International Journal of Plant & Soil Science

Introduction: Volcanism is an important natural origin of Arsenic (As) contamination.

Aims: Oxidative stress parameters, antioxidant defense system, the expression of transcripts involved in defense responses and the As genotoxicity were analyzed.

Study Design: The plants were separated into two groups (Control and As-treated ones) until they were exposed to As (2.5 and 5 ppm) at day 10.

Methodology: Biochemical, molecular and cytogenetic determinations were carried out.

Results: Arsenic treated plants show growth abnormalities. The antioxidant defenses and oxidative parameters in roots and leaves showed different tissue-specific responses. Whereas leaf tissues display an active antioxidant defense, root cells are unable to produce defense molecules and show oxidative stress. Moreover, the analysis of antioxidant enzymes such as ascorbate peroxidase and superoxide dismutase, showed higher activity in leaves than in roots, except for isocitrate dehydrogenase. The expression of GR and MAPK decreased significantly in all the treatments during the time curve. ICDH showed an increase in its expression with 24 hours of treatment and falls at 72 hours compared to their controls. Genotoxicity assays showed a decrease of mitotic index (MI) and the presence of altered nucleus, in samples exposed for 72 hours.

Conclusion: Our results suggest that the physiological, biochemical, molecular and cytogenetic behavior of the plants depends on the As concentration and the length of the exposure.