Synergistic effects of Vermi-Co extracts mixture with cytokinins on shoot regeneration of Lindernia minima (Benth.) Mukerjee—An endangered medicinal plant

Abstract

The present investigation illustrates the synergistic growth effect of Vermi-Co (Vermicast and Coconut-water) extracts mixture with cytokinins on in vitro shoot regeneration of Lindernia minima. Due to less distribution threat status, this plant species has been considered as an endangered plant by IUCN (International Union for Conservation of Nature). Hence, it is necessary to conserve and to develop an efficient plant regeneration protocol for the rapid multiplication of L. minima. The nodal explants were inoculated on (¼) quarter-strength MS (Murashige and Skoog) medium supplemented with different concentrations (0.5 – 2.5 mg L-1) of BA (6-Benzyladenine), KIN (Kinetin) and TDZ (Thidiazuron) combined with various percentages of (5%, 15%, and 25%) Vermi-Co extracts mixture. Among the concentrations tested, 1.5 mg L-1 TDZ with 15% of Vermi-Co extracts mixture produced the maximum percentage of response with the highest (19.5 ± 0.20 shoots/explant) number of shoots and (10.2 ± 0.14 cm) shoot length. Then, the well-elongated shoots were transferred to rooting medium (quarter-strength MS) supplemented with 0.5 – 3.0 mg L-1 of IBA (Indole -3- butyric acid) and IAA (Indole -3- acetic acid). The highest percentage of response (98%) and maximum number of roots were observed in 1.5 mg L-1 IBA with 11.5 ± 0.29 roots per shoot and 6.6 ± 0.28 cm root length. Finally, well-developed plants were successfully transferred to the natural field condition with a survival rate of 97%. The present research revealed that, the combined growth stimulating effect of Vermi-Co extracts mixture combined with cytokinins increased the number of shoots and shoot length on shoot regeneration of L. minima from nodal explants. Our findings will be very useful for regeneration of Lindernia minima through plant tissue culture.