Fig. 2. Activities of acid phosphatase (a, b), alkaline phosphatase (c, d), and chitinase (e, f) in the rhizosphere of lateral roots (N) and young (Y), mature (M), and senescent (S) cluster roots of white lupine at 27 and 35 days after transplanting (DAT) as affected by P supply and atmospheric CO₂ concentrations. Data represent means and SD of independent determination.