Fisiologia do desenvolvimento e senescência de flores de capuchinha (Tropaeolum majus L.)

• Autor(a) principal: Silva, Tania Pires da
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/993
• topic: Tropaeolum majus; Estádios de desenvolvimento; Etileno; Antocianina.; Tropaeolum majus; Stages of development; Ethylene; Anthocyanins; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS::FISIOLOGIA POS-COLHEITA

This study aimed to characterize physiologically five stages of flower development of Tropaeolum majus L. as: the production of ethylene and CO2, carbohydrate metabolism and content of anthocyanin pigments. Additionally, we investigated the effect of ethylene on the sensitivity of flowers to this hormone, and evaluate the benefits of 1-methylcyclopropene (1-MCP) and preservative solutions on postharvest longevity of nasturtium flowers. The CO2 production decreased with flower opening and senescence. There was an increase in ethylene production in the first three stages of development, followed by the accentuated decline in the last two stages. Regardless of the stage of flower development, the starch was the lowest nonstructural carbohydrates, total soluble sugars increased since the stadium 1 to 2, remaining stable until stage 4, decreasing thereafter. The anthocyanins increased with the progression of flower senescence. In the second and third stages concentrations equal to or above 10 μL L-1 ethylene caused a greater degree of wilting of flowers, and inhibiting the development of the buttons of the first stage. The 1-MCP was effective in prolonging the longevity postharvest nasturtium flowers at any concentration used, even with presence of exogenous ethylene. The anthocyanins showed changes in the presence of ethylene but not in the presence of 1-MCP. The conditioning of flowers in the form of "pulsing" with sucrose did not prevent the loss of fresh or flower senescence, or in any of the concentrations tested periods. Treatments with aminoethoxyvinylglycine (AVG) in the two application methods tested, aminooxiacetic acid (AOA) and acetylsalicylic acid (ASA), were unable to extend the postharvest longevity of nasturtium flowers. Treatment with greater capacity to minimize postharvest losses among all tested products was the silver thiosulfate (STS), which prolonged the longevity of flowers after harvesting within 4 days after application. Both as the STS only the silver applied in the form of silver nitrate (AgNO3) were effective in minimizing losses of fresh material, and thereby maintain the turgor of flowers, however, the STS solution, was superior. None of the tested periods between application anti-ethylene then the solution of the copper solution, prevented the action of ethylene in flowers. Thus, copper was capable of efficiently removing silver from the ethylene receptor site, thereby, the action of the same.