Alterações fisiológicas e bioquímicas de sementes de Melanoxylon brauna envelhecidas natural e artificialmente

• Autor(a) principal: Corte, Viviana Borges
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/527
• topic: Sementes; Floresta; Envelhecimento; Deterioração; Germinação; Armazenamento; Seeds; Forest; Aging; Decay; Germination; Storage; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::SILVICULTURA

The knowledge at present about the biochemical and physiologic changes in forest tree seeds is limited, as well as those of vigour evaluation testes during this stage. The objective of this work was to evaluate the physiological and biochemical changes of Melanoxylon brauna seeds during storage and the accelerated aging, establishing relations between these changes and decay of the seeds. Seed samples were taken to carry out germination, electrical conductivity and tetrazolium tests, as well as of emergence of the seedlings and water stress, besides the quantified biochemical and enzymatic analyses in the cotyledons and embryonary axis. The germination percentage of the naturally and artificially aged seeds at 40 and 45ºC were reduce, starting at six months in the first one and at 96 and 24 hours for the two last ones, respectively. The electrical conductivity increased and the number of viable seeds dropped significantly in both aging methods. The fat and oligosaccharides contents showed a steady reduction in both compartment of the seed and of the aging method, in correlation with the decaying process. Correlation between the fat acid contents and the seed decay of the species was not detected. Evidence that the fat acids were responsible for the decay of the seeds was not observed. The SOD activity increased at 12 months and 72 hours of natural and artificial aging, respectively. Activities of CAT and POX and the fat reserve decrease with aging. There was a correlation between the results of both aging systems.