High-B-induced NGAL1 expression and ngal1 growth under high B. (A) NGAL1 mRNA accumulation was quantified in roots and shoots of Col-0 plants grown for 14 d under control-B (+B) and high-B (++B) conditions. Tissues of five to six individual plants were pooled as one sample replicate, and data are mean of n = 9 sample replicates. Relative expression was normalized to the root data of Col-0 at +B as 1.0. Asterisks indicate significant increases under high B (Student’s t-test; *, P < 0.05, **, P < 0.01). (B) Histochemical GUS staining in 12-day-old pNGAL1::GUS transgenic seedlings grown under control B and high B. Scale bar: 1 cm. (C) and (D) Shoot and root FWs of seedlings, respectively, were measured in wild-type Col-0 and ngal1 mutant alleles grown under the treated conditions for 16 d. Data are mean of 48–60 individual plants. Different letters within each B condition indicate significant reductions in ngal1 mutants (Dunnett’s test; P < 0.05). B concentrations in the treated conditions were as follows: control B (+B: 30 µM B) and high B (++B: 3000 µM B).