Developmental and Structural Section
Angyalossy, Veronica , Angeles, Guillermo , Madero-Vega, Carolina .
Lateral communication between vessel elements through perforated ray cells in tropical plants.
The perforated ray cells (PRC) of the secondary xylem, produced by the radial initial cells of the cambium, are radial cells with perforations, generally are on the side walls, connecting two vessels on either side of the ray. The perforation type may be simple, scalariform, reticulate, or foraminate, not always coinciding with that of the vessel elements in the same wood. They occur in several plant families. As seen in literature and personal observations, they are almost exclusively present in species that have no axial parenchyma around the vessels, i.e., in wood with apotracheal parenchyma, and generally on the uniseriate part of the multiseriate rays. It is also worth noting that in some families, like Bignoniaceae, composed of trees, shrubs and liana species, the perforated ray cells occurs only in the liana xylem. Although there are some anatomical descriptions of PRC, there are no evidences of their functionality in hydraulic transport, or of the complexity of the vessel network that they form. In order to obtain a three-dimensional view of the communication between vessel elements and PRC, we elaborated direct replicas or micro-casts of the secondary xylem of some species of representative families presenting PRC. We demonstrate, for the first time, that there is a continuous network formed by the vessels and the perforated ray cells, as indicated by the micro casting.
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1 - Universidade de São Paulo, Departamento de Botânica., Rua do Matão, 277. Cidade Universitaria. 05422-970, Sao Paulo, Sao Paulo, 05422-970, Brasil
2 - Instituto de Ecología, A.C., Unidad de Recursos Forestales, Km 2.5 ant. carr. a Coatepec, Xalapa, Veracruz, 91070, Mexico
3 - Instituto de Ecología, A.C., Ecología Funcional, Francisco Moreno No 172, Apt. 1, Xalapa, Veracruz, 91070, México
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 3:45 PM