Fruit Morphology and Seed Anatomy of Ormosia macrocalyx Ducke

Ormosia macrocalyx grows in tropical forests and is endangered in Mexico. The species has ecological and economic importance. To evaluate the relationship between fruit length and seed number, Pearson correlation and principal component analysis were used. A linear mixed-effects model was also applied. Pearson correlation, principal components analysis (PCA) and a Linear Mixed-Effects Model (LMM) were performed on an exploratory basis. In addition, seed coat and cotyledon anatomy were examined, and histochemical tests for secondary metabolites were carried out. Two high correlations and two components were obtained from the PCA, and the LMM showed that fruit length influenced the number of seeds per fruit. In the seed coats, differentiated layers of macrosclereids and osteosclereids were identified, where the hilar region presented macrosclereids and a pyriform bar of tracheids, the reserved cotyledons showed double-walled cells and simple plasmodesmata, the histochemical analyses demonstrated the presence of cellulose, condensed tannins, lipids, alkaloids, and proteins, and no starch was present. This study provides the first description of seed coat and cotyledon anatomy in O. macrocalyx, as well as the first report of secondary metabolites in storage cotyledons. These results could be useful for further studies of this species.