Functional and structural roles of wiry and sturdy rooted emerged macrophytes root functional traits in the abatement of nutrients and metals

Abstract

Macrophytes root functional traits (RFTs) play central roles in the cycling of aquatic contaminants, and there is evidence that emerged macrophytes differ in macronutrients (N and P) and heavy metals (Cd, Cr, Cu, Ni, Pb, V, Zn) abatement due to difference in RFTs. However, it remains ambiguous what root type of emerged macrophytes and their RFTs play more significant roles in the mineralization and removal of nutrients and heavy metals in aquatic systems. There is a clear need of intensive investigation on fibrous- and thick-root emerged macrophytes and their diverse RFTs in previous literatures to identify appropriate plants for phytoremediation technology. Morphological, physiological, anatomical, and symbiotic RFTs of fibrous-root emerged macrophytes favour the nutrients and heavy metals uptake. Thick-root emerged macrophytes with greater root rhizomes, lignifications and suberization illustrate tolerance under higher stress. Besides higher removal abilities of fibrous-root macrophytes, their limited lifespan and stress tolerance are the challenges for long-term removal of metals. Thus, it is still infancy to wrap up at once that the fibrous-root macrophytes and their RFTs are equally efficient for removal of heavy metals from aquatic ecosystems. Several advance techniques include cisgenesis intragenesis, symbiotic endophytes, and plant-harboring microbes are emerging to improve the RFTs of plants. These techniques need to be employed in emerged macrophytes to achieve desirable RFTs and targets. Still, these macrophytes require advanced studies on emerging contaminants, such as pharmaceutical and personal care products, organic carbon stability, and mitigation of greenhouse gases emission.

Keywords: Fibrous-root; Nutrients; Root-traits; Sediments; Thick-root; Toxic-metals.