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Made available in DSpace on 2013-08-12T19:11:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 Made available in DSpace on 2013-09-30T18:36:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:48:44Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T13:48:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 The origin and structure are described of the secondary protective tissue in the stem of Erythorxylum tortuosum Mart., a fire tolerant shrubby species common in Brazilian cerrado. The highly tortuous stems are covered with thick bark which is more developed at the base of the stem. After fire in the cerrado, rhytidome fragments of the burned stem flake off, revealing newly formed cork. The first periderm appears near of the terminal buds and is iniated by periclinal divisions in subepidermal cells giving rise to radial rows of cells. The first phellogen is discernible only after the differentiation of the several radial rows of cork cells. Other phellogens have their origin in successively deeper layers of the cortex. The sucessive periderms are discontinuous around the circumference. The collapsed cells with phenolic substances and the accumulated dead cells cause the formation of discontinuous blackish lines, which delimit the sucessive periderms in the rhytidome. The rhytidome contains large quantities of sclereids developed from cell wall thickening of cortex cells. The occurrence of periderm, in the young parts of the stem and of rhytidome in the older parts represents pyrophytic characteristics and may explain, in part, the fire tolerance of this species. Univ Estadual Paulista, Dept Bot, BR-18618000 Botucatu, SP, Brazil Univ Estadual Paulista, Dept Bot, BR-18618000 Botucatu, SP, Brazil

Made available in DSpace on 2013-08-12T17:56:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 Made available in DSpace on 2013-09-30T17:48:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:48:39Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T13:48:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundação para o Desenvolvimento da UNESP (FUNDUNESP) 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. UNESP, Fac Agron Sci, Dept Nat Resources, BR-18603970 Botucatu, SP, Brazil UNESP, Biosci Inst, Dept Bot, BR-13618000 Botucatu, SP, Brazil UNESP, Fac Agron Sci, Dept Nat Resources, BR-18603970 Botucatu, SP, Brazil UNESP, Biosci Inst, Dept Bot, BR-13618000 Botucatu, SP, Brazil FAPESP: 00/12469-3 FAPESP: 03/13578-9 FAPESP: 05/59499-8

Made available in DSpace on 2022-04-28T20:17:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-01-01 The genus Styrax L. (Styracaceae) has a wide distribution in Brazil, occurring in diverse ecosystems. To get a better insight into the ecological adaptations of wood structure, we studied two species, S. camporum and S.ferrugineus from the cerrado, and three species, S. latifolium, S. martii and S. leprosus from the Atlantic forest. For each species, the wood of root and stem was analyzed separately and observations included qualitative as well as quantitative wood characteristics. The results show that there were significant anatomical differences between the forest and cerrado species as well as between the root and stem wood within single species. Quantitatively, the most informative features in the root wood that separated the forest from the cerrado species were diameter, length and number of vessels, length of fibres, and width and frequency of rays. In the stem wood, length and frequency of vessels, length of fibres, and width and frequency of rays were the most informative features. In contrast to the forest species, which had larger vessel diameters in their stem wood, the cerrado species had larger vessel diameters in their root wood. The calculated vulnerability index indicates that all Styrax species have adaptations to mesic conditions. The cerrado species had the smallest index values, which could be related to the seasonally dry condition of this environment. Departamento de Botânica Institute de Biociências Universidade Estadual Paulista, Botucatu, SP, CP510, CEP 18618-000 Departamento de Botânica Instituto de Biociências Universidade de São Paulo, SP, CP 11461, CEP 05422-970 Departamento de Recursos Naturais - Ciências Florestais Universidade Estadual Paulista, Botucatu, SP, CP 237, CEP 18603-970 Departamento de Botânica Institute de Biociências Universidade Estadual Paulista, Botucatu, SP, CP510, CEP 18618-000 Departamento de Recursos Naturais - Ciências Florestais Universidade Estadual Paulista, Botucatu, SP, CP 237, CEP 18603-970