Editorial: Trace Elements and Aquatic Plants: Accumulation, Ecological Impact, and Biomonitoring Applications

Ludmiła Polechońska ^* Agnieszka Klink

• Department of Ecology, Biogeochemistry and Environmental Protection, University of Wrocław, Wrocław, Poland

Aquatic plants (macrohydrophytes) form a greatly variable group of plants, in terms of their life form, ecology and habitat preferences. The group includes permanently or periodically submerged, floating or emergent plants (mosses, ferns and angiosperms) and filamentous macroalgae (Pokorny and Kvet, 2003;Wetzel et al., 2001). They are the major components of most types of aquatic ecosystems playing a significant role in shaping the physical and chemical environment as well as establishing the structure and functioning of biocenosis. To mention only their most important functions, macrohydrophytes provide a considerable number of ecological niches and, as primary producers, constitute the basis of the food web. They also have the ability to absorb and accumulate numerous chemical substances from water and/or bottom sediments, including trace elements. Therefore, they contribute to regulating nutrient availability and controlling water eutrophication and purification, which can be utilized in phytoremediation. Importantly, aquatic plants are recognized as bioindicators and biomonitors because they respond to a variety of environmental conditions and pollutants (De et al., 2019;Chaurasia, 2022).Macrohydrophytes are recognized bioaccumulators which can bioconcentrate trace elements in their tissues up to thousands of ppm and even 1000-fold the element concentration in the habitat (Yang and Ye, 2009;Tanwir et al., 2020). The uptake of trace elements is regulated by biological factors such as degree of plant development, morphology, genetic characteristics, as well as phenophase and non-biological factors such as exposure time, redox, Eh, pH, salinity, temperature, organic matter content, metal form and concentration in water and/or sediment (Lewis 1995;Yang and Ye, 2009;Krems et al., 2013). Low concentrations of some trace elements (e.g., Mn, Fe, Co, Cu, Zn, Ni) are vital and essential for normal plant metabolism and development (Maleva et al., 2012). As Szabó et al. reported in this Research Topic, Mn and Fe deficiency leads to reduced total chlorophyll content and limited growth of Lemna gibba. On the other hand, in case of too high concentrations of trace elements in habitat, the bioaccumulation in macrohydrophyte tissues may not equate with the physiological benefits of the element and reach toxic levels causing stress responses (Krems et showed that La mediates the production of flavonoids and lipids in the tissues of G. bailiniae, and 74 thus plays a protective role against Cd. Lanthanum limits the negative impact of Cd on 75 photosynthetic pigments content, photosynthetic efficiency and overall plant growth. 76