Abstract:
This research aimed to investigate appropriate culture media for micropropagation of Beijing bamboo or Chinese bamboo or Meng Son bamboo (Dendrocalamus sp.) via shoot multiplication. Nodal segments were cultured for 2 weeks on modified solid Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA) at the concentrations of 2.5, 5.0 and 7.5 mg/l or thidiazuron (TDZ) at 0.3, 0.6 and 1.0 mg/l alone or in combinations (2.5 and 5.0 mg/l BA in combinations with 0.5 mg/l TDZ) . It was found that modified MS medium containing 0.6 mg/l TDZ and modified MS medium containing 2.5 mg/l BA in combination with 0.5 mg/l TDZ provided the highest number of shoots at 4.7 and 4.9 shoots per nodal segment, respectively, with shoot length at 4.0 and 3.6 cm., respectively. For shoot multiplication, a 3-shoot clump derived from a nodal segment was cultured for 2 weeks on modified MS medium supplemented with TDZ (0.3 mg/l) or BA (2.0, 3.0, 4.0 mg/l) or BA at the concentrations of 2.0, 3.0 and 4.0 mg/l in combination with kinetin (Kn) at the concentrations of 3.0, 2.0 and 1.0 mg/l, respectively. The results showed that modified MS medium containing 0.3 mg/l gave the highest number of multiple shoots at 11.8 or 10.5 shoot per clump with shoot length at 1.72 or 2.56 cm on solidified or liquid medium, respectively. The obtained shoots were 12 and 21 times more than shoots from MS medium without growth regulator. Moreover, modified solid MS medium containing 0.3 mg/l TDZ also gave the highest shoots at 4.6 shoots per node with shoot length at 2.02 cm. from nodal segments of cultured shoots. For increasing efficiency of multiple shoot induction, organic substances, adenine sulphate (30 and 50 mg/l), malt extract (200 and 400 mg/l), tryptone (200 and 400 mg/l), biotin (0.05 and 0.1 mg/l) or glutamic acid (0.5 and 1.0 mg/l) were added in modified liquid MS medium supplemented with 0.3 mg/l TDZ. The highest number of multiple shoots were obtained from medium added with 400 mg/l tryptone in the second week and the fourth week of culturing, providing 9.4 and 12.5 increasing shoots per clump, respectively, with shoot length at 3.64 and 3.33 cm, respectively. The obtained shoots were 12 and 16 times more than shoots from MS medium without growth regulator. For rooting, a 3-shoot clump was cultured on modified solid MS medium containing 10 mg/l coumarin and 2.0 mg/l AgNO3 and added with 3-indole butyric acid (IBA) at the concentration of 3.0 or 6.0 mg/l in combination with sucrose at the concentration of 30 or 60 g/l. Furthermore, liquid MS medium containing 400 mg/l tryptone and added with 5.0 mg/l a-naphtaleneacetic acid (NAA) alone or in combination with 0.3 mg/l BA or medium added with 3.0 mg/l IBA and 2.0 mg/l NAA with or without 0.3 mg/l BA as well as modified solid ½MS medium added with NAA or IBA at the concentration 5.0 mg/l alone or NAA concentration 3.0 and 2.0 mg/l in combination with IBA at the concentration of 2.0 and 3.0 mg/l were used for rooting. No root was found in all rooting media, but 0.2-0.6 increasing shoots were observed in some rooting media.