Study of the antioxidant response of several bean variants to irrigation with water containing MC-LR and cyanobacterial crude extract.

Cyanobacterial toxins have adverse effects on both terrestrial and aquatic plants. Agricultural plants may come in contact with cyanobacterial toxins when surface waters are used for its irrigation. In the present study the effects of MC-LR and cyanobacterial crude extract on three variants of bean by irrigating the seedlings with water containing 5 μg L(-1) MC-LR were assessed. Study of the antioxidant enzymes activities glutathione-S-transferase (GST), peroxidases (POD) and glutathione reductase (GR) was performed in leaves and roots of the seedling exposed to the cyanotoxin compared to a control group and to a group exposed to cyanobacterial crude extract without MCs. Damage of oxidative status was observed in view of the fact that the antioxidant enzymes activities were altered. It is interesting to point out that each variant of bean was affected in a very different way, being GST the most altered enzyme and the B1 the most sensitive variant showing the greatest alterations in the majority of the studied enzymes.