Mimosa Scabrella Research Articles

Modelación del volumen de rodal para especies secundarias en bosques nativos de Mimosa scabrella en la región metropolitana de Curitiba, Paraná, Brasil

Forest formations known as bracatingais - bracatinga forest - were initially composed only by the Mimosa scabrella – bracatinga – which, over the years, has been being replaced by several secondary species. The wood produced in these bracatingais is mainly sold for firewood and charcoal, being an important source of income for the small owners of this region. To facilitate the quantification of volumetric wood production, the objective of this work was to model the volume of firewood with bark per unit of area for the other hardwood species of the bracatingais. The data base comes from 320 plots measured in stands with ages varying from 3 to 20 years, measured between 1996 and 2011 in several municipalities of the metropolitan region of Curitiba. In these plots were measured in all the trees, with at least 5 cm in diameter, the variables total height and diameter at breast height. The individual volume of each tree in each plot was estimated using equations adjusted for similar forest formations. Twenty nine forest models selected from the forest literature, plus one arithmetic and one logarithmic, were adjusted by the forward stepwise process. The logarithmic equation adjusted by the forward stepwise process was the one with the best overall performance, with coefficient of determination adjusted of 0.992 and standard error of 10.17 %, which has no correlation among the residues by the Durbin Watson test and which was validated andconsidered suitable for estimating the volume per hectare of the hardwood species of bracatingais.

THE USE OF HYDROGEL COMBINED WITH APPROPRIATE SUBSTRATE AND FERTILIZER IMPROVE QUALITY AND GROWTH PERFORMANCE OF Mimosa scabrella BENTH. SEEDLINGS

ABSTRACT Mimosa scabrella is a pioneer species that occurs mainly in the ombrophilous mixed forests of southern Brazil, assuming considerable economic relevance. As limited information is available concerning the most adequate substrates for producing seedlings of this species, we evaluated the combined effect of hydrogel with three types of substrates and four fertilizers in the initial growth and quality of seedlings of M. scabrella. The substrates were prepared with distinct proportions of a commercial organic substrate, vermiculite (VM) and pine bark (PB): 1 (70% of TF, 10% of VM and 20% of PB), 2 (40% of each TF and VM and 20% of PB), and 3 (70% of TF, 10% of VM and 20% of PB). The fertilizers consisted of a slow release formula (A), a traditional NPK (B), a compost of superphosphate and potassium chloride (C) and no fertilizer (D). The three soil mixtures were combined with each fertilizer in the presence or absence of hydrogel (factorial arrangement). The use of hydrogel promoted a positive effect on the growth of M. scabrella seedlings, probably by retaining more water and enabling increased nutrient absorption. In general, the polymer implicated in increased Dickson quality index (DQI). Additionally, the combination of organic compound and vermiculite in equilibrated proportions aid by pinus bark (substrate 2) were the best substrate. Finally, adding the fertilizers A or B resulted in the best growth performance. In conclusion, the combined effect of hydrogel, substrate mixture and fertilizers improved the quality indexes of M. scabrella seedlings.

Genetic divergence among provenances of Mimosa scabrella Benth. based on seed analysis

It was aimed through this work to evaluate the genetic divergence among four provenances of bracatinga (Mimosa scabrella Benth.) belonging to the state of Santa Catarina, namely: Abelardo Luz (AB), Chapadao do Lageado (CL), Lages (PB) and Tres Barras (TB) by means of multivariate analyses, they are the principal components analysis and hierarchical clustering based on the Euclidian distance. Seeds of 40 mother trees, ten from each site, were evaluated as to the biometric aspects of seeds and variables coming from germination test. The traits which contributed for the most toward divergence among the provenances were the length and breadth of seeds, % of normal seedlings, % of germination and germination velocity index. Genetic divergence among the provenances was found and separated into two groups. The cross between the superior individuals of the provenances Abelardo Luz and with the superior individuals from the provenances of group I (CL and PB) are the most promising for future genetic breeding programs.

POTENCIAL DE FRAGMENTOS FLORESTAIS INSERIDOS DENTRO DE FLORESTA DE EXÓTICAS PARA A RESTAURAÇÃO DA FLORESTA COM ARAUCÁRIAS

A fragmentação florestal e o uso da matriz da paisagem por culturas agrícolas ou florestais pode alterar a composição de espécies, a ponto que estes não representem mais a estrutura da floresta nativa. Assim, fragmentos podem perder o potencial de fornecimento de propágulos para a restauração quando perdem espécies, ou quando têm a estrutura alterada em função dos efeitos da fragmentação. O objetivo deste estudo foi avaliar o potencial de uma rede de fragmentos florestais remanescentes formados há aproximadamente 50 anos em uma fazenda com povoamento florestal de exóticas, para atuar como fonte de propágulos no processo de regeneração natural. O sítio utilizado pertence a uma Floresta Ombrófila Mista (FOM), utilizado para produção florestal de espécies exóticas, com área de 798 ha, localizada no município de Ponte Alta - SC. Foram utilizados dados de levantamentos de fitossociologia desta formação para comparação, utilizando-se curvas construídas com base na rarefação do indivíduo, a distribuição das seis espécies mais abundantes, proporção de espécies e indivíduos zoocóricos e análise de similaridade, entre os locais. Os fragmentos florestais apresentaram riqueza de espécies compatíveis e por vezes maior ao que se pode encontrar em outras situações de FOM. Mimosa scabrella foi a espécie mais abundante, diferindo dos demais levantamentos. A quantidade de espécies com mecanismos de dispersão zoocórica foi semelhante ao esperado para FOM, entretanto, a quantidade de indivíduos zoocóricos foi inferior ao que poderia ser esperado. Os resultados indicam que os fragmentos apresentam potencial para atuar como fonte de propágulos no processo de restauração das áreas inseridas na fazenda, contudo, a capacidade pode ser limitada, uma vez que os fragmentos apresentaram algumas características diferentes de outras florestas com Araucárias.

Climatic factors defining the height growth curve of forest species

The aim of this study was to modify several existing biological models by including several predictive variables that take into account the effect of climatic factors on tree height growth. Tree height was measured from 2007 to 2014 on 18 trees for each of the following species: Eucalyptus urophylla × Eucalyptus grandis, Parapiptadenia rigida, Peltophorum dubium, Mimosa scabrella and Schizolobium parahybae. Different existing nonlinear models were fitted to the observed data, and the best fitting models were selected. The inclusion of climatic variables into the selected models (mainly minimum temperature and rainfall) improved their predictions of tree height growth with age, and provided more accurate estimates than those obtained by traditional nonlinear models. Simulations were carried out to explore the variation of tree height growth under different minimum temperature and precipitation regimes. The effects of frost and rainfall variation on height growth curves and their consequences for forest management are discussed.

Effect of in vitro gastrointestinal digestion on the bioaccessibility of phenolic compounds, minerals, and antioxidant capacity of Mimosa scabrella Bentham honeydew honeys

Honey is a product traditionally consumed due to its possible health benefits promoted by natural antioxidants. However, few studies have evaluated the effect of in vitro gastrointestinal digestion on these compounds in honeys. To improve the knowledge of this subject, the present study aimed to investigate the influence of simulated digestion on the stability of antioxidant capacity (FRAP, DPPH, and Folin-Ciocalteu assays), phenolic compounds (LC-ESI-MS/MS), and minerals (CE-DAD) in Mimosa scabrella Bentham honeydew honeys. The results show that the digestive system, mainly after duodenal digestion, significantly decreased the antioxidant capacity assessed by FRAP (410.3±18.3 to 564.7±8.4μmolFe+2100g−1), DPPH (30.1±0.8 to 33.9±1.4mgAAE100g−1), and Folin-Ciocalteu assays (58.3±2.6 to 142.0±1.6mgGAE100g−1) of this honey. However, phenolic compounds and minerals showed high stability and in some cases, significantly increased after the simulated digestion, presenting a bioaccessible fraction that ranged from 78.2±6.4 to 174.38±6.82% and 94.0±4.3 to 220.5±3.4%, respectively. Therefore, these honey constituents may be considered highly bioaccessible and potentially bioavailable. Additionally, the correlation between the investigated parameters suggests that other honey constituents could also possibly affect antioxidant capacity of this honey. In conclusion, the bracatinga (Mimosa scabrella Benth.) honeydew honey can be highlighted as an important natural source of bioaccessible polyphenols, besides presenting highly bioaccessible minerals in its composition, maintaining a satisfactory antioxidant capacity.

Germinação de sementes de Mimosa scabrella Benth. submetidas a diferentes condições de temperatura, armazenamento e tratamentos pré-germinativos

The objective of this study was to evaluate the effect of temperature, storage time and pre-germination treatments in the germination of Mimosa scabrella Benth seeds. The study was conducted at the University of the State of Santa Catarina, Lages. The experimental design was completely randomized, and analysis of variance was performed under the factorial 2×2×7 (two temperatures, two periods of storage, and seven pre-germination treatments). The average values were compared by Scott-Knott test at 5% probability. The temperatures employed were 25 and 30°C, the storage periods were eight months and no storage and pre-germination treatments were immersion in water at 80°C for periods of 3, 6, 9, 12, 15 and 18 hours. The results showed higher germination of seeds bracatinga in temperature 30°C, regardless of storage, and immersion for 3 hours in water at 80°C.

Proteome comparison for discrimination between honeydew and floral honeys from botanical species Mimosa scabrella Bentham by principal component analysis

Due to the increasing valuation and appreciation of honeydew honey in many European countries and also to existing contamination among different types of honeys, authentication is an important aspect of quality control with regard to guaranteeing the origin in terms of source (honeydew or floral) and needs to be determined. Furthermore, proteins are minor components of the honey, despite the importance of their physiological effects, and can differ according to the source of the honey. In this context, the aims of this study were to carry out protein extraction from honeydew and floral honeys and to discriminate these honeys from the same botanical species, Mimosa scabrella Bentham, through proteome comparison using two-dimensional gel electrophoresis and principal component analysis. The results showed that the proteome profile and principal component analysis can be a useful tool for discrimination between these types of honey using matched proteins (45 matched spots). Also, the proteome profile showed 160 protein spots in honeydew honey and 84 spots in the floral honey. The protein profile can be a differential characteristic of this type of honey, in view of the importance of proteins as bioactive compounds in honey. © 2017 Society of Chemical Industry.

Tolerância ao frio e características silviculturais do cedro-australiano no sul do Brasil

O cedro australiano (Toona ciliata M. Roem) é uma espécie difundida no Sudeste, Centro-Oeste e Nordeste do Brasil, onde alcança boa produtividade. Possui madeira de excelente qualidade para finalidades nobres. Entretanto, na região Sul do Brasil apresenta problemas de adaptação devido à ocorrência de geadas. O objetivo deste estudo foi verificar a tolerância ao frio e o potencial silvicultural de cedro-australiano em dois locais no Sul do Brasil. Os tratamentos consistiram de plantio puro de cedro-australiano e misto, com Mimosa scabrella e Eucalyptus benthamii em Lages, SC, e puro e sob Pinus taeda em Ibiam, SC. Durante dois anos após a implantação avaliou-se sobrevivência, danos por geada, bifurcação/brotação, altura total e diâmetro do colo. O cedro-australiano apresentou sérios danos pela geada no município de Lages, reduzindo drasticamente a sobrevivência e prejudicando as características silviculturais. O plantio do cedro-australiano sob pínus em Ibiam apresentou baixa taxa de mortalidade devido a geadas. O plantio puro nesta mesma região também apresentou baixa mortalidade, contudo, os efeitos das geadas foram consideráveis. O plantio de cedro-australiano não é indicado para as regiões com geadas intensas, contudo, em locais com geadas menos severas, o plantio sob pínus é uma alternativa potencial.

Free amino acid determination by GC-MS combined with a chemometric approach for geographical classification of bracatinga honeydew honey (Mimosa scabrella Bentham)

Honeydew honey is increasingly being valued by consumers and the food industry worldwide, particularly bracatinga honeydew honey (Bhh) obtained from honeydew of plant-sucking insects (Tachardiella sp.) that infest the tree species bracatinga (Mimosa scabrella Bentham) from Santa Catarina State (SC), Brazil. Due to mixture between honeys, authentication is an important aspect of quality control and its regard with the origin guarantee in terms of source and geographical documentation needs to be determined. We therefore determined the free amino acids (FAA) by GC-MS to elucidate the contribution of plant-sucking insects (Tachardiella sp.) and Apis mellifera bees to the Bhh in order to classify this honey from five different geographic areas of Santa Catarina, using chemometric approach. The results showed that proline is provided exclusively by Apis mellifera bees, and this honey could be differentiated into geographic regions based on the FAA profile. Principal component analysis identified the main FAA responsible for clustering of the samples in these regions (the sum of the first 2 principal components account for 82% of the total variance) and provided a similar discrimination of the geographical location map, particularly with regard to the northern and southern geographical orientations. This method is therefore a reliable analytical strategy for the authentication of this honey.

Mimosa scabrella BENTH. (FABACEAE) ENHANCES THE RESTORATION IN COAL MINING AREAS IN THE ATLANTIC RAINFOREST

ABSTRACT A Pilot Reclamation Project (PRP) was developed in 1982 by the Environmental Protection Agency of the State of Santa Catarina-Brazil, with the objective to evaluating the adaptation of woody species to a land degraded by coal mining. After a full topographic reconstitution of the landscape, addition of nutrient load and sowing of herbaceous species, the area was split into 12 plots in which seedlings of 12 tree species were planted: three native trees [Bastardiopsis densiflora (Hook. & Arn.) Hassl., Mimosa scabrella Benth., Schizolobium parahyba (Vell.) Blake] and nine exotic species [Eucalyptus saligna Sm., E. viminalis Labill., E. citriodora Hook., Grevillea hilliana F.Muell., Hovenia dulcis Thunb, Melia azedarach L., Pinus elliottii Engelm., P. taeda L., Syzygium cumini (L.) Skeels]. After 22 years, from the beginning of the PRP, the exotic species presented higher percentage of survival than native species; the plots which received either B. densiflora and S. parahyba or were covered only with herbaceous vegetation associated with solely a few shrubs. Conversely, the plots which received seedlings of M. scabrella displayed clear evidence of restoration in progress. The study conducted in plots that have received M. scabrella indicate an improvement of nutrient load (N, K, organic matter) in the substrate, a diversified composition of tree coverage (very similar to the nearby remnants of the Atlantic Rainforest) and other life forms, with prominent establishment of native trees with predominance of zoophilous and zoochorous species. Some characteristics of M. scabrella that could explain its outstanding capacity to enhance the restoration of the Atlantic Rainforest are also discussed along this paper.

Development and validation of the first SSR markers for Mimosa scabrella Benth.

Mimosa scabrella Benth., popularly known as ''bracatinga'', is a pioneer and endemic species of Brazil, occurring in Mixed Ombrophilous Forest associated with Brazilian Atlantic Rainforest biomes. It is a fast-growing tree of the Fabaceae family that facilitates the dynamics of ecological succession. SSR development, when there is no genome sequence, is time and labor intensive and there are no molecular markers for M. scabrella. We developed and validated the first microsatellite markers for this tetraploid species, evaluating mother trees and progenies. Using Illumina sequencing, we identified 290 SSR loci and 211 primer pairs. After 31 SSR loci PCR/agarose electrophoresis selection, a subset of 11 primer pairs was synthetized with fluorescence in the forward primer for PCR and capillary electrophoresis validation with leaf DNA of 33 adult and 411 progeny individuals. Polymorphic locus percentage was 36, 4 in 11 loci, 3 chloroplast SSRs, and 1 nuclear SSR. Allele number of polymorphic loci ranged from 2 to 11 alleles considering all sampling. All 11 primer pairs were also tested for cross-species amplification for five Fabaceae-Mimosoideae species, ranging from 2 loci transferred to Calliandra tweedii Benth. and all 11 loci transferred to Mimosa taimbensis Burkart. The assessed and validated SSR markers for M. scabrella are suitable and useful for analysis and population genetic studies.

Parâmetros genéticos para caracteres de crescimento inicial em progênies de bracatinga

Objetivou-se com este trabalho estimar parâmetros e valores genéticos para os caracteres diâmetro do coleto e altura de progênies de bracatinga em fase inicial de desenvolvimento. As sementes foram coletadas de 40 matrizes nativas nos municípios de Abelardo Luz, Chapadão do Lageado, Lages e Três Barras, SC. O teste de progênie foi conduzido na Fazenda Experimental do Centro de Ciências Agroveterinárias da Universidade do Estado de Santa Catarina, em Lages, visando à seleção de materiais genéticos adaptados ao local. O delineamento utilizado foi o de blocos ao acaso, com quarenta tratamentos (progênies), 30 repetições e dez plantas por parcela em linhas simples. Aos 12 meses de idade, foram avaliados os caracteres: diâmetro do coleto e altura total dos indivíduos. Diferenças significativas foram observadas entre procedências e progênies. Os coeficientes de herdabilidade em nível de indivíduo e de média de progênies, assim como os coeficientes de variação genética foram altos, para os dois caracteres avaliados, e os maiores valores foram encontrados para as procedências de Abelardo Luz e Chapadão do Lageado, indicando um forte controle genético na herança destes caracteres e possibilidade de encontrar indivíduos superiores.

English

The objective of this study was to evaluate the effect of input vectors in an artificial neural network (ANN) and determine their best combination to estimate the individual dry biomass of native bracatinga. The dataset consisted of 178 trees of Mimosa scabrella Benth. (bracatinga) from the Metropolitan Region of Curitiba. The ANN used was a Multi-Layer Perceptron; the learning algorithm was the Levenberg-Marquardt, consisting of an occult layer where 50% of the data were used for training, 25% for cross-validation and the other 25% for the test. The input vectors were all the variables collected in the field, such as: diameter at breast height (dbh), total height (ht), crown height (hc), stem height (hf), crown diameter (dc) and age (i). The treatment 1 consisted of all the vectors; after the MLP trained, the Garson algorithm was executed for obtaining relative contribution of each vector; the less important vector was deleted and the MPL was retrained (treatment 2) and so on until only one vector was left. Based on the coefficient of determination and root mean square error, treatment 3 provided the best performance (i, hc, ht and dbh), followed by treatment 6 (dbh). The method of selecting attributes by the Garson algorithm was remarkable and provided the definition of essential vectors, allowing minimal costs and optimizing the performance of the MLP. Key words: Bracatinga, multi-layer perceptron, Garson algorithm, relative contribution.

ESTRUTURA POPULACIONAL, PADRÃO ESPACIAL E ESTOQUE DE CARBONO EM BRACATINGAIS NO PLANALTO SUL CATARINENSE

O conhecimento de aspectos relacionados ao comportamento de populações naturais é premissa básica para elaboração de tecnologias adequadas para viabilizar o manejo e conservação de uma espécie. Objetivou-se investigar a estrutura populacional e a distribuição espacial, assim como estimar a biomassa aérea, teor de carbono e a quantidade de CO2 equivalente removido da atmosfera pela biomassa aérea de populações de Mimosa scabrella Benth. com diferentes idades, inseridas em áreas de floresta secundária. Foram alocadas três unidades amostrais, com dimensões de 40x40 m, em quatro locais distintos, totalizando 1,92 ha de área amostral, onde foram calculados os valores de densidade relativa dos indivíduos nas categorias regenerantes (DAP < 5 cm) e adultos (DAP ≥ 5 cm). O padrão de distribuição espacial foi calculado pelo índice de Morisita para as diferentes populações e a quantidade de CO2 equivalente pela estimativa do carbono total. A estrutura e o padrão de distribuição espacial de M. scabrella são compatíveis aos resultados registrados para outras espécies pioneiras (estádio inicial = agregado; estádio avançado = aleatório). Os maiores valores médios de biomassa, carbono total e CO2 equivalente registrados foram 91,4, 40,1 e 147,2 t.ha-1 respectivamente. As populações de M. scabrella demonstram potencialidades de prestação de serviço ambiental no que tange o sequestro e estocagem de carbono, além de contribuírem para o aporte de carbono no solo e serapilheira.

Development and validation of a LC-ESI-MS/MS method for the determination of phenolic compounds in honeydew honeys with the diluted-and-shoot approach

A simple, reproducible and sensitive method has been optimized and validated for simultaneous determination of 32 phenolic compounds in bracatinga (Mimosa scabrella Benth.) with the diluted-and-shoot approach, without the need of any additional clean-up steps. It has been based on high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry and electrospray ionization (HPLC-ESI-MS/MS). The chromatography conditions were optimized, and due to the selectivity provided by MRM monitoring, LC separation required only 9min. The developed method was validated on the basis of Eurachem and European Commission Decision 2002/657/EC guidelines. Mean recoveries ranged from 70.4 to 110%. Intra-day and inter-day precision with RSD (relative standard deviations) from 0.14 to 18.9% and 0.34 to 20.0%, respectively were achieved. Limits of detection (LOD) and quantification (LOQ) ranged from 0.03 to 3.20μgL−1 and 0.20–12.8μgL−1. Finally, the method was applied to samples and 20 phenolic compounds were quantified in all the samples analyzed, representing a contribution to the characterization and quantification of phenolic compounds from bracatinga (M. scabrella Bentham) honeydew honey.

RESISTÊNCIA DE PAINÉIS AGLOMERADOS PRODUZIDOS COM MISTURA DE MADEIRA DE ESPÉCIES FLORESTAIS TRADICIONAIS E NÃO TRADICIONAIS

Este trabalho teve como objetivo avaliar a resistência de painéis aglomerados fabricados com partículas de madeira de Pinus taeda (pinus), Eucalyptus saligna (eucalipto), Mimosa scabrella (bracatinga) e Hovenia dulcis (uva-do-japão) em diferentes proporções de misturas e em duas composições de camadas. Os painéis foram produzidos em misturas de duas, de três e das quatro espécies para painéis monocamada, e nas proporções de duas espécies para painéis multicamadas. Foram também produzidos painéis com madeira de pinus pura. O adesivo usado foi à base de ureia-formaldeído e a massa específica nominal estabelecida foi de 0,65 g/cm³. Foram avaliadas as propriedades físico-mecânicas de massa específica, teor de umidade, flexão estática, ligação interna e arrancamento de parafusos. As análises permitiram avaliar o efeito da utilização da madeira das diferentes espécies em misturas na fabricação dos painéis aglomerados. Os resultados foram também comparados aos requisitos das normas ANSI A 208.1. Verificaram-se aumentos nos valores das propriedades de flexão estática, ligação interna e arrancamento de parafusos com o aumento da proporção de pinus e uva-do-japão e diminuição com aumento da proporção de bracatinga e eucalipto. Portanto, pode-se concluir que as espécies que mais se destacaram foram o pinus e a uva-do-japão. Em relação à composição, os painéis multicamadas, em sua maioria, apresentaram-se superiores aos painéis monocamada.

Floristic evolution in an agroforestry system cultivation in Southern Brazil.

Bracatinga (Mimosa scabrella Bentham) is an important pioneer tree species in Ombrophylous Mixed Forest of Brazil and is widely used as an energy source. In traditional agroforestry systems, regeneration is induced by fire, then pure and dense stands known as bracatinga stands (bracatingais) are formed. In the first year, annual crops are intercalated with the seedlings. At that time the seedlings are thinned, then the stands remain at a fallow period and cut at seven years old. The species is very important mainly for small landowners. We studied the understory species that occur naturally during the succession over several years in order to manage them rationally in the future and maintain the natural vegetation over time. Three to 20 year-old Bracatinga stands were sampled between 1998 and 2011. All tree species with diameter at breast height (DBH) ≥ 5 cm were measured.The floristic evolution was assessed with respect to Sociability Index, the Shannon Diversity Index and the Pielou Evenness Index. Graphs of rank/abundance over different age groups were evaluated using the Kolmogorov-Smirnov test. We identified 153 species dispersed throughout the understory and tend to become aggregated over time.

MICORRIZAS ARBUSCULARES NO CRESCIMENTO DE LEGUMINOSAS ARBÓREAS EM SUBSTRATO CONTENDO REJEITO DE MINERAÇÃO DE CARVÃO

RESUMO O objetivo desse trabalho foi avaliar o efeito da inoculação de fungos micorrízicos arbusculares (FMA) no crescimento, colonização micorrízica e absorção de P e elementos-traço em leguminosas arbóreas expostas a rejeito de mineração de carvão. Ensaios independentes para as leguminosas Mimosa scabrella Benth. (bracatinga), Mimosa bimucronata (DC.) Kuntze (maricá) e Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) foram conduzidos em casa de vegetação em delineamento inteiramente casualizado com seis tratamentos. Foram avaliados cinco isolados de FMA autóctones de áreas de mineração (Acaulospora colombiana, Acaulospora morrowiae, Dentiscutata heterogama, Rhizophagus clarus e Rhizophagus irregularis), além de um tratamento controle não inoculado, com quatro repetições. Verificou-se que a colonização micorrízica foi superior a 60% para a bracatinga e o maricá, enquanto que, para o angico-vermelho, foi de no máximo 26%. De maneira geral, a inoculação de FMA favoreceu o crescimento das leguminosas arbóreas, atingindo incrementos de até 1430%. A absorção de fósforo foi beneficiada principalmente pela inoculação de A. colombiana, R. irregularis e A. morrowiae. Apesar de se verificar redução nos teores de elementos-traço na parte aérea das plantas, a inoculação de FMA ocasionou incrementos significativos no acúmulo de As, Cu, Zn e Cr para todas as leguminosas avaliadas. Desta forma, os FMA desempenham papel importante para o crescimento de espécies arbóreas em áreas de mineração de carvão, as quais apresentam ambientes pobres, degradados e muitas vezes contaminados.

EVOLUÇÃO ESTRUTURAL DE BRACATINGAIS DA REGIÃO METROPOLITANA DE CURITIBA, PARANÁ, BRASIL

http://dx.doi.org/10.5902/1980509821102O objetivo deste trabalho foi estudar a evolução estrutural de espécies arbóreas em bracatingais, ao longo de vinte anos. A bracatinga (Mimosa scabrella Benth.) é a espécie pioneira, de vida curta, que caracteriza os bracatingais. Sob as bracatingas forma-se um sub-bosque com outras espécies arbóreas, que vai assumindo o lugar da bracatinga com o passar dos anos e que é tratado como se fosse lenha da própria bracatinga, quando a área é cortada a cada 7 anos e a regeneração da bracatinga é novamente induzida com o uso do fogo. O processo de sucessão em bracatingais ainda não foi estudado e é útil identificar a idade em que as demais espécies passam a dominar o bracatingal. Trabalhou-se com 320 parcelas, distribuídas em bracatingais com idades variando de 3 a 20 anos, medidas entre 1998 e 2011. Foram medidos os DAP (diâmetro a altura do peito) e altura total de todas as espécies com DAP ≥ 5 cm. Observou-se que, aos 11 anos, o conjunto das espécies supera a bracatinga em número de indivíduos e aos 19 anos as espécies arbóreas já apresentam uma distribuição diamétrica semelhante ao de uma floresta em fase mais avançada. De forma geral observou-se que, após os 10 anos de idade, um bracatingal já começa a tomar forma de um capoeirão.