Effect of explants and some plant growth regulators on regeneration and amount of ‎periwinkle’s vincristine (Catharanthus roseus L.)‎

The aim of this study was to optimize different concentrations of some growth regulators and introduce the effective explants which lead to increase callus induction and regeneration efficiency in Catharanthus roseus L. and recognize growth stage which produce the highest amount of vincristine. The experiment was conducted as a factorial with a completely randomized design. The first factor was explant type at eight levels and the second factor was different concentrations of growth regulators at nine levels. The results showed that the highest percentage of callus induction was observed the medium containing 8 μM 2,4-D with 2 μM BAP in single node (100 percent), hypocotyl (100 percent), leaf (100 percent), root (99.16 percent), ovary (98.33 percent), petiole (95.83 percent), anther (94.16 percent) and cotyledon (93.33 percent) explants, respectively. Calluses derived from hypocotyl, anther and ovary explants were able to produce highly efficient somatic embryos. 0.8 g L-1 casein hydrolyzate cause the highest percentage of embryogenesis. The maximum germination percentage was obtained from explants drived from hypocotyl (53.66 %), anther (51.00 %) and ovary (46.00 %). Also, the regeneration percentage of hypocotyl, anther and ovary explants was 78, 73 and 68 percent, respectively. The topmost amount of vincristine in comparison with different types of calluses and different stages of growth was obtained from plants regenerated from callus which derived from anther, ovary and hypocotyl explants and the amount was 1.4 μg g-1 dry weight more than non-embryonic callus of the mentioned explants.