Figure 4. Effect of different Arg concentrations on the primary root growth. (A-F) Germinated seeds of wild type (left) and mutant (right) were exposed for 5 days to a 0.5 mM CaCl₂ solution containing 0 (A), 0.05 mM (B), and 0.1mM (C) arginine or 0 (D), 0.2 mM (E), and 0.5 mM (F) arginine.