Comparação de métodos de extração de pigmentos fotossintéticos em folhas de Myrciaria dubia da Amazônia

Abstract

Camu-camu, a species from the Amazon, considered a superfruit, mainly due to its high concentration of vitamin C. To assist in seedling production, domestication and adaptation, chlorophyll analysis methods are important, as they provide information on the behavior and proper management of the plant in place different from its natural environment. The study aimed to compare three methods of pigment extraction: dimethyl sulfoxide (DMSO), 90% ethanol and 80% acetone, select one of the solvents to evaluate the effect of time and temperature to determine an appropriate protocol for the species. Seedlings, obtained from seeds, were kept in a nursery at 50% shade for 270 days. Leaf discs were used, incubated in acetone, dimethylsulfoxide or ethanol, for 24 hours at 65ºC, or to test the effect of time and temperature in DMSO. Contents of chloroplast pigments and phaeophytinization index were evaluated. The design was completely randomized (DIC), with three treatments and 4 replications to evaluate the solvents, in a factorial scheme 2 x 3 (temperature x time) x 4 repetitions, to examine the time and temperature results with dimethylsuffoxide. Among the solvents tested, DMSO showed the highest efficiency. The results indicated a significant influence of the temperature of 25ºC for chlorophyll a e, 65ºC for chlorophyll b, and little interference of the incubation time. The pheophytinization index suggested chlorophyll a degradation and chlorophyll b stability at 65°C. The experimental conditions of this study recommend DMSO as the most suitable solvent in the process of extracting chlorophylls from Myrciaria dubia leaves, using low temperatures and a short incubation period (6 hours).