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U.S. Department of Energy
Office of Scientific and Technical Information

Effects of ozone on the growth and reproduction of grasses

Conference ·
OSTI ID:5474110
Fumigation studies were undertaken to determine the effects of photochemical pollutants on the productivity and reproductive potential of gamble oak and quaking aspen, the most important watershed communities of the Wasatch Mountains of Utah. Sensitivity thresholds, based on visible injury, for a species were determined by fumigating transplanted plants with 5-35 pphm ozone for 4 hr. Once the sensitivity threshold was established, the species was fumigated consecutively for 5 days to determine the acute threshold. This was the level at which daily tissue injury occurred and was generally 3-4 pphm higher than the sensitivity threshold. To determine the effects of long-term ozone fumigation, a regime of 15-18 pphm for 1 hr, 28-33 pphm for 2 hr, and 18-20 pphm for 1 hr was followed during the life cycle fumigation of selected plants. Leaf length and number, total dry weight of plant, and weight and number of inflorescences and florets were measured as parameters of productivity and reproduction. The results indicate a potential decline in the plant populations studied can occur under conditions producing chronic injury to leaf tissue. Automotive exhaust emissions must be controlled and ozone concentrations prevented from exceeding 20 pphm.
OSTI ID:
5474110
Report Number(s):
CONF-780504-
Country of Publication:
United States
Language:
English