Shade Avoidance Influences Stress Tolerance in Maize

[ "Postdoctoral research associate, postdoctoral research associate, graduate student, Professor, and Professor, Department of Plant Agriculture, Crop Science Building, University of Guelph, 50 Stone Road E., Guelph, ON N1G 2W1, Canada. Current address of first author: Agriculture and Agri-food Canada, Greenhouse and Crops Processing Centre, 2585 County Rd. 20, Harrow, ON N0R 1G0, Canada. Corresponding author's E-mail: "]
Weed Science (Impact Factor: 1.68). 07/2011; DOI: 10.1614/WS-D-10-00159.1

ABSTRACT Previous studies have suggested that the reduction in the root/shoot ratio that accompanies the shade avoidance response may reduce the tolerance of individuals to subsequent nutrient or moisture limitations. In this work, we examined the impact of the shade avoidance response on maize seedling growth and development and the response of these plants to a subsequent abiotic stress. Seedlings were grown in a field fertigation system under two light quality environments, ambient and a low red to far-red ratio, which were designed to simulate weed-free and weedy conditions, respectively. This system also enabled the controlled restriction of water and nutrients, which reduced the relative growth rate of the crop and created a secondary stress. Results of this study indicate that, while the shade avoidance response did reduce the root/shoot ratio in maize, this effect did not reduce plant tolerance to subsequent abiotic stress. Rather, the apparent additivity or synergism of shade avoidance and the secondary stressor on yield loss depended on whether the net effect of these two stressors was sufficiently large to shift the population toward the point where reproductive allometry was broken. Nomenclature: Maize, Zea mays L.

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