Phytotoxicity of Bisphenol A to Allium cepa Root Cells Is Mediated through Growth Hormone Gibberellic Acid and Reactive Oxygen Species

Phytotoxicity of trihalomethanes and trichloroacetic acid on Vigna radiata and Allium cepa plant models

Disinfection by-products (DBPs) are a concern due to their presence in chlorinated wastewater, sewage treatment plant discharge, and surface water, and their potential for environmental toxicity. Despite some attention to their ecotoxicity, little is known about the phytotoxicity of DBPs. This study aimed to evaluate the individual and combined phytotoxicity of four trihalomethanes (THMs: trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM) and their mixture (THM4)), and trichloroacetic acid (TCAA) using genotoxic and cytotoxic assays. The analysis included seed germination tests using Vigna radiata and root growth tests, mitosis studies, oxidative stress response, chromosomal aberrations (CA), and DNA laddering using Allium cepa. The results showed a progressive increase in root growth inhibition for both plant species as the concentration of DBPs increased. High concentrations of mixtures of four THMs resulted in significant (p < 0.05) antagonistic interactions. The effective concentration (EC50) value for V. radiata was 5655, 3145, 2690, 1465, 3570, and 725 mg/L for TCM, BDCM, DBCM, TBM, THM4, and TCAA, respectively. For A. cepa, the EC50 for the same contaminants was 700, 400, 350, 250, 450, and 105 mg/L, respectively. DBP cytotoxicity was observed through CAs, including C-metaphase, unseparated anaphase, lagging chromosome, sticky metaphase, and bridging. Mitotic depression (MD) increased with dose, reaching up to 54.4% for TCAA (50-500 mg/L). The electrophoresis assay showed DNA fragmentation and shearing, suggesting genotoxicity for some DBPs. The order of phytotoxicity for the tested DBPs was TCAA > TBM > DBCM > BDCM > THM4 > TCM. These findings underscore the need for further research on the phytotoxicity of DBPs, especially given their common use in agricultural practices such as irrigation and the use of sludge as manure.

Bioaccumulation Capacity of Onion (Allium cepa L.) Tested with Heavy Metals in Biofortification

On a worldwide scale, A. cepa is among the most commonly consumed vegetables. In Europe, the leading onion producers are Russia, the Netherlands, Spain, Poland and Germany. In this study, the bioaccumulation of heavy metals (Cr, Cu, Zn, Ni, Fe, Mn, Co, Sr, Cd and Pb) by Allium cepa L. plants was followed under hydroponic conditions. The heavy metals were applied at six concentrations (0, 25, 50, 100, 200 and 400 mg L-1) over three weeks. The quantitative analysis of selected heavy metals in plant tissues (bulbs, roots and assimilation leaves) was performed using atomic absorption spectrometry with flame atomization (F-AAS). The accumulation of metal ions was strongly dependent on their concentrations in the solution and the analyzed parts of plants. The highest accumulation of metal ions was confirmed for the roots and ranged from 8.48 to 5912.34 µg g-1 DW (dry weight). All parts of A. cepa were characterized by the high accumulation of Mn2+. The lowest accumulation was confirmed for Co2+ in the roots, Pb2+ in the assimilation leaves and Cu2+ in the bulbs of onion. Moreover, the study showed that the highest concentrations of heavy metals decreased the growth of bulbs and even caused them to die off. In contrast, lower concentrations of some elements stimulated plant development.

The Essential Oil of Petroselinum crispum (Mill) Fuss Seeds from Peru: Phytotoxic Activity and In Silico Evaluation on the Target Enzyme of the Glyphosate Herbicide

Petroselinum crispum (Mill) Fuss is an aromatic plant belonging to the Apiaceae family and used in gastronomy as a spice. Several studies have been developed in leaves but studies are limited in seeds, especially the essential oils obtained from seeds. The aim of this study was to determine the phytochemical profile of the volatile compounds of this essential oil by gas-chromatography-mass spectrometry (GC-MS) in order to evaluate its phytotoxic activity on Lactuca sativa seeds and to carry out an in silico analysis on the target enzyme of the herbicide glyphosate 5-enolpyruvylshikimate 3-phosphate synthase (EPSP). The essential oil was obtained by steam distillation for two hours and then was injected into a GC-MS, the phytotoxic assay was carried out on Lactuca seeds and the in silico evaluation on the EPSP synthase focused on the volatile compounds similar to glyphosate, docking analysis, and molecular dynamics to establish the protein-ligand stability of the most active molecule. The chromatographic analysis revealed 47 compounds, predominated by three compounds with the most abundant percentage in the total content (1,3,8-ρ-menthatriene (22.59%); apiole (22.41%); and β-phellandrene (15.02%)). The phytotoxic activity demonstrated that the essential oil had a high activity at 5% against L. sativa seed germination, inhibition of root length, and hypocotyl length, which is comparable to 2% glyphosate. The molecular docking on EPSP synthase revealed that trans-p-menth-6-en-2,8-diol had a high affinity with the enzyme EPSP synthase and a better stability during the molecular dynamic. According to the results, the essential oil of P. crispum seeds presented a phytotoxic activity and might be useful as a bioherbicide agent against weeds.