Criopreservação de germoplasma de oleaginosas de importância econômica para o nordeste brasileiro

• Autor(a) principal: Lopes , Kilson Pinheiro
• Data de Publicação: 2005
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/tede/8136
• topic: Sementes; Gossypium hirsutum L.; Mamoneira; Ricinus communis L.; Algodoeiro; CIENCIAS AGRARIAS::AGRONOMIA

The conservation of germplasm of oleaginous species of the cotton (Gossypium hirsutum L.) and the castor bean (Ricinus communis L.) it is of great importance to guarantee the readiness of the resources genetic vegetables for the improvement. The cryoopreservation is seen as great alternative for conservation long term of the resources genetic vegetables. To present research it was developed in the National Center of Research of the Cotton (CNPA) of the Brazilian Company of Agricultural Research (EMBRAPA), Laboratory of Biotechnology, in Campina Grande, PB, with the objective of evaluating cryopreservation protocols for the cotton and the castor bean culture. Cotton seeds were used of the you cvs. BRS 200 and BRS 201 and of the castor bean seeds of the cvs. BRS 188 - Paraguaçu and BRS 149 - Nordestina for the obtaining of your embryonic axes and of the plantlets for the excision of the explants (shoot apices and nod cotiledonare). Among the cryopreservation techniques, they were appraised protocols of vitrification and encapsulation-dehydration for cotton explants and desiccation of embryonic axes of the cotton and of the castor bean culture. In the vitrification, the DMSO was used (0; 5; 10; and 15%) and/or sucrose (0; 0,1; 0,25 and 0,5 M) in the preculture of the explants for 48 hours. In the encapsulation-dehydration, explants were submitted or not to the preculture for 24 hours MS liquid medium supplemented with 0,3 M of sucrose and dived in the encapsulation solution, containing 3% of Na-alginate, forming a bead that involved the explant, which were maintened by 12 hours in MS liquid medium with 0,75 M of sucrose, on a rotary shaker at 130 rpm. The beads containing the explants was submitted to the desiccation by 0; 3; 6 and 9 hours in the flow camera to laminate, with subsequent determination of the content of water. In the procedure of desiccation of the embryonic axes, cotton and castor bean seeds they were submitted the imbibition in water for 24 hours for subsequent extraction of the embryonic axes in the flow camera to laminate, where axes stayed desiccation for 0; 30; 60 and 90 minutes after extraction, with subsequent determination of the content of water. In all experiments the explants they were them placed in cryotubes and directly plunged into liquid nitrogen (-196°C), during 0; 5; 30 and 60 days. At the end of each period, the thawing of the explants was accomplished fast (38±2°C for 1-2 min) and slowly (25±2°C for 60 min) and then cultured in vitro for four weeks, moment in that took place them analysis of viability of the cotton explants and embryonic axes of both species. The desiccation of the cotton embryonic axes for 60 minutes (16% of the content of water) and of the castor bean for 90 minutes (5% of the content of water), when obtained of imbibed seeds, it guaranteed regeneration after cryopreservation. The employment of the DMSO above 5% affected the viability of the explants. The encapsulation induced a reduction in the development of the explants and the desiccation it affected the regeneration. The vitrification and the encapsulation-dehydration didn't guarantee regeneration of the cotton explants cryopreserved.