In vitro shoot multiplication through shoot tip cultures of Decalepis Hamiltonii Wight & Arn., a threatened plant endemic to Southern India

An efficient and rapid micropropagation system was developed for a food and medicinally important endangered shrub, Decalepis hamiltonii ('swallow root'), through shoot multiplication. The influence of 2.5-7.5 muM isopentenyladenine (2iP), 4.4-17.7 muM 6-benzyladenine, 2.3-4.7 muM kinetin, 2.8-6.8 muM thidiazuron, and 2.3-11.4 muM zeatin alone and in combination with 0.3-0.9 muM indole-3-acetic acid (IAA) on in vitro multiple shoot production was studied. The maximum number of multiple shoots (6.5 +/- 0.4) was induced front shoot tips cultured on agar-based Murashige and Skoog (MS) medium containing 4.9 muM 2iP. But, both zeatin (9.1 muM) and kinetin (4.7 muM) in combination with IAA (0.6 muM) were able to produce a maximum of 5.0 +/- 0.4 and 5.1 +/- 0.4 multiple shoots, respectively. Further elongation of shoots and adventitious shoot formation was obtained on medium containing 2.5 muM 2iP and 0.3 muM gibberellic acid. Elongated shoots were separated and rooted on MS medium supplemented with 9.8 muM indole-3-butyric acid (IBA) and various phenolic compounds within 5-6 wk. Phloroglucinol and salicylic acid interaction with IBA stimulated in vitro rooting of shoots. Successful field transfer was achieved in rooted plantlets.