IMPROVEMENT OF THE IN VITRO DEVELOPMENT OF Mentha piperita L. AND Mentha longifolia (L.) Huds. VARIETIES.

Peppermint varieties are representative regarding therapeutical properties. The aim of this paper was to study the in vitro germination and micropropagation potential of two mint cultivars, namely Mentha piperita and M. longifolia. In vitro germination of Mentha longifolia seeds has been stimulated with gibberellic acid. Using an experimental system with two stages of three months, we obtained 50 microshoots per culture from every variety. Two variants of the basal Murashige - Skoog medium supplemented with benzyl adenine (BAP), 1 - naphthylacetic acid and yeast extract have been optimal for in vitro microshoot multiplication of the both cultivars. The proportions of the growth factors differed, i.e. 5:1:100 mg/L for Mentha piperita and 3:0.5:100 mg/L for M. longifolia. The capacity of both mint cultivars to maintain their viability for a long period between transfer on a fresh culture medium was evident. We developed an in vitro conservation strategy and obtained an increased number of regenerants that can ensure a considerable amount of biomass to cover the required vegetal material useful in cosmetic and pharmaceutical industry. [ABSTRACT FROM AUTHOR]