Biochemical and physiological changes in Combretum leprosum Mart. seeds during storage

• Autor(a) principal: Guirra, Bruno Silva
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/jspui/handle/123456789/30013
• topic: Forest seeds; Seed physiological quality; Seed metabolic responses; Viability; Vigor

Combretum leprosum Mart., Combretaceae family, has exclusive distribution in South America. It is a species that significantly contributes to conservation and improvement of soil quality, as it facilitates the processes of recovery of degraded areas and succession in dry forests. Despite the ecological importance, there are still no basic studies aimed at the storage of its seeds. Thus, the objective was to evaluate the biochemical and physiological changes in C. leprosum seeds, based on the degradation of reserve tissues and accumulation of soluble metabolites during the storage period. The experimental design was completely randomized, in a factorial scheme (2 x 2 x 7), with two storage conditions x two forms of seed processing x seven storage periods (0; 60; 120; 180; 240; 300 and 360 days) and four replicates per treatment. After collecting C. leprosum fruits, half of the lot was manually processed by removing the external protection that covered the seed, while in the other half, the diaspores were kept. For storage, all seeds, both naked and protected with diaspores, were placed in kraft paper bags and kept under two storage conditions: natural environment and air-conditioned chamber (10±1°C; 53±7% relative humidity). At the beginning and at intervals of 60 days, for 360 days, the seeds were analyzed for moisture content, physiological quality (emergence, emergence speed index, and seedling length and dry mass) and biochemical quality (neutral lipids, total and reducing sugars, total free amino acids, starch and lipid peroxidation). Physiological variables showed better results under the condition of natural environment, regardless of the form of seed processing. This environment also promoted less degradation of lipid reserve. Regarding starch, there was hydrolysis of this polysaccharide throughout the storage period. Finally, it was found that seed deterioration after 180 days of storage is associated with the attack of reducing sugars against amino acids, reducing viability and vigor.