Fig. 2

Net photosynthetic rate (a), RuBisCO activities (b) and carbonic anhydrase activities (c) in leaves of alfalfa seedlings with apical buds grown in 1.5 mM Ca(NO₃)₂ medium (pH 4.5) containing 0 μM AlCl₃ (pH 4.5), 100 μM AlCl₃ (pH 4.5 + Al), 100 μM AlCl₃ and 50 μM ZnCl₂ (pH 4.5 + Al + Zn), 100 μM AlCl₃ and 6 mg L^− 1 IAA (foliar spray) (pH 4.5 + Al + IAA) or 100 μM AlCl₃ and 50 μM ZnCl₂ and 6 mg L^− 1 IAA (foliar spray) (pH 4.5 + Al + Zn + IAA) on 3 days. Data are means ± SE of three replicates from three independent experiments. Bars with different letters indicate significant difference at P < 0.05 (Leas significant difference test)