Thin cell layer technology in micropropagation of Jatropha curcas L

Abstract

Physic nut plant (Jatropha curcas L.) is considered as one of potential sources for a non-edible biofuel-producing energy crop throughout the world. The conventional propagation methods for this species present many problems including poor seed viability, low germination, unstable yield and high oil content. In addition to the problems associated with establishing seedlings, Jatropha curcas was found to be largely recalcitrant to in vitro regeneration and unresponsive to many plant growth regulators. Recently, a rapid and effective system of somatic embryogenesis and organogenesis from leaf transverse thin cell layers (tTCLs) of Jatropha curcas L. was established. By inducing several thin cell layers precisely with various plant growth regulators, numerous small shoot clumps formed directly. These small shoot clumps were then transferred to a new medium for shoot elongation. Besides, tTCL promoted indirect organogenesis, through callus formation, on media containing kinetin and IBA. Nodular callus structures started to differentiate into shoot buds when hard compact ones were transferred to fresh medium containing kinetin only. Embryogenic calli were induced and proliferated on MS medium supplemented with kinetin and 2,4-D, including vigorous somatic embryos. These embryos developed to plants with normal phenotype and rooted easily in growth regulator-free half-strength MS medium. Regenerated plantlets from organogenesis and somatic embryogenesis were acclimatized under the controlled greenhouse conditions with a high survival rate.