Premium
Water Relations of Differentially Irrigated Cotton Exposed to Ozone
Author(s) -
Temple Patrick J.
Publication year - 1990
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1990.00021962008200040029x
Subject(s) - shoot , loam , irrigation , lint , soil water , agronomy , malvaceae , gossypium hirsutum , fiber crop , water content , drought tolerance , xylem , water potential , horticulture , chemistry , biology , ecology , geotechnical engineering , engineering
This field study was conducted to test the hypothesis that plants chronically exposed to O 3 may be more susceptible to drought kcause OM 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 (coarseloamy, 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 3 concentrations of 0.015, 0.074, 0.094, or 0.111 μL L −1 . Leaf xylem pressure potentials (Ψ 1 ) and soil water content (Ψ v ) were measured weekly from June to October. Mean seasonal Ψ 1 increased from −1.89 MPa to −1.72 MPa in low to high O 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 3 in OW and SO, but noit in SS treatments. Drought‐stressed plants extracted proportionally greater amounts of water from deeper in the soil profile than OW cotton, and O 3 had no apparent effect on this redistribution of roots in the soil. Since O 3 had no apparent effect on the ability of droughtstressed cotton to maintain Ψ 1 and to increase root growth relative to shoot growth, this suggests that O 3 may have little or no effect: on the potential of cotton to adapt to or tolerate drought.