Study on induction and maturation of somatic embryos of Jatropha Curcas L. initiated from different types of explants and plant growth regulators

Abstract

Jatropha curcas L. is a potential plant for biodiesel. This plant produces seeds containing oil from 33 to 60%. However, up to now, there are lack of high-quality of clones and limited research in the plant breeding. Therefore, an alternative method is needed including the application of biotechnology. Propagation of plants through somatic embryogenesis is not only helps to obtain a large number of plants throughout the year, but also it can be used as a good tool for genetic improvement of crops through genetic engineering. This study was aimed to induce somatic embryogenesis using different type of explants and several concentrations of plant growth regulators, as well as to study the development of the somatic embryos. Hypocotil and leaf used as explants were obtained from 1week-old seedling germinated on MS medium. Young embryos and embryo axis from immature and mature fruits were also used as explants for the induction of somatic embryos. After surface sterilization, explants were cultured on solid MS medium containing 3% of sucrose, 0; 0.5; 1; 1.5; 2; 2.5; 3; 4 or 5 mgL-1 of Picloram or 0; 0.5; 1; 1.5; 2 or 2.5 mg L-1 of 2,4-D. Cultures were incubated in the dark, at a temperature of 26±2°C, for 8 weeks. The results showed that embryo axis explants from mature fruit produced somatic embryos in globular, heart, torpedo and cotyledonary stages 6 weeks after culture (WAC) in the medium containing 2.5 mg/l of Picloram, whereas in medium containing 3, 4, or and 5 mg/l of Picloram, the somatic embryos were found after more than 7 WAC. Somatic embryos formed either directly or indirectly. Proliferation and maturation can be performed in solid or liquid MS medium without growth regulators and in liquid MS with the addition of 2.5 mg L-1 of Picloram with 3% of sucrose and B5 vitamin.

Jatropha curcas L. merupakan salah satu tanaman non pangan yang memiliki potensi untuk dikembangkan sebagai biodisel. Tanaman ini dapat menghasilkan biji dengan kandungan minyak mencapai 33-60%. Kendala yang dihadapi adalah kurangnya klon-klon bermutu tinggi dan pemuliaan tanaman yang belum maksimal, sehingga mempengaruhi produktivitas. Oleh karena itu diperlukan metode alternatif dengan penerapan bioteknologi untuk peningkatan produksi. Propagasi tanaman melalui embriogenesis somatik tidak hanya membantu untuk mendapatkan jumlah tanaman besar sepanjang tahun, tetapi juga dapat digunakan sebagai metode yang baik untuk perbaikan genetik tanaman melalui rekayasa genetika. Pada penelitian ini dilakukan dua kegiatan yaitu (1) induksi embrio somatik dari berbagai jenis eksplan J. curcas komposit IP3-P dan genotipe Dompu dan (2) proliferasi dan pendewasaan kalus embriogenik. Penelitian dilakukan pada bulan November 2010 – Januari 2012 di Laboratorium Kultur Jaringan, Institut Pertanian Bogor dan Pusat Penelitian Bioteknologi-LIPI. Penelitian ini bertujuan untuk mendapatkan informasi yang tepat mengenai jenis eksplan dan konsentrasi zat pengatur tumbuh auksin yaitu Picloram dan 2.4-D dalam media induksi yang didukung dengan kajian mengenai struktur dan perkembangan embrio somatik secara morfologi dan anatomi.