Rare Earth Element Fluxes in Diverse Soils and Their Absorption by Coconut Palm

A review on the potentiality of Rare Earth Elements to trace pedogenetic processes

“…Indeed, only slight and not systematic fractionations of LREEs, or MREEs or HREEs are observed in contradictory studies Ding et al, 2006;Miao et al, 2007). Nevertheless, uptake sometimes fractionates only one REE, since positive anomalies for Eu Ding et al, 2006), Sm (Wahid et al, 2003), Tb and Nd were recorded.…”

“…Transfers from soils to plants remain usually restricted, except for some hyperaccumulators, such as ferns (Tyler, 2004a;Hu et al, 2006b). Consequently, REE contents in plants, despite variations of several orders of magnitude, are usually low, from few ng g − 1 to few mg g − 1 dry weights, especially in the potentially harvested aerial organs (Wahid et al, 2003;Tyler, 2004a;Wang et al, 2005;Hu et al, 2006b).…”

“…Several soil parameters-notably pH, Eh, CEC, contents of clay minerals, of OM and of Fe-Mn-oxides-as well as plant type, influence the intensity of REE uptake (Wahid et al, 2003;Tyler, 2004a;Hu et al, 2006b;Miao et al, 2007). Transfers from soils to plants remain usually restricted, except for some hyperaccumulators, such as ferns (Tyler, 2004a;Hu et al, 2006b).…”

Rare earth elements in plants

“…The uptake and transport of REE in plants have attracted attention during the last decade, but the available information on the soil-plant system enriched with REE is limited and fragmented (Wahid et al 2003, Hu et al 2004. With changing environmental conditions, understanding the biological impact of REE especially on natural plants is required.…”

“…Firstly, the adsorption and desorption of REE are affected by the physico-chemical properties of the soil (Wahid et al 2003, Loell and Albrecht 2011, Miao et al 2011, De Araújo et al 2012: 1) Uptake of REE via roots is linked to Fe-oxyhydroxides in the rhizosphere (Brioschi et al 2013, Durães et al 2014; 2) The mobility of elements within the soil profile depends on the pH value of the rhizosphere and the redox potential of the soil (Cao et al 2001, Shan et al 2002, Tyler 2004b, Durães et al 2014; 3) Uptake of REE by plants tends to be higher at a low pH (Cao et al 2001, Shan et al 2002, Tyler 2004a; 4) Biochemical cycling and fractionation of REE in soil resulting from atmospheric deposition (Stille et al 2009); 5) The cation exchange capacity (CEC) of soil is an important factor affecting the adsorption and desorption of (not only) REE (Jones 1997, Shan et al 2002, Shan et al 2003b; 6) The plant uptake rate is dependent on the valence of an element (Tyler 2004b); 7) The Casparian stripes in plant root endodermis limit uptake of REE (Hu et al 2004, Brioschi et al 2013; 8) Complexes formed by low-molecular-mass-organic acids and other plant root exudates predict the bioavailability of REE (Fu et al 2001, Zhimang et al 2001, Shan et al 2002, 2003a; 9) Organic and inorganic ligands play an important role in REE absorption by plant roots and fractionation of REE (Fu et al 1998, Zhimang et al 2001, Shan et al 2003b, Zanin and Zamirailova 2009, Durães et al 2014; 10) The addition of fulvic, humic, malic, and citric acids, histidine, or ethylene diamine tetraacetic acid (EDTA) changes bioaccumulation of REE in plants as metals complexed with, e.g., fulvic acids, are more available to plant roots…”