Conclusions
This work approached, for the first time, the effects of cyanobacterial cell extracts containing CYN on plant growth and oxidative defense mechanisms. The work evidences that short term plant exposure to toxic A. ovalisporum cyanobacterial extracts can lead to an increase of oxidative stress (increase in GST and GPx activities). Moreover, longer exposure periods can lead to tissue necrosis (loss of tissue fresh weight) concomitant with the oxidative stress. This work allowed verifying that the presence of low concentrations of cyanotoxins such as CYN and MCs, simultaneously, can have a synergistic effect on the oxidative stress in plants. Environmentally relevant concentrations of CYN were considered in this work which permits to raise some concerns on the use of contaminated waters for plant growth and food production. This work emphasizes that more research needs to be done, regarding the dynamics of CYN accumulation in plant tissues, its partition as well as the effects of mixtures of cyanotoxins, at different combinations of concentrations