Molecular evidence for benzo[a]pyrene and naphthalene genotoxicity in Trifolium repens L

Polycyclic aromatic hydrocarbons (PAHs) are among the most dangerous environmental contaminants due to their toxic, carcinogenic and mutagenic effects. Although there are many data in literature that detail the effects of PAHs on animals, little is known about their action on higher plants which are often used as bioindicators. The aim of the present study was to evaluate the genotoxicity of two different PAHs, benzo[a]pyrene (BaP) and naphthalene (Naph), on Trifolium repens L. Clover plants were exposed to soil which had been artifcially contaminated with three concentrations of BaP (5, 10 and 20 lg g 1) or Naph (25, 50 and 100 lg g 1). After 15 days, changes in the DNA content and sequence of roots and shoots were evaluated by fow cytometry (FCM) and amplifed fragment length polymorphism (AFLP). Root and shoot dry weight were also determined to assess plant growth. Results showed that BaP and Naph were both genotoxic for white clover, inducing signifcant changes in root and shoot DNA sequence. Damage was more severe in the root than in the shoot suggesting that the translocation of these compounds and their genotoxic metabolites was limited. Ploidy alterations were not detected and the extent of damage caused by all the tested PAH concentrations was not suffcient to affect plant development.