Cotton crop responses to a changing environment
- Mississippi State Univ., MS (United States)
- USDA-ARS, Mississippi State, MS (United States). Crop Simulation Research Unit
Interest and concern for the Earth`s changing atmosphere has increased dramatically in recent years. Future increases in atmospheric CO{sub 2} concentration will directly affect physiological processes and growth rates of plants. Indirect climatic effects such as global warming, changing precipitation patterns, increasing cloud cover, and frequency of weather extremes may have a greater impact than the direct CO{sub 2}-induced changes on plant processes. The authors conducted several experiments in naturally-lit, temperature-, and CO{sub 2}-controlled chambers and measured both upland (Gossypium hirsutum L.) and pima (G. barbadense L.) cotton crop responses to the direct and interactive effects of temperature, CO{sub 2}, and water deficits. Absolute differences in photosynthetic rates at different CO{sub 2} concentrations became progressively greater with time as plants entered reproductive phases of growth. The photosynthetic response to CO{sub 2} increased up to {approx} 700 to 900 {micro}mol mol{sup {minus}1} CO{sub 2}, and the authors did not detect any feedback inhibition of photosynthesis in cotton over time. The relative photosynthetic response of plants growth at 700 {micro}mol mol{sup {minus}1} CO{sub 2} compared with plants grown at 350 {micro}mol mol{sup {minus}1} CO{sub 2} was at a maximum of 1.5 at 30 C, but decreased to near 1.0 at 24 and 38 C. This relative response was very similar to responses of growth to CO{sub 2} and temperature and thus photosynthetic responses may be related to sink size. Plants grown in high CO{sub 2} atmospheres produced more photosynthesis under optimum and in water stress conditions than plants grown in ambient CO{sub 2} atmospheres. High CO{sub 2} grown plants transpired less at high plant leaf water potentials than low CO{sub 2} grown plants, but transpiration rates were not different when leaf water potentials decreased below {minus} 2.0 MPa. 37 refs., 21 figs.
- OSTI ID:
- 248045
- Report Number(s):
- CONF-9211217-; ISBN 0-89118-126-1; TRN: IM9628%%145
- Resource Relation:
- Conference: 1992 annual meeting of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Minneapolis, MN (United States), 1-6 Nov 1992; Other Information: PBD: 1995; Related Information: Is Part Of Climate change and agriculture: Analysis of potential international impacts; PB: 399 p.; ASA special publication, Number 59
- Country of Publication:
- United States
- Language:
- English
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