Resumo A composição florística dos campos rupestres compreende um mosaico de espécies com adaptações distintas, exibindo alta diversidade e endemismo. Entretanto, as plantas dos campos rupestres possuem dependência às condições específicas do local e sua reprodução quase sempre é limitada, tornando difícil a regeneração natural após perturbações. O banco de sementes do solo representa um fator potencial para a regeneração deste ambiente. Objetivou-se avaliar o banco de sementes do solo de diferentes profundidades de uma área de campo rupestre, coletado em duas estações climáticas e submetido a duas condições de luminosidade. Foram coletadas amostras compostas de serapilheira e de solo (0-5 cm) em 13 parcelas de 100 m2, em uma área de campo rupestre na Serra do Cipó (Minas Gerais), nas estações seca e chuvosa. As amostras foram submetidas às condições de luminosidade pleno sol e sombreamento. No total, emergiram 185 plântulas pertencentes a 31 espécies e a nove famílias botânicas. As famílias com maior riqueza foram Cyperaceae, Poaceae e Asteraceae. Houve variação de riqueza, abundância e composição florística entre as profundidades do solo, mas não foi observada variação em relação à estacionalidade e às condições de luminosidade. As amostras de solo apresentaram valores superiores dos parâmetros avaliados em relação àquelas da serapilheira, mostrando que o banco de sementes é mais representativo no solo. Esses resultados demonstram que existe potencial de regeneração do campo rupestre por meio do banco de sementes do solo.

Abstract The floristic composition of the rupestrian grasslands comprises a mosaic of species with different adaptations exhibiting high diversity and endemism. However, the plant species from rupestrian grasslands are dependent on site-specific conditions and their reproduction is almost always limited, making natural regeneration after disturbances difficult. The soil seed bank represents a potential factor for the regeneration of this environment. The objective was to evaluate the soil seed bank of different depths of a rupestrian grassland area, collected in two climatic seasons and submitted to different light conditions. The samples composed of litter and soil (0-5 cm) were collected in 13 plots of 100 m2, in a rupestrian grassland area in Serra do Cipó (Minas Gerais state), in dry and rainy seasons. The samples were subjected to full sun and shading conditions. In total, 185 seedlings of 31 species and nine botanical families emerged. The richest families were Cyperaceae, Poaceae and Asteraceae. There was variation in richness, abundance and floristic composition among the soil strata, but no variation was observed in relation to seasonality and light conditions. The soil samples presented higher values of the evaluated parameters in relation to those ones of litter, showing that the seed bank is more representative in the soil stratum. These results demonstrate that there is potential for rupestrian grassland regenerations through the seed bank, especially the soil stratum.

ABSTRACT Our research focused on the reproductive phenology of Mauritiella armata, a key veredas species in southeastern Brazil, and aspects of its floral and fruit morphology and sexual system. We observed the reproductive phenological patterns of M. armata for 36 months, and examined the relationships between phenophases and environmental variables to describe its phenological patterns in relation to environmental filters, as well as its floral and fruit morphologies, sexual system (to evaluate dioecy), and the biometry of its reproductive parts. Flowering was observed in the dry season and at the beginning of the rainy season, with fruiting occurring during the rainy season. The reproductive phenophases responded to environmental seasonality, principally temperature in the period immediately preceding the expression of the phenophase, as well as to environmental variations that had occurred up to six months earlier. The dioecious sexual system of M. armata was confirmed, with flowering synchronization between the sexes. The population studied did not exhibit apomixis, having xenogamy as its reproductive system. The staminate inflorescences were larger than the pistillate inflorescences and had greater numbers of flowers, although the pistillate flowers were larger. Wind pollen dispersal was not observed, thereby indicating that this species requires biotic pollination for fruit production.

Abstract Many factors can influence the structures and distributions of plant communities. Plant diversity of swamp forests reflect responses to water stress conditions. We evaluated the floristic diversity, structure, and composition of the regenerating shrub-tree species of six swamp forests in veredas ecosystems (northern Minas Gerais, Brazil), and the floristic similarities between them. All individuals ≥ 1 cm in diameter at ground level and < 3 cm in diameter at breast height were sampled in one hundred 25 m2 plots in each area. A total of 5442 individuals were recorded, distributed among 134 species, 85 genera, and 47 botanical families, with a diversity (Shannon) of 3.38 and equability (Pielou) of 0.69. Beta diversity was high, while similarities between the areas were low, with only two species common to all six sites. The forests showed different compositions, diversities, and natural regeneration structures, reflecting their ecotone nature and past anthropic impacts.

Abstract Several plant-related factors can influence the diversity of gall-inducing species communities. In the present study we performed an inventory of gall-inducing arthropods and we tested if the plant species richness and the abundance of super-host plants (Copaifera oblongifolia) influenced positively in the diversity of gall-inducing arthropod species. The study was realized in an area of Neotropical savanna (cerrado sensu stricto) in the Environmental Protection Area (EPA) of Rio Pandeiros, Minas Gerais, Brazil. Host-plant species and gall-inducing arthropods were sampled in 18 10 × 10 m plots distributed in the vegetation. In total we found 40 arthropod gall morphotypes, distributed on 17 botanical families and 29 plant species. Cecidomyiidae (Diptera) induced the most arthropod galls (85%), and the plant family Fabaceae had the greatest richness of gall morphotypes (16). The plant species Copaifera oblongifolia and Andira humilis (Fabaceae) were the most important host species with five and three morphotypes, respectively. Galling species richness was not affected by none of explanatory variables (plant species richness and abundance of super-host plants). On the other hand, galling species per plant species was negatively affected by plant species richness and positively affected by abundance of super-host plants. This is the first study of arthropod-induced galls conducted in EPA of Rio Pandeiros, Brazil. Our results corroborate previous studies that highlight the importance of super-host plants for galling arthropod diversity on a local scale.

ABSTRACT The soil seed bank is an important natural regeneration strategy for plant communities and can determine floristic composition after disturbances. The aim of the present study was to evaluate the seed bank richness and abundance at different soil depths and under different light conditions in a dry forest. Litter and soil samples were collected at depths of 0-5 and 5-10 cm and submitted to two light conditions (light and shady). In total, 1,725 individuals from 85 species and 19 families emerged. Significant differences in richness between soil depths were observed, being greater at 0-5 cm, while abundance was similar. There were no variations in richness or abundance of germinated seeds between light conditions. Malvaceae and Verbenaceae families were the most representative in this study.

Resumo Este estudo analisou as variações florísticas, estruturais e suas relações com variáveis do solo em dois trechos de vegetação ripária em uma região ecotonal entre savana e zonas semi-áridas. Propomos a hipótese de que, apesar da proximidade entre as áreas amostradas, as condições do solo são distintas e levam a mudanças na estrutura e composição da vegetação, mas essas mudanças também são influenciadas pelo caráter ecotonal. Este estudo foi desenvolvido na APA do rio Pandeiros, Minas Gerais, onde alocamos 140 parcelas de 10 ×10 m (100 m2), com 10 m de distância entre parcelas, em duas áreas de vegetação ripária denominadas Larga e São Domingos (70 parcelas em cada área), onde realizamos o levantamento fitossociológico e coletamos amostras de solo. No total, 751 indivíduos arbóreos foram amostrados, distribuídos em 89 espécies e 35 famílias botânicas. As áreas diferiram fortemente na estrutura e composição das espécies, e apresentaram peculiaridades florísticas e influência da vegetação circundante. Apesar da baixa distância entre as áreas amostradas, estes são ambientes singulares influenciados por diferentes solos, pela composição mista da área ecotonal e os impactos antropogênicos a que estão expostas.

Abstract This study analyzed the floristic, structural variations and their relationships with soil variables in two stretches of riparian vegetation in an ecotonal region between savanna and semiarid zones. We following the hypothesis of despite the proximity between the sampled areas, soil conditions are distinct and lead to changes in structure and composition of the vegetation. This study was development at EPA of Pandeiros River, Minas Gerais, where we allocated 140 plots of 10 × 10 m (100 m2), with 10 m distance between plots, in two areas of riparian vegetation, named Larga and São Domingos (70 plots in each area), where we conducted the phytosociological survey and collected soil samples. In total, 751 arboreal individuals were sampled, distributed in 89 species and 35 botanical families. The areas differed strongly in structure and species composition, and showed floristic peculiarities and influence of surrounding vegetation. Despite of low distance between the sampled areas, these are singular environments influenced by different soils, by the mixed composition of the ecotonal area and the anthropogenic impacts to which they are exposed.

ABSTRACT This study monitored the survival of saplings planted according to different recovery models in a riparian forest of the Pandeiros river (Januária, MG). The models consisted of planting the saplings in lines of 2 or 4 m with presence (T2S and T4S, respectively) or absence of direct seeding (T2 and T4, respectively). We planted 16,259 saplings of 17 botanical families, 32 genera and 33 species. The saplings, in general, presented a survival rate after one year of 34.4% (±1.8). The species with highest survival rates were Jacaranda brasiliana, with 85.0% (±13.5) of survival, Anadenanthera colubrina, with 70.1% (±7.0), and Triplaris gardneriana, with 69.3% (±9.1). Survival did not vary between the models tested, probably due to the short evaluation period (12 months).

RESUMO Myracrodruon urundeuva, mais conhecida no Brasil como “Aroeira”, é uma espécie arbórea altamente utilizada por seu valor comercial e farmacológico. Apesar do alto valor comercial no mercado, esta espécie carece de estudos sobre o tempo de recuperação e crescimento em diferentes estágios de sucessão nas florestas secas tropicais brasileiras. O principal objetivo deste estudo foi determinar as taxas de crescimento diamétrico das árvores em três estágios sucessionais da floresta tropical seca no Parque Estadual Mata Seca, em Minas Gerais, Brasil. Nós medimos todos os indivíduos (≥5cm de DAP) anualmente em 18 parcelas permanentes em estágios sucessionais inicial, intermediário e tardio durante um período de 8 anos (2006-2014). Calculamos os incrementos anuais de diâmetro para cada indivíduo desta espécie, para cada estágio sucessional e por classe diamétrica. Foram obtidos os seguintes incrementos médios anuais por estágio sucessional: inicial (10,53 mm/ano), intermediário (2,09 mm/ano) e tardio (2,90 mm/ano). As taxas de incremento foram semelhantes entre os estágios sucessionais intermediário e tardio. O maior aumento incremental de diâmetro foi obtido nas classes de diâmetro 5-15 cm e 15-25 cm no estágio inicial, e para o estágio intermediário, incrementos máximos foram encontrados na classe de 5-15 cm de diâmetro e na classe de 35-45 cm no estágio tardio. Os resultados deste estudo permitem concluir que esta árvore não é apenas uma espécie pioneira, mas que também tolera as condições de estágios sucessionais avançados. Tendo em conta os incrementos diametrais rápidos e elevados observados no estágio inicial de sucessão e nas classes de diâmetro menores, esta espécie demonstra grande potencial para o manejo silvicultural.

ABSTRACT Myracrodruon urundeuva, better known in Brazil as “Aroeira”, is an arboreal species highly used for its commercial and pharmacological value. Despite the high commercial value in the timber market, this species lacks studies analyzing the recovery time and growth in different stages of succession in the Brazilian tropical dry forests. The main objective of this study was to determine growth rates of this species in three successional stages of a tropical dry forest in Mata Seca State Park, in Minas Gerais, Brazil. We measured all individuals (≥5cm of DBH) annually in 18 permanent plots in early, intermediate, and late successional stages over a period of 8 years (2006-2014). We calculated the annual diameter increments for each individual of this species, for each successional stage and by diameter class. We obtained the following mean annual increments by successional stage: early (10.53 mm/yr), intermediate (2.09 mm/yr), and late (2.90 mm/yr). Increment growth rates were similar between the intermediate and late successional stages. The highest incremental increase in diameter was obtained in the diameter classes 5-15 cm and 15-25 cm in the early stage, and for the intermediate stage, maximum increments were found in the 5-15 cm diameter class and 35-45 cm class for the late stage. Results from this study support the conclusion that this tree is not only a pioneering species but that it also tolerates the conditions of advanced successional stages. Given the fast and high diametric increments observed in the early stage of succession and the smaller diametric classes, this species demonstrates great potential for silvicultural management.

ABSTRACT Seed predation is a natural phenomenon that can occur either before or after dispersal and can significantly reduce the economic value and reproductive potential of plants. The babassu palm (Attalea vitrivir, Arecaceae) is important to rural communities that extract oil from its fruits for a wide variety of uses. We evaluated the predation and germination of A. vitrivirseeds in Pandeiros River Environmental Protection Area (EPA-Pandeiros) in Minas Gerais State, Brazil. Sixty individual plants were evaluated to determine their fruiting patterns. Seed predation and germination were evaluated in the natural environment for eight months for fruits divided into two treatments: scarified and intact. Germination of fruits submitted to these same treatments was also evaluated under greenhouse conditions. Our results indicated that fruiting is continuous in this species and that fruit morphology does not influence either germination or predation. Likewise, fruit scarification did not influence seed germination. Pachymerus cardo (Coleoptera: Chrysomelidae) preferentially oviposited on scarified fruits, but only after their dispersal. The predation rate in the natural environment was 14.6%. Germination was not observed under natural conditions, but reached 33.05% under greenhouse conditions.

RESUMO Este trabalho testou a influência de métodos de escarificação térmica e mecânica na emergência e estabelecimento de plântulas de Guazuma ulmifolia. As sementes foram submetidas aos tratamentos pré-germinativos de (1) escarificação mecânica (lixa), e (2) escarificação térmica (água quente), além do tratamento-controle (3) no qual as sementes foram deixadas intactas. O tratamento feito com escarificação térmica diferiu dos demais tratamentos, apresentando o maior número de plântulas emergidas. As sementes tratadas com lixa obtiveram a menor porcentagem de emergência, não diferindo do tratamento-controle. Para o índice de velocidade de germinação não foi verificada diferença significativa entre os tratamentos e o pico de emergência de plântulas foi entre o 13º e 15º dia de incubação em todos os tratamentos. Quanto ao estabelecimento, o crescimento (altura, diâmetro e número de folhas e de nós) das plântulas diferiu entre os tratamentos pré-germinativos. Observou-se maior crescimento das plântulas após suas sementes passarem por escarificação térmica. Assim, a escarificação com água quente é o método mais adequado para quebra da dormência das sementes de Guazuma ulmifolia, proporcionando plântulas mais vigorosas.

ABSTRACT This study tested the influence of mechanical and thermal scarification methods on emergence and establishment of Guazuma ulmifolia seedlings. Seeds were subjected to pre-germination treatments of (1) mechanical scarification (sandpaper), and (2) thermal scarification (hot water), in addition to the control treatment (3) from which the seeds were left intact. The thermal scarification treatment differed from the other treatments featuring the largest number of seedling emergence (70%). The seeds treated with sandpaper achieved the lowest emergence percentage not differing from the control treatment. For the germination speed index no significant difference between treatments has been verified and the emergence peak was between the 13rd and 15th days of incubation in all treatments. In the establishment, the seedlings growth (height, diameter and number of leaves and nodes) presented differences between the treatments. It was observed further development of seedlings after their seeds go through thermal scarification. Therefore, scarification with hot water is the most appropriate method for breaking the dormancy of seeds of Guazuma ulmifolia, providing more vigorous seedlings.

RESUMO As veredas são um tipo de vegetação associada aos cursos d'água, caracterizada pela presença da palmeira arbórea Mauritia flexuosa. Estes sistemas não são bem compreendidos e sofrem grande pressão antrópica. Os objetivos deste estudo foram descrever a regeneração natural de duas florestas higrófilas em sistemas de veredas com diferentes impactos antropogênicos e investigar se a variação nesta comunidade de plantas está associada as condições edáficas. O estudo foi realizado em sítios preservado e impactado localizado na área de Proteção Ambiental do rio Pandeiros, norte de Minas Gerais. Em cada sítio, 100 parcelas de 25 m2 foram estabelecidas para o levantamento dos arbustos e árvores regenerantes (≥1 cm de diâmetro na base do caule e < 3 cm de diâmetro na altura do peito). A estrutura da vegetação foi avaliada pelos parâmetros fitossociológicos, índice de similaridade e distribuição de tamanhos dos indivíduos. O estrato regenerativo correlacionou com as análises químicas e físicas do solo. A vegetação no sítio preservado foi caracterizada por um maior número de indivíduos e menor diversidade, mas continha espécies típicas de ambientes alagados. Os resultados também mostraram diferenças na disponibilidade de nutrientes do solo entre os sítios que influenciaram a distribuição de espécies nas duas áreas estudadas.

ABSTRACT Veredas (palm swamps) is a type of vegetation associated with watercourses, characterized by the presence of Mauritia flexuosa palm trees. These systems are not well understood and suffer from high anthropogenic pressure. The aims of this study were to describe the natural regeneration of two swamp forests in vereda systems with different anthropogenic impacts and investigate if the variation in these plant communities are associated to edaphic conditions. The study was performed in preserved and impacted sites located in the Environmental Protection Area of the Pandeiros River in northern Minas Gerais. At each site, one hundred 25 m2 plots were established for surveying regenerating shrubs and trees (≥1 cm diameter at the base of the stem and < 3 cm diameter at breast height). Vegetation structure was evaluated by phytosociological parameters, similarity index, and size distribution of individuals. Regenerating strata was correlated with chemical and physical soil analyses. The vegetation at the preserved site was characterized by a higher number of individuals and a lower diversity but contained species that were typical of flooded areas. The results also showed differences in soil nutrient availability between sites that influenced the distribution of species at the two study sites.

RESUMO Este trabalho objetivou avaliar o crescimento e sobrevivência de sete espécies arbóreas nativas em diferentes tratamentos, em uma área degradada na Reserva da COPASA (Juramento, MG). Para tal, foram utilizados aproximadamente 1,2 ha da área, onde foram plantadas 899 mudas, de sete espécies nativas (Anadenanthera colubrina, Copaifera langsdorffii, Dilodendron bipinatum, Myracrodruon urundeuva, Pterogyne nitens, Schinopsis brasiliensis e Senegalia polyphylla), acompanhadas durante 24 meses. A área foi dividida em cinco parcelas de 0,24 ha, que representaram os seguintes tratamentos: (T1) parcela semeada com capim (Brachiaria sp.); (T2) parcela onde as covas foram tratadas com condicionador de solo; (T3) parcela semeada com capim consorciado com leguminosa (Cajanus cajan); (T4) parcela semeada com leguminosa; e (T5) controle. A porcentagem de mortalidade foi maior no T2 e menor no T3, sendo as espécies C. langsdorffii (43,66%) e S. brasiliensis (11,64%) aquelas com maior e menor porcentagem de mortalidade, respectivamente. O crescimento (altura e diâmetro) das mudas foi maior no T2 (24,32 ± 26,05 cm e 0,51 ± 0,37 mm, respectivamente) e menor no T1 (10,82 ± 22,57 cm e 0,26 ± 0,27 mm; respectivamente). As espécies com maior crescimento em altura foram A. colubrina e S. polyphylla, já D. bipinatum e S. brasiliensis apresentaram maior crescimento em diâmetro. Pterogyne nitens apresentou o menor crescimento, além de alta mortalidade, mostrando baixa capacidade de estabelecimento em ambientes degradados.

ABSTRACT This study aimed to evaluate the growth and survival of seven native tree species in different treatments in a degraded area at COPASA Reserve (Juramento, MG). Approximately 1.2 ha area was used, where 899 seedlings were planted of seven native species (Anadenanthera colubrina, Copaifera langsdorffii, Dilodendron bipinatum, Miracrodruon urundeuva, Pterogyne nitens, Schinopsis brasiliensis and Senegalia polyphylla) followed for 24 months. The area was divided into five plots of 0.24 ha, which represented the following treatments: (T1) plot sown with grass (Brachiaria sp.); (T2) plot where the pits were treated with soil conditioner; (T3) plot sown with grass and legumes (Cajanus cajan) together; (T4) plot sown with legumes; and (T5) control. The mortality percentage was higher in T2 and lower in T3, and the species C. langsdorffii (43.66%) and S. brasiliensis (11.64%) were the ones with higher and lower mortality rate, respectively. The growth (height and diameter) of seedlings was higher in T2 (24.32 ± 26.05 cm and 0.51 ± 0.37 mm; respectively) and lowest in T1 (10,82 ± 22,57 cm and 0,26 ± 0,27 mm; respectively). The species with the largest growth in height were A. colubrina and S. polyphylla, and D. bipinatum and S. brasiliensis showed the highest growth in diameter. Pterogyne nitens showed the lowest growth, and highest mortality, presenting low ability to establish in degraded environments.

As veredas são fitofisionomias do bioma Cerrado, onde, no estrato arbóreo, predomina a palmeira arbórea Mauritia flexuosa L.f. - buriti, espécie considerada recurso-chave para muitos animais, que a utilizam como moradia e fonte alimentar, e também pelo próprio homem, que usa suas folhas e frutos como matéria-prima e alimento. Apesar de ocorrerem em ambientes protegidos pela legislação ambiental, ações antrópicas nas veredas têm afetado as populações do buriti, por meio da diminuição do número de indivíduos ocasionada por desmatamento, assoreamento e drenagem dessas áreas. O objetivo desse trabalho foi avaliar a morfometria de frutos e sementes de buriti oriundos de seis veredas em diferentes estágios de conservação, situadas na Área de Proteção Ambiental do Rio Pandeiros (norte de Minas Gerais). Foram amostrados, no total, 1800 frutos e sementes, que foram mensurados em comprimento, largura, espessura e peso. Para detectar diferenças das medidas morfométricas dos frutos e das sementes entre as áreas de coleta foi feita a análise de variância. Foram observadas variações nas medidas morfométricas de frutos e sementes entre as áreas de estudo, sendo que 87,5% das maiores médias ocorreram em áreas com menores intervenções antrópicas. Esse fato, possivelmente, está relacionado aos impactos ocorridos nas veredas, além das variações genéticas que podem incidir sobre os indivíduos.

'Veredas' (palm swamps) are phytophysiognomies of the 'Cerrado' biome, where the palm tree Mauritia flexuosa Lf. - buriti predominates on the tree layer; this species is considered the key resource for many animals, that use it as shelter and source of food, and also by the man who uses their leaves and fruits as raw material and food. Although, they occur in environments protected by the environmental legislation, human actions have affected the populations of 'buritis', by means of the decrease of individuals caused by deforestation, siltation and drainage of these areas. The objective of this study was to evaluate the morphometric parameters of fruits and seeds of Mauritia flexuosa from six different 'veredas' at different conservation stages, located in the Environmental Protection Area of 'Pandeiros' River (north of Minas Gerais state). In total, 1,800 fruits and seeds were sampled, they were measured in length, width and thickness and, after that, they were weighed. To detect differences in morphometric measurements of fruits and seeds among the sampling areas, the analysis of variance was done. There were differences in morphometric measurements between the studied areas, in which 87.5% of the highest averages occurred in areas with the slightest anthropic interventions. This fact is possibly related to the impacts occurred, besides the genetic variations that may fall upon the individuals.

RESUMO Este trabalho teve como objetivo avaliar a germinação e a capacidade de armazenamento de diásporos de Astronium fraxinifolium. Para o experimento de germinação, utilizaram-se seis tratamentos pré-germinativos: tratamento controle (diásporos intactos); diásporos imersos em água a temperatura ambiente (25º C) por 5 min.; diásporos imersos em água a 70° C por 5 min.; diásporos imersos em água a 100° C por 5 min.; diásporos imersos em solução de hipoclorito de sódio (1:1000) por 2 min.; e diásporos escarificados mecanicamente, com lixa nº 80. Para determinar a capacidade de armazenamento, foram testados dois diferentes tipos de embalagem (saco de papel permeável e vidro transparente) e duas condições ambientais (câmara fria e condições de laboratório). Foram realizados testes de germinação antes do armazenamento (tempo zero) e após 60, 120, 180, 240, 300 e 360 dias de armazenamento. Os efeitos dos diferentes tratamentos pré-germinativos e das condições de armazenamento na germinação dos diásporos foram avaliados por meio da ANOVA, seguida do teste de Tukey. Em relação aos tratamentos pré-germinativos, foram observadas altas taxas de germinação nos tratamentos com imersão em hipoclorito (98,0 ± 4,22%), controle (97,0 ± 4,83%), imersão em água destilada a temperatura ambiente (96,0 ± 6,99%) e imersão em água aquecida a 70ºC (83,0 ± 29,08%). Dessa forma, os diásporos de Astronium fraxinifolium não apresentaram dormência. No armazenamento, os diásporos permaneceram viáveis durante todo o período de estudo, apresentando altas porcentagens de germinação, com exceção do tratamento em saco de papel acondicionado em câmara fria, que perdeu a viabilidade no oitavo mês de armazenamento, não sendo, portanto, um método de armazenamento recomendado para esta espécie.

ABSTRACT The goal of this study was to evaluate the germination and the storage capacity of Astronium fraxinifolium diaspores. Six pre-germination treatments were used in the experiment: control treatment (intact diaspores); diaspores immersed in water at room temperature (25º C) for 5 min; diaspores immersed in water at 70° C for 5 min; diaspores immersed in water at 100° C for 5 min; diaspores immersed in sodium hypochlorite solution (1:1000) for 2 min; and diaspores mechanically scarified with sandpaper #80. To evaluate storage conditions, we tested two different types of packaging (permeable paper bag and transparent glass jar) and two environmental conditions (cold chamber and room conditions), resulting in four treatments. The germination tests were performed for zero (control) and 60, 120, 180, 240, 300 and 360 days after storage. The effects of different treatments on germination and storage of diaspores were evaluated by ANOVA, followed by Tukey test. Regarding to pre-germination treatments, high germination rates were observed in the hypochlorite (98.0 ± 4.22%), control (97.0 ± 4.83%), water at room temperature (96.0 ± 6.99%) and water at 70º C (83.0 ± 29.08%) treatments. Thus, Astronium fraxinifolium diaspores do not present dormancy. During storage, the diaspores remained viable throughout the study period with high germination rates, except for the treatment in paper bags placed in the cold chamber, in which the diaspores lost their viability in the eighth month of storage. Therefore, this is not a recommended storage method for this species.

Este estudo teve como objetivo relacionar as variações na riqueza e estrutura da comunidade arbórea com variáveis edáficas em um gradiente de floresta ciliar, no Parque Estadual da Mata Seca, Norte de Minas Gerais. Os estudos das variáveis edáficas e da diversidade e estrutura da vegetação arbórea (DAP ≥ 5 cm) foram conduzidos em 39 parcelas de 400 m², divididas equitativamente em três trechos previamente selecionados, sendo eles: São Francisco (menor teor de umidade), Meio (alagamento durante a maior parte do ano) e Lagoa da Prata (alagamento durante a estação chuvosa). A análise de solo superficial (0 a 20 cm) evidenciou diferenças significativas entre os diferentes trechos florestais. Nos três ambientes foram amostrados 2.482 indivíduos, pertencentes a 36 espécies, 31 gêneros e 16 famílias botânicas. Houve diferença significativa nos diferentes trechos no índice de diversidade de Shannon, número de indivíduos, área basal e dominância absoluta. A distribuição diamétrica da comunidade apresentou grande número de indivíduos nas menores classes, decrescendo gradualmente. Vale salientar que a área basal e a densidade de indivíduos obtiveram correlações significativas com a maior parte das variáveis edáficas analisadas. Assim, a estrutura dos três trechos estudados está correlacionada com os fatores texturais, químicos e umidade do solo, ocasionando variações fitossociológicas nas comunidades estudadas.

This study aimed to relate variations in richness and tree community structure to soil characteristics in a gradient of riparian forest, at Parque Estadual da Mata Seca, north of Minas Gerais. Studies of soil characteristics and the richness and structure of trees (DBH ≥ 5 cm) were conducted in 39 plots of 400 m², divided equally into three sections previously selected, these being: São Francisco (lower moisture), Meio (flooding during most of the year) and Lagoa da Prata (flooding during the rainy season). The analysis of topsoill (0-20 cm) showed significant differences between the different forest sections. In all three environments were sampled 2482 individuals belonging to 36 species, 31 genera and 16 plant families. There were significant differences for the different sections in the Shannon diversity index, number of individuals, basal area and absolute dominance. The diameter distribution of the community had a great number of individuals concentred in the smallest classes, decreasing gradually. It is noteworthy that the basal area and density of subjects had significant correlations with soil most variables analyzed. Thus, the structure of the three sections studied is correlated with the textural, chemical and soil moisture, causing variations in phytosociological communities studied.