Viabilidade e conservação de grãos de polén de milho

• Ano de defesa: 2008
• Autor(a) principal: Alvim, Patrícia de Oliveira
• Orientador(a): Von Pinho, Renzo Garcia
• Banca de defesa: Souza, João Cândido de, Guimarães, Renato Mendes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: UNIVERSIDADE FEDERAL DE LAVRAS
• Programa de Pós-Graduação: DAG - Departamento de Agricultura
• País: BRASIL
• Palavras-chave em Português: Zea mays; Atividade enzimática; Melhoramento genético; Conservação de recursos genéticos; Conservation; Desiccation tolerance; Storage
• Área do conhecimento CNPq: CNPQ_NÃO_INFORMADO
• Link de acesso: https://repositorio.ufla.br/handle/1/3841

In corn breeding programs factors related to the duration of the stigma receptivity, pollen grain longevity in the plant, differences in flowering periods among plants and conservation of genetic resources are aspects which reinforce the importance of researches related to factors interfering in corn pollen grains conservation. In this work, it was aimed to evaluate the conservation of corn pollen grains in different environments and water contents. The experiments were performed at the Agricultural Department of the Federal University of Lavras in the Laboratories of Seed Analysis and Molecular Biology and in an experimental field. In the pre-tests, different culture media for germination and temperatures for incubation and different times of pollen grain collection were evaluated. The tolerance of pollen grain to dissection was also determined. Following in a second experiment, pollen grains with water contents of 51.7% and 29.4% were stored in a deep freezer (-86ºC), refrigerator (4ºC) and in liquid nitrogen (-196ºC). After storage, germination and viability of the pollen grains were evaluated in vitro in a culture medium, in vivo by the staining test and through self-fecundation in plants of Le-57 line and of GNZ 2004 hybrid. The enzyme activity of pollen grains stored under the different conditions was evaluated using the enzymes esterase, malate dehydrogenase, peroxidase, superoxide dismutase and was also evaluate the expression of heat resistant proteins. Higher values of pollen grains germination were found in culture medium containing 10% of sucrose, 0.03 of Boric Acid and 0.15 of Sodium Chlorite at 25ºC and when the collection of the pollen grains was performed at 9 a.m. The conservation of the pollen grains varied with storage environment and with the water content and decreasing during storage. The germination of the pollen grains reduced with desiccation. Different patterns of enzymes and protein were observed in pollen grains under storage at different conditions.