PRELIMINARY EVALUATION OF DIESEL REMOVAL BY CHRYSOPOGON ZIZANIOIDES (VETIVER GRASS): IMPACTS ON PLANT PHYSIOLOGY AND PHYTOREMEDIATION PERFORMANCE

BON, IVÁN CARRALERO; HERRERO, MARÍA SOL; L. M. SALVATIERRA; L. M. PÉREZ

Barcelona

Congreso; International Congress on Water and Sustainability; 2021

International Congress on Water and Sustainability

Locally-available specimens of Chrysopogon zizanioides (Vetiver grass) were assessed in order to evaluate the potential of low-cost plants for use in remediation of hydrocarbon-polluted environments. Experiments were carried out over 15 days (24 ± 2 °C with dark/light cycles of 12 h) in glass flasks containing 300 g soil sample contaminated with 10% (w/w) commercial diesel oil purchased from a local service station. Maximum removal efficiency of the major petrochemical compounds present in the diesel sample (i.e., C11-C20 alkanes) was 33 ± 2%. In addition, diesel was highly deleterious for C. zizanioides, which was evidenced by a marked chlorosis of the plant leaves. In fact, photosynthetic pigments and carbohydrate content of Vetiver leaves were highly affected by diesel exposure. The content of chlorophyll a, b, and total carotenoids decreased 93%, 82%, and 76%, respectively, with respect to the control untreated plants (p < 0.05). Accordingly, a decrease in biomass growth was also observed in all treated-specimens after 15-days diesel exposure. Conversely, the content of soluble carbohydrates in the plant leaves showed a 3.3-fold increase (p < 0.05) compared to the control group. These results might be explained by a reduction in carbohydrate utilization as a consequence of a lower rate in carbon assimilation caused by the reduction in the photosynthetic pigments. Further, the environmental stressful conditions caused by diesel exposure could induce the mobilization of soluble sugars in order to preserve leaf survival, since these biomolecules play an active role as intracellular signaling molecules involved in the regulation of metabolic processes associated with ATP production. In general, C. zizanioides showed a low potential to remove high diesel oil concentration (i.e., 10% w/w) in the tested conditions. However, more evidence is still needed in order to consider Vetiver grass as a low-cost flora useful in phytoremediation strategies towards management of hydrocarbon-polluted environments.