Estudos anatômicos e ultraestruturais de sistemas de regeneração in vitro de Passiflora cincinnata Masters e Passiflora edulis Sims (Passifloraceae)

• Autor(a) principal: Rocha, Diego Ismael
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2527
• topic: Maracujá; Morfogênese; Embriogênese somática; Organogênese in vitro; Anatomia; Ultraestrutura; Passion fruit; Morphogenesis; Somatic embryogenesis; In vitro organogenesis; Anatomy; Ultrastructure; CNPQ::CIENCIAS BIOLOGICAS::BOTANICA

This study aimed to describe, using anatomical and ultrastructural analysis, the process of in vitro regeneration of Passiflora cincinnata Masters via somatic embryogenesis from zygotic embryos and Passiflora edulis Sims via organogenesis from root explants. Mature zygotic embryos of P. cincinnata were placed on MS induction medium supplemented with 18.1 μM 2,4-D and 4.4 μM BAP. Somatic embryos originated from pro-embryogenic zones that differentiated in the peripheral layers of protuberances formed by the meristematic proliferation of cells of the protoderm and ground meristem of cotyledons. The pro-embryogenic zones were formed by a group of individual cells, showing the multicellular origin of somatic embryos. These cells had large nuclei, dense cytoplasm with predominance of mitochondria, dictyosomes and a few reserve compounds. In the initial stages of embryogenesis, non-embryogenic cells had starch grains, which was not found in the starting explant, indicating de novo synthesis. Lesser amounts of lipids and storage proteins have also been found in this stage. In the in vitro organogenesis, root explants of P. edulis were cultured on MS induction medium supplemented with 2.35 μM BA. Direct and indirect regeneration patterns were recorded. In direct organogenesis, meristemoids were formed from cells of the cambium or pericycle, depending on the developmental stage of the explant. In indirect organogenesis, meristemoids were formed in the peripheral layers of the callus, which in turn differentiated from the cortical region of the explant. Meristemoids formed via direct system had spherical nuclei with one or more prominent nucleoli. These characteristics were not visualized in meristemoids formed via indirect system, which had lobed nuclei with evident nuclear pore complexes. The findings reported in this work are relevant to a better understanding of these morphogenetic pathways in Passiflora, providing insight into the characterization of molecular events in these regeneration systems, as well as studies aiming at the use these systems in genetic transformation protocols for the studied species.