Clonal multiplication of Syzygium alternifolium (WIGHT.) WALP., through mature nodal segments
1999
Khan, P.S.S.V. | Hausman, J.F. | Rao, K.R.
Clonal multiplication of Syzygium alternifolium (WIGHT.) WALP., (Myrtaceae), a rare medicinal tree was achieved through mature nodal segments on modified MURASHIGE and SKOOG's (MS) medium. Shoot initiation was dependent on cytokinin supply, but the synergistic combination of 4.0 mg/l N-6 benzyladenine and 0.5 mg/l 1-naphthaleneacetic acid induced the highest percentage of nodal segments sprouting (69.5 +/- 2.9%), number of shoots per node (3.9 +/- 0.1), shoot length (2.9 +/- 0.2 cm), the number of new nodal segments generated per active explant (2.2 +/- 0.1) and the multiplication co-efficient (1.5) within 6 weeks. Explants harvest period influenced the shoot initiation in nodal segments. Repeated subculturing through five passages of nodes of shoot cultures enabled continuous production of healthy shoots. At the end of the 5th passage, 72% to 73% of nodal segments produced 8 to 9 shoots, each having 4 cm height and 3 to 4 nodes. Multiplication co-efficient was also increased from the Ist subculture (1.5) to the 5th subculture (2.3). Rooting involved a two step method: root initiation on solidified half-strength MS medium supplemented with 1.0 mg/l indole-3-butyric acid (IBA), and root elongation following transfer to half-strength MS medium devoid of growth regulators. Repeating this two step sequence yielded up to 70% of rooted shoots. Shoots derived from subcultures exhibited better rooting response than those from cultures of shoot initiation. About 70% of the rooted plants were established in 20 cm diameter pots containing a mixture (1:1) of soil and sand after 3 weeks of hardening.
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