Effect of AlCl3 and BHA on root growth of SR1 and AER-OE lines (P1#14 and P1#18). Seeds were sown on MS agar plates, the seedlings were cultured for 14 d, and then the seedlings were transferred into sterilized filter paper soaked by following solutions: (1) one-sixth-strength HS (Control), (2) 10 μm BHA in one-sixth-strength HS (+BHA), (3) 500 μm AlCl3 in one-sixth-strength HS (+Al), and (4) 500 μm AlCl3 + 10 μm BHA in one-sixth-strength HS (+Al+BHA) for 5 d as described in “Materials and Methods.” After the treatment, root elongation was measured. Data are means ± se of three replications (each replication included 10 plants). Values followed by the same letter are not significantly different according to Tukey-Kramer test (P < 0.05).