Abstract
Aims Arsenic is a nonessential element for plants, however, high levels of As can inhibit plant growth. Toxicity of As is largely influenced 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.