MICROPROPAGATION OF Myrtus communis L. AND COMPARISON OF EPIDERMAL Glandular trichomes CHARACTERISTICS BETWEEN in vivo AND ex vitro PLANTLETS

The myrtle (Myrtus communis L.) is a shrubby species, typical of the Mediterranean area and very common in Albanian Flora. Interest for this species is related to its uses as aromatic medicinal plant in medicine, food, industry, handicraft, cosmetics, etc. Micropropagation is considered as a useful method to produce the homogeneous plants for large scale cultivation. The goal of this study is to find an optimum micropropagation protocol by using different PGRs ratio and/or types. Also glandular trichomes characteristics between in vivo and ex vitro plants were also evaluated. The samples were stained with toluidine blue and type, distribution, density and diameter of glandular trichomes were evaluated for both categories under study. Regarding micropropagation stages, during proliferation stage a specific cytokinin/auxin ratio equal to 40 resulted optimum for this purpose, meanwhile for rhisogenesis induction the auxin IBA at 0.1 mg/l gave a higher number of roots in comparison to NAA at the same level. Glandular trichomes are distributed in both epidermis for in vivo and ex vitro plantlets. Regarding to the diameter and density of the glands, the difference between the two categories in the study is significant. In vivo samples resulted with a lower density and a smaller diameter of glandular trichomes. This micropropagation protocol may be beneficial for mass propagation and will serve as a base to establish effectively in vitro genetic collection. In this context, altering in vitro culture conditions gives possibilities in improving secondary metabolites production in aromatic medicinal plants.