Fig. 4

NRT1.5-regulated root growth is dependent on auxin accumulation. A Root growth of seedlings (Col, nrt1.5) under MS or LK medium containing auxins (IAA, 2,4-D), auxin biosynthesis precursor (IBA), and auxin biosynthesis inhibitor (Kyn). Four-day-old seedlings were transferred to MS or LK medium containing 2.4-D (10 nM, 50 nM), IAA (25 nM, 50 nM), IBA (25 nM, 50 nM) and Kyn (0.1 μM, 1 μM) for 3 days, bar = 1 cm. B The lengths of the primary root growth shown in (A). Data are shown as means ± SE (n = 20). Student’s t-test (* P < 0.05; ** P < 0.01) was used to analyze statistical significance