Abstract:

Histological and chemical features in seeds of Myrsine laetevirens are described. Seed is endospermous and the endosperm consists of several layers of thick cell walls that store mainly xyloglucans. Next to the embryo, the endosperm cell walls are rich in pectins. In the endosperm, proteins are stored in typical protein bodies. In the embryo, vacuoles with small deposits of protein inside were distinguished. Globoids, found in the protein bodies of the endosperm, are absent in the embryo tissues. Energy-dispersive x-ray analysis of globoid revealed P, Mg, K, and Ca as the main nutrient minerals. Lipid vesicles are present in embryo and endosperm; in the embryo they are found mainly along the periphery of the plasmalemma. Determination of neutral sugars was performed after acid hydrolysis. Sugars were identified by high-performance anion exchange chromatography (Dionex). Arabinose, xylose, glucose, and galacrose are the main monosaccharides, but the ratio differs in endosperm and embryo tissues. Uronic acids were determined by a colorimetric reaction. Analysis of fatty acids by capillary gas-liquid chromatography revealed the presence of C16:0, C18:0, C18:1, and C: 18:2 fatty acids in embryo and endosperm. In the latter, traces of C12:0 also were detected. Soluble proteins were analyzed by polyacrylamide gel electrophoresis, which showed a different profile in both tissues. Few bands are glycosylated. This investigation was undertaken in order to initiate studies of the seed in the genus Myrsine. Similar studies in other genera of Myrsinaceae have not been reported, precluding a taxonomical comparison.