EXTRAÇÃO DE PIGMENTOS CLOROPASTÍDICOS EM TOMATEIRO: AJUSTE DE METODOLOGIA

Abstract

The production of crops of agricultural interest depends in part on the proper functioning of the photosynthetic machinery. The extraction of these chloroplast foliar pigments can be used as indicative of stress in the plants, besides showing their photosynthetic capacity. The classical methodology for measuring the photosynthetic pigments is the result of the destructive collect of plant leaves. Dimethylsulfoxide (DMSO) is an extractor of chlorophyll and carotenoids that can be used instead of acetone, with the advantage of not requiring maceration and centrifugation, which simplifies the classical methodology, showing a better efficiency in the field. Therefore, the objective of this work was to adjust the temperature and incubation time for chloroplastinic pigment extraction in tomato leaves. The experiment was carried out in a completely randomized design (DIC), using 7 replicates in each treatment. Leaf discs were collected and then placed in test tubes containing 5mL of DMSO saturated with calcium carbonate 5% and subjected to temperature conditions of 30 and 65 °C in periods of 12, 24, 36 and 48 hours. After the incubation time at each temperature, the samples were read in a spectrophotometer at absorbances of 665 nm to determine the chlorophyll a content, 649 nm for chlorophyll b, 480 nm for carotenoid values, and 415 nm and 435 nm to calculate the pheophytination index (FI). After the analyzes, it was found that tomato leaves should be incubated for 15 hours, regardless of temperature 30 and 65 °C.