Análises morfológicas e determinação química de sementes de três espécies de Leguminosae do semiárido

Abstract

The objective of this study was to investigate the morphological and chemical characteristics of Jurema-Branca (Piptadenia stipulacea) at different germination times (T0, T1, T2, T3, T4), with emphasis on the characteristics of the cell wall polysaccharide of the endosperm cells. Was investigated also the cell wall polysaccharide from the endosperm cells of the seeds of Canafístula (Senna lechriosperma) and Pau-violeta (Darbergia cearensis). Morphological analyzes were performed with all species mentioned above using Toluidine Blue, Xylidine Ponceau, PAS Reaction and Lugol. The chemical determinations were performed only with Jurema-Branca seeds, where the methods of Antrona (for the determination of carbohydrates), Bradford (for the determination of proteins) and gravimetry (for the determination of lipids) were used. Extractions were made for cell wall polysaccharide in all the mentioned species. For structural determination of the extracted cell wall polysaccharide, δ13C and δ1H NMR (Nuclear Magnetic Resonance) were performed. The results showed that Jurema-Branca seeds contain about 60% lipids, 22.8% carbohydrates and 11.6% proteins. During germination, the hypothesis was raised that starch and proteins are produced to be used by the embryo at the cost of the lipid and cell wall polysaccharide reserves of endosperm cells. NMR analyzes showed the Jurema-White mannose / galactose ratio is 2.49: 1, at T0, and 1.53: 1, at T2. The ratio of Canafistula Man / Gal is 1.8: 1, similar to that of the commercially available Guar gum (Cyamopsis sp). The Pau-violeta Man / Gal ratio cannot be achieved.