GUAR GUM AS A GELLING AGENT FOR PLANT TISSUE CULTURE MEDIA

Guar gum, a galactomannan derived from the endosperms of Cyamopsis tetragonoloba, has been successfully used as a sole gelling agent for plant tissue culture media. Its suitability as a gelling agent was demonstrated by using guar gum-gelled media for in vitro seed germination of Linum usitatissimum and Brassica juncea, in vitro axillary shoot proliferation in nodal explants of Crataeva nurvala, rooting of regenerated shoots of the same, in vitro androgenesis in anther cultures of Nicotiana tabacum, and somatic embryogenesis in callus cultures of Calliandra tweedii. The media used for these were gelled with either guar gum (2, 3, or 4%) or agar (0.9%). Guar gum-gelled media, like agar media, supported all these morphogenic responses. Rather, axillary shoot proliferation, rhizogenic and embryogenic responses were better on guar gum-gelled media than on agar media.