Fig. 1. Effect of CO2 (ambient CO2. approximately 400)xmolmol-' and elevated
CO2, 700nmolmol-') and increasing doses of NH4NO3 (0. 10 and 15mM) on net
photosynthesis (A„„, (imol CO2 m^^ s ') of nodulated alfalfa at the age of 44 (A and
C, corresponding to 2 weeks of treatment) and 60 days (B and D. corresponding to 4
weeks of treatment), at 400 and 700 (imol m o l " ' CO2. Bars represent the mean ± SE;
n - 4. Bars with the same letter are not significantly different (P > 0.05) according LSD
test.
significant differences were evaluated using Lees Significant Difference
post hoc tests (LSD) (P< 0.0