Effect of IAA and 2,4-D on somatic embryogenesis and pigments synthesis of carrot root secondary phloem

Plants secondary metabolites are widely used in medicinal and cosmetic industries. These compounds can be produced by in vitro culture of plants. The production of secondary metabolites and somatic embryogenesis in vitro are affected by different factors such as the type and concentration of plant growth regulators. In present study, the effect of 2,4-dichlorophenoxyacetic acid (2,4-D) and Indol-3-Acetic Acid (IAA) on anthocyanin, carotenoid, and chlorophylls synthesis as well as somatic embryogenesis of carrot root secondary phloem in liquid and solid media were investigated. Induction of somatic embryogenesis of carrot root secondary phloem was carried out in different concentrations of 2,4-D (0, 2.26, 4.52 and 9.04 ^mol) in B5 liquid medium and IAA (0, 2, 5 and 9 ^mol) in NL liquid medium. The experiment was conducted in a factorial completely randomized design with four replications. Obtained results showed that liquid medium treatments supplemented with 2,4-D had higher amount of anthocyanin (10.15 ^mol/g.f.w) than those supplemented with IAA (p<0.01). While the highest amounts of chlorophyll a, b and ab observed in solid medium supple¬mented with IAA. Also solid medium supplemented with IAA had more carotenoid than liquid medium supplemented with IAA (p<0.05). The highest number of somatic embryos produced in media supplemented with 2,4-D (p<0.01). In media supplemented with IAA, without proceeding to globular and heart-shape, torpedo-shape embryos and plantlets were formed The highest number of globular-shape and heart-shape embryos formed in media supplemented with 9.04 and 2.26 ^mol of 2,4-D, respectively (p<0.01).