Jatropha curcas, belonging to the family of Euphorbiaceous, is a plant of Latin American origin, widely spread throughout the arid and semi-arid tropical regions of the world. Jatropha is a large genus comprising over 170 species. The most common species in India are J. curcas, J. glandulifera, J. gossypifolia, J. multifida, J. nana, J. panduraefolia, J. villosa and J. podagrica. 
J. curcas is a small tree or shrub with smooth gray bark, which exudes whitish colored, watery, latex when cut. Normally, it grows between three and five meters in height, but can attain a height of up to eight or ten meters under favorable conditions. It is a drought-resistant plant, living up to 50 years and growing on marginal lands.
J. curcas has large green to pale green leaves, which are aligned alternate to sub-opposite. The leaves are three-five lobed with a spiral phyllotaxis. The petiole of the flowers ranges between 6-23 mm in length. The flowers are formed in hot seasons. Several crops are formed provided the soil is moisture is good and temperatures are high. In conditions where continuous growth occurs, an imbalance of pistillate or staminate flower production results in a higher number of female flowers. Fruits are produced in winter when the shrub is leafless. Each inflorescence yields a bunch of approximately 10 or more ovoid fruits. Three, bi-valved cocci are formed after the seeds mature and the fleshy exocarp dries. The seeds become mature when the capsule changes from green to yellow, after two to four months from fertilization. The blackish, thin-shelled seeds are oblong and resemble small castor seeds.
This plant has various medicinal uses especially in nutraceuticals, pharmaceutical, dermatological, and personal care products. The latex of Jatropha curcas has anticancer properties due to the presence of an alkaloid known as “jatrophine.” The tender twigs are used for cleaning teeth. The juice of the leaf is used for external application for piles. The roots are used as an antidote for snake-bites. The seeds are used for antihelmithic purposes.
The bark yields a dark blue dye used for coloring cloth, fish net and lines.
Most of the Jatropha species are ornamental except for J. curcas and J. glandulifera which are oil-yielding species (as projected in presentation on “Biotechnological interventions for production and plantation of improved quality of Jatropha” by Dr. Renu Swarup, 2004). The seeds of these species contain semi-dry oil which has been found useful for medicinal and veterinary purposes (Gubitz et al., 1999 “Esterase and lipase activity of Jatropha curcas seeds J. Biotechnology October 8:75(2-3): 117-26).
The oil content is 25-30% in the seeds and 50-60% in the kernel. The oil contains 21% saturated fatty acids and 79% unsaturated fatty acids. Jatropha oil contains linolenic acid (C18:2) and oleic acid (C18:1) which together account for up to 80% of the oil composition. Palmitic acid (C16:0) and stearic acid (C18:0) are other fatty acids present in this oil.
The oil is non-edible, however it has the potential to provide a promising and commercially viable alternative to diesel oil as it has all the desirable physicochemical and performance characteristics as that of diesel. The plant J. curcas has lately attracted particular attention as a tropical energy plant. The seed oil can be used as a diesel engine fuel for it has characteristics close to those of fossil fuel diesel. Moreover, due to its non-toxic and biodegradable nature, Jatropha biodiesel meets the European EN 14214 standards of a pure and blended automotive fuel for diesel engines. Jatropha curcas seed yields approach 6-8 MT/ha with ca 37% oil. Such yield could produce the equivalent of 2100-2800 liters of fuel oil/ha, whose energy is equivalent to 19,800-26,400 kwh/ha (Gaydou, A. M., Menet, L., Ravelojaona, G., and Geneste, P. 1982. Vegetable energy sources in Madagascar: ethyl alcohol and oil seeds (French). Oleagineux 37(3):135-141).
Because of its very high saponification value and its ability to burn without emitting smoke, the oil of the seeds is commercially useful. For example, it is extensively used for making soaps.
Therefore, in view of the above, there is a need to provide method for micropropagation of Jatropha curcas which are economical and allow production on a commercial scale of uniform quality, true-to-type, disease-free plants.
Plant Tissue Culture
Micropropagation is the in vitro regeneration of plants from organs, tissues, cells or protoplast using techniques like tissue culture for developing true-to type resultant plants of a selected genotype. In general, tissue from a plant commonly known as an explant is isolated to create a sterile tissue culture of that species in vitro. A culture is initiated from an explant. Once a culture is stabilized and growing well in vitro, multiplication of the tissue or regeneration of entire plant can be carried out. Shoots (tips, nodes or internodes) and leaf pieces are commonly used but cultures can be generated from many different tissues. Juvenile tissues generally respond best. Besides the source of the explant, the chemical composition of the culture medium and the physical environment of cultures have been found to be of a great influence on the regeneration capacity, multiplication ratio, growth and development of new plants in the culture system. Therefore one needs to optimize these factors for each individual plant species.
Sujatha and Mukta (“Morphogenesis and Plant regeneration from tissue cultures of Jatropha curcas”, Plant Cell Tissue & Organ Culture, 44(135-141)1996) have reported a method for the differentiation of adventitious shoots through callus derived from hypocotyl, petiole, and leaf explants of J. curcas. Weida Lu, Tang Lin, Yan Fang & Chen Fang (2003) (“Induction of callus from Jatropha curcas and rapid propagation,” College of Life Science, Sichuan University Chengdu 610064, China) have reported induction of adventitious buds and regenerated shoots from epicotyl explants through callus.
All of the above studies focused on callus-mediated regeneration. Plant tissue regeneration through a callus stage is vulnerable to somaclonal variations and hence will not ensure true-to-type plants from elite mother plants. In addition, all of the above studies used non-meristem tissue, which is more likely to be infected with disease than meristem tissue. Therefore, there remains a need in the art for micropropagation methods that allow the production of true-to-type, disease-free plants.