Figure 1.

GABA inhibits Arabidopsis root growth. Histogram showing mean primary root lengths of 7-day-old Arabidopsis seedlings grown on vertical agar plates containing a modified Gamborg's B5 medium¹⁶ with the addition of either 10 mM GABA or glutamate (Glu), or with no supplementary amino acids (control). Error bars represent SEM. Nitrate was included in the medium in the form of 0.33 mM NH₄NO₃ (1 mM total N) to suppress the inhibition of root growth by Glu reported by Walch-Liu et al.¹⁷