Salinity Modulates Juncus acutus L. Tolerance to Diesel Fuel Pollution

Abstract

Soil contamination with petroleum-derived substances such as diesel fuel has become a major environmental threat. Phytoremediation is one of the most studied ecofriendly low-cost solutions nowadays and halophytes species has been proved to have potential as bio-tools for this purpose. The extent to which salinity influences diesel tolerance in halophytes requires investigation. A greenhouse experiment was designed to assess the effect of NaCl supply (0 and 85 mM NaCl) on the growth and photosynthetic physiology of Juncus acutus plants exposed to 0, 1 and 2.5% diesel fuel. Relative growth rate, water content and chlorophyll a derived parameters were measured in plants exposed to the different NaCl and diesel fuel combinations. Our results indicated that NaCl supplementation worsened the effects of diesel toxicity on growth, as diesel fuel at 2.5% reduced relative growth rate by 25% in the absence of NaCl but 80% in plants treated with NaCl. Nevertheless, this species grown at 0 mM NaCl showed a high tolerance to diesel fuel soil presence in RGR but also in chlorophyll fluorescence parameters that did not significantly decrease at 1% diesel fuel concentration in absence of NaCl. Therefore, this study remarked on the importance of knowing the tolerance threshold to abiotic factors in order to determine the bioremediation capacity of a species for a specific soil or area. In addition, it showed that NaCl presence even in halophytes does not always have a positive effect on plant physiology and it depends on the pollutant nature.

Stimulation of PGP Bacteria on the Development of Seeds, Plants and Cuttings of the Obligate Halophyte Arthrocaulon (Arthrocnemum) macrostachyum (Moric.) Piirainen & G. Kadereit

“…Finally, they were dried to confirm the dry weight of both the branches and the roots. With these data, the relative water content (RWC) [ 46 ] and the relative growth rate (RGR) [ 47 ] were calculated.…”

Response to Hypersalinity of Four Halophytes Growing in Hydroponic Floating Systems: Prospects in the Phytomanagement of High Saline Wastewaters and Extreme Environments

“…Thus, major aspects of the halophytes' response to hypersalinity remain unknown. Conversely, some halophytes have been tested in the phytoremediation of saline waters and soils contaminated by organic pollutants, as in the case of Juncus maritimus or Phragmites australis for PW containing petroleum-hydrocarbon residues [22,23], Halocnemum strobilaceum in oil-polluted contaminated sites [24], or J. roemerianus and J. acutus for diesel fuel in saline soil [25,26]. Other studies show that halophytes have already been successfully used for the remediation of heavy metal-polluted soils affected by salinity [8,27].…”