Influence of putrescineon in vitro shoot morphogenesis from shoot-tip explants of Nyctanthes arbor-tristis (L.): An important medicinal plant

Seed An improved and effective method for shoot organogenesis and plant regeneration in Nyctanthes arbor-tristis (L.) was established. Shoot-tip explants were cultured on Murashige and Skoog (MS) media fortified with different concentrations of benzyl amino purine (BAP), naphthalene acetic acid (NAA) and zeatin for efficient shoot induction. BAP at 1.0 mgl-1 was found most effective for initial shoot bud induction. About 76.67% explants responded, resulting in the highest (5.9 ±0.11) number of shoots per explant after 30 days of culture. A combination having 1.0 mgl-1 BAP with 0.3 mgl-1 NAA in MS medium, performed best as shoot multiplication medium with highest (10.33 ±0.09) number of shoots per explant with a mean shoot length of 3.81 ±0.09 cm after six weeks. For improving the shoot morphogenesis, different concentrations of putrescine (10-100 mgl-1) were tested as an ethylene modulator. Putrescine at a concentration of 50 mgl-1 had maximum promoting influence on percentage of culture response (93.33%) and number of shoots (12.67 ±0.13) regenerated per explants with a mean shoot length of 6.84 ±0.13cm. The in vitro rooted plantlets were hardened and finally successfully transplanted in natural soil with almost 92% field survival rate.