Regeneration in Chlorophytum borivilianum through Somatic Embryogenesis

Chlorophytum borivilianum, an important medicinal plant belonging to the Lilliaceae family is valued for its dried fasciculated roots, which have aphrodisiac properties and also form an important ingredient of various herbal medicines. A high frequency regeneration protocol for rapid multiplication of C. borivilianum through the induction of somatic embryos was attempted. Microshoots along with a part of the stem disc were cultured on Murashige and Skoog (MS) medium supplemented with a low concentration range (0.25, 0.5, 0.75 and 1.0 mg l -1 ) of 2,4-Dichlorophenoxyacetic acid (2,4-D) alone, and in combination with different concentrations of cytokinins like 6benzylaminopurine (BAP) and kinetin (Kn). One hundred per cent callus induction and embryogenic response was noticed at all low concentrations of 2,4-D. The number of days required for callusing (29.8), the number of embryos (67.2), the diameter of embryogenic callus (2.28 cm) was more with1.0 mg l -1 2,4-D, the average fresh (1.073 g) and dry (0.100 g) weights of callus were more when 1.0 mg l -1 2,4-D was used. The callus resulting from these treatments was friable, glossy and creamish-yellow in appearance. After 60 days of culture in induction media, 100% maturation was achieved on plain MS and on MS medium with 0.1 mg l -1 abscisic acid (ABA). Embryos derived from treatments with 2,4-D did not show 100% embryo maturation, which could, however be achieved if these were added to cytokinin-supplemented medium. Sixty two per cent of matured embryos formed shoots on media devoid of plant growth regulators but these took nine days to germinate unlike the precocious germination (5 days) demonstrated by matured embryos treated with 0.5 mg l -1 gibberellic acid (GA3). Shoot induction formed in 60% of embryos treated with 0.5 mg l -1 TDZ and 0.5 mg l -1 Kn but most shoots showed malformation during growth. Stereo and fluorescence microscopy study confirmed all the different developmental stages of embryos, including the suspensor.