Effects of TDZ and 2,4-D growth regulators on callus production and organogenesis in Eucalyptus rubida

Document Type : Research Paper

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Abstract

Eucalyptus species belongs to Myrtaceae family and native of Australia. Eucalyptus rubida with medicinal usage is a fast growing tree species, with high wood yielding. Iran is a country with low cover forest, therefore, it is suitable for silviculture programs in some part of the country. Auxins and cytokinines are two main groups of growth regulators with different concentrations, having important role in callus formation and in somatic embryogenesis as well as organogenesis stages. Requirement of seedling production of E. rubida was the reason for this study. Effects of 2,4-D and TDZ as the growth regulators on callus production and organogenesis of the species was investigated. E. rubida seeds were sterilized and cultured on MS medium with half of required nitrate concentration for a large number of sterile seedlings production. Explants of cotyledon, root and stem of the seedlings were planted on MS medium with nine different treatments of TDZ and 2,4-D hormones levels in order to callus formation and then organogenesis phenomena. The best recognized treatment for callus production was: TDZ with 0.5 mgl-1 and 2,4-D with 1 mgl-1; for organogenic callus production was TDZ: 0.1 mgl-1, 2,4-D: 1 mgl-1 and for embryogenic callus production was TDZ:0.5 mgl-1, 2,4-D: 0.5 mgl-1.

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