Functional morphology of subtropical tree seedlings in southern Brazil

Abstract The objective of this study was to analyze the morphofunctional attributes of Mixed Ombrophyllous Forest species of different successional categories. Fruits were collected from forest remnants in Curitiba, Paraná. It was analyzed the biometrics of seeds and seedlings of all species and the following ratios were estimated: shoot/seedling length, shoot/seedling mass, cotyledons/seedling mass, eophyll/seedling mass and seedling/ seed mass. Statistical differences among sucessional groups were observed in many of the evaluated traits. The variability among species is mainly explained by seedling size, tissue investment for light interception and shoot resource allocation. Late secondary species have larger seedlings with characteristics that indicate slower initial development, dependent on seed reserves. The pioneers species have smaller seedlings but faster development and earlier dependence on photosynthesis. These morphological and functional differences can result in different strategies for the establishment of seedlings in the successional process. The cluster analysis results on formation of two major groups. The first group is comprised of the late secondary species. The second group includes two distinct subgroups that separate the pioneers, and most of the early secondary species. These results indicate that the number and quality of available data should be considered in the definition of successional categories adopted in ecological studies. Resumo O objetivo deste estudo foi analisar os atributos morfofuncionais das espécies da Floresta Ombrófila Mista, pertencentes a diferentes categorias sucessoriais. Frutos foram coletados de remanescentes florestais em Curitiba, Paraná. Foi realizada a biometria das sementes e plântulas e estimados os seguintes índices: comprimento da parte aérea/plântula; massa da parte aérea/plântula; massa dos cotilédones/plântula; massa dos eofilos/plântula e massa da plântula/semente. Diferenças estatísticas entre os grupos foram observadas em muitas das características avaliadas. A variabilidade entre as espécies é explicada pelo tamanho das plântulas, investimento em tecidos para interceptação da luz e alocação de recursos na parte aérea. As secundárias tardias têm plântulas maiores com características que indicam um desenvolvimento inicial mais lento, dependente das reservas da semente. As pioneiras têm plântulas menores, desenvolvimento mais rápido e são dependentes da fotossíntese. Essas diferenças morfofu