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ORAL COMMUNCATION 11
Detection of lead toxicity by morphological parameters and ISSR markers
in Lactuca sativa L.
Patrícia Silva 1 , Manuela Matos 1 , Sónia Silva 2 , Conceição Santos 2 , and Olinda Pinto-Carnide 1
1 Institute for Biotechnology and Bioengineering, Centre of Genomics and Biotechnology, University of
Trás-os-Montes and Alto Douro (IBB/CGB-UTAD), PO BOX 1013, 5001-801, Vila Real, Portugal; 2 CESAM
and Department of Biology, Laboratory of Biotechnology and Cytomics, - University of Aveiro, Campus
Universitário de Santiago, 3810-193 Aveiro, Portugal
Toxic heavy metal pollution has become an increasing worldwide environmental problem
since the onset of the industry revolution. Lead (Pb) is a nonessential metal and has
significant ecological relevance in many studies, since it is one of the most severe
pollutants. This metal induces a broad range of toxic effects to living organisms, including
morphological, physiological and biochemical alterations. Additionally, plants that grow in
contaminated soils can absorb and accumulate Pb, thereby introducing the metal into the
food chain by trophic transfer, including in the human diet.
In this study, plants of the cultivar “Reine de Mai” (Lactuca sativa L.) were grown
hydroponically with Pb (0, 0.05, 0.5 and 5ppm), during a 14-days exposure period, in
controlled conditions. Morphological characters including roots and shoot biomass and
length were recorded in four plants of each concentration. The genotoxicity effect of Pb
was evaluated in the roots of the same plants using ISSRs (Inter Simple Sequence Repeats)
for DNA changes analysis.
In general, both shoot length and biomass decreased with increasing Pb concentration.
Comparing with control condition, we observed an increase in the roots biomass and length
for the concentration of 0.05 ppm, and a decrease in the others concentrations.
The DNA damages in plant roots were analysed with eight ISSR primers. The differences in
DNA patterns were evaluated by the presence or absence of bands in treated samples,
compared with the untreated. On average, the rate of polymorphism increased with the Pb
concentration.
The present study shows the environmental risk of Pb on plant growth since it affected the
length and biomass of the roots and shoots of this lettuce cultivar. The comparison
between ‘untreated’ and ‘treated’ plants showed that ISSR analysis can be used to evaluate
how the environmental pollutants modify the structure of DNA in lettuce and this method
seems to be a useful tool for measuring genotoxic activity due to environmental pollutants.
Acknowledgements: This research was supported by FCT project (FCT/PTDC/AAC-AMB/112804/2009)
and fellowship (SFRH/BPD/74299/2010)
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