Diesel Tolerance in the Antarctic Grass Deschampsia antarctica: From Laboratory to Field in Extreme Conditions.

Diesel spills represent a significant challenge to Antarctic ecosystems, particularly in ice-free areas where stations and wildlife co-occur. Taking into consideration the Protocol on Environmental Protection to the Antarctic Treaty, the use of native species emerges as a suitable solution for this problem. Here, we evaluate the tolerance and potential of the native grass Deschampsia antarctica for phytoremediation of diesel-contaminated soils, combining in vitro and field assays at Carlini Research Station. Using a dose-response approach, we measured biometric parameters, photosynthetic pigments, and antioxidant enzyme activities under varying diesel concentrations. In vitro experiments suggested high half-maximal inhibitory dose (ID50) values: 3741, 5709 and 8425 mg kg^-1 for root growth, chlorophyll content, and total biomass, respectively. Field experiments showed a 14.5%, 47.9%, and 27.5% reduction in biomass, root growth and chlorophyll content at the highest diesel concentration (40,000 mg kg^-1), suggesting that root growth is the most sensitive parameter. Antioxidant enzyme activities, including guaiacol peroxidase (GPX, EC 1.11.1.7) and superoxide dismutase (SOD, EC 1.15.1.1), presented contrasting trends between in vitro and field conditions, underscoring the influence of environmental factors on stress responses. These results propose root growth as an indicator of diesel-induced stress, contributing to optimizing phytoremediation strategies. Overall, our findings highlight the plant's tolerance to high contaminant levels, even under conditions of maximum bioavailability, and demonstrate its potential for phytoremediation in extreme environments, supporting the development of sustainable remediation strategies for Antarctic soils.