Response of wheat and pea seedlings on increase of bromine concentration in the growth medium

The Effect of Copper Salts on Bioactive Compounds and Ultrastructure of Wheat Plants

Abiotic stress agents, among them metal stress, can cause oxidative damage to plant cells. In defense, plants can increase the production of secondary metabolites in order to mitigate the harmful effects caused by them. The purpose of this work was to evaluate the effect of two types of copper salts (CuSO₄ and Cu(NO₃)₂), added in two different amounts in soil (150 mg/kg, respectively 300 mg/kg), on assimilating pigments, total polyphenols, antioxidant activity and the elemental composition of wheat. The obtained results were compared with those from control plants grown in the same conditions but without copper salts. The amount of assimilating pigments, total polyphenols, and antioxidant activity respectively increases or decreases in the plants treated with copper salts compared to the control depending on the stage of development of the plant. No significant damage induced in the leaves of the wheat plants treated with the selected salts was observed following the TEM analysis. In six-week-old plants it was observed by EDX analysis that the salts are transformed into nanoparticles. The bioactive compounds, elemental composition and their interaction is influenced by concentration of metal’s salt, type of salt and exposure period.

Response of wheat and barley seedlings on soil contamination with bromides

Environmental pollution is becoming one of the most important global problems. Understanding the main factors affecting accumulation of toxic trace elements in consumed crops is of particular value. Unfortunately, possible toxicity of many trace elements is still poorly studied. The development of measures on identification of new potentially toxic trace elements is critical for high quality and safety of food. In the research, we performed greenhouse pot experiments with two major crops, wheat and barley, that were grown in the soil contaminated with bromides of ammonium and neodymium. The concentrations of elements in the plants and soil were determined by ICP-MS/ICP-OES after leaching the samples with tetramethyl ammonium hydroxide. Additionally, variations in the biomasses and concentrations of pigments in the plant leaves were studied. Although wheat and barley are botanically similar and were grown under the same conditions, concentrations of several elements in the plants were rather different. Both wheat and barley were capable of accumulating high concentrations of bromine (Br) when the plants grow in the soil contaminated with this trace element, but demonstrated different response on the soil contamination. The Br concentrations were always higher in barley, while the concentrations of pigments in barley leaves were lower than in leaves of wheat. During first days, biomass of the plants grown in the soil contaminated with bromides was slightly lower than biomass of the wheat and barley grown in uncontaminated soil. However, with time the bromides exhibited positive effect on the plant biomass.

The Effect of TiO2 Nanoparticles on the Composition and Ultrastructure of Wheat

The present work aims to follow the influence of TiO2 nanoparticles (TiO2 NPs) on bioactive compounds, the elemental content of wheat, and on wheat leaves' ultrastructure. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). The concentration of phenolic compounds, assimilation pigments, antioxidant capacity, elemental content, as well as the ultrastructural changes that may occur in the wheat plants grown in the presence or absence of TiO2 NPs were evaluated. In plants grown in the presence of TiO2 NPs, the amount of assimilating pigments and total polyphenols decreased compared to the control sample, while the antioxidant activity of plants grown in amended soil was higher than those grown in control soil. Following ultrastructural analysis, no significant changes were observed in the leaves of TiO2-treated plants. Application of TiO2 NPs to soil caused a significant reaction of the plant to stress conditions. This was revealed by the increase of antioxidant capacity and the decrease of chlorophyll, total polyphenols, and carotenoids. Besides, the application of TiO2 NPs led to significant positive (K, Zn, Br, and Mo) and negative (Na, Mn, Fe, As, Sr, Sb, and Ba) variation of content.

Bioavailability and toxicity of bromine and neodymium for plants grown in soil and water

Information about biological significance and possible phytotoxicity of many trace elements is still scarce. Bromine and neodymium are among the poorly investigated trace elements. In the research, greenhouse experiment was conducted to study the effects of bromide of neodymium on wheat seedlings grown in soil and water. The wheat seedlings were capable of accumulating large amounts of both Br and Nd. Compared to the soil-grown plants, the water-grown plants accumulated higher concentrations of the trace elements. The bioaccumulation of Br and Nd resulted in statistically significant variations in the concentrations of several elements. The concentrations of P, Cl, and Ca in roots and Cl in leaves of the plants grown in the contaminated water and the concentration of I in roots of the soil-grown plants decreased. In the water-grown seedlings, the concentrations of Na and P were higher and concentrations of Mg and K were lower than those in the seedlings grown in soil. In leaves of the plants grown in water, the concentration of Cl was lower than that in leaves of the soil-grown plants. In roots of the water-grown plants, the concentration of Zn was higher, and in leaves, it was lower compared with Zn content in roots and leaves of the plants grown in soil. The K/Na ratios were 4 (leaves) and 20 (roots) times higher in the soil-grown plants, while the Ca/Mg ratios were 8 - 19 times higher in the water-grown plants. Marked distinctions were also observed in relationships between different elements in the soil-grown and water-grown plants.

About plant species potentially promising for phytoextraction of large amounts of toxic trace elements

There is no information yet about plant species capable of accumulating many different metals/metalloids. The plants feasible for phytoremediation aims must grow fast, have high biomass, deep roots, and should accumulate and tolerate a range of toxicants in their aerial parts. In our research, greenhouse and field experiments have been performed to investigate accumulation and tolerance of not well-studied trace elements such as Br, Eu, Sc, Th (and also U) in couch grass and wheat. We compared bioaccumulation abilities of the plants with those of some other plant species grown under the same conditions. Additionally, we tested the effects of inoculation of seeds with Cellulomonas bacteria on phytoextraction of the trace elements from contaminated soils. For determination of elements, we used neutron activation analysis and ICP-MS. It was found that couch grass and wheat can grow in heavily contaminated soils and accumulate different toxic trace elements to levels that exceed physiological requirements typical for most plant species. Infection of seeds with bacteria resulted in a significant increase in the uptake of various trace elements and their translocation to upper plant parts. The use of couch grass and/or wheat, either alone or in combination with microorganisms, is a promising way to phytoextract metals/metalloids from contaminated soils.

Potential of wheat (Triticum aestivum L.) and pea (Pisum sativum) for remediation of soils contaminated with bromides and PAHs

The aim of the research was to study a removal of polycyclic aromatic hydrocarbons (PAHs) and phytoextraction of bromine (Br) from contaminated soils. The experiments using pea and wheat seedlings as potential candidates for soil remediation were performed. The soil for the experiments was collected from a site slightly contaminated by some PAHs. Before planting, the soil was exposed to 20 mg of Br/kg of soil. In the soil taken from rhizosphere of pea and wheat, the concentrations of many PAHs decreased up to 7 times compared to the concentrations of the compounds in the initial soil. Pea was capable of more effectively influencing the soil PAHs than wheat. The growth of pea and wheat in the soil spiked with Br resulted in a significant increase of Br concentration in a plant. Concentration of Br in roots of pea and wheat increased 21 and 3 times, respectively. Bromine content in leaves of wheat and pea increased 10 and 4.5 times. This accumulation of Br in the plants led to a decrease of its concentration in the rhizosphere soil. The experimental results demonstrated a good ability of the plants to cleanup the soils contaminated with organic and inorganic compounds.