Photosynthesis of wheat under field conditions. III. Seasonal trends in carbon dioxide uptake of crop communities

Abstract

Photosynthesis of two wheat cultivars grown in the field was examined during three seasons by use of a portable field assimilation chamber. There were large differences in dry weight, leaf area, and carbon dioxide uptake between seasons. Variations in carbon dioxide uptake by the community were related mainly to changes in leaf area index (LAI). There were changes in carbon dioxide uptake per unit LAI with time, and between the two cultivars in the first season, but the effects of these changes were small compared with the effects of LAI. Differences in grain yield were correlated with LAI and carbon dioxide uptake in the period after anthesis.