Fac. of Grad. Studies, Mahidol Univ. M.Sc. (Plant Science) / 33
3.2.3 The effects of -napthaleneacitic acid (NAA), benzylaminopurine (BA) and thidiazuron (TDZ) on survival, PLB formation, shoot and root formation from PLBs of R. gigantea (Amethyst purple).
Base on the varying effects of basal media on maximum PLB formation, modified VW medium and SH medium were selected to future examine the effect of plant growth regulators (PGRs) on PLB multiplication and subsequent plantlet development. About 0.2 cm in diameter of R. gigantea PLBs were cultured on modified VW and SH basal medium containing 1% (w/v) sucrose, pH 5.3, 5.8 respectively and supplemented with auxin like α-napthaleneactic acid (NAA) (0.5 and 1 mg/L) and cytokinins like benzylaminopurine (BA) (1, 2 and 4 mg/L) and thidaizuron (TDZ) (0.1, 0.5 and 1 mg/L) individually and in several combinations. Each treatment consisted of 21 treatments replicated four times and in each tube had three PLBs. The cultures were incubated at 25 2 oC under white fluorescent light at the intensity of 37 mol/m2/s for 16 h per d. Numbers of shoot and root formation were observed at 12 weeks of culture.
3.2.4 The effects of -napthaleneacitic acid (NAA) and activated charcoal on root induction.
Shoots from PGR treatments in SH agar medium supplemented with 0.1 mg/L TDZ were harvested an inoculated into SH medium that supplemented with NAA and activated charcoal (AC). The purpose was to determine the morphogenetic effect of NAA and AC on subsequent plantlet growth. Modified VW cannot produce plantlets but induce PLB formation. While SH medium can induce shoots and roots. About 5 mm of tiny shoots were cultured on SH solid medium containing 1% (w/v) sucrose, pH 5.8 and supplemented with 0, 0.5 and 1 mg/l and 1% (w/v) AC. Tiny shoots were cultured under the same condition as described above. Numbers of shoot and root formation were observed at 12 weeks of culture.