title: Effects of a CO2-enriched atmosphere on the growth and competitive interaction of a C3and a C4grass.
abstract: Festuca elatior L., C3, and Sorghum halepense (L.) Persoon, C4, were grown in mixed and unmixed cultures under 350 and 600 ppm CO2for 112 days. High CO2levels stimulated increases of total dry weight and leaf surface area in Festuca despite unfavorably high temperatures. In Sorghum, delay of leaf senescence and of floral initiation was attributed to high CO2concentrations. Growth of unmixed cultures of Sorghum under 600 ppm CO2was relatively poor because of an apparent interaction of high CO2with self-shading. All instances of culturexCO2interactions are offered in supported of the hypothesis that elevated CO2levels will effect the competitive interaction of C3and C4species. Peak net assimilation rates of C3and C4plants were seasonally separated at 350 ppm CO2but coincided at 600 ppm. Based on our observations of Festuca and Sorghum, we project that global CO2enrichment may alter competitive balance between C3and C4plants and subsequently affect seasonal niche separation, species distribution patterns, and net primary production within mixed communities.
authors.affiliation: Department of Botany, Clemson University, 29631, Clemson, SC, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Carter
authors.affiliation: Department of Botany, Clemson University, 29631, Clemson, SC, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Peterson