Abstract
Herbicides are agrochemicals used worldwide for crop protection against weeds, with the objective to increase the crop yields. Among them, triazines are a very widely-used class of herbicides which kills the infesting weeds, by interrupting the photosynthetic electron transport at level of photosystem II. Some general concerns are linked to the risk that these chemicals can drift off target reaching non-target crops and other organisms. In addition, some herbicides can be very persistent in soils representing a risk of pollution for both surface and ground waters. As the environmental pollution caused by toxic compounds is becoming one of the main concerns, phytoremediation technologies are being considered, among all the techniques available, the more promising for remediating polluted environments.
Therefore, this work was aimed at ascertain the possibility to use Italian ryegrass in the remediation of
aqueous solutions polluted with terbuthylazine (TBA), a herbicide belonging to the triazines class. To this
purpose, the phytoextraction potential of this plant species has been assessed using a plant-based biotest
(RHIZOtest), verifying its possible use in studies focused on the agrochemical cycle in the soil-water-plant
interface.
Three TBA concentrations were chosen to evaluate the tolerance capacity of the ryegrass. Even though the
treatments negatively affected plants, they were able to remove up to 30-40% of TBA. In addition, some
enzymatic activities involved in the response to TBA-induced stress were determined. Glutathione Stransferase (GST) has been activated with a TBA-dose dependent trend; ascorbate peroxidase (APX) activities have been induced within the first hours after the treatments, followed by decreases or disappearance in plants exposed to two higher dosages.
In conclusion, this case-study highlights that the combination of ryegrass and RHIZOtest resulted to be
effective in the remediation of aqueous solutions polluted by TBA. The research was financed by MIUR-FIRB 2012 Futuro in Ricerca.