The effects of ozone exposure during the cropping season on rice grain quality were investigated in chamber experiments employing four ozone treatments (charcoal filtered air, ambient, 2× ambient, and 2.5× ambient concentration) and six genotypes. The concentrations of protein and lipids in brown rice increased significantly in response to ozone, while starch concentration and thousand kernel mass decreased. Other parameters, including the concentrations of iron, zinc, phenolics, stickiness and geometrical traits did not exhibit significant treatment effects. Total brown rice yield, protein yield, and iron yield were negatively affected by ozone. Numerous genotypic differences occurred in the response to ozone, indicating the possibility of optimizing the grain quality in high ozone environments by breeding. It is concluded that although the concentrations of two important macronutrients, proteins and lipids, increased in ozone treated grains, the implications for human nutrition are negative due to losses in total grain, protein and iron yield.

Microplastics (MPs) are a modern societal concern and recognized as a growing environmental hazard by careless disposal. This study aimed to assess the MPs content in white shrimp (Metapenaeus affinis) inhabiting in a natural habitat affected by high anthropogenic pressures, and recognize if the shrimp could be a suitable bioindicator for MPs pollution. To assess spatial changes of MPs presence in shrimps, sampling was carried out by a trawl net from 13 stations across the entire Musa Bay. Tissues of shrimps were examined for MPs following floatation, digestion, microscopic observation and identified by Confocal Raman Spectroscopy. MPs were observed in the shrimps of all stations. The average MPs abundance was 1.02 items/g of digestive tissues. About 37% of recorded MPs in M. affinis samples exceeding 500 μm that could be related to surface area and stickiness as notable controls beyond ingestion. The dominant shape of MPs was fiber, followed by film. Five different colors were recorded in tissues of M. affinis samples, and the white/transparent MPs were the most abundant, followed by blue and black. In addition, a wide range of recorded colors of MPs in the study area could suggest a variety of sources of MPs. Confocal Raman Spectroscopy confirmed that polyethylene terephthalate (46%), polypropylene (27%) and polystyrene (27%) were dominant polymers. As the average annually consumption of shrimp in the region is 2.3 g/person/day, therefore each person could consume 857 MPs per year. In conclusion, the results of this research provide a detailed and useful information for a better understanding of MPs contamination in the region and suggest Jinga shrimp as a suitable species for monitoring MPs in marine ecosystems.

Clopyralid is one of the synthetic pyridine-carboxylate auxin herbicides and used to control perennial and annual broadleaf weeds in wheat, sugar beets, canola, etc. In this study, dose-dependent cytotoxicity and genotoxicity of clopyralid at different concentrations (25, 50, and 100 μg/mL) have been evaluated on the Allium cepa roots. The evaluation has been performed at macroscopic (root growth) and microscopic levels [mitotic index (MI), chromosome aberrations (CAs) in ana-telophase cells, and DNA damage] using root growth inhibition, Allium ana-telophase, and comet tests. The percentage of root growth inhibition and concentration of reducing root growth by 50% (EC₅₀) of clopyralid were determined compared with the negative control by using various concentrations of clopyralid (6.25–1000 μg/L). The 96 h EC₅₀ of clopyralid was recorded as 50 μg/L. The gradual decrease in root growth and the MI reveals the cytotoxic effects of clopyralid. All the tested concentrations of clopyralid induced total CAs (polyploidy, stickiness, anaphase bridges, chromosome laggards, and disturbed ana-telophase) and DNA damage dose and time dependently. These results confirm the cytotoxic and genotoxic effects of clopyralid on non-target organism.

Allium test has already been used to determine cytotoxicity of waste drilling fluids. In the present work the cytotoxicity of four pure chemicals (Defoamex, Idthin 400, Magco Thin and Slick Pipe) was investigated. Those chemicals are components of drilling fluids, therefore, they are usually constituents of oil and gas industry waste waters. The tested chemicals were prepared in 1:9 dilution and cytotoxic effects on root-tip meristem ofAllium ascalonicum were analysed after 24-, 48- and 72-hour-treatments. All samples showed cytotoxicity which was proved by cytogenetic parameters such as inhibition of mitotic activity and increase of mitotic abnormalities and chromosomal aberrations in comparison with the control. Almost all mitotic abnormalities induced by four chemicals tested were the result of disturbed spindle mechanisms accompanied with stickiness. Slick Pipe revealed the most prominent mitodepressive effect and induced a high number of abnormalities. It caused a significant decrease of mitotic activity and increase of mitotic abnormalities after all three treatment durations, while chemicals Defoamex and Magco Thin showed a significant decrease of mitotic activity only after 72-hour-treatment. Chemicals Defoamex, Idthin 400 and Magco Thin revealed a significant increase of mitotic abnormalities after 48- and 72-hour-treatments.

Copper oxychloride gained great importance due to its broad-spectrum antifungal action to combat various fungal diseases of plants. However, excess quantity of cupric fungicides on plants causes enzymatic changes and toxic effects. Thus, the current study was aimed to investigate the cytotoxicity and genotoxicity of copper oxychloride on Allium cepa root cells. The root growth, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage were assessed through root growth inhibition, A. cepa ana-telophase, and alkaline comet assays. Furthermore, molecular docking was performed to evaluate binding affinities of two copper oxychloride polymorphs (atacamite and paratacamite) on DNA. In root growth inhibition test, onion root length was statistically significantly decreased by changing the copper oxychloride concentration from lower (2.64±0.11 cm) to higher (0.92±0.12 cm). Concentration- and time-dependent decrease in MI was observed whereas increase in CAs such as disturbed ana-telophase, chromosome laggards, stickiness, anaphase bridges, and DNA damage were caused by the copper oxychloride on A. cepa root cells. Molecular docking results revealed that the two main polymorphs of copper oxychloride (atacamite and paratacamite) bind selectively to G and C nucleotides on the B-DNA structure. It is concluded that the atacamite- and paratacamite-induced DNA damage may be through minor groove recognition and intercalation. Findings of the current study revealed the cytotoxic and genotoxic effects of copper oxychloride on A. cepa root cells. However, further studies should be carried out at the molecular level to reveal the cyto-genotoxic mechanism of action of copper oxychloride in detail.

The effluent of the ornamental rock industry is characterized by presenting great concentrations of total solids, high contents of iron, and elevated pH, all responsible for the contamination of the superficial and ground waters, destruction of the soil, the vegetation, and the silting of the rivers. The purpose of this study is to assess the cytotoxic and genotoxic effects and the anatomical changes caused by the effluents arising from the ornamental rock polishing industry in root apex cells of Allium cepa L. (Amaryllidaceae). The samples of the effluent were collected in a polishing industry located in Nova Venécia, State of Espírito Santo, and were analyzed by mass spectrometry and atomic emission. Bulbs of A. cepa were exposed to the effluent at 12.5, 25, 37.5, 50, 75, and 100 % concentrations (residue in raw form) (v/v) for a period of 20 days. For the positive control, metilmethanesulfonate (MMS) at 4 × 10⁻⁴-M concentration was used, and distilled water was used for the negative control. The experiment was assessed taking into consideration the following parameters: mitotic index, frequency of chromosomal and nuclear abnormalities in the root apical meristem, and root anatomy. The mitotic index suffered a decrease proportional to the increase in the concentration of effluent. All the concentrations of the effluent led to chromosomal and nuclear abnormalities being stickiness and nuclear shoots the most frequent. The root apex evidenced changes that reflected on the decrease of the percentage area of the protoderm and the fundamental meristem and the increase in the areas of the cap and quiescent center. The symptoms of toxicity are related to the high frequency of cell in cellular death process observed in the roots exposed to the higher concentrations and to the decrease in the mitotic index of the apical root meristem.

Due to the accelerating use of manufactured nanomaterials, more research is needed to define their impact on plants. The present investigation aimed at evaluating the effect of different levels (0.0, 10, 25, 50, and 100 mg/L) of ZnO nanoparticles (NPs) on Vicia faba during seed germination and seedling establishment. Additionally, V. faba root meristems were used as a model to monitor the cytotoxic and genotoxic effects resulting from exposure to ZnO NPs. The influence of ZnO NPs on three isoenzyme systems, peroxidase, α, and β esterase, was also evaluated using native-PAGE. Our results showed that lower concentrations of ZnO NPs (especially 10 and 25 mg/L) enhanced seed germination and improved seedling growth, while higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. Cytological investigations of ZnO NPs-treated V. faba root cells denoted the clastogenic and aneugenic nature of ZnO NPs. Differential increase in mitotic index and significant alterations in cell cycle were observed upon exposure to ZnO NPs. High concentrations of ZnO NPs markedly induced chromosomal aberration, micronuclei, and vacuolated nuclei formation. Chromosomal breakage, chromosomal bridges, ring chromosomes, laggard chromosomes, and stickiness were also observed at a higher rate. The PAGE analysis showed that ZnO NPs treatments altered the expression patterns of all studied enzyme systems. Collectively, results from this work will help to further understand the phytotoxic effects of nanomaterials.

The present study assessed the phytotoxic and cytotoxic potential of the essential oil (EO) extracted from aboveground parts of Mentha longifolia (L.) Huds. Gas chromatography–mass spectrometry revealed 39 compounds constituting 99.67% of the EO. The EO was rich in monoterpenoids (mostly oxygenated monoterpenes), which accounted for 89.28% of the oil. The major components in EO were monoterpene ketones such as piperitone oxide (53.83%) and piperitenone oxide (11.52%), followed by thymol (5.80%), and (E)-caryophyllene (4.88%). The phytotoxic activities of EO were estimated against Cyperus rotundus, Echinochloa crus-galli, and Oryza sativa (rice) through pre- and post-emergence assays at concentrations ranging from 10 to 250 μg/ml and 0.5–5%, respectively. In pre-emergence assay, the phytotoxic effect of EO was most pronounced on C. rotundus, thereby significantly affecting percent germination, plantlet growth, and chlorophyll content. On the contrary, the impact was comparatively lesser on rice, with ~ 40% germination in response to 250 μg/ml of EO treatment. In the post-emergence assay, the spray treatment of EO caused a loss of chlorophyll and wilting in test plants, and subsequently affected the growth of plants, even leading to death in some cases. The cytotoxic activity of EO (at 2.5–50 μg/ml) was studied in meristem cells in onion (Allium cepa L.) root tips. EO exposure to the onion roots induced various chromosomal aberrations such as chromosomal bridges, c-mitosis, stickiness, vagrant chromosomes, etc., and negatively affected the mitotic index. At 50 μg/ml, EO treatment triggered the complete death of roots. The study concludes that M. longifolia EO has phytotoxic activities due to the mito-depressive effect, along with other physiological effects on target plants. Therefore, EO of M. longifolia could be developed into a novel bioherbicide for sustainable management of weeds in agricultural systems.

2-Chlorophenol (2-CP), a class of chlorinated organic pollutants like other chlorophenols, is used as intermediate in the synthesis of the higher chlorinated congeners, certain dyes, preservatives, herbicides, fungicides, and plastics. In this study, cytotoxic and genotoxic effects of 2-CP were investigated on the root meristem cells of Allium cepa for its effects on root growth, mitotic index (MI), mitotic phases, chromosomal abnormalities (CAs), and DNA damage by using Allium anaphase-telophase and Comet assays. EC₅₀ of 2-CP value was determined as approximately 25 mg/L by Allium root growth inhibition test. Three concentrations of 2-CP (12.5, 25, and 50 mg/L), distilled water (negative control), and methyl methane sulfonate (MMS, 10 mg/L, positive control) were applied to onion stem cells under different exposure periods (24, 48, 72, and 96 h). All the applied doses of 2-CP slightly decreased MIs. 2-CP induced total CAs such as disturbed anaphase-telophase, chromosome laggards, stickiness, and bridges and also DNA damage at significant levels. These results demonstrate that 2-CP has genotoxic effects in A. cepa root meristematic cells.

Conditions of environmental stress are known to lead genetic and epigenetic variability in plants. DNA methylation is one of the important epigenetic mechanisms and plays a critical role in epigenetic control of gene expression. Thus, the aim of the study was to investigate the alteration of genome methylation induced by zinc stress by using coupled restriction enzyme digestion-random amplification (CRED-RA) technique in maize (Zea mays L.) seedlings. In addition, to determine the effect of zinc on mitotic activity and phytohormone level, high-pressure liquid chromatography (HPLC) and mitotic index analysis were utilized. According to the results, mitotic index decreased in all concentrations of zinc except for 5 mM dose and chromosome aberrations such as c-mitosis, stickiness, and anaphase bridges were determined. It was also observed that increasing concentrations of zinc caused an increase in methylation patterns and decrease in gibberellic acid (GA), zeatin (ZA), and indole acetic acid (IAA) levels in contrast to abscisic acid (ABA) level. Especially increasing of ABA levels under zinc stress may be a part of the defense system against heavy metal accumulation in plants.