Fig. 1.

Infection and nodule development in wild type (WT) and gibberellin-deficient na-1 plants 9 d after inoculation with lacZ-labelled Rhizobium leguminosarum bv. viciae. (A) Number of infection structures, including infection threads, bacterial accumulations, and nodules per root epidermal cell, in experiment 1. (B, C) Data from four independent experiments shown: (B) ratio of bacterial accumulations to infection threads and (C) ratio of nodules to infection threads. (D) Number of infection structures per root epidermal cell in the WT and na mutants with and without exogenous gibberellin (10 µg GA₃). Values are the mean ±SE (1–6 secondary roots from n=5–12 plants). For (A–C) asterisks indicate significant differences (**P<0.01, ***P<0.001, ****P<0.0001) na was compared with the corresponding WT line and for (D) values with different letters are significantly different (P<0.05); n.d., not detected.