Studies on influence of different hormonal concentrations on in vitro micropropagation of Mentha piperita

Abstract

Mentha piperita L. (Family Lamiaceae) is a perennial herb which contains essential oil that has been used as an ingredient in medicine. It thrives well in humid and temperate climate and mostly cultivated in temperate region of Asia, Europe, United States and India. Peppermint is widely used in food, cosmetics and medicines. It has been proven helpful in symptomatic relief of common cold. Due to its industrial importance in such vast areas of human need this species is drastically collected and in near future it may loose its presence on mother earth. So, it s an urge to perform tissue culture in preserving such important herbs and devise a protocol for rapid proliferation of Mentha piperita L. So this study was performed to develop a new protocol by standardizing the different hormonal concentrations and getting large number of genetically identical plantlets rapidly. Regeneration of Mentha piperita plantlets was obtained by treating explants viz. nodal segments of Mentha with different concentration and combinations of Auxin and Cytokinin for the formation of microshoots. Sterilization of the explants was obtained by treating with 0.1% HgCl2 for 3 minutes with 2-3 drops of Tween-20 (a detergent) and then rinsed thrice with double distilled water. Fully developed plantlets were successfully transferred to suitable growing media for acclimatization and there further growth and development. Experiment was performed to study the effect of different concentration and combination of Auxin including IAA and Cytokinin i.e KN on the shoot proliferation of Mentha piperita explants, the parameters under study were number of days to shoot intiation, number of shoot per explants and shoot length were studied. The in vitro micropropagation was carried out on MS medium at different concentrations of growth regulators like KN (0.5, 1 and 1.5mg/l) and IAA (0.5, 1 and 1.5mg/l) on MS medium. After 6 weeks of incubation the best shoot induction medium for shoot multiplication and proliferation with higher number of shoots was recorded at 1.0mg/l of IAA and 1.5mg/l of KN.