SA-induced ARF increases in mung bean hypocotyl cuttings.
(a) Hypocotyls were incubated with 0, 0.1, 0.2, 0.4, 0.6 and 0.8 mM SA for 24 h and washed three times, and then the cuttings were transferred into distilled water. The cuttings were continuously grown for 5 days in this distilled water at 25±2°C, with a 14-h photoperiod (PAR of 200 µmol m−2 s−1). The distilled water was replaced every day. The root numbers were determined at 5 d after treatment. In addition, adventitious roots of more than 1 mm long were quantified. The values represent the means of 30 explants, and the different letters above the bars indicate significant differences among the treatments at a P<0.05 level, according to the LSD test. (b) Time course of adventitious root formation induced by application of SA or water in mung bean hypocotyls. Hypocotyls were treated with 0.4 mM SA (the optimal concentration) or CK (water) for 24 h and were then transferred into distilled water and continuously grown for 7 days at 25±2°C, with a 14-h photoperiod (PAR of 200 µmol m−2 s−1). The root numbers were determined in 24-h intervals. The distilled water was replaced every day, and the number of adventitious roots of more than 1 mm long was recorded. The values represent the means of 30 explants, and the error bars represent the SE (P<0.05) .