Water stress reduces ozone injury via a stomatal mechanism

• Published in: Plant physiology (Bethesda) Vol. 77; no. 4; pp. 944 - 947
• Main Authors: Tingey, D.T, Hogsett, W.E
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-04-1985
• Subjects: Agrochemicals products; Biological and medical sciences; Dehydration; ESTOMA; Ethylene production; Fundamental and applied biological sciences. Psychology; INJURIES; Leaves; Other agrochemicals used in plant protection (herbicides, fungicides, etc.); OZONE; OZONO; PHASEOLUS VULGARIS; Phytopathology. Animal pests. Plant and forest protection; Plant interaction; Plant physiology and development; Plant response; Plants; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; Soil water; STOMATA; Stomatal resistance; STOMATE; STRESS; Water and solutes. Absorption, translocation and permeability; Transpiration; Leguminosae; Phaseolus vulgaris; Dicotyledones; Water deficit; Angiospermae; Ozone; Spermatophyta
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.77.4.944

Various studies have shown that water-stressed plants are more tolerant of ozone exposures than are unstressed plants. Two probable explanations for this tolerance are (a) stomatal closure which reduces ozone uptake and (b) biochemical or anatomical changes within the leaves. Phaseolus vulgaris cv Pinto bean plants were established and transferred to membrane systems which controlled the osmotic potential around the roots at -35 or -80 kilopascals for 5 days prior to ozone treatment (0 or 1.0 microliters per liter for 2 hours). Both water-stressed and unstressed plants were sprayed with various concentrations of abscisic acid to close the stomata or with fusicoccin to induce stomata opening. The abaxial stomatal resistances of primary and trifoliate leaves were measured just prior to ozone exposure. Plant response to ozone was determined by stress ethylene production and chlorophyll loss. Both water stress and abscisic acid induced stomatal closure and reduced ozone injury. In water-stressed plants, fusicoccin induced stomatal opening and those plants were as sensitive to ozone as were the non-water-stressed plants. These data suggest that water stress protects plants from ozone injury mainly through its influence on stomatal aperture rather than through biochemical or anatomical changes.