Heavy metal uptake by plant parts of Populus species: a meta-analysis

Abstract

Populus species are well documented for being potentially suitable for phytoremediation purposes regarding their accumulation characteristics. However, published results are contradictory. Based on the data gathered during an extensive literature search, we aimed to assess and revise the metal accumulation potential in the root, stem, and leaf of Populus species growing in contaminated soils, with meta-analysis. We evaluated the influences of pollution level, soil pH, and exposure time on the metal uptake patterns. We found accumulations of Cd, Cr, Cu, Pb, and Zn to be significant in each plant part, while that was only moderate for Ni, and limited for Mn. By calculating the soil pollution index (PI), we observed significantly intensive, PI-independent accumulation for Cd, Cr, Cu, Ni, Pb, and Zn. A decrease in soil pH significantly increased the uptake of Mn and significantly decreased the accumulation of Pb in the stem. Metal uptake was significantly influenced by exposure time as well; Cd concentration was significantly decreased in the stem, while concentrations of Cr in the stem and leaf, and Mn in the stem were significantly increased with time. These aforementioned findings support a well-founded metal-and-growth condition-specific application of poplars in phytoremediation processes, also triggering further in-depth assessments to enhance the efficiency of relevant poplar-based technologies.

Ecophysiological response of Populus alba L. to multiple stress factors during the revitalisation of coal fly ash lagoons at different stages of weathering

“…Cr content in P. alba leaves at L3 and L11 was higher than normal, but not toxic (>0.5 mg kg -1 ; Kabata-Pendias and Pendias, 2001 ). In our study, much higher Cr concentrations were measured in P. alba roots than in leaves, confirming earlier findings for poplar trees ( Pulford and Watson, 2003 ; Ancona et al., 2017 ; Tőzsér et al., 2023 ). BCF Root<1 and TF<1 make P. alba suitable for the phytostabilisation of this element.…”

“…Under these conditions at the TENT A landfills, P. alba accumulated toxic concentrations of B and Zn (>50 mg kg -1 , >100mg kg -1 ; Kabata-Pendias and Pendias, 2001 ) at L3 and L11 and also toxic concentrations of As (>5 mg kg -1 ; Kabata-Pendias and Pendias, 2001 ) at L11, while Mn content was in the deficit range (<30 mg kg -1 ; Kabata-Pendias and Pendias, 2001 ). The accumulation potential for B and Zn in P. alba leaves at L3 and L11 is also confirmed by earlier studies on poplars ( Madejón et al., 2004 ; Robinson et al., 2005 ; Dos Santos Utmazian et al., 2007 ; Robinson et al., 2007 ; Di Lonardo et al., 2011 ; Rees et al., 2011 ; Huang et al., 2019 ; Pilipović et al., 2019 ; Kostić et al., 2022b ; Tőzsér et al., 2023 ). The lower content of B in P. alba leaves at L11 compared to L3 was accompanied by changes in B content in FA because its solubility at pH>6 is conditioned only by its total concentration ( Iwashita et al., 2005 ).…”

“…The poor solubility of Mn in FA is the cause of its characteristic deficit in plants growing at ash landfills ( Adriano et al., 2002 ; Mitrović et al., 2008 ; Kostić et al., 2022b ). Namely, earlier findings suggest that Mn content in P. alba leaves correlates to its availability in surface soil ( Madejón et al., 2004 ) and that the accumulation potential of poplar for Mn is limited ( Tőzsér et al., 2023 ). The higher uptake and transport of Zn through plant tissue to P. alba leaves at L11 may be caused by the lower Mn content in leaves resulting from its reduced bioavailability in FA at L11 due to the altered physical and chemical characteristics of FA when compared to L3 ( Kabata-Pendias and Pendias, 2001 ; Aref, 2011 ).…”

“…Species from the Salicaceae family stand out when it comes to being used for the phytoremediation and revitalisation of polluted habitats, and in particular those from the Populus genus, which is characterised by high tolerance to a variety of environments ( Zacchini et al., 2009 ; Guerra et al., 2011 ). However, species of Populus , as a thoroughly mapped genus, differ widely in their uptake patterns, as well as adaptation abilities under varying abiotic conditions ( Dos Santos Utmazian et al., 2007 ; Zacchini et al., 2009 ; Di Lonardo et al., 2011 ; Tőzsér et al., 2023 ). To date, research has mostly focused on accumulation, phytoremediation potential, and tolerance of poplars to metal pollution ( Madejón et al., 2004 ; Robinson et al., 2005 ; Borghi et al., 2008 ; Todeschini et al., 2011 ; Kostić et al., 2022b ) or their physiological response to individual stress factors such as drought, salinity or high temperatures ( Chen and Polle, 2010 ; Yoon et al., 2014 ; Zhang et al., 2019 ; Kim et al., 2022 ).…”

Field study of irrigation strategies with treated wastewater and saline water on heavy metal accumulation in barley grain

“…Some researchers stated higher heavy metal uptake by plants at higher soil moisture due to the increase in biomass of plants (Mirzaei et al, 2020;Onder et al, 2016). Furthermore, soil salinity resulting from deficit irrigation may impact the competition between some heavy metals and multivalent cations such as Ca + and Mg +2 for adsorption on soil particles and plants (Acosta et al, 2011;Pulford & Watson, 2003;Silva & Mendonça, 2007;T} ozsér et al, 2023). These findings confirm the dual behavior of elements in their absorption by plants under different conditions.…”