ABSTRACT
Lavandula spp. are widely cultivated aromatic crops in Mediterranean areas, because lavender essential oil constitutes a very important natural product of a high industrial interest (Ivanov and Nikolov, 1988; Charlword et al., 1986). Although these species can be vegetatively propagated, the poor rooting ability of the stem cutting, as well as the lack of selected clones restrain its economical exploitation (Calvo and Segura, 1989). For these reasons, an interest has been developed recently in producing these valuable compounds using a biotechnological approach. The tissue culture technology offers the ways for overcoming these limitations by providing methods for both rapid multiplication and improvement of the species. The first report on the in vitro multiplication of the Lavandula spp. from axillary buds was published in 1980 (Quazi, 1980). Later, a complex investigation on the Lavandula latifolia Medicus (a species which is one of the most widely cultivated in the Mediterranean areas) was performed by Calvo et al. (1988; 1988a; 1989; 1989a) and Jordan et al. (1990). They found that the hypocotyl explants of L. latifolia Medicus were with the potential for mass propagation (Calvo et al., 1988a). On this basis, they succeeded in establishing the culture requirements for promoting morphogenesis from hypocotyl and from cotyledon and root explants as well (Calvo et al., 1988a; Calvo and Segura, 1989) and from cultured leaves of L. latifolia (Calvo and Segura, 1989a). They also extended this research to procedures and factors, promoting plant regeneration from callus and isolated cells of L. latifolia Medicus (Calvo et al., 1988a; Jordan et al., 1990). The knowledge gained from these studies may enable mass production of L. latifolia plants. Also, plants regenerated from single cells can be an important source of genetic diversity and some cloned variations which could be used for selecting strains that produce large amounts of essential oils (Jordan et al., 1990).
