Figure 5.

N movement from the ERM to the IRM in mycorrhizal carrot roots based on the timing of labeling free amino acids in the mycorrhizal roots after the addition of 4 mm K¹⁵NO₃ to the fungal ERM. A, The percentage of total free amino acids represented by Arg (including ¹⁵N-labeled and unlabeled molecules; white bars) and the percentage of total free amino acids represented by only ¹⁵N-labeled Arg (black bars) in the colonized roots (plant plus IRM tissue) after 4 mm K¹⁵NO₃ was applied to the ERM. B, The percentage labeling in the free amino acids in the mycorrhizal roots at 4 h (white bars), 8 h (black bars), 24 h (gray bars), and 72 h (hatched bars) after adding 4 mm K¹⁵NO₃ to the ERM compartment. GABA, γ-Aminobutyrate.