Spectrophotometric Determinations of Chloroplastidic Pigments in Physalis angulata L. Leaves Using Different Methodologies

The aim of this study was to compare different protocols for extraction and quantification of photosynthetic pigments, considering different solvents, extraction time and temperature, to determine the best methodology for Physalis angulata L. leaves. The efficiency of immersion of leaf discs in 95% ethanol, 80% acetone and dimethyl sulfoxide (DMSO) was evaluated for 24, 48 and 72 hours. The effect of temperature on extraction with DMSO was also evaluated, with the samples incubated at room temperature and in a water bath at 65 °C. These protocols were compared with the classical methods of plant tissue maceration in 80% acetone followed by filtration, which proved to be the most efficient for Physalis angulata plants and indicated for use in the laboratory. The use of high temperatures (65 °C) is not necessary for the chlorophyll extraction process with DMSO, the room temperature is most efficient in the extraction of carotenoids. Considering the total chlorophyll content, the leaf discs immersion technique in a solvent is acceptable, with 95% ethanol and 24 hours incubation and the most economically viable alternative.

Chloroplastid pigment contents and chlorophyll a fluorescence in Amazonian tropical three species

Plants react to changes in light and hydrological conditions in terms of quantity and composition of chloroplastidic pigments, which affects the photosynthetic properties and consequently the accumulation of plant biomass. Thus, the chloroplastidic pigment concentration and chlorophyll a fluorescence of three Amazonian species (Bertholletia excelsa, Carapa guianensis e Dipteryx odorata) were investigated in sun and shade leaves form the tree crown collected during two distinct periods of precipitation (dry and rainy seasons). Pigment contents were determined by spectrophotometry and fluorescence variables were determined using a portable fluorometer. The results demonstrated that the species showed high concentrations of Chl a, Chl b e Chl total during the wet season in relation to the dry season, especially in shade leaves. A higher concentration of carotenoids was found in B. excelsa, when compared with leaves of C. guianensis and D. odorata. In leaves of B. excelsa and D. odorata no significant difference was found in relation to the photochemistry of photosystem II (Fv/Fm) between the wet and dry seasons. In conclusion, the three species react differently to variations in the light and precipitation conditions regarding light capture, aspects that might be considered in the management of forest plantations.