Growth and Monoterpene Production in Shoot Culture and Regenerates of Mentha arvensis

Axenic shoot culture of Mentha arvensis was established from young shoots of plants cultivated in a field. In the shoots cultured on Murashige-Skoog solid and liquid media for 3-4 weeks, pulegone was the main constituent in both cases, and the content of pulegone in liquid medium was much more than that on solid medium. The shoots cultured in the dark for 3 weeks produced only pulegone. However the shoots placed under 16 h/day light condition started to produce menthone and menthol together with pulegone which was the main compound. The plantlets obtained by culturing on hormone-free Murashige-Skoog solid medium at 25oC in 16 h/day light were transplanted to pots, and formed pulegone at the early cultivation stage, then menthol was detected as the main compound in the later cultivation stage at week 8.