Perforated ray cells in the wood of roots and branches of cerrado species from Brazil

摘要

Perforated ray cells (PRCs) are recorded here for the first time in the roots and branches of Schefflera vinosa, Caryocar brasiliense, Acosmium subelegans, Byrsonima basiloba, B. coccolobifolia, B. verbascifolia and Alibertia concolor which occur in Pratania's cerrado (SP, Brazil). PRCs are larger than normal ray cells, occurring isolated or in groups of two or more in the same ray, and are present predominantly in the uniseriate portion of multiseriate rays in all species studied. In the roots and branches, the types of perforation plates (PP) of the PRCs are similar to those of the vessel elements (VE) in most species, with the exception of the branches of Schefflera vinosa and the branches and roots of Caryocar brasiliense. The diameter of the PRC plates was greater in the roots than in the branches, but the differences were only statistically significant in Schefflera vinosa, Byrsonima basiloba and B. verbascifolia. In a general way the PRC plates were greater in diameter than the VE plates in both roots and branches of most species.