EFFECT OF AUXINS ON INDIRECT IN VITRO MORPHOGENESIS AND EXPRESSION OF gusA TRANSGENE IN A LECTINACEOUS MEDICINAL PLANT, EUPHORBIA NIVULIA BUCH.-HAM

• Published in: In vitro cellular & developmental biology. Plant 2005-09, Vol.41 (5), p.695-699
• Main Authors: SUNANDAKUMARI, C., ZHANG, C.-L., MARTIN, K. P., SLATER, A., MADHUSOODANAN, P. V.
• Format: Article
• Language: English
• Subjects: 2,4-D; Auxins; benzyladenine; beta-glucuronidase; Callus; culture media; Embryos; Euphorbia; Euphorbia nivulia; genetic markers; gibberellic acid; growing season; in vitro regeneration; indole butyric acid; light; Medicinal plants; Morphogenesis; naphthaleneacetic acid; Organogenesis; Plant cells; Plantlets; Plants; Research Reports; seasonal variation; shoots; Somatic embryogenesis; transformation; Transgenes; transgenic plants
• ISSN: 1054-5476; 1475-2689
• DOI: 10.1079/IVP2005651

The types of auxin in Murashige and Skoog (MS) medium containing N6-benzyladenine (BA) determined indirect morphogenesis, i.e. development to bipolar somatic embryos or monopolar shoots in Euphorbia nivulia Buch.-Ham. Indirect in vitro morphogenesis depended on growth regulators, explant excision period, and light. Calli induced from explants collected in March–April were superior in the induction of indirect morphogenesis to those collected in July–August. Light enforced in vitro morphogenesis, while darkness was inhibitory. The presence of kinetin in the medium also inhibited morphogenesis. Calli developed on explants collected in March–April grown on MS medium fortified with α-naphthaleneacetic acid (NAA) and BA facilitated indirect organogenesis, while those developed on medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) and BA underwent somatic embryogenesis. MS medium with 13.3 μM BA and 2.69 μM NAA was the best for induction of shoots from callus, which developed a mean of 15.7 shoots. Shoots were best rooted on half-strength MS medium enriched with 2.46 μM indole-3-butyric acid with a mean of 5.1 roots per shoot. MS medium supplemented with 2.26 μM 2,4-D and 4.44 μM BA induced the highest number (mean of 13.4) of somatic embryos. Of the embryos transferred on half-strength MS medium containing 2.89 μM gibberellic acid, 78% of embryos developed to the cotyledonary stage. Most cotyledonary embryos (80%) underwent conversion to plantlets upon being transferred to half‐strength MS basal medium in light. The survival rate of organogenesis and embryo-derived plants was 80 and 90%, respectively. Calli transformed with Agrobacterium tumefaciens showed expression of the gusA transgene and resistance to kanamycin, but did not undergo morphogenesis.