Effect of ozone on stomatal aperture and transpiration
Ozone, a major component of photochemical smog, is an important phytotoxicant responsible for damage to field crops representing losses of millions of dollars each year. The study of the effects of ozone on the major life processes of plants is, therefore, an important one. Stomates are the major means of entry for ozone into the leaf. Stomatal movements also affect the rates of photosynthesis and transpiration, processes which are important to the life of the plant. In the present study, the effects of ozone on stomatal movement and transpiration were investigated. Two approaches were used in the investigation of these effects. First, several species of plants were fumigated with ozone, and stomatal apertures were measured from leaf surface impressions. Secondly, attached trifoliate leaves of Pinto bean were enclosed in a small leaf chamber and were fumigated with ozone. The transpiration rate of the enclosed leaf was measured by determining the difference in the relative humidity of the air before entering, and after leaving, the leaf chamber. Ozone was observed to cause stomatal closure in a number of species of plants and the degree of closure varied with the different species. Since the degree of stomatal closure for a given species varied inversely with the amount of damage which subsequently appeared on the leaves, such ozone-induced stomatal closure may afford the plant some measure of protection from damage by reducing further entrance of the toxicant into the leaves. 152 references.
- Research Organization:
- Utah Univ., Salt Lake City (USA)
- OSTI ID:
- 5014996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BEANS
BIOLOGICAL EFFECTS
FEDERAL REGION VIII
FOOD
INJURIES
LEAVES
NORTH AMERICA
OPENINGS
OZONE
PHOTOCHEMICAL OXIDANTS
PLANTS
STOMATA
TRANSPIRATION
USA
UTAH
VEGETABLES