In vitro rejuvenation of nodal segment explants for clonal propagation of Rauvolfia serpentina (L) Benth ex Kurz

Abstract

Abstract Rauvolfia serpentina (L) Benth ex Kurz is an endangered medicinal woody species, widely distributed in Asia and used in several traditional medicine systems. Application of in vitro clonal propagation offers alternative strategies for biomass production useful in the production of pharmaceuticals but, difficulty in explant selection and low response to clonal production are impediment to the success. The present study evaluated efficiency of in vitro rejuvenation of nodal segment explants derived from basal offshoots and terminal buds collected across growth seasons and effect of serial subcultures on shoot morphogenesis in R. serpentina. Effect of culture medium strength (quarter, half and full strength MS) on shoot morphogenesis and proliferation through four (4) subcultures were also evaluated. Of the PGRs tested, BAP was more efficient over Kin and TDZ, and addition of NAA (0.5 mg L− 1) to the PGRs promoted shoot morphogenesis. Rhizogenesis was achieved using half basal MS medium added with IBA, NAA and IAA with IBA been the most efficient over other auxins tested. However, lower concentration of the IBA showed most appropriate results on good root differentiation. As a result, IBA has been the most efficient over other auxins tested but, lower concentration is the most appropriate for good root differentiation. Differential accumulation of pigment molecules and cellular osmolytes in response to the culture condition were evaluated in the dark-green and pale-green leaf morpho-types observed in the shoot cultures. Results of the present experiment suggests that explants collection season and PGRs influenced in vitro rejuvenation of nodal segment explants through physiological and biochemical changes essential for shoot morphogenesis.