Study of milkweed (Calotropis procera) regeneration potential in vitro culture conditions

Milkweed is a valuable medicinal plant, which grows in some regions of Iran. Its immense medicinal properties, which are of high value, have made it an important crop to be cultivated commercially. This plant is propagated from seed and root and shoot cuttings, both of which have some problems. Therefore, new propagation methods should be studied, for example, tissue culture. This study aimed at obtaining the appropriate concentrations of plant hormones in tissue culture conditions. The experiment was carried out based on a completely randomized design with three replications. we study effect of 2,4-D concentration(0.1, 0.5, 1, 2, and 3 mgL-1) for callus initiation and BA and NAA, each at five levels (0.1, 0.5, 1, 2, and 3 mgL-1) for explants regeneration. Medium was MS with the following modifications: ammonium nitrate, potassium nitrate, calcium chloride, thiamin and Myo-Inositol concentrations were, respectively, 2000, 2400, 600, 4, 300 mg, 30 g sucrose and activated charcoal (3%). Mature embryos were used as explants and morphological traits such as embryo size, produced callus size, number and size of shoots and roots were recorded. Results showed that 2,4-D increased the size of cultured embryos, significantly (P≤0.05). Highest embryo volume was observed in cultures treated with 3 mgL-1 2,4-D. The highest callusing was recorded in 1 mgL-1 NAA. Effects of BA and NAA concentrations were significant; the highest values were observed with combined of 1 mgL-1 BA and 2 mgL-1 NAA. In rooting stage, 1 mgL-1 NAA treatment was able to induce the highest root number.