RESUMOEsse estudo avaliou comparativamente os parâmetros fitossociológicos da regeneração natural e da vegetação arbórea em dois manguezais distintos no Estado do Paraná, um pertencente à Baía de Paranaguá (manguezal de Antonina) e outro à Baía de Guaratuba (manguezal de Guaratuba). Em cada área, três subáreas foram marcadas e amostradas cinco parcelas de 10 x 10 m para avaliação do componente arbóreo e quinze subparcelas de 1 x 1 m para avaliação da regeneração natural. Avicennia schaueriana, Rhizophora mangle e Laguncularia racemosa exibiram domínio e densidade relativa distintos entre as áreas. Manguezais de Antonina e Guaratuba diferiram tanto na estrutura da regeneração natural como no componente arbóreo. A Análise de Coordenadas Principais (PCoA) mostrou que as diferenças entre as áreas em relação às variáveis abióticas do solo estão fortemente relacionadas com os parâmetros estruturais do componente arbóreo dos manguezais. Os fatores edáficos dos manguezais têm grande importância na separação entre as áreas, já que reflete na capacidade de adaptação das plantas. Palavras-chave: fitossociologia; mangue; salinidade; solo. ABSTRACTWe analyzed the structures of two mangrove forests of Paraná (Brazil) (Antonina Bay and Guaratuba Bay), considering adult trees and regeneration component. In each area, we marked three sub-areas and sampled five plots of 10 x 10 m, equivalent to 0.05 ha to adults trees and fifteen 1 x 1m sub-plots to assess the regeneration component. Avicennia schaueriana, Rhizophora mangle and Laguncularia racemosa exhibited distinct dominance and relative density between the areas. Mangroves of Antonina and Guaratuba differed both in the structure of natural regeneration as the tree component. The Principal Coordinates Analysis (PCoA) show that differences between areas in relation to abiotic variables of soil are strongly related to the structural parameters of trees. The different types of mangrove soil are the most significant factor in the differentiation between the mangrove areas since influences the salinity values and consequent adaptability of plants.

This study assessed the relation between Cu, Fe, Mn, and Zn

R E S U M OA composição química do solo e das folhas e a eficiência do uso de nutriente por Avicennia schaueriana Stapf & Leachman, Laguncularia racemosa (L.) Gaertn e Rhizophora mangle L. foram analisadas num manguezal de Guaratuba, PR. Dada à complexa interação entre os fatores bióticos e abióticos dos manguezais, empregou-se o estudo da eficiência do uso de nutrientes (EUN). Dez indivíduos, por espécie, foram demarcados para coleta das folhas. Amostras de solo entre 0-10 cm de profundidade foram coletadas na projeção de cada árvore selecionada. As características químicas do solo pouco diferiram entre as espécies com exceção dos valores de C, N e MO, que foram maiores na área de R. mangle. As três espécies estudadas apresentaram concentrações foliares de nutrientes distintas mostrando absorção seletiva. A eficiência do uso de nutrientes seguiu a ordem crescente L. racemosa > R. mangle > A. shaueriana. Esses resultados mostraram que as espécies estudadas apresentam estratégias diferenciadas quanto ao acúmulo e utilização de nutrientes. Assim, o maior acúmulo de determinado nutriente nas folhas não necessariamente significa menor eficiência no seu uso, particularmente tendo em vista que a planta se utiliza de diferentes estratégias para a manutenção do equilíbrio iônico.Chemical composition of soil and leaves and nutrient use efficiency of mangrove species A B S T R A C TThe chemical composition of soil and leaves, and nutrient use efficiency of Avicennia schaueriana Stapf & Leachman, Laguncularia racemosa (L.) Gaertn e Rhizophora mangle L. were analysed in the mangrove of Guaratuba, PR. Given the complex interaction between biotic and abiotic factors of mangrove ecosystems the nutrient use efficiency (NUE) was applied. In the study area ten individuals for each species were marked for leaf sampling. Soil samples were also collected at 0-10 cm depth under the crown projection of the selected trees. The analysed soil attributes, did not differ among species except C, N and O.M. which were greater in the area of R. mangle. The three studied species presented different leaf nutrient concentrations, showing selective absorption, even sharing the same soil. In general and in ascending order, the nutrient use efficiency obeyed the following sequence: L. racemosa > R. mangle > A. shaueriana. The results suggest that the studied species show distinct strategies related to nutrient storage and usage. The greater amount of a determined nutrient in leaf not necessarily means lower nutrient use efficiency, particularly due to the various strategies utilized by the plants for maintenance of ionic equilibrium. Palavras-chave:Avicennia schaueriana Laguncularia racemosa Rhizophora mangle

No abstract

-(Description of the soil and root biomass of two subtropical mangroves in Antonina and Guaratuba Bay, Paraná State, Brazil). The soil of the mangroves influences the root anchorage and the nutrition processes of the plant community. This study evaluated the relationships among edaphic conditions, volume and biomass of roots, and tree structure of two mangroves in Paraná State. Five soil cores of 50 cm depth were collected from each mangrove for physicochemical analysis. Organosoil thiomorphic salic sodic predominated in Antonina Bay, while in Guaratuba Bay were observed the Gleysoil thiomorphic salic sodic and the Organosoil thiomorphic salic sodic. Fifteen root samples were collected from each mangrove area for root volume and dry mass analysis'?'. The higher values of root mass were found in Guaratuba Bay. The chemical analysis of the soil showed no correlation between biomass and root volume. The high coefficients of variation attested the high heterogeneity in the root distribution in both areas. However, in the Guaratuba Bay, root mass and volume are higher due to the textural composition of the soil and higher tree density.