Tradescantia

A planta Tradescantia pallida (Rose) D.R. Hunt var. purpurea tem sido utilizada em diversos modelos experimentais para detecção de danos morfofisiológicos e genéticos, por ser uma planta sensível a poluentes atmosféricos. No entanto, dentre os biotestes utilizados para avaliação do potencial mutagênico de contaminantes ambientais, o bioensaio de micronúcleo em Tradescantia (Trad-MCN) é um dos testes mais utilizados em estudos de monitoramento das condições atmosféricas. Diante do exposto, foi realizada uma revisão de literatura, identificando regiões brasileiras que utilizaram o bioensaio de micronúcleo em Tradescantia para monitorar alterações genéticas advindas da contaminação atmosférica. O levantamento de trabalhos indexados foi realizado em bancos de referência, como Portal de Períodicos CAPES, SciELO, ScienceDirect e PubMed, sendo os mesmos investigados quanto às regiões brasileiras biomonitoradas, período, área, exposição, monitoramento ativo ou passivo e planta natural ou clone. Os resultados indicaram que pesquisas baseadas no bioensaio Trad-MCN foram realizadas em diversas regiões brasileiras. Verificou-se que a maioria dos trabalhos são oriundos da região sudeste, especialmente do estado de São Paulo. Esse fato pode ser atribuído ao maior número de indústrias e automóveis em circulação existentes neste estado quando comparado aos demais, podendo interferir diretamente na qualidade do ar, despertando assim o interesse no meio científico. Com base nesta investigação, o bioensaio Trad-MCN revelou eficácia, e a planta Tradescantia demonstrou ser importante indicadora biológica de danos genéticos ocasionados pela exposição aos poluentes atmosféricos, e é amplamente utilizada na região sudeste do país. ABSTRACT The Tradescantia pallida (Rose) D.R. Hunt var. purpurea plant has been used in several experimental models to detect morphophysiological and genetic damage due its susceptibility to atmospheric pollutants. However, among the bioassays used to evaluate the mutagenic potential of environmental contaminants, the Tradescantia-Micronucleus (Trad-MCN)

Soil pollution with industrial leftovers is of real danger to living organisms since harmful effects can arise after exposure to the contaminants in the soil. In our study, we applied a plant bioassay battery to monitor soil genotoxicity after short-term exposure to the soil. The soil was collected in 3 rounds: at the central part of the brownfield before (S-I) and after (S-III) topsoil removal, and at the brownfield periphery (S-II). The permissible value of the total contamination index is <16 and the corresponding values were 780 in S-I, 69 in S-II and 133 in S-III soil showing that whole brownfield territory is extremely polluted with heavy metals. Cytogenetic markers were recorded in Allium and Tradescantia test-systems and two types of molecular markers, RAPD and ISSR, were analysed in Allium. Our results revealed that the most polluted soil sample has induced an alarming increase of apoptotic cells in onion roots. Chromosome aberration and micronuclei frequency in Allium decreased inconsistently along with the pollution reduction in the soil. Increased frequencies of all cytogenetic markers were revealed in Tradescantia cuttings after exposure to the S-I soil extracts. Cluster analysis of Allium RAPD and ISSR markers showed that the most polluted soil samples induced genetic changes in onions different from those induced by the least polluted soil. Both plant test-systems in this study confirm that soil from the brownfield is harmful to plants and is potentially hazardous to humans.

The biomonitoring of genotoxic effects in environmental complex mixtures using higher plants is very useful for hazard evaluation. In this study we evaluated the potential application of plant genotoxicity tests in monitoring mutagens in landfill environment. The clastogenic effects of gaseous emissions (biogas)from three municipal landfills were evaluated by in situ monitoring using the Tradescantia micronucleus assay. The cytotoxicity and genotoxicity of leachates were studied using the Allium cepa test. We found no significant differences in micronuclei frequency in pollen cells of Tradescantia. Leachate samples showed elevated toxicity that inhibited root tip development in Allium cepa. Genotoxicity of the leachates was evaluated in diluted samples only. We found a significant increase in chromosomal metaphase aberrations only in one of the samples analyzed. In conclusion, biogas was not shown to be a real hazard, whereas leachates were found to display elevated toxicity. It wou...

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The biomonitoring of genotoxic effects in environmental complex mixtures using higher plants is very useful for hazard evaluation. In this study we evaluated the potential application of plant genotoxicity tests in monitoring mutagens in landfill environment. The clastogenic effects of gaseous emissions (biogas)from three municipal landfills were evaluated by in situ monitoring using the Tradescantia micronucleus assay. The cytotoxicity and genotoxicity of leachates were studied using the Allium cepa test. We found no significant differences in micronuclei frequency in pollen cells of Tradescantia. Leachate samples showed elevated toxicity that inhibited root tip development in Allium cepa. Genotoxicity of the leachates was evaluated in diluted samples only. We found a significant increase in chromosomal metaphase aberrations only in one of the samples analyzed. In conclusion, biogas was not shown to be a real hazard, whereas leachates were found to display elevated toxicity. It wou...