity at two of the three locations; (3) taller plants and wider internode lengths are related to increased fleck intensity at two of the three locations; (4) days to flower, filling capacity, and bum duration are associated with increased fleck intensity in a positive manner and total alkaloid contents in a negative manner at single locations only; and (5) correlation values for either total nitrogen content or leaves per plant with weather fleck intensity are not significant at all locations. Tumer et al (1972) assessed ozone damage to tobacco by measuring height, dry weight, leaf area, amount of fleck injury, as well as total leaf stomatal conductance (an indirect measure of photosynthesis and respiration). Four cultivars of varying sensitivity were grown under field conditions during both years of the study and in greenhouses during the second year.…”