Leaf nitrogen concentration of wheat subjected to elevated [CO2] and either water or N deficits

Sinclair, T.R. and et al, . (2000) Leaf nitrogen concentration of wheat subjected to elevated [CO2] and either water or N deficits. Agriculture, Ecosystems & Environment, 79 (1). pp. 53-60.

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Leaf N concentration is important because it is associated with the CO2 assimilatory capacity of crops, and in grasslands, it is an important determinant of forage nutritive value. Consequently, the productivity of both domestic and native animals in future global environments may be closely linked to possible changes in leaf N concentration of grasses. Since grasslands are frequently subjected to water-deficit or N-deficit conditions, it is important to investigate the interactive responses between elevated [CO2] and these stress conditions. Therefore, this 4-year research program was undertaken with wheat (Triticum aestivum L.) as a model system for forage grasses, to document the potential changes in leaf N concentration in response to global environment changes. Wheat crops grown under field conditions near Phoenix, AZ, USA, were subjected to elevated [CO2] and either water-deficit or N-deficit treatments using large Free Air Carbon dioxide Enrichment (FACE) arrays. Surprisingly, the elevated [CO2] treatment under optimum conditions resulted in little change in leaf N concentration. Therefore, no change in the nutritive value of forage from highly managed pastures would be expected. Further, water-deficit treatment had little influence on leaf N concentration. To some extent, the lack of response to the water-deficit treatment resulted because severe deficits did not develop until late in the growing seasons. Only on one date late in the season was the water-deficit treatment found to result in decreased leaf N concentration. The low N treatment in combination with elevated [CO2], however, had a large influence on leaf N concentration. Low levels of applied N resulted in decreased leaf N concentration under both [CO2] treatments, but the lowest levels of leaf N concentration were obtained under elevated [CO2] through much of the growing season. These results point to a potential problem with grasslands in that the nutritive value of the forage consumed by animals will be decreased under future global environment changes.

Item Type: Article
Uncontrolled Keywords: CO2 enrichment; Forage quality; Leaf nitrogen; Nitrogen deficit; Water deficit
Author Affiliation: USDA-ARS, Agronomy Physiology & Genetics Laboratory, University of Florida, Gainesville, FL 32611 0965, USA
Subjects: Plant Production
Crop Improvement
Divisions: Other Crops
Depositing User: Mr. SanatKumar Behera
Date Deposited: 03 Feb 2012 06:26
Last Modified: 03 Feb 2012 06:26
Official URL: http://dx.doi.org/10.1016/S0167-8809(99)00146-2
URI: http://eprints.icrisat.ac.in/id/eprint/3001

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