Alterações fisiológicas e bioquímicas em sementes de Jatropha curcas L. em função do estádio de maturação dos frutos e do armazenamento

• Autor(a) principal: Silva, Laércio Junio da
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1255
• topic: Jatropha curcas; Sementes - Maturação; Sementes - Qualidade; atropha curcas; Seeds - Maturation; Seeds - Quality; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

Jatropha curcas L. species has been listed as a promising source of raw material for biodiesel and bio-jet fuels production. The success of the commercial exploration of that culture depends on obtaining seeds with high physiological quality. However, this species lacks researchs to define appropriate strategies for the production of high quality seeds. In this sense, there is little information relating to the conservation of the physiological quality of the seeds obtained from fruits at different maturation stages during storage and also about the relationship between seed viability, lipid peroxidation and activity of antioxidant enzymes. Thus, the aim of this study was to evaluate the physiological quality and investigate the activities of enzymes of the antioxidant defense system and the lipid peroxidation during storage of J. curcas seeds obtained from fruits at different maturation stages. At the flowering, daily, female flowers were tagged at anthesis. Fruits were collected at different maturity stages based on external color, i.e., yellow, yellow-brown and brown, about 60, 70 and 80 days after anthesis, respectively. The seeds were manually extracted from the fruits and after natural drying, were packing in Kraft paper bag and stored for 18 months at laboratory environment (23.2 ± 2.7 oC; 64 ± 11% of RH). Initially and every three months, the seeds were evaluated for moisture content, germination, first count of germination, accelerated aging, cold test, electrical conductivity, emergence and seedling growth. In addition, the embryos of the seeds were evaluated for lipid peroxidation, protein content, and activity of superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX). The experiment was conducted in a completely randomized design with four replications with the treatments arranged in split plots. The means obtained for the maturity stages were compared by Tukey test (P <0.05). The data obtained for the period of storage were subjected to regression analysis, with the exception of biochemical data, which were expressed as mean ± standard deviation. No difference between the germination of the three fruit maturation stages during the storage period was observed. There was reduction in seed physiological quality, with decrease in germination and vigor, especially after nine months of storage. The seeds extracted from yellow and yellow-brown fruits are the most vigorous and hold the physiological quality for a longer period. Furthermore, there was reduction in protein content and antioxidant enzymes activity of the seed embryo of the three maturity stages, with the exception of SOD. No relationship between reduced seed viability and lipid peroxidation was observed.