Elevated carbon dioxide and nitrogen supply affect photosynthesis and nitrogen partitioning of two wheat varieties

The response of wheat to elevated carbon dioxide concentration (e[CO2]) is likely to be dependent on nitrogen supply. To investigate the underlying mechanism of growth response to e[CO2], two wheat cultivars were grown under different carbon dioxide concentration [CO2] in a chamber experimental facility. The changes in leaf photosynthesis, C and N concentration, and biomass were investigated under different [CO2] and N supply. The result showed an increase in photosynthesis under e[CO2] at all N level except the one with the lowest N supply. Furthermore, a significant decrease in g(s) and Tr for both the cultivars was also observed under e[CO2] at all N levels. A considerable increase in WUEi was observed for both the cultivars under e[CO2] at all N levels except for the lowest concentration one. Therefore, the study shows that a stimulation of plant growth under e[CO2] to be marginal at higher N supply.