In Vitro Micropropagation of Silybum marianum L from Various Explants and Silybin Content

Regeneration from leaf, shoot apex and nodal segments of in vivo and in vitro seedlings, and enhancement in silybin content have been achieved in Silybum marianum. The explants callused within four weeks on Murashige and Skoog's medium (MS) (1) supplemented with a-naphthaleneacetic acid (NAA, 0.1 mg I⁻¹) + 6-benzylaminopurine (BAP, 0.3 mg I⁻¹) + Zeatin (Zt, 0.3 rng I⁻¹). Upon transfer to MS + NAA (0.1 mg I⁻¹) + Zt (0.5 mg I⁻¹), the callus differentiated multiple shoots followed by rooting in 100% cultures of all the explants within ten weeks. Direct shoot regeneration could be obtained only from nodal segments after 4 weeks on MS + Indoled-acetic acid (IAA, 0.1 mg I⁻¹) + Kinetin (Kn, 0.5 mg I⁻¹) in 100% cultures. Rooting of these shoots was achieved after 2 weeks on MS + NAA (0.1 mg I⁻¹) + Zt (0.5 mg I⁻¹). Plantlets could be successfully transplanted to soil. Yield of silybin content in the cultured tissues varied with age and composition of the medium. Maximum yield resulted after eight weeks on media supplemented with zeatin.