For several species, the occurrence of variant leaves seems to be associated with high
concentration of auxin in the medium (Vajrabhaya, 1977; George and Sherrington, 1984).
However, there is a possibility that the tissue culture procedure itself is mutagenic. In
an assay on colour mutagenesis, in stamen hairs of Tradescantia, medium components
including 2,4-D (2,4-dichlorophenoxyacetic acid) appeared not to be mutagenic (Dolezel
and Novak, 1984). Micropropagation of Gerbera jamesonii is enhanced by increasing the
level of cytokinin in the medium. This may satisfy the demand for rapid propagation, but
could lead to the abnormality called bushiness, resulting in a production loss of up to 30%
(Topoonyanont et al., 1999).