Fig. 3. Chemical complementation with GA₃ restores nodulation phenotypes to GA knockout.

The soil substrate of soybeans nodulated by GA⁺ or ga⁻ B. diazoefficiens was treated weekly with 1, 10, or 100 nM GA₃ in water, or GA-free water as a negative control. The following phenotypes were measured at the early pod stage: A number of nodules per plant B average mass per nodule, and C total nodule mass. D Representative root nodules from each experimental group. Each image shows nodules isolated from one plant. n = 7 for each treatment. Shown for each experimental group is the mean ± SD. Statistical significance was assessed using a two-way ANOVA and Dunnett’s multiple comparison test with the GA⁺ water treatment as the control group. n.s. indicates p > 0.05. Individual p values are shown when ≤0.1.