Comparison of growth and phytochemical identities in Withania somnifera plants produced through conventional methods and tissue culture

Abstract

Withania somnifera (L.) Dunal (Sin: Amukkara, San: Ashwaganda) is a valuable medicinal plant, belongs to the family Solanaceae. W somnifera is normally propagated by seeds but wall of the fruit contains a chemical which prevent seed germination. n 21 {:(':...i,:; ::' .)·'I~) ·~~;I·.'~ .;__ ~l .):_1,. (~. ~\ .. ' ..or,. (.~. '\" . 1 " J \.' ::;,-- ... .J <: " .:. The objective of this study was to develop successful protocol to acclimatize in vitro propagated plants of Withania somnifera and compare tissue cultured plants with seed raised plants based on growth, physiology, anatomy and chemically. In the present study nodal segments, shoot tips and leaf pieces were used as explants in different growth regulator combinations (auxines and cytokinines). All tested explants produced calli and best callus production was observed in MS medium supplemented with 1.0 uM Kin, 4.5 uM BAP and 1.5 uM NAA under 14 days dark period. Shoot initiation was observed in the same medium from the calli produced from shoot tips and nodal segments. Highest shoot multiplication was observed in MS medium supplemented with 9.0 uM BAP and 1.0 ulvl IAA. Callus produced from leaf pieces did not respond in any medium to produce shoots. No significant difference was observed among tested treatments for rooting, suggesting growth regulator free MS medium was the best medium for rooting of W somnifera. In vitro produced plants were acclimatized successfully in a potting mixture of river sand: top soil: compost in 2: 1: I ratio. Rate of photosynthesis was higher in tissue cultured plants at three months and six months compared to seed raised plants. TLC finger prints and densitometry was used to compare chemical identities (steroids considered) and it was found that there is no significant difference in chemical identities present in tissue cultured and seed raised plants.