Variabilidade fenotípica de frutos e atividade da enzima endo-- mananase em sementes de Butia capitata (Mart.) Becc.

• Ano de defesa: 2012
• Autor(a) principal: Welha Carlos da Mota
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Galactomanano; Atividade enzimática; Cultivo in vitro; Populações; Biometria; Complementação (Genética); Coquinho-azedo; Frutas
• Link de acesso: http://hdl.handle.net/1843/NCAP-9BMJTC

The objectives of this research were to analyze the differences between populations of coquinho-azedo (Butia capitata), in relation to the characteristics of the fruit, of the pyrene, of the seed, of the embryo, of the germination and of the seedling vigor; verify what is the main component of phenotypic variance for the characteristics of the seed, of the germination and of the seedling vigor and what characteristics of the seed and of the embryo present the greatest variation among populations. Moreover, it was aimed, also, to get a new spectrophotometric method more efficient, from high sensitivity, low cost and easy execution to determine the enzymatic activity of the endo--mannanase in seeds, and apply it to samples of coquinho-azedo (Butia capitata) to determine the location of enzyme activity in different parts of the seeds. Coquinho-azedo fruits (B. capitata) were obtained from five populations located in north of Minas Gerais. In samples of 1000 fruits from each population was evaluated the length, the diameter and the dry mass of the fruits and of the pyrene (endocarp + seed). In samples of 200 seeds from each population were evaluated also the length, the diameter and the fresh mass. The embryos were excised of the seeds for evaluation of total length, length and diameter of petiole and length and diameter of haustoria. The embryos were cultured in vitro and evaluated after 30 days as for germination, emission of roots and sheaths. It was observed that there is variability among populations for fruit characteristics, of the pyrene, of the seed, of the germination and of the seedling vigor. The genotypic variability is the main responsible for the phenotypic variability for the characteristics of the seed, embryo, germination and seedling vigor, and the dimensions of the embryo and seed mass are the main features that discriminate the populations. The obtained spectrophotometric method for determine the activity of the endo--mannanase consists in extracting the seed enzyme and using it to hydrolyze the galactomannan Locust Bean Gum. The reducing sugars formed are subjected to a reaction with the p-hydroxybenzoic acid hydrazide and quantified by spectrophotometry in the visible region. The method presented low limits of quantification for the reducing sugar formed and for the enzymatic activity of mannanase with the respective values of 6g of mannose and 1000 µU (peak mol of reducing sugar formed per time unit). The coefficient of variation among replicates was satisfactory with values below 10%. Seeds coquinho-azedo (B.Capitata) without operculum presented upper enzymatic activity to the seeds with the operculum, and in both of them the higher enzyme activity was detected in the region adjacent to the embryo.