Role of polyamines on in vitro regeneration and podophyllotoxin production in Podophyllum hexandrum Royle

Podophyllum hexandrum is a popular medicinal plant endemic to Himalayas. In the present investigation, we report an efficient mass propagation protocol and Podophyllotoxin (PTOX) production in in vitro -derived plants of P. hexandrum, cultured on MS medium containing various plant growth regulators and polyamines. A combination of BA (1.5 mg/L), IAA (0.2 mg/L) and spermidine (20 mg/L) produced the highest number of multiple shoots per explant (23 shoots) after 6 weeks of culture; the regenerated shoots were elongated on the same medium. The elongated-shoots were rooted on root induction medium (half strength MS medium) supplemented with IBA (1.5 mg/L) and putrescine (15 mg/L). The rooted plantlets were successfully hardened and acclimatized with a survival rate of 68% in the greenhouse. The highest content of PTOX (4.23 mg/g DW) was recorded in in vitro derived roots followed by leaves when compared to field-grown parent plants. The present system offers the possibility to use in vitro culture techniques for mass propagation and PTOX production for commercial utilization.