Leaf water use efficiency of C{sub 4} plants grown at glacial to elevated CO{sub 2} concentrations
- USDA-ARS, Temple, TX (United States)
Leaf gas exchange and stable carbon isotope compositions were measured on C{sub 4} species grown from near glacial to current CO{sub 2} concentrations (200 to 350 {mu}mol/mol) and from the current concentration to levels possible in the future (700 and 1000 {mu}mol/mol) to determine effects of rising CO{sub 2} on intrinsic water use efficiency (CO{sub 2} assimilation, A/stomatal conductance to water, g) of C{sub 4} plants. The increase in A/g was proportionally greater than that in CO{sub 2} from near glacial to present concentrations in the perennial grass Schizachyrium scoparium and, in one of two years, in the annual grass Zea mays, because of a corresponding decrease in the ratio of leaf intercellular (c{sub i}) to external CO{sub 2} concentration (c{sub a}). Leaf A/g increased 66% in S. scoparium and 80% in the perennial shrub Atriplex canescens from 350 to 700 {mu}mol/mol CO{sub 2}, but averaged across species declined 15% from 700 to 1000 {mu}mol/mol because of an accompanying increase in c{sub i}/c{sub a}. At each CO{sub 2} level, A/g was higher in the grass than shrub. There were substantial differences in A/g at a given CO{sub 2} concentration and in the response of A/g to CO{sub 2} among the species examined. Because much of the positive response of C{sub 4} plants to CO{sub 2} derives from higher water use efficiency, these differences could influence the relative productivities of C{sub 4} species.
- OSTI ID:
- 107134
- Report Number(s):
- CONF-9507129--
- Journal Information:
- Bulletin of the Ecological Society of America, Journal Name: Bulletin of the Ecological Society of America Journal Issue: 3 Vol. 76; ISSN BECLAG; ISSN 0012-9623
- Country of Publication:
- United States
- Language:
- English
Similar Records
Responses of the C[sub 4] grass Schizachyrium and grassland invader Prosopis over glacial to present CO[sub 2] concentrations
Increasing CO[sub 2]: Comparative responses of the C[sub 4] grass Schizachyrium and grassland invader Prosopis