Ação do metil jasmonato e do ácido salicílico na redução pós-colheita da injúria por frio em strelitzia reginae
Objetivou-se com este trabalho determinar a ação do pulsing com metil jasmonato (MJ) e ácido salicílico (AS) na qualidade e redução pós-colheita da injúria por frio em flores de corte de Strelitzia reginae. Foram realizados dois experimentos. No primeiro, as hastes foram colocadas em soluções de pul...
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Universidade Federal de Viçosa
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|Citação:||PEREIRA, Ariana Mota. Ação do metil jasmonato e do ácido salicílico na redução pós-colheita da injúria por frio em strelitzia reginae. 2015. 68f. Dissertação (Mestrado em Fisiologia Vegetal) - Universidade Federal de Viçosa, Viçosa. 2015.|
|Resumo inglês:||This study aimed to determine the action of pulsing with methyl jasmonate (MJ) and salicylic acid (SA) on the quality and reduction of the incidence of chilling injury in cut of flowers of Strelitzia reginae. Two experiments were conducted. In the first, the stems were placed in pulsing solutions with 20% of sucrose plus MJ at concentrations of 100, 250 and 400 μM, and control (without MJ) for 24 hours. In the second experiment, the stems were placed in pulsing with 20% of sucrose with the addition of AS at dosages of 2, 4 and 6 mM, and control for 24 hours. Subsequently, stems were placed in a recipient with water during 28 days at 5°C for chilling injury induction and at room temperature over 7 days. The analysis made were determined weekly at 5° C in the beginning and in the ending of storage at room temperature concerning water uptake rate, transpiration rate, the fresh weight (MF), leakage of electrolytes, activity of peroxidase (POD) and phenolic compounds of the bracts and sepals. There was a linear reduction in water uptake rate by the stems in all treatments at 5°C, with lower dose reduction of 250 μM and greater uptake with 100 mM on days 14 and 21. MJ was not effective in reducing transpiration rate and in maintenance of MF of flowers at 5°C. There was an increase of electrolyte leakage on the last day of evaluation in relation to day zero, being superior in bracts treated with MJ. The POD activity of the bracts at 5°C was reduced only with the use of 100 mM of MJ, while in sepals all MJ doses increased the POD activity. At 5°C, the bracts treated with 250 and 400 μM of MJ and the sepals to 250 μM obtained the lowest increase in phenolic compounds on the last day of evaluation in relation to day zero. At room temperature, the treatment with MJ reduced uptake of water, electrolyte leakage and phenolic compounds bracts on day zero. However, in this room temperature, the MJ was not effective in the reduction of the variation of fresh weight, transpiration rate, the POD activity in the bracts and sepals and of the compounds phenolic of sepals. The dose of 2 mM of AS provided the smallest variation in uptake of water at 5°C on day 28 compared to day 7 while the dose of 4 mM allowed a negative water balance later and the highest fresh weight. There was a lower increase in electrolyte leakage at a dose of 6 mM of AS and a bigger low in the POD activity in the bracts and sepals on the last day of evaluation in relation to day zero at a dose of 2 mM at 5°C. At room temperature, AS reduced uptake of water and transpiration, but it was not effective in reducing the variation of fresh weight, electrolyte leakage and POD activity of the bracts. The POD activity in sepals, at room temperature, was lower at doses of 4 and 6 mM on day 7. All doses of AS reduced phenolic content of sepals on day 0 and the doses of 2 mM and 6 mM in bracts. It was concluded that MJ and AS improved flower quality at 5°C, however only AS reduced the incidence of chilling injury, being 2 mM the best dose. At room temperature, only the AS improved flower quality.|