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Background Astronium fraxinifolium is an endangered tree species from Brazil. Due to its high importance for environmental reforestation, as well as for the use of its wood, it is necessary to implement management programs for conservation of this species. Simple sequence repeats (SSR) or microsatellite markers have been widely used in population genetic studies across diverse organisms. In this study, we reported for the first time SSR markers for A. fraxinifolium as well as its frequency and distribution from transcriptome data. Results More than 125 thousand RNA-seq sequences derived microsatellites, with predominant distribution of trinucleotides repeats. From the initial screening, we selected 20 microsatellite loci, validated and evaluated genetic indexes in two natural populations. All loci were polymorphic, ranging from four to eleven alleles per locus. The observed and expected heterozygosities ranged from 0 to 1.0 and from 0.533 to 1.0, respectively. Genetic differentiation between populations (= 0.363) showed higher diversity within than among populations. Conclusions The developed SSR loci from RNA-seq consists in a base for future studies of genetic diversity and population structure, mating system and gene flow in A. fraxinifolium populations as well as related species, aiming the conservation and management of the species.

Gene flow studies provide information on gene exchange between populations, which is essential for developing genetic conservation strategies. Such analyses enable a better understanding of the life history and seed and pollen dispersal mechanisms of plant species. In this study, we investigate pollen and seed flow in a regenerant population of the pioneer species Astronium fraxinifolium in an area degraded during the construction of a hydroelectric dam. We mapped, sampled, sexed, and genotyped 386 individuals in the regenerant population (RP), as well as 128 adult trees located along two highways adjacent to the degraded area; one in Mato Grosso do Sul State (MS) and other in São Paulo State (SP). Parentage analyses was carried out for 370 individuals of the RP population, using as putative parents 348 individuals from RP and all 128 individuals sampled in MS and SP. Based on parentage analysis and eight microsatellite loci, our analyses revealed that for individuals of the RP with an identified father (pollen donor), 1.1% of the pollen was dispersed up to 532 m, while for those with an identified mother (seed donor), 0.5% of seeds were dispersed up to 4,782 m. However, a large proportion of pollen (76.5%) and seeds (57%) immigrated from trees outside the sampled populations. Pollen and seeds were dispersed through a pattern of isolation by distance. Genetic diversity was significantly similar between adults of both highway populations and individuals from RP, with significant levels of inbreeding detected only in RP. Our results demonstrate that the nearest trees contributed pollen and seeds for the recovery of the degraded area, indicating reproductive spatial isolation among the sampled populations due to the damming of the river. Such results help to understand the process of regeneration for A. fraxinifolium in regenerant populations to inform strategies for conservation and environmental recovery with this species.

RESUMO O estudo apresenta uma experiência do uso de cinzas de casca de arroz (C.C.A) para a produção de argamassas auto adensáveis. Para tanto, utilizou-se cimento CPZ II 32, areia natural, cinza de casca de arroz industrializada, superplastificante de atuação estérica e eletrostática, e água. Foram produzidos dois tipos de argamassas, sendo uma série a ser adensada com o auxílio de vibração, e uma outra série com a incorporação de C.C.A no teor de 35% com relação ao valor da massa do cimento, e de superplastificante, a ser adensada pela ação do seu peso próprio. Os valores da relação água/cimento adotados foram 0,40, 0,50 e 0,60 para os casos de argamassas vibradas e 0,68, 0,63 e 0,55 para os casos de argamassas auto adensáveis. Para os casos de argamassas vibradas foram realizados no estado fresco os ensaios de consistência com auxílio da mesa de golpes, ensaios de abatimento, e da avaliação da massa específica aparente; e para as argamassas auto adensáveis foram realizados no estado fresco os ensaios de espalhamento “slump-flow” e o ensaio de escoamento confinado com auxílio do funil; além da avaliação da massa específica aparente. No estado endurecido foram realizados os ensaios de resistência à compressão simples e diametral, e de absorção d’água aos 7, 28, 60 e 90 dias de cura. Observou-se que as argamassas com a adição de C.C.A e as vibradas apresentaram condições de mobilidade compatíveis com relação à cada caso e ausência de segregação; as argamassas com C.C.A apresentaram valores de resistência mecânica ligeiramente superiores aos apresentados pelas argamassas vibradas, assim como apresentaram valores de absorção inferiores, não obstante os valores mais elevados para a relação “água/cimento” em comparação aos casos das argamassas vibradas.

Pervious concrete pavements are interesting from an environmental and social viewpoint. However, this type of pavement has as the main disadvantage of losing permeability over time by the clogging process. The aim of this work is to evaluate the periodic cleaning efficiency of using a blower, mainly during the first four months after paving. A pervious concrete sidewalk was constructed and cleaning was carried out, monthly in one half and weekly in the other half. Infiltration rate tests, following ASTM C1701, were performed weekly at eight spots arranged symmetrically on each half of the pavement. The results showed that using a blower for periodic cleaning was efficient. Both halves, with monthly and weekly cleaning, did not present significant statistical difference in their infiltration rates. In this sense, monthly maintenance is the most suitable due to less time and fuel are spent for cleaning, collaborating as an environmental-friendly alternative. This work showed that the performance of periodic maintenance can be useful, in order to maintain the efficiency of the pervious pavement over time.

Este artigo traz uma pesquisa do solo-cimento com substituição parcial de solo por isopor em flocos. A mistura é composta de solo, cimento, areia, isopor, superplastificante e água. Foi realizada uma mistura sem substituição, com substituição de 5% e 10% de isopor. Utilizando-se da norma técnica de solo-cimento e baseando-se na norma de concreto auto adensável, se efetuou os ensaios com o solo-cimento no estado fresco, sendo eles, ensaio de segregação por peneiramento, ensaio de abatimento de Abrams e ensaio do Funil, e ensaios no estado endurecido, sendo, ensaio de compressão axial e diametral, ensaio de absorção de água. Percebe-se que quanto mais se substitui solo por isopor mais o material sofre segregação, o isopor em flocos cria vazios dentro do produto final, alcançando resultados não muito satisfatórios na resistência a compressão diametral. Porém a pesquisa não se encerra por ai, observa-se que a mistura teve um bom desempenho com a substituição de 5%, esses resultados levantam a hipótese de se trabalhar com o traço inicial e apenas adicionar isopor, ou chegar a um valor adequado em que o isopor trabalhe a leveza do material sem alterar a resistência.

Astronium fraxinifolium is an endangered tree species from Brazil. Due to its significance in environmental reforestation, as well as the continued exploitation of its wood, it is necessary to develop management programs that support the conservation of the species. Simple sequence repeats (SSR) or microsatellite markers are widely used in population genetic studies across a range of diverse organisms. In this study, we present the first SSR markers developed for A. fraxinifolium as well as their frequency and distribution based on transcriptome data. From transcriptome data, we identified more than 100 thousand sequences presenting microsatellites, with a predominant distribution of trinucleotide repeats. From the initial screening, we selected 20 microsatellite loci which were validated and evaluated for genetic indices in two natural populations. All loci were polymorphic, ranging from four to 11 alleles per locus. The observed and expected heterozygosities ranged from 0 to 1.0 and from 0.533 to 1.0, respectively, while the genetic differentiation (G ST = 0.363) was greater within than between populations. The developed SSR loci from RNA-Seq data provides a foundation for future studies on genetic diversity and population structure, mating system, and gene flow for A. fraxinifolium populations and related species, aiming at conservation and management.