Growth and Yield Responses of Winter Wheat to Mixtures of Ozone and Carbon Dioxide
- A. S. Heagle *a,
- J. E. Millerb and
- W. A. Pursleyb
- a USDA-ARS Air Quality - Plant Growth and Development Research Unit, 3908 Inwood Road, Raleigh, NC 27603 and Dep. of Plant Pathology, North Carolina State Univ, Raleigh, NC USA
b USDA-ARS Air Quality - Plant Growth and Development Research Unit, 3908 Inwood Road, Raleigh, NC 27603, and Dep. of Crop Science, North Carolina State Univ. Cooperative Investigations of the USDA-ARS Air Quality Research Unit and the North Carolina State University USA
Ozone (O3) in the troposphere can cause plant stress, whereas elevated CO2 generally enhances plant growth. Until recently, few studies have considered whether O3 can affect plant response to CO2 or vice versa. We examined these possibilities for soft red winter wheat (Triticum aestivum L.). Plants were grown in 14-L pots and exposed in open-top field chambers to all combinations of three CO2 and three O3 treatments. The CO2 treatments were ambient (approximately 380 μL L−1), or ambient with CO2 added for 24 h d−1 to achieve mean concentrations of approximately 540, or 700 μL L−1 The O3 treatments were charcoal-filtered air (CF), nonfiltered air (NF), or NF with O3 added for 12 h d−1 (NF+). Mean O3 concentrations in the CF, NF, and NF+ treatments were approximately 27, 45, and 90 nL L−1 In the first experiment, eight cultivars with widely different genetic backgrounds were tested. `Coker 9835' was relatively resistant to O3 and `Coker 9904' was relatively sensitive; these cultivars were tested in Exp. 2. Foliar injury caused by O3 was suppressed by elevated CO2 in both experiments. In Exp. 1, plant size and yield increased with CO2 enrichment in the NF and NF+ treatments, but not in the CF treatment. However, the O3 × CO2 interaction was rarely significant. In Exp. 2, growth and yield of C9904 was suppressed more by O3 than was that of C9835. Because of cultivar differences in sensitivity to O3, CO2 enrichment caused greater amelioration of O3 stress and greater enhancement for C9904 than for C9835. Significant cultivar × O3 × CO2 interactions occurred for all growth and yield measures. These results are similar to results with other crops, and further emphasize the need to consider possible interactions between O3 and CO2 when investigating effects of O3 or CO2 on plant systems.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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