Water relations of differentially irrigated cotton exposed to ozone

Journal Article · · Agronomy Journal; (USA)

DOI:https://doi.org/10.2134/agronj1990.00021962008200040029x· OSTI ID:5852632

Temple, P J ^[1]

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1. Univ. of California, Riverside (USA)

This 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 (Gossypium hirsutum L. cv. Acala SJ-2) was grown in open-top chambers on Hanford coarse sandy loam (coarse-loamy, mixed, non-acid, thermic, Typic Xerorthents) 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} concentrations of 0.015, 0.074, 0.094, or 0.111 {mu}L L{sup {minus}1}. 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 {minus}1.89 MPa to {minus}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.

• OSTI ID: 5852632
• Journal Information: Agronomy Journal; (USA), Journal Name: Agronomy Journal; (USA) Vol. 82:4; ISSN 0002-1962; ISSN AGJOA
• Country of Publication: United States
• Language: English

Related Subjects

553000* -- Agriculture & Food Technology
60 APPLIED LIFE SCIENCES
BIOLOGICAL STRESS
COTTON
DROUGHTS
GROWTH
IRRIGATION
OZONE
PLANT GROWTH
SOILS