The successful regeneration of Jatropha curcas requires easily reproducible methods. Therefore, this study was undertaken to evaluate the effects of sources of explants, growth regulators, coconut water, nitrogen and flask sealing on the quality and quantity of shoots derived from leaf segments of Jatropha curcas after in vitro manipulation. The highest morphogenetic responses, 4.8 and 4.56 (numbers of adventitious shoots), were obtained from leaf cotyledon plantlets cultured in half-strength MS medium in the presence of BAP separately or combined with IAA (at a concentration of 4.4 μM of BAP + 2.8 μM of IAA). Enhanced shoot multiplication rates of 2.07 and 1.84 were observed in MS medium without coconut water and with the flask sealed with plastic film or a polypropylene lid with a filter, respectively. This result demonstrated the positive effects of minimum air circulation between the internal and external environments of the culture medium during regeneration. Concentrations of KNO3 and NH4NO3 between 50 to 100 % in MS medium favored the induction of callus and shoot formation at the 60th day of culture. Observations using a scanning electron microscope permitted visualization of dedifferentiated cells, and the reinitiation of meristematic activities resulted in the formation of a unipolar structure called a vegetative primordium. From these results, it is possible to conclude that regeneration efficiency (quality and quantity of material regenerated) in Jatropha curcas can be increased with the use of balanced medium constituents, growth regulators and modifications of culture conditions that include the absence of light.
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