Figure 2.

Nitrate effects on nodulation and plant growth in the Ljnrt2.1 mutants. A–C, Nitrate effects on nodulation in the WT and Ljnrt2.1-1 mutants. A, The number of infection threads in plants growing in 0 (−) or 10 mM KNO₃ (+) at 7 dai with rhizobia that constitutively express DsRED (n = 11–12 plants). B, The number of nodules in the presence of 0 (−) or 10 mM KNO₃ (+) for 21 dai (n = 15 plants). C, Nodule size of the WT and Ljnrt2.1-1 mutants (n = 19–22 nodules). The WT and Ljnrt2.1-1 plants were inoculated for 7 days in nitrate-free agar plates. After the formation of nodule primordia, the plants were transferred to new plates containing 0 or 10 mM KNO₃. Individual nodule size was measured at 0, 5, 10, 15, and 20 days after the transfer. Error bars indicate standard error of the mean (SEM). *P < 0.05 by a two-sided Welch’s t test. D and E, Fresh shoot weight (D) and shoot growth (E) of the WT, Ljnlp4-1, Ljnlp1, and the Ljnrt2.1-1 mutants grown in 0 (−) or 10 mM KNO₃ (+) in the absence of rhizobia for 13 days (n = 12 plants). Error bars indicate sem. Different letters indicate statistically significant differences (P < 0.05, one-way analysis of variance (ANOVA) followed by multiple comparisons). Scale bar = 1 cm.