Elevated CO2 and water-availability effect on gas exchange and nodule development in N2-fixing alfalfa plants

N2-fixing alfalfa plants were grown in controlled conditions at different CO2 levels (350 μmol mol−1 versus 700 μmol mol−1) and water-availability conditions (WW, watered at maximum pot water capacity versus WD, watered at 50% of control treatments) in order to determine the CO2 effect (and applied at two water regimes) on plant growth and nodule activity in alfalfa plants. The CO2 stimulatory effect (26% enhancement) on plant growth was limited...