Thiols as biomarkers of heavy metal tolerance in the aquatic macrophytes of Middle Urals, Russia

Abstract

Aquatic macrophytes, viz. Sagittaria sagittifolia L., Lemna gibba L., Elodea canadensis Michx., Batrachium trichophyllum (Chaix.) Bosch., Ceratophyllum demersum L. and Potamogeton sp. (P. perfoliatus L., P. alpinus Balb., P. crispus L., P. berchtoldii Fieber, P. friesii Rupr., P. pectinatus L.) were collected from 11 sites for determining their metal accumulation and thiols content. Cu(2+), Ni(2+), Mn(2+), Zn(2+), and Fe(3+) exceeded maximum permissible concentrations in chosen sites. Significant transfer of metals from water to leaves is observed in the order of Ni(2+) < Cu(2+) < Zn(2+) < Fe(3+) < Mn(2+). The maximum variation of bioconcentration factor was noticed for manganese. The accumulation of heavy metals in leaves was correlated with non-protein and protein thiols, confirming their important role in metal tolerance. The largest contribution was provided by Cu(2+) (on the average r = 0.88, p < 0.05), which obviously can be explained as an important role of these ions in thiols synthesis. Increased synthesis of thiols in the leaves allows the usage of SH-containing compounds as biomarkers of metal tolerance. Considering accumulation of metals and tolerance, B. trichophyllum, C. demersum and L. gibba are the most suitable species for phytoremediation of highly multimetal contamination, while E. canadensis and some species of Potamageton are suitable for moderately metal-polluted sites.

Potential Mechanisms of Abiotic Stress Tolerance in Crop Plants Induced by Thiourea

“…Another possible mechanism of reduced loading of metal ions in xylem from roots to shoots with TU supplementation is chelation of metal ions with thiols (TU contains thiol- group) in the cytosol. Presence of thiols facilitates efficient utilization of SH-containing compounds as biomarkers of metal tolerance (Borisova et al, 2016; Meng et al, 2019). Thiols also permit vacuolar compartmentation (Guo et al, 2012), which might be a vital mechanism through which TU reduces metal-toxicity, but this has not yet been experimentally proven.…”

Accumulation of Heavy Metal Ions by Eichhornia Crassipes from Battery Industry Effluent under the Influence of Cattle Manure

“…Many researchers have mentioned that the higher concentration of metal ions were accumulated in root than in shoots [18]. Also it is found out that non-essential metal ions had higher TF value than the essential metal ions [20]. And the same has been obtained for the study with non-essential elements (Ar an Pb) had higher TF value then Ca, Fe and Zn.…”

Improved physiological defense responses by application of sodium nitroprusside in Isatis cappadocica Desv. under cadmium stress

“…It has been suggested that proline minimizes Cd toxicity not by Cd sequestration into vacuoles but by decreasing Cd‐induced oxidative damage, thus maintaining a more reduced environment in the cell (Hassan et al ., 2009). Similarly, several studies have shown that, by acting as antioxidants, organic compounds with SH groups (e.g., GSH, NPTs, PCs) can take an active part in the neutralization of ROS produced during oxidative stress (Anjum et al ., 2012; Bashir et al ., 2015; Borisova et al ., 2016; Noctor et al ., 2018). Among them, GSH plays a decisive role in antioxidant defense, cell redox homeostasis, and plant development under stress and in normal metabolism (Farooq et al ., 2016, 2019).…”