Proliferation and differentiation from endosperms of Carthamus tinctorius

The endosperms of Carthamus tinctorius cv. HUS-305, excised at globular to heart-shaped stages of zygotic embryo development, were cultured on Murashige and Skoog's medium (MS) supplemented with different concentrations of 6-benzylaminopurine (BAP), kinetin, thidiazuron (TDZ), 2,4-dichlorophenoxyacetic acid (2,4-D) or alpha-naphthalene-acetic acid (NAA). The highest incidence of callusing was on 2,4-D supplemented media. However, embryos differentiated only from the calli developed on media supplemented with BAP, kinetin or TDZ with the last eliciting maximum embryogenic response. The addition of a reduced nitrogen source, casein hydrolysate to MS medium supplemented with BAP and/or NAA, did not stimulate the response. However, adenine sulphate (100 mg dm(-3)) promoted the induction of somatic embryos. Upon transfer to MS basal medium or the same supplemented with 0.61 mu M gibberellic acid (GA(3)), plumular poles of few embryos elongated resulting in the development of shoots.