Water relations of differentially irrigated cotton exposed to ozone

Technical Report · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5669154

Temple, P J

The field study was conducted to test the hypothesis that plants chronically exposed to O{sub 3} may be more susceptible to drought because O{sub 3} typically inhibits root growth and increases shoot-root ratios in plants. Cotton was grown in open-top chambers on Hanford coarse sandy loam in Riverside, CA. Plants were grown under three irrigation regimes: Optimum water for lint production (OW), suboptimum or moderate drought stress (SO), and severely drought stressed (SS) and were exposed to seasonal 12 h (0800-2000) O{sub 3} centrations of 0.015, 0.074, 0.094, or 0.111/microLL. Leaf xylem pressure potentials Psi(sub 1) and soil water content Theta(sub v) were measured weekly from June to October. Mean seasonal Psi(sub 1) increased from -1.89 MPa to -1.72 MPa in low to high O{sub 3} treatments, averaged across soil water regimes. Ozone had no effect on seasonal water use of cotton, but water use efficiency was significantly reduced by O{sub 3} in OW and SO, but not in SS treatments. Drought-stressed plants extracted proportionally greater amounts of water from deeper in the soil profile than OW cotton, and O{sub 3} had no apparent effect on this redistribution of roots in the soil. Since O{sub 3} had no apparent effect on the ability of drought-stressed cotton to maintain Psi(sub 1) and to increase root growth relative to shoot growth, this suggests that O{sub 3} may have little or no effect on the potential of cotton to adapt to or tolerate drought.

• Research Organization: California Univ., Riverside, CA (United States)
• OSTI ID: 5669154
• Report Number(s): PB-91-183202/XAB
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR POLLUTION
BIOLOGICAL STRESS
COTTON PLANTS
DROUGHTS
FIELD TESTS
GROWTH
IRRIGATION
MAGNOLIOPHYTA
MAGNOLIOPSIDA
OZONE
PLANT GROWTH
PLANTS
POLLUTION
SEASONAL VARIATIONS
TESTING
TOXICITY
VARIATIONS
WATER USE