Somatic Embryogenesis and Plantlet Regeneration in Safflower (Carthamus tinctorius.L)

In this paper, we show how regenerated plantlets were obtained from Safflower (Carthamus tinctorius L.) plants through indirect and direct somatic embryogenesis, for the first time in Iran. After a week,the callus was observed on the hypocotyl of explants obtained from seedlings that was grown on theMurashige and Skoog (MS) basal medium supplemented with 0.1-1 mg/L α-naphthalene acetic acid (NAA) and 6-benzylaminopurine (BAP). Embryogenic calli developed within 4 weeks after transferring to MS medium with different concentrations of auxins like 2,4-D, NAA, IAA; and cytokinins like BAP and KN, separately and in combination with auxins. MS medium supplemented with 0.5 mg/L NAA and 2 mg/L IAA was the most effective medium for indirect emberyogenesisinduction, that has the highest embryogenesis frequency per explants. About 30-40% of regeneratedsomatic embryos germinated into complete plantlets. Direct somatic embryogenesis without an intervening callus phase was conducted from intact seedlings on MS medium supplemented withgrowth regulators like: 2,4-D, NAA, IAA and Kin at different concentrations. After a week, embryosfrom cotyledon explants in a medium contain1 and 1.5 mg/L 2,4-D was observed. 13 embryos was the highest number of observed embryos for each explant and almost 40% of embryos from cotyledons developed to perfect plants; rooting procedure was performed in MS medium supplemented by 0.5 NAA. Also, histological observations revealed different stages of embryogenesis in Safflower such as globular, heart and torpedo stages.

Keywords:

Somatic embryogenesis , Safflower , Plantlet regeneration , Oil seed