Embryo culture and in vitro induction of shoots for micropropagation of physic nut

Abstract

The objective of this work was to optimize the cultivation and embryo development, as well as to evaluate in vitro micropropagation induction of physic nut (Jatropha curcas). In the initial stage, the influence of sucrose (concentrations of 0, 15, 30 and 60 g L^-1) on the development of embryos in basal MS medium was evaluated. From the seedlings generated in the embryo culture, microcuttings were excised and inoculated on MS medium supplemented with the plant regulators 6‑benzyladenine (BA), 6‑benzylaminopurine (BAP), kinetin (6‑furfuryladenine) (KIN) and 4‑(3‑indolyl) butyric acid (IBA), in the concentrations of 0.5, 1.0, 2.0 and 3.0 mg L^-1. The results showed that the range of 15 to 30 g L^-1 of exogenous supplementation with sucrose promotes the best shoot elongation of plants; however, rhizogenesis is more vigorous in the range from 30 to 60 g L^-1, in which a significant increase of the number of roots occurs. In the micropropagation phase, BAP at 2.0 mg L^-1 concentration induces a higher number of shoots, while KIN (1.0 and 2.0 mg L^-1) promotes a higher number of leaves. Callogenesis occurs on the shoot base, being more significant when supplemented with 2.0 mg L^-1 of 6‑BAP. The best sucrose concentration, for plant vigor and speed in obtaining explants, is 30 g L^-1. In micropropagation, the best results for direct shoot organogenesis occur at 2.0 mg L^-1 BAP concentration.