233 Cryopreservation of Embryonic Axes of Castor Bean Cultivar ‘AL-Guarany 2002’ G.F. Nogueira, R. Paiva, A.C.A.L. Campos, F.C. Nery, D.P. Vargas and P.D. de O. Paiva Federal University of Lavras Department of Biology Sector of Plant Physiology Lavras - MG Brazil Keywords: Ricinus communis, cryoprotectant, micropropagation, PVS2, conservation Abstract The castor bean (Ricinus communis) is an oleaginous plant with many applications in the society and economy. Castor bean seeds tolerate storage in seed banks for a short period compared to orthodox seeds, probably due to its high lipid content. This study aimed elaborate a cryopreservation protocol for castor bean embryonic axes. After seeds disinfection, embryonic axes of the cultivar ‘AL- Guarany 2002’ were isolated, dehydrated and inoculated directly on culture medium (control) or cryostored in liquid nitrogen at -196°C, during one hour, in the presence or absence of cryoprotectant solutions (PVS2 or modified PVS2) prior to inoculation on culture. It was obtained 100% of in vitro regeneration for all treatments. After acclimatization a surviving rate of 100% was obtained for embryonic axes cryostored only in liquid nitrogen. Axes stored in the presence of PVS2 presented a survival rate of 35%. The results obtained showed that the cryopreservation of castor bean embryonic axes in LN without cryoprotectants is a suitable technique to preserve the genetics resources of this species. INTRODUCTION The castor bean (Ricinus communis L.), belonging to the family Euphorbiaceae, has a great evidence the worldwide market, mainly because of its medicinal properties, which are very interesting for the pharmaceutical industry and also because of its potential for biodiesel production. Recent studies are establishing protocols for the storage of various species of economic importance. The germplasm conservation of zygotic embryos, with high genetic and biological integrity, is more feasible when compared to other structures that need larger storage spaces. Although castor bean seeds are considered orthodox, they tolerate a short period of storage probably due to their high lipid content (Santos, 2000; Carvalho et al., 2005). Currently, the big challenge of cryopreservation among the methods of germplasm conservation is to achieve freezing without the formation of ice crystals within the cells. The use of cryoprotectants is one way to overcome the problem of injuries caused by freezing (Mazur, 1984; Engelmann, 2004). The biological and technical complexity of the cryopreservation technique should be observed carefully in order to guarantee its success (Almeida, 2000; Engelmann, 2000). Studies related to the conservation of castor bean are essential to add genetic variety to germoplasm banks and consequently assist plant breeding programs (Camillo et al., 2009). In addition, it may contribute to the development of technologies related to the culture production and commercial profiteering. Therefore, this study aimed developing a protocol for the cryopreservation of castor bean embryonic axes. MATERIALS AND METHODS This work was performed at the Laboratory of Plant Tissue Culture, Plant Physiology Sector, Federal University of Lavras (UFLA). Ricinus communis ‘AL-Guarany 2002’ seeds were obtained from the Coordenadoria de Assistência Técnica Integral (CATI), São Paulo - Brazil, and kept in Proc. First IS on Cryopreservation in Hort. Species Eds.: B. Panis and P. Lynch Acta Hort. 908, ISHS 2011