Diversity of low-molecular weight organic acids synthesized by Salix growing in soils characterized by different Cu, Pb and Zn concentrations

Abstract

The aim of the study was to evaluate the biosynthesis and exudation of 10 low-molecular weight organic acids (LMWOAs) into the rhizosphere with a simultaneous analysis of the acid contents in the roots and leaves of 9 Salix taxa growing on two experimental areas, differing in their concentrations of copper (Cu), lead (Pb) and zinc (Zn) in the soil (Area 1-low, Area 2-high concentration). The obtained results reveal a significant difference in the phytoextraction of the tested Salix taxa for the analysed metals in both areas. The highest contents of Cu, Pb and Zn were observed for all Salix collected from Area 2, especially in S. 9 smithiana roots (116 ± 8.76, 87.84 ± 7.30 and 203.42 ± 14.62 mg kg -1 DW, respectively). The results obtained in Area 2 also revealed acidification of the rhizosphere and a higher concentration of acids, mainly oxalic, malic, malonic, acetic and citric acids. Contents of oxalic, malic, acetic and citric acids increased in the roots of Salix taxa from Area 2, while in the leaves formic and succinic acids were also present. S. 9 smithiana was the taxon with the highest concentration of acids in the rhizosphere and roots (73.48 ± 6.77 and 49.79 ± 2.65 lM 100 g -1 DW, respectively), while in leaves a higher content was observed for S. alba and S. viminalis 'PR' taxa (78.12 ± 3.95 and 71.12 ± 3.75 lM 100 g -1 DW, respectively).

Responses of Swamp Cypress (Taxodium distichum) and Chinese Willow (Salix matsudana) Roots to Periodic Submergence in Mega-Reservoir: Changes in Organic Acid Concentration

“…Oxalic acid is one of the most important secondary metabolites in plants under adverse stress conditions, it can stimulate peroxidase activity and improves the antioxidant capacity [33]. Herein, the concentrations of oxalic acid in the roots of T. distichum and S. matsudana were greatly affected by the experimental period but not significantly affected by different flooding treatments.…”

The influence of environmental condition on the creation of organic compounds in Pinus sylvestris L. rhizosphere, roots and needles

“…Samples of P. sylvestris L. roots and needles (~ 1.0 g), ground to powder in a mortar chilled using liquid nitrogen were collected in 50 mL centrifuge tubes and stored frozen (− 80 °C) until analysis. The extraction method for ALMWOAs and phenolic compounds analysis in all the studied matrices was presented in detail by Magdziak et al (2017) and Gąsecka et al (2017). The obtained solutions were evaporated to dryness and stored frozen (− 80 °C) until analysis.…”

“…sorption and desorption (Wang et al 2015), oxidation and reduction (Blaylock and James 1994) and precipitation and dissolution (Zhou et al 2007). Moreover, in some of the previously mentioned studies, ALMWOAs and phenolic compounds have been found in plant tissues (mainly, roots and leaves) (Drzewiecka et al 2017;Magdziak et al 2017), where next to the rhizosphere, plants use ALMWOAs to transport, sequestrate and prevent cytoplasmic precipitation of toxic elements in cells, or in the case of phenolic compounds, in participation in adaptation and detoxification mechanisms mainly related to their structure and antioxidant properties (Ivanov et al 2012;Jiang et al 2017a, b;Benbettaieb et al 2018).…”

“…Differences in biomass and phytoextraction ability clearly demonstrate the influence of environmental conditions of growth, but at the same time indicate the importance of physiological changes in the studied plants. In the light of the diverse potential of the studied plants and limited literature data on the creation and exudation by woody plant roots of different organic compounds (aliphatic low molecular weight organic acids (ALMWOAs), enzymes, amino acids, phenolic compounds, simple and complex sugars, vitamins, purines, proteins and flavonoids) into the rhizosphere (Ryan et al 2001;Adeleke et al 2017;Magdziak et al 2017), we investigated the effects of flotation tailings in organic biomolecule activity in the rhizosphere. The rhizosphere is the most important soil zone, where fundamental processes occur that are responsible for plant functioning.…”

Insights into Heavy Metals Leakage in Chelator-Induced Phytoextraction of Pb- and Tl-Contaminated Soil

“…In addition, with the addition of DTPA, the accumulation of Tl in barley was enhanced markedly [26]. Salix taxa performs at a higher extraction efficiency of heavy metals from Cu, Pb, and Zn contaminated soil, which is mainly related to the rhizosphere secreting more small molecular organic acids, such as oxalic acid and malic acid [27]. The bioavailability of heavy metals reached the maximum at the second day after the addition of the chelating agent, EDTA (ethylene diamine tetraacetic acid), and its combination with small molecular organic acids (citric acid and oxalic acid) could significantly improve the extraction efficiencies of Cd and Zn.…”