Accumulation, translocation, and toxicity of arsenic in barley grown in contaminated soil

Abstract

Aims Arsenic is a nonessential element for plants, however, high levels of As can inhibit plant growth. Toxicity of As is largely in uenced by its speciation in soil. The objectives of the present study were to determine fractional composition of As in soil, its accumulation in plants, and toxic effects on the morphological, anatomical, and ultrastructural levels.Methods In a model experiment, barley (Hordeum sativum) was planted in Haplic Chernozem spiked with three different concentrations of As (20, 50 and 100 mg/kg). The fraction composition of As in the experimental soil was analysed using a method of sequential fractionation. The effect of As on plants was analysed microscopically at tissue, cellular, and intracellular levels.Results Analysis of the fraction composition of As revealed a higher amount of mobile forms of As that contaminated the generative organs of plants. Oxides of Fe, Al, and Mn became the main soil components to retain As when contamination of As increased. Arsenic toxicity inhibited plant growth by affecting morphological parameters (shape, size, and colour). It was shown impairment in the root cells and a reduction in the size of the chlorophyllic parenchyma in the leaves. Ultrastructural analysis found changes in the main cellular organelles (chloroplasts, mitochondria, and peroxisomes).Conclusions The bioconcentration factor (BCF), bioaccumulation factor (BF-soluble), and translocation factor (TF) allowed evaluation of plant protection mechanisms and determination of hazardous concentrations of As in soil. Despite high buffering capacity of soil, high As concentration affected morphological and ultrastructural parameters of the H. sativum.

Changes in the photosynthetic response of lettuce exposed to toxic element multicontamination under hydroponic conditions

“…Nazir et al (2021) and Rabêlo et al (2018) described the direct effect of Cd-enriched solutions on the morphology and anatomy of roots. Arsenic also affects root morphology (Zemanová et al 2020(Zemanová et al , 2022Burachevskaya et al 2021). Zn is also associated with a reduced plant root system (Genc et al 2007, Namdjoyan et al 2017.…”

Biocrusts significantly affect the bioavailability and ecological risk of heavy metals in gold mine tailings

“…Our results indicated that biocrusts affect heavy metal forms in the underlying layer, compared with bare soil, with the proportion of F4 (by 4.01-8.04%) decreasing and the proportion of F2, F3 and F1 increasing, more so in F2 (3.54-6.69%). This could be because: (1) biocrust succession improves soil texture in degraded ecosystems, changing the proportion of metals bound to Fe/Mn oxides and the heavy metal distribution (Bartoli et 2) Fe/Mn oxides in the soil environment immobilise heavy metals through adsorption and co-precipitation, and the metal could react with Mn or Fe to form relatively stable compounds (Burachevskaya et al 2021, Krupadam, 2007, Zhang et al 2017).…”

“…3). The available As and Cr increased most in the underlying mixed crust and moss crust, respectively, due to the different As and Cr solubility in the underlying of different biocrust (Burachevskaya et al 2021, Zakir et al 2008).…”

“…Therefore, biocrusts may regulate the pH of alkaline soil. With the development and succession of biocrusts, pH gradually decreased (Table 3), with organic matter and exchangeable cations in soil solution adsorbed to soil colloids and clay mineral surfaces (Burachevskaya et al 2021, Tyopine et al 2018, Orlekowsky et al 2013, facilitating the conversion of heavy metal from inactive to active forms. In this study, pH and Eh signi cantly decreased with biocrust development, while CEC and SOM signi cantly increased in the underlying layer (Table 2).…”