ABSTRACT
Secondary metabolites of plant origin have long been used as drugs, perfumes, spices, or pigments, and there is an increasing demand for these natural products. In contrast to the extensive utilization of substances from higher plant sources, bryophytes have rarely been considered as a source of substances useful for human beings. However, progress in the phytochemistry of bryophytes has revealed that they contain substances with various biological activities. Actively growing meristematic tissues in seedlings, roots, or stems are generally utilized as the starting material for the induction of callus in vascular plants. These tissues can be sterilized by successive or combined treatments with benzalkonium chloride, ethyl alcohol, chlorinated water, and sterilized water. The cultured cells of liverworts have several unique physiological attributes differing from those of vascular plants. The dedifferentiation of thallus and redifferentiation of callus into thallus are primarily regulated by the concentrations of sugars included in the medium.
