Physiological and Biochemical Responses of Solanum lycopersicum L. to Benzo[a]pyrene Contaminated Soils.

Benzo[a]pyrene (BaP) is noted as one of the main cancer-causing pollutants in human beings and may damage the development of crop plants. The present work was designed to explore more insights into the toxic effects of BaP on Solanum lycopersicum L. at various doses (20, 40, and 60 MPC) spiked in Haplic Chernozem. A dose-dependent response in phytotoxicity were noted, especially in the biomass of the roots and shoots, at doses of 40 and 60 MPC BaP and the accumulation of BaP in S. lycopersicum tissues. Physiological and biochemical response indices were severely damaged based on applied doses of BaP. During the histochemical analysis of the localization of superoxide in the leaves of S. lycopersicum, formazan spots were detected in the area near the leaf's veins. The results of a significant increase in malondialdehyde (MDA) from 2.7 to 5.1 times, proline 1.12- to 2.62-folds, however, a decrease in catalase (CAT) activity was recorded by 1.8 to 1.1 times. The activity of superoxide dismutase (SOD) increased from 1.4 to 2, peroxidase (PRX) from 2.3 to 5.25, ascorbate peroxidase (APOX) by 5.8 to 11.5, glutathione peroxidase (GP) from 3.8 to 7 times, respectively. The structure of the tissues of the roots and leaves of S. lycopersicum in the variants with BaP changed depending on the dose: it increased the intercellular space, cortical layer, and the epidermis, and the structure of the leaf tissues became looser.

Responses of Spring Barley to Zn- and Cd-Induced Stress: Morphometric Analysis and Cytotoxicity Assay.

Heavy metals such as cadmium (Cd) and zinc (Zn) could be dangerous and pollute the environment due to their high migration ability, robust bioavailability, and acute toxicity to soil biota and plants. Considering the above characteristics of these elements, the study's aim was to explore the individual and combined impact of Cd and Zn contamination of Haplic Chernozem on growing two-row spring barley (Hordeum vulgare L.). The accumulation and distribution of Cd and Zn in various parts of H. vulgare have also been studied, which showed that Cd accumulation by H. vulgare occurred more intensely than that by Zn up to eight times. Cadmium and Zn suppress plant growth up to two times, more effect was noted by the combined impact of Cd and Zn. The study of plant morphological characteristics revealed that growth suppression and structural changes in the root and leaf tissues increased in proportion to Cd and Zn concentrations. Detailed analysis of the localizations of Zn and Cd in various organelles of H. vulgare cells was performed. Heavy metals change the ultrastructure of prominent energy-producing organelles in leaf cells, especially chloroplasts and mitochondria. Overall, the current findings offer insights into phytotoxicity induced by Cd and Zn individual application as well as in combination with the H. vulgare plant. Zinc showed protective effects against high doses of Cd under the combined application. These antagonistic interactions reduce their accessibility to H. vulgare. The present work can be useful in restricting the entry of these elements into the food chain and preventing creating a threat to human health.

Phragmites australis cav. As a bioindicator of hydromorphic soils pollution with heavy metals and polyaromatic hydrocarbons.

The work is devoted to evaluation of the ability of Phragmites australis Сav. to indicate the soil pollution with heavy metals (HMs) and priority polycyclic aromatic hydrocarbons (PAHs) by studying changes in the plant's ultrastructure. The concentration of Mn, Cu, Cr, Cd, Pb, Zn, Ni as well as 16 priority PAHs in hydromorphic soils and macrophyte plants (Phragmites australis Cav.) were increasing with distance decreasing to the power station and approaching to the direction of prevailing wind (northwest). The analyze of distribution of the studied pollutants in plants showed that the highest concentration have prevailed in the roots. A decrease in the diameter of the roots, and an increase in the thickness of the leaf blade was established. The transmission electron microscopy analysis showed that the ultrastructure of P. australis chloroplasts changed affected by accumulation of HMs and PAHs: a rise in the number of plastoglobules; a drop in the number of lamellae in granules, as well as changes in the shape, size, and electron density of mitochondria and peroxisomes. The most serious destructive violations of the main cellular organelles were noted for plants from the site within a 2.5 km from the emissions source and located on the predominant wind rose (north-west) direction. These macrophytes reflect spatial variations of pollutants metals in hydromorphic soils, therefore they are of potential use as bioindicators of environmental pollution.

Uptake of potentially toxic elements and polycyclic aromatic hydrocarbons from the hydromorphic soil and their cellular effects on the Phragmites australis.

The current study provides an information on the combined effect of pollution with potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in hydromorphic soils on the accumulation, growth, functional and morphological-anatomical changes of macrophyte plant, i.e., Phragmites australis Cav., as well as information about their bioindication status on the example of small rivers of the Azov basin. The territory of the lower reaches of the Kagalnik River is one of the small rivers of the Eastern Azov region was examined with different levels of PTEs contamination in soils, where the excess of the lithosphere clarkes and maximum permissible concentrations (MPC) for Mn, Cr, Zn, Pb, Cu, and Cd were found. The features of the 16 priority PAHs quantitative and qualitative composition in hydromorphic soils and P. australis were revealed. The influence of soil pollution on accumulation in P. australis, as well as changes in the morphological parameters were shown. It has been observed that morphometric changes in P. australis at sites experiencing the сontamination and salinity are reflected with the changes in the ultrastructure of plastids, mitochondria, and EPR elements of plant cells. PTEs accumulated in inactive organs and damaged cell structures. At the same time, PAHs penetrated through the biomembranes and violated their integrity, increased permeability, resulted cell disorganization, meristem, and conductive tissues of roots. The nature and extent of the structural alterations found are dependent on the type and extent of pollution in the examined regions and can be utilized as bioindicators for evaluating the degree of soil phytotoxicity characterized by the accumulation of PTE and PAHs.

Influence of carbon-containing and mineral sorbents on the toxicity of soil contaminated with benzo[a]pyrene during phytotesting.

Benzo[a]pyrene (BaP) is a member of polycyclic aromatic hydrocarbons known for high persistency and toxicity. Technologies of BaP sorption through solid matrixes have received relatively more attention. The present study was devoted to the phytotesting investigations of two different groups of sorbents, such as carbonaceous, including biochar and granulated activated carbon (GAC), and mineral, including tripoli and diatomite. Evaluation of the BaP removing efficiency was carried out using the phytotesting method with spring barley in Haplic Chernozem contaminated with different levels of contamination (200 and 400 µg kg-1 BaP). The sorbents' efficiency for BaP remediation was estimated in the sorbents doses from 0.5 to 2.5% per kg of soil. It was shown that biochar and GAC decreased the soil toxicity class to a greater extent than mineral sorbents ones. The effect intensified with an increase in applying sorbents doses. The optimal dose of carbonaceous sorbents into the soil contaminated with 200 µg kg-1 was 1%, decreasing the BaP content up 57-59% in the soil. Simultaneously, the optimal dose of the mineral sorbents was found to be 1.5%, which decreased the BaP content in the soil up 41-48%. Increasing the BaP contamination level up to 400 µg kg-1 showed the necessity of a sorbent dose increasing. In these conditions, among all applied sorbents, only 2% GAC could reduce the soil toxicity class to the normal level up to 0.91-1.10. It was shown that BaP tended to migrate from the soil to the roots and further into the vegetative part of barley.

Influence of soil pollution on the morphology of roots and leaves of Verbascum thapsus L.

The impact of inorganic pollutants in the zone of industrial wastewater settling tanks (South of Russia) was studied. The levels of Mn, Cr, Ni, Cu, Zn, Pb, Cd were determined for Verbascum thapsus L., which are part of the mesophilic succession of wild plants in the studied technogenically polluted territory. The bioavailability of heavy metals (HM) for plants from transformed soils has been established. Anatomical and morphological features in the tissues of the plants affected by HM were analyzed using light-optical and electron microscopic methods. Contamination of the soil cover with Mn, Cr, Ni, Cu, Zn, Pb and Cd has been established with maximum content of Zn. It was revealed that the HM content in the V. thapsus plants exceeded the maximum permissible levels (Russian state standard): Zn by 23, Pb by 2, Cr by 31 and Cd by 3 times. The lower level of HM content in the inflorescences of mullein plants in comparison with the root system, stems and leaves indicates the resistance of generative organs to technogenic pollution. In the root and leaves of the V. thapsus, the anatomical and ultrastructural observation were carried out using light-optical and transmission electron microscopy. Changes in the ultrastructure of plants under the influence of anthropogenic impact have been revealed. The most significant changes of the ultrastructure of the polluted plants were found in the cell organelles of leaves (mitochondria, plastids, peroxisomes, etc.) including spatial transformation of the thylakoid system of plastids during the metal accumulation by plants, which may determine the mechanism of plant adaptation to technogenic pollution.

Effects of Zinc Oxide Nanoparticles on Physiological and Anatomical Indices in Spring Barley Tissues.

The aim of the present work was to investigate the toxic effects of zinc oxide nanoparticles (ZnO NPs, particle size < 50 nm) on the physiological and anatomical indices of spring barley (Hordeum sativum L.). The results show that ZnO NPs inhibited H. sativum growth by affecting the chlorophyll fluorescence emissions and causing deformations of the stomatal and trichome morphology, alterations to the cellular organizations, including irregularities of the chloroplasts, and disruptions to the grana and thylakoid organizations. There was a lower number of chloroplasts per cell observed in the H. sativum leaf cells treated with ZnO NPs as compared to the non-treated plants. Cytomorphometric quantification revealed that ZnO NPs decreased the size of the chloroplast by 1.5 and 4 times in 300 and 2000 mg/L ZnO NP-treated plants, respectively. The elemental analysis showed higher Zn accumulation in the treated leaf tissues (3.8 and 10.18-fold with 300 and 2000 mg/L ZnO NPs, respectively) than the untreated. High contents of Zn were observed in several spots in ZnO NP-treated leaf tissues using X-ray fluorescence. Deviations in the anatomical indices were significantly correlated with physiological observations. The accumulation of Zn content in plant tissues that originated from ZnO NPs was shown to cause damage to the structural organization of the photosynthetic apparatus and reduced the photosynthetic activities.

The Effect of Granular Activated Carbon and Biochar on the Availability of Cu and Zn to Hordeum sativum Distichum in Contaminated Soil.

The presence of heavy metals in the soil could impose serious problems on soil-plant systems due to the accumulation of heavy metals in plants. Even vital elements such as Cu and Zn have a toxic effect in the case of excessive intake by living organisms. The present work aimed to investigate the content of loosely bound (exchangeable, complexed, and specifically sorbed) compounds of Cu and Zn and their availability to spring barley (Hordeum sativum distichum) in contaminated Haplic Chernozem soil under the conditions of a model experiment (five approximate permissible concentrations (APC) and 10 APC of metal). Changes in the bioavailability of the metals upon application of carbon sorbents were observed. An increase in loosely bound metal compounds has been shown under conditions of soil contamination with metals (up to 57% of the total content). The increase in the availability of Cu in the soil was mainly due to the formation of complexed metal forms with organic matter (up to 17%). The availability of Zn was found to be associated with an increase in exchangeable (up to 21%) and specifically sorbed compounds (up to 27%). Granular activated carbon (GAC) and biochar have high sorption properties. A decrease in the content of loosely bound compounds of metals was established, especially in the most mobile forms such as exchangeable and complexed forms. The introduction of sorbents into the soil opened up a new venue for binding heavy metals in situ, eventually leading to a decrease in their bioavailability. The inactivation of Cu and Zn in the soil upon the application of sorbents led to a decrease in metal absorption by spring barley. The highest efficiency of biochar application was established at a dose of 2.5% and 5% in soil contaminations of 5 APC and 10 APC of Cu or Zn. The efficiency of the use of sorbents was more influenced by the dose of application than by the type of sorbent. There was no significant difference between biochar and GAC. Stabilization and inactivation of metals may improve soil fertility and plant growth.

The toxic effect of CuO of different dispersion degrees on the structure and ultrastructure of spring barley cells (Hordeum sativum distichum).

Nowadays, nanotechnology is one of the most dynamically developing and most promising technologies. However, the safety issues of using metal nanoparticles, their environmental impact on soil and plants are poorly understood. These studies are especially important in terms of copper-based nanomaterials because they are widely used in agriculture. Concerning that, it is important to study the mechanism behind the mode of CuO nanoparticles action at the ultrastructural intracellular level. It is established that the contamination with CuO has had a negative influence on the development of spring barley. A greater toxic effect has been exerted by the introduction of CuO nanoparticles as compared to the macrodispersed form. A comparative analysis of the toxic effects of copper oxides and nano-oxides on plants has shown changes in the tissue and intracellular levels in the barley roots. However, qualitative changes in plant leaves have not practically been observed. In general, conclusions can be made that copper oxide in nano-dispersed form penetrates better from the soil into the plant and can accumulate in large quantities in it.

Sustainability of agricultural and wild cereals to aerotechnogenic exposure.

In recent decades, the problem of the constantly increasin level of anthropogenic load on the environment is becoming more and more acute. Some of the most dangerous pollutants entering the environment from industrial emissions are heavy metals. These pollutants are not susceptible to biodegradation over time, which leads to their accumulation in the environment in dangerous concentrations. The purpose of this work is to study the sustainability of cultivated and wild plants of the Poaceae family to aerotechnogenic pollution in the soil. The content of heavy metals in couch grass (Elytrigia repens (L.) Nevski), meadow bluegrass (Poa pratensis L.) and soft wheat (Triticum aestivum) plants grown in the impact zone of Novocherkassk Power Station has been analyzed. Contamination of cultivated and wild cereals with Pb, Zn, Ni and Cd has been established. It has been shown that the accumulation of heavy metals is individual for each plant species. An average and close correlation have been established between the total HM content and the content of their mobile forms in the soil and their content in plants. For the plants studied, the translocation factor (TF) and the distribution coefficient (DC) of HM have been calculated. The TF is formed by the ratio of the concentration of an element in the root plant dry weight to the content of its mobile compounds in the soil. The DC value makes it possible to estimate the capacity of the aboveground parts of plants to absorb and accumulate elements under soil pollution conditions and is determined as the ratio of the metal content in the aboveground biomass to its concentration in the roots. TF and DC values have shown a significant accumulation of elements by plants from the soil, as well as their translocation from the root system to the aboveground part. It has been revealed that even within the same Poaceae family, cultural species are more sensitive to man-made pollution than wild-growing ones.

Effects of benzo[a]pyrene toxicity on morphology and ultrastructure of Hordeum sativum.

Many studies have been devoted to investigation of toxic benzo(a)pyrene (BaP) compound, but studies involving changes at the cellular level are insufficient to understand the mechanisms of polycyclic aromatic hydrocarbons (PAHs) effect on plants. To study the toxicity of BaP, a model vegetation experiment was conducted on cultivation of spring barley (Hordeum sativum distichum) on artificially polluted BaP soil at different concentrations. The article discusses the intake of BaP from the soil into the plant and its effect on the organismic and cellular levels of plant organization. The BaP content in the organs of spring barley was determined by the method of saponification. With an increase in the concentration of BaP in the soil, its content in plants also rises, which leads to inhibition of growth processes. The BaP content in the green part of Hordeum sativum increased from 0.3 µg kg-1 in control soil up to 2.6 µg kg-1 and 16.8 µg kg-1 under 20 and 400 ng/g BaP applying in soil, as well as in roots: 0.9 µg kg-1, 7.7 µg kg-1, 42.8 µg kg-1, respectively. Using light and electron microscopy, changes in the tissues and cells of plants were found and it was established that accumulation of BaP in plant tissues caused varying degrees of ultrastructural damage depending on the concentration of pollutant. BaP had the greatest effect on the root, significant changes were found in it both at histological and cytological levels, while changes in the leaves were observed only at the cytological level. The results provide significant information about the mechanism of action of BaP on agricultural plants.

Soil PAHs contamination effect on the cellular and subcellular organelle changes of Phragmites australis Cav.

The concentrations of ∑16 priority polycyclic aromatic hydrocarbons (PAHs) for soils, roots, and above-ground parts of reed (Phragmites australis Cav.) were determined on different monitoring plots located near the city of Kamensk-Shakhtinsky, southern Russia, where historically received industrial sewage and sludge. The total PAHs concentration in monitoring soil plots was significantly higher than those in the background site which situated at the distance of 2 km from the contamination source. Accordingly, the maximum accumulation was found for phenanthrene and chrysene among the 16 priority PAHs in most of the plant samples collected in the impact zone. The effects of PAHs' pollution on changes of Phragmites australis Cav. cellular and subcellular organelles in the studied monitoring sites were also determined using optical and electron microscopy, respectively. The obtained data showed that increasing of PAHs contamination negatively affected the ultrastructural changes of the studied plants. Phragmites australis Cav. showed a high level of adaptation to the effect of stressors by using tissue and cell levels. In general, the detected alterations under the PAHs effect were possibly connected to changes in biochemical and histochemical parameters as a response for reactive oxygen species and as a protective response against oxidative stress. The obtained results introduce innovative findings of cellular and subcellular changes in plants exposed to ∑16 priority PAHs as very persistent and toxic contaminants.

Design of new anti-Alzheimer drugs: ring-expansion synthesis and synchrotron X-ray diffraction study of dimethyl 4-ethyl-11-fluoro-1,4,5,6,7,8-hexa-hydro-azonino[5,6-b]indole-2,3-di-carboxyl-ate.

The title compound, C20H23FN2O4, is the product of a ring-expansion reaction from a seven-membered fluorinated hexa-hydro-azepine to a nine-membered azonine. The nine-membered azonine ring of the mol-ecule adopts a chair-boat conformation. The C=C and C-N bond lengths [1.366 (3) and 1.407 (3) Å, respectively] indicate the presence of conjugation within the enamine CH2-C=C-N-CH2 fragment. The substituent planes at the C=C double bond of this fragment are twisted by 16.0 (3)° as a result of steric effects. The amine N(Et) N atom has a trigonal-pyramidal configuration (sum of the bond angles = 346.3°). The inter-planar angle between the two carboxyl-ate substituents is 60.39 (8)°. In the crystal, mol-ecules form zigzag chains along [010] by inter-molecular N-H⋯O hydrogen-bonding inter-actions, which are further packed in stacks toward [100]. The title azonino-indole might be considered as a candidate for the design of new Alzheimer drugs.