ABSTRACT Areas of cerrado (Brazilian savanna) in the Amazon have been poorly studied from the perspective of fire impacts on environmental sustainability, especially with regard to disturbances to soil and vegetation structure. This study aimed to analyze the influence of edaphic variables and fire together on the composition and structure of tree and shrub vegetation of three cerrado remnants in the Amazon. Eight plots were systematically installed in burned and unburned environments in each remnant. Data were submitted to floristic diversity, similarity, and diametric and altimetric structural assessments. Phytosociological parameters were obtained and submitted to Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). A total of 808 individuals (34 species, 30 genera, and 21 families) were recorded. The CCA indicated that the distribution of species is influenced by edaphic factors, as confirmed by the strong direct correlation of tree and shrub species with the reduced nutrition and high acidity of the soils common in the analyzed remnants. Our results support the hypothesis that fire plays a relevant role in structuring vegetation since it contributed to good indicators of soil properties and caused changes in the composition of woody species.

Resumo: O estudo objetivou descrever a morfologia de fruto, semente e plântula, bem como a anatomia da semente e plântula de Pentaclethra macroloba (Willd.) Kuntze. A morfo-biometria foi realizada em cinquenta frutos e cem sementes. Para descrição das sequências dos eventos morfológicos dos estágios de germinação, dez sementes foram colocadas para germinar. A análise anatômica foi realizada em microscópio eletrônico de varredura com amostras de sementes e folhas de plântulas. A espécie apresenta fruto do tipo legume, medindo 16,1 a 45,2 cm de comprimento, e 4,1 a 7,3 cm de largura; semente com pleurograma, eurispérmica, ovoide, deltoide a elíptica, possuindo dimensões entre 3,8 a 6,1cm de comprimento e 2,5 a 5,7 cm de largura. Anatomicamente, os cotilédones são compostos de células parenquimáticas de paredes delgadas e com diversas células oleíferas. As plântulas possuem folhas bipinadas, com ceras e tricomas simples nas margens da face adaxial e estômatos paracíticos na face abaxial. O epicótilo é levemente tortuoso; com catáfilos caducos e primeiro par de eófilos alternos. A germinação é do tipo fânero-hipógea-armazenadora. O reconhecimento taxonômico da referida espécie é possível no campo por meio dos caracteres morfológicos externos, podendo auxiliar na identificação de plantas jovens.

Abstract: The aim of this study was to describe the morphology of fruit, seeds and seedlings, as well as the anatomy of the seed and the seedling of Pentaclethra macroloba (Willd.) Kuntze. Morpho-biometry was performed on fifty fruit samples and one hundred seeds. To describe the sequences of the morphological events of the germination stages, ten seeds were placed to germinate. Anatomical analysis was performed in a scanning electron microscope with seed samples and seedling leaves. The species has leguminous type fruit of 16.1 to 45.2 cm length and 4.1 to 7.3 cm width; seeds have a pleurogram and are eurispermic, ovoid, deltoid to elliptical and measure from 3.8 to 6.1 cm length and 2.5 to 5.7 cm width. Anatomically, the cotyledons are composed of thin-walled parenchyma cells with various oil cells. The seedlings have bipinnate leaves, with waxes and simple trichomes at the margins of the adaxial surface and paracytic stomata on the abaxial surface. The epicotyl is slightly twisted, with caducous cataphylls and a first pair of alternate eophylls. Germination is of the phanero-hypogean-reserve type. Taxonomic recognition of this species is possible in the field through the external morphological traits and can help in identification of saplings.

ABSTRACT Urban afforestation greatly contributes to the ex situ conservation of native species in urban centers of Brazil. In this way, the aim of the present work was to analyze the similarity of the arboreal-shrub flora among urban afforestation in southeastern Brazil. For this analysis, a binary matrix with data of 283 species present in 20 municipalities in the Southeastern Region of Brazil was adopted, in which the Principal Component Analysis (PCA) was also used aiming at enabling refinement in the grouping obtained by the floristic similarity (FS) of Sørensen with similarity from values provided by PCA. FS among municipalities was intermediate, but the highest similarity of urban flora was found among the geographically closest municipalities. In the southeastern region, 283 species were recorded, being distributed in 71 botanical families, with Fabaceae having the largest number of species, and with emphasis on the predominance of exotic plants over native plants.