Criopreservação, indução de poliploidia e avaliação da estabilidade genética de orquídeas
Carregando...
Arquivos
Data
2013-10-08
Autores
Galdiano Júnior, Renato Fernandes [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A criopreservação como forma de conservação em longo prazo de recursos genéticos e a poliploidização de orquídeas são importantes estratégias para o melhoramento genético destas plantas. Os objetivos gerais deste trabalho foram criopreservar e poliploidizar explantes de orquídeas com avaliação da estabilidade genética. Métodos criopreservantes baseados na vitrificação foram desenvolvidos para explantes de Dendrobium Swartz. híbrido ‗Dong Yai‘ e Oncidium flexuosum Sims. Sementes maduras de Dendrobium Swartz. híbrido foram criopreservadas em diferentes tempos de exposição à solução vitrificante de plantas 2 (PVS2) entre 0-6h a 0 °C e mergulhado em nitrogênio líquido durante 30 min. Após este período, as sementes foram recuperadas e colocadas para germinar em meio nutritivo MS com metade da concentração de sais (½ MS), incubadas em condições in vitro e avaliadas por meio da contagem de protocormos brotados após 30 dias. Os períodos de exposição à PVS2 entre 1-3h foram mais eficientes para a germinação do híbrido avaliado. Os protocormos desenvolveram plantas completas que foram aclimatizadas com sucesso em casa de vegetação. A análise de citometria de fluxo de plantas controles (não criopreservadas) e daquelas originadas de sementes vitrificadas não apresentou alteração no conteúdo de DNA total. Sementes maduras e protocormos brotados após 30 dias foram investigados para a vitrificação e vitrificação em gotículas, respectivamente, com a utilização dos aditivos floroglucinol e Supercool X1000. Sementes vitrificadas durante 1h com adição de 1% de floroglucinol resultou em 79% de germinação. Para protocormos, o pré-tratamento com sacarose 0,3M durante 24h seguido da exposição a solução PVS2 contendo 1% de floroglucinol por 15 min retornou 14% de sobrevivência após 75 dias de cultivo em condições in vitro. As plantas produzidas...
Cryopreservation as a long-term conservation form of genetic resources and polyploidization of orchids are important strategies for genetic breeding. The aims of this work were to make cryopreservation and polyploidization of orchid explants, with genetic stability evaluation. Vitrification-based methods were developed for Dendrobium Swartz. hybrid ‗Dong Yai‘ and Oncidium flexuosum Sims explants. Mature seeds of Dendrobium Swartz. hybrid were cryopreserved in different time exposures to plant vitrification solution 2 (PVS2) for 0-6h at 0 °C and plungged into liquid nitrogen for 30 min. Later, seeds were recovered and germinated in halfstrength MS medium (½ MS), incubated in vitro and, after 30 days, germinated protocorms were evaluated. PVS2 time exposures between 1-3h were more efficient for the hybrid germination. Protocorms developed whole seedlings that were successfully acclimatized in greenhouse. Flow-cytometry analysis of seedlings from control (not cryopreserved) and those originated from vitrified seeds did not present any DNA total content difference. Mature seeds and 30-day-old protocormos were investigated for vitrification and droplet-vitrification, respectively, with cryoprotection additives phloroglucinol and Supercool X1000. Seeds vitified for 1h with 1% phloroglucinol resulted 79% germination. Protocorms pretreated with sucrose 0.3M for 24h and exposed to PVS2 with 1% phloroglucinol for 15 min returned 14% survival at 75 days after cultivation in vitro. Seedlings originated presented normal growth. For cryopreservation of Oncidium flexuosum Sims., mature seeds vitrified for 2h with PVS2 and 1% phloroglucinol presented germination extended in 68%. After 6 months in culture, there were no differences on seedlings growth in vitro and ex vitro for phenotypical characteristics. Comparative analysis of seedlings from control and cryopreserved using flow-cytometry indicated ...
Cryopreservation as a long-term conservation form of genetic resources and polyploidization of orchids are important strategies for genetic breeding. The aims of this work were to make cryopreservation and polyploidization of orchid explants, with genetic stability evaluation. Vitrification-based methods were developed for Dendrobium Swartz. hybrid ‗Dong Yai‘ and Oncidium flexuosum Sims explants. Mature seeds of Dendrobium Swartz. hybrid were cryopreserved in different time exposures to plant vitrification solution 2 (PVS2) for 0-6h at 0 °C and plungged into liquid nitrogen for 30 min. Later, seeds were recovered and germinated in halfstrength MS medium (½ MS), incubated in vitro and, after 30 days, germinated protocorms were evaluated. PVS2 time exposures between 1-3h were more efficient for the hybrid germination. Protocorms developed whole seedlings that were successfully acclimatized in greenhouse. Flow-cytometry analysis of seedlings from control (not cryopreserved) and those originated from vitrified seeds did not present any DNA total content difference. Mature seeds and 30-day-old protocormos were investigated for vitrification and droplet-vitrification, respectively, with cryoprotection additives phloroglucinol and Supercool X1000. Seeds vitified for 1h with 1% phloroglucinol resulted 79% germination. Protocorms pretreated with sucrose 0.3M for 24h and exposed to PVS2 with 1% phloroglucinol for 15 min returned 14% survival at 75 days after cultivation in vitro. Seedlings originated presented normal growth. For cryopreservation of Oncidium flexuosum Sims., mature seeds vitrified for 2h with PVS2 and 1% phloroglucinol presented germination extended in 68%. After 6 months in culture, there were no differences on seedlings growth in vitro and ex vitro for phenotypical characteristics. Comparative analysis of seedlings from control and cryopreserved using flow-cytometry indicated ...
Descrição
Palavras-chave
Orquídea, Orquídea - Melhoramento genético, Sementes, Plantas - Propagação, Plantas - Conservação, Plant-breeding
Como citar
GALDIANO JÚNIOR, Renato Fernandes. Criopreservação, indução de poliploidia e avaliação da estabilidade genética de orquídeas. 2013. xiv, 111 p. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, 2013.