Cloning of Rauvolfia serpentina-An Endangered Medicinal Plant

Abstract

Rauvolfia serpentina Benth. ex Kurz called sarpagandha(the snake root) in Hindi, belongs to family Apocynaceae. This plant is listed in earliest Ayurvedic medicinal text the Charaka Samhita(c. 700 B.C.) and has been used since at least that time to treat mental illness and insomnia. The roots of R. serpentina contain numerous alkaloids. Its indiscriminate use and poor method of conventional propagation have led this species to be included in the list of endangered plants. Thus, a need arises to generate an efficient protocol for cloning of R. serpentina in order to regenerate propagules to replenish depleting forests and meeting the demand of commercial cultivation. We report here on development of an efficient and simple process for large-scale clonal micropropagation of selected plants of R. serpentina and their successful field establishment. Nodal shoot explants produced multiple shoots (3-5 shoots per node) by axillary bud proliferation on Murashige and Skoog (MS) medium + 10 μM 6-benzylaminopurine (BAP) and 0.5 μM indole-3-acetic acid (IAA). Shoots were further multiplied on MS medium + 5.0 μM BAP + 0.5 μM IAA. After 3-4 subculture cycles (each cycle of 15-20 days) shoot multiplication rate increased up to 20-25 fold. Subsequently, shoots were multiplied on MS + 4.0 μM BAP to prevent hyperhydration. The micropropagated shoots were pulse-treated with 50 μM each of indole-3-butyric acid and P-naphthoxyacetic acid. About ninety-eight percent of in vitro- produced shoots rooted in vivo. The plantlets were transferred to bottles containing soilrite moistened with half-strength MS macrosalts. Eighty percent of these were hardened. Hardened plants were transferred to soils in black polybags. Micropropagated Rauvolfia serpentina plants grew normal in a nursery and these flowered, having set fruit/seed. The protocol developed is reproducible and can be used for germ plasm conservation and mass propagation of selected plant/ clone.