Pós-colheita de gérberas sob aplicação de etanol

Abstract

From the evidence that ethanol slows the effects of senescence on cut flowers, four experiments were carried out using Gerbera jamesonii L., with the objectives: i) evaluate three ethanol application methods in different concentrations, postharvest and cultivars Latara Mistique; ii) to verify the effect of different concentrations of ethanol (Et) and/or citric acid (AC), under pulsing 48 hours, on the longevity of cv. Mistique; Iii) verify the effect of different concentrations of ethanol and/or citric acid, under maintenance, on the longevity of cv. Mistique; iv) study the physical, chemical and biochemical changes that compromise the longevity of the cv. Mistique, subjected to pulsing with ethanol and/or citric acid. All experiments were conducted in a completely randomized design, and the data obtained were submitted to the Tukey test at 5%. The stems were transported at 20 ± 2 ºC for approximately 5 hours, selected and standardized at 35 cm in length, maintained at 20 ± 2 ºC and RH 65 ± 2%, under continuous lighting. In the first experiment the concentrations of 5, 10 and 15% of ethanol and distilled water (control) were tested under the methods of spraying, pulsing and maintenance, in five days of evaluation, in which the analysis was performed every two days Visual analysis with the aid of descriptive notes scale and estimated its longevity for cvs. Latara and Mistique. It was verified that the maximum longevity obtained was 6 days for both cultivars, and that the higher concentrations of ethanol reduced longevity, except for cv. Latara sprayed. While the lowest concentrations, 5%, applied via pulsing or maintenance, maximum longevity of 6 days was also obtained. In order to increase the useful life, was added in subsequent experimentsthe biocidal citric acid (100 or 200 mg L-1) to the ethanol solutions (4, 6 and 8%), or in isolation, under the pulsing and maintenance methods, in cv. Mistique. It was observed that the isolated AC did not increase the longevity, but in the combination of 4% Et + 100 mg L-1 AC it maintained the gerberas for the maximum time of four days, independent of the application method, compared to 2 days of conservation in the control stems . In the fourth and last experiment, using pulsing as a more economical form, it was possible to verify that ethanol (4%) combined with citric acid (100 mg L-1) reduced physicochemical and physiological changes related to loss of fresh bulk, relative water content, electrolyte extravasation, polyphenoloxidase activity and peroxidase, providing better appearance of the inflorescences and retardation of the tipping of the gerbera stems cv. Mistique. This resulted in an increase in the longevity of the gerberas in two days, compared to the other stems in which ethanol and citric acid were applied in isolation. Therefore, the gain of two days in the conservation in the level of commercialization at long distance is still not satisfactory, but before the improvements presented the combination of ethanol and citric acid presents potential to increase the longevity of cut gerberas.