CYTOGENETIC ANALYSES ON SEVERAL IN VITRO REGENERANTS OF MELISSA OFFICINALIS L.
DIANA-ELENA MAFTEI University “Vasile Alecsandri” of Bacău, Faculty of Sciences, Dpt. of Biology, Ecology and Environmental Protection; 157 Calea Mărăşeşti Str., 600 115, e-mail: diana.maftei@ub.ro
Melissa officinalis (lemon balm) is a medicinal plant used by herbal medicine for more than 2000 years for its positive therapeutic actions, mostly on the nervous and digestive systems.There were analyzed several regenerants of lemon balm that were provided in vitro on hormone-free MS medium (control variant), and on its variants enriched with growth regulators (medium variants A2, KN1, BG1). Regarding the mitotic activity, it was ascertained that the regenerants registered a mitotic index that ranged between 39.73 to 43.12 for the variants comprising growth regulators, compared to 46.18 in control. The distribution of cells on various phases of mitotic division does not alter compared to control plants; the highest frequency is held by prophases, followed by metaphases and telophases, and the lowest by anaphases. The high percentage of cells with chromosomal aberrations depicted in the root meristems of the in vitro regenerated plants confirms, once more, the fact that this culture method is accompanied by a high variability at the cytogenetic level, important for the practical valorization.
