Perfil eletroforético de proteínas em sementes de pinhão-manso(Jatropha curcasl.) sob condições de restrição hídrica

Abstract

Physic nut (Jatropha curcas L.) is a Euphorbiaceae of great economic interest for the production of biodiesel, but toxic components limit the use of its seeds. The aim of the study was to check the influence of water restriction in the electrophoretic profile of proteins during imbibition of seeds of physic nut. Two seeds lots from Cafarnaum/BA were characterized by analyzing germination percentage, weight of thousand seeds, biometry and moisture of seeds. The lot with higher germination percentage was imbibied water restriction in PEG 8000 solution (-0,8 MPa) and incubated at 25 °C in continuous darkness for 0, 2, 4, 6, 8, 10, 12 and 14 days. Embryonic axis and endosperm were isolated, macerated in liquid nitrogen, added to phosphate buffer pH 7.5, centrifuged at 14.000 rpm at 4 °C for 15 minutes for extraction of total proteins. The supernatant was collected for quantification of total protein using BSA as standard and performing absorbance reading at 595 nm in a spectrophotometer. Was carried the polyacrylamide gel electrophoresis at 300 V, 60 mA at 1:20 h to verify the protein profile in seed tissues. The proteins were visualized in the gel with coomassie blue solution. The electrophoretic profile differed between samples imbibed in water and in PEG 8000 (-0.8 MPa). It was possible to visualize protein bands related to plant defense to water restriction as well as an increased on intensity of bands corresponding to the molecular weight of the curcin in samples of endosperm of seeds imbibed under water restriction, when compared to dry seeds