Márcio Hisayuki Sasamori

Biomonitoring the genotoxic potential of the air on Tradescantia pallida var. purpurea under climatic conditions in the Sinos River basin, Rio Grande do Sul, Brazil

The present study evaluated the genotoxic effects of the atmospheric air on Tradescantia pallida var. purpurea in urban areas with different intensities of vehicular traffic and in riparian forest fragments in the Sinos River Basin (Rio Grande do Sul, Brazil), considering the influence of climatic conditions prevailing in these environments. Bimonthly, from May 2012 to March 2013, cuttings with flower buds were exposed for 8 h in urban and riparian forest environments in the municipalities of Caraá, Taquara and Campo Bom in the upper, middle and lower sections, respectively, of the Sinos River Basin. Simultaneously, negative controls were made and climatic data were recorded. Micronuclei (MCN) frequencies were determined in young tetrads of pollen mother cells and expressed as MCN/100 tetrads. Significantly higher MCN frequencies were observed in buds exposed in urban and riparian forest environments in Taquara (up to 7.23 and 4.80, respectively) and Campo Bom (up to 4.90 and 4.23, respectively) than in buds exposed in Caraá (up to 2.90 and 2.50, respectively), in the majority of samplings, and in relation to the negative control (up to 1.93) in all months. Over the course of the period monitored, there were significant variations in MCN frequencies at all sampling points, with the exception of the urban environment in Caraá. For the urban environments, relation between the MCN frequency, vehicular traffic and mean temperature was observed. For the riparian forest fragments, there was no association between MCN frequency and climatic factors. Tradescantia pallida var. purpurea can be considered a useful tool to point out areas with increased atmospheric pollution, since the exposure of plants under severe climatic conditions is avoided to minimize their negative influence on the formation of micronuclei.

Biomonitoring of water genotoxicity in a Conservation Unit in the Sinos River Basin, Southern Brazil, using the Tradescantia micronucleus bioassay

The Tradescantia micronucleus (Trad-MCN) bioassay was used to investigate genotoxicity of water bodies in the Parque Municipal Henrique Luís Roessler (PMHLR), a conservation unit in the city of Novo Hamburgo, Southern Brazil, from November 2010 to October 2011. Every month, cuttings with young inflorescences of Tradescantia pallida var. purpurea were exposed for 24 hours to water collected at three sites in the park: (S1) head of the main stream; (S2) head of a secondary stream; (S3) a point past the junction of the two water bodies in which S1 and S2 were located. As a negative control, cuttings were exposed to distilled water for 24 h every quarter. Micronuclei (MCN) frequency was determined in young tetrads of pollen mother cells and described as MCN/100 tetrads. Rainfall data were also recorded. In nine months at S1 and S2, and in eleven months at S3, micronuclei frequencies were significantly higher than in quarterly controls, in which frequencies varied from 1.19 to 1.62. During sampling, no significant differences were found in MCN frequencies at S1, which ranged from 2.2 to 3.6. At the other sampling sites, there were significant differences between the months evaluated, and MCN frequencies ranged from 1.3 to 6.5 at S2 and from 2.3 to 5.2 at S3. There were no associations between rainfall and MCN frequencies at the three sampling sites. Tradescantia pallida var. purpurea confirmed genotoxicity in the water bodies of the PMHLR, even at the head of the streams, which suggests that actions should be promoted to control anthropogenic effects in the streams of this conservation unit.

Helionothrips errans (Thysanoptera: Thripidae): A New Threat to Native Orchids in Brazil

Helionothrips errans (Williams) (Thysanoptera: Thripidae) is reported for the first time in the Neotropics. This thrips breeds exclusively on Orchidaceae (Asparagales) leaves and has previously been found in Australia, USA, Europe, and southwestern Asia. We observed H. errans damaging the leaves of reintroduced Cattleya intermedia Graham ex Hook. plantlets, and attacked individuals showed reduction in the height of the aerial portion and in the average number of leaves per individual. Sumario Helionothrips errans (Williams) (Thysanoptera: Thripidae) e registrado pela primeira vez para os Neotropicos. A especie se alimenta exclusivamente em folhas de Orchidaceae (Asparagales) e ja foi encontrada para Australia, EUA, Europa e sudoeste asiatico. Nos observamos H. errans danificando folhas de plântulas reintroduzidas de Cattleya intermedia Graham ex Hook. e individuos atacados mostraram uma reducao na altura da porcao aerea e no numero de folhas por individuo. View this article in BioOne

Baixas concentrações de macronutrientes beneficiam a propagação in vitro de Vriesea incurvata (Bromeliaceae), uma espécie endêmica da Floresta Atlântica, Brasil

A cultura in vitro e uma ferramenta eficiente para a propagacao de plantas de importância ecologica e economica e permite o entendimento acerca de aspectos ecofisiologicos das especies. Este estudo teve por objetivo avaliar a influencia de diferentes concentracoes de macronutrientes sobre o desenvolvimento in vitro e a sobrevivencia ex vitro de plântulas de Vriesea incurvata, visando a conservacao desta bromelia epifitica endemica da Floresta Atlântica. A germinacao in vitro foi avaliada aos 60 dias e as plântulas foram cultivadas por 180 dias em meio MS com 25 ou 50% dos macronutrientes, 25 ou 50% dos sais nitrogenados, bem como com 100% da formulacao original do meio. As sementes apresentaram 95% de germinacao. Em todos os tratamentos, houve 100% de sobrevivencia das plântulas cultivadas in vitro. A reducao de todos os macronutrientes ou dos sais nitrogenados mostrou-se benefica, proporcionando maior comprimento da parte aerea e da raiz maior, maior numero de folhas e de raizes, bem como maior massa fresca, alem de ter propiciado 97% de sobrevivencia das plântulas aclimatizadas ex vitro. Os dados obtidos permitem o estabelecimento de um protocolo de propagacao in vitro de V. incurvata, com o objetivo de sua futura reintroducao no habitat natural.