ABSTRACT
Abstract Individual leaf area (LA) is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length – L and width – W) of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx) with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx) had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.
Resumo Área foliar individual (AF) é uma variável chave em estudos sobre a ecofisiologia de arbóreas, porque influencia diretamente a interceptação de luz, a fotossíntese e a evapotranspiração das árvores adultas e das mudas. Foram analisadas as dimensões foliares (comprimento - C e largura - L) de indivíduos adultos e de mudas de sete espécies arbóreas de florestas neotropicais (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera e Tabebuia stenocalyx), com o objetivo de testar a viabilidade de modelos de regressão linear para estimar a AF de indivíduos adultos e mudas. No sul da Bahia, Brasil, um primeiro conjunto de dados foi coletado entre março e outubro de 2012. A partir das sete espécies analisadas, apenas duas (P. cattleyanum e T. stenocalyx) apresentaram relações muito semelhantes entre e AF e CL, em ambos os estádios ontogenéticos. Para estas duas espécies, um segundo conjunto de dados foi coletado em agosto de 2014, a fim de validar os modelos únicos que englobam folhas de indivíduos adultos e mudas. Nossos resultados mostram a possibilidade de desenvolvimento de modelos para a predição da área foliar, abrangendo diferentes estádios ontogenéticos para espécies arbóreas tropicais. O desenvolvimento destes modelos foi mais dependente das espécies do que das diferenças entre o tamanho das folhas de mudas e de indivíduos adultos.
Subject(s)
Trees/growth & development , Plant Leaves/growth & development , Seedlings/growth & development , Rainforest , Brazil , Regression Analysis , Models, TheoreticalABSTRACT
Aims: The study was designed to explore the floristic composition and biological characteristics. Place and Duration of Study: A record of plant species of Sheikh Maltoon Town Mardan was organized during 2008 – 2009. Methodology: A record of plant species was organized on the source of field trips conducted in winter, summer and monsoon, and identified with available literature. The plants were classified into different life form and leaf size classes after standard methods. Results: The flora consisted of 91 plant species belonging to 76 genera and 38 families. Asteraceae, Poaceae and Cucurbitaceae are the dominant families of the floristic composition of research area. The biological spectrum explains that therophytes (52 spp., 57.14%), magaphanerophytes (11 spp., 12.09%) were the dominant followed by hemicryptophytes (9 spp., 9.89%), chamaephytes (8 spp., 8.79%), nanophanerophytes (6 spp., 6.59%), geophytes (4 spp., 4.39%) and parasite (1 spp., 1.1%). Leaf spectra of plants consisted of microphylls (46.2%), mesophylls (25.3%), nanophylls (13.2%), leptophylls (9.59%) and megaphylls (5.49%). Conclusion: Analysis of the present work reveals the phytoclimate to be of therophytic type. The domination of therophytes indicates that the investigated area is under deep biotic stress.