Resumo

PEREZ, Alexander; MARTINEZ, Dalila; BARRAZA, Zafiro  e  MARRUGO, José. ENDOPHYTIC BACTERIA ASSOCIATED TO GENUS Cyperus AND Paspalum IN SOILS WITH MERCURY CONTAMINATION. rev.udcaactual.divulg.cient. [online]. 2016, vol.19, n.1, pp.67-76. ISSN 0123-4226.

The objective of this study was to isolate and identify endophytic bacteria mercury resistant, associated to the genus Cyperus and Paspalum in the locality of Mine Santa Cruz, Bolivar, Colombia. Soil and herbaceous plant samples were collected to evaluate total mercury concentration in soil and plant tissues, using cold-vapour atomic absorption spectrophotometry. The plant tissue samples were used for isolation and population determination of endophytic bacteria. The mercury resistance of isolates was evaluated in nutrient agar supplemented with HgCl₂, the resistant isolates were identified molecularly. The total concentration of mercury in the soil of Mine Santa Cruz was 4.7mg.kg^-1. Plant species collected were Paspalum arundinaceum, Cyperus luzulae and Cyperus laxus. The highest concentration of mercury in plant tissues was found in root with a range of 1.5 to 3,8mg.kg^-1. The species P. arundinaceum and C. laxus presented the greater population densities of endophytic bacteria in their tissues about 1 x 10⁸ UFC. Seven endophytic bacteria, resistant to concentrations of 350 and 400ppm of mercury were isolated. From P. arundinaceum tissues four bacteria corresponding to Burkholderia cepacia,Burkholderia sp. and two isolates similar to Bacillus sp., from C. luzulae two endophytic bacteria resistant to mercury, one identified as Ralstonia solanacearum and the other one as Burkholderia sp.; from C. laxus tissues one bacteria belonging to family Xanthomonadaceae, resistant to mercury, was isolated.

Palavras-chave : Mining; heavy metals; resistance; herbaceous plants.

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