Response of two aquatic plant species to metallic nanoparticles and their potential for phytoremediation

Certain plants have been identified with the capability to take up metallic and metal oxide nanoparticles (ENPs), thus suggesting their potential role in phytoremediation. The reported study evaluates the response of two aquatic plants, sedge (Carex rostrata) and cattail (Typha latifolia), on their exposure to Ag, ZnO, TiO2, BiVO4/Pd, and Cu2O/Pd nanoparticles over 15 weeks. Plant physiological responses (chlorophyll content, carbonic anhydrase (CA) activity, leaf area, production of new shoots, and root length) varied according to the plant species and the ENP type. By week 15, sedge treated with BiVO4/Pd ENP had a high chlorophyll content and increased CA activity and leaf area compared to the control. In contrast, cattail had reduced chlorophyll levels and number of new shoots when exposed to exogenously applied BiVO4/Pd. The highest sedge chlorophyll content at week 15 was measured in the mixed-ENPs, Cu2O, and Ag (53.2, 35.8, and 32.7%, respectively, greater than the control). The ZnO ENPs were beneficial for sedge chlorophyll content, cattail shoot production, and root length. The mixed-ENPs treatment imparted positive effects to several sedge properties (CA and new shoots) and cattail (chlorophyll, leaf area, and root length). Additional research is needed to assess the capabilities of different aquatic plant species to tolerate metal-based ENPs for remediation purposes.