Phenetic phytoindication and biotesting of soils in recreation zones of Tver city

Исследованы фенофонды ценопопуляций подорожника большого (Plantago major L.) и сныти обыкновенной (Aegopodium podagraria L.) в рекреационных зонах г. Твери с разным уровнем загрязнения почв тяжелыми металлами (ТМ). Параллельно проведено биотестирование почв модельных биотопов по параметрам развития семян тест-растений - горчицы белой (Sinapis alba L.), кресс-салата (Lepidium sativum L.), сорго черного (Sorghum nigrum L.) в соответствии с ГОСТ Р ИСО 18763-2019. По мере возрастания суммарной токсической нагрузки на биотопы среднее число фенов у сныти и подорожника снижается. Однако доля редких фенов у сныти возрастает, а у подорожника уменьшается. Общие показатели фенетического разнообразия (среднее число и доля редких фенов) у сныти коррелируют с суммарной токсической нагрузкой на почвы в большей степени, чем у подорожника. Параметры развития семян разных видов тест-растений неоднозначно отражают фитотоксичность почв. В большей степени с суммарным содержанием ТМ в почве коррелируют показатели всхожести семян и размеры корней проростков у горчицы. Данные по фитоиндикации биотопов на основе фенетических показателей ценопопуляций сныти и, в меньшей степени подорожника, в целом согласуются с результатами биотестирования почв. The phenofonds of Plantago major L. and Aegopodium podagraria L. cenopopulations in recreation zones of Tver with different levels of soil contamination with heavy metals (HM) were studied. In parallel, biotesting of soils of model biotopes was carried out according to the parameters of test plants seeds development - Sinapis alba L., Lepidium sativum L., Sorghum nigrum L. in accordance with ISO 18763:2016. With an increase in the total toxic load on biotopes, the average number of phenes in P. major and A. podagraria decreases. However, the share of rare phenes increases in A. podagraria, and decreases in P. major. The general indicators of phenetic diversity (average number and proportion of rare phenes) in A. podagraria correlate with the total toxic load on soils to a greater extent than in P. major. The development parameters of seeds of different species of test plants ambiguously reflect the phytotoxicity of soils. To a greater extent, the indicators of seed germination and the seedlings root size in S. alba correlate with the total content of HM in the soil. The data on the phytoindication of biotopes based on the phenetic indices of the cenopopulations of A. podagraria and, to a lesser extent, P. major, are generally consistent with the results of soil biotesting.

Phytotoxicity of Tires Evaluated in Simulated Conditions

Illegal dumps and landfills with disposed of tires are a fact of today, which should not be neglected as they represent a great ecological burden for the environment, affect the surrounding nature and disturb the landscape. This research was focused on testing the phytotoxicity of aqueous leachates from the fractions of tires in two sets of experiments—to simulate laboratory conditions (tire leaching in distilled water) and natural conditions (tire leaching in water from a recipient) using the Phytotoxkit testing kit (kit for the establishment of inhibition/stimulation effect on the root development) and the watercress test of phytotoxicity (biological method for the assessment of leachate phytotoxicity). Plants whose seeds were selected for the test were watercress (Lepidium sativum L.) and white mustard (Sinapis alba L.). The aqueous leachate was tested for 38 weeks. During the experiment, physical and chemical parameters were measured at intervals of 14 days by the testing instrument HACH TEST KIT: electric conductivity (EC), amount of dissolved oxygen (LDO) and pH. Results of root growth inhibition (IR) on the seeds of Lepidium sativum L. and Sinapis alba L. exhibited values ranging from 11.73% to 47.74% in the tested samples. Results of germination index (GI) on the seeds of Lepidium sativum L. exhibited values below 66% in the tested samples, which indicated the leachate phytotoxicity. In spite of the fact that similar studies are tackling the acute toxicity of leachates from tires (particularly to algae, embryos and animals), this research brings complementary information in testing the acute phytotoxicity of tire leachates to higher plants.

Reduction of heavy metal phytotoxicity using Rhodococcus-biosurfactants

The influence of heavy metals on the germination of crop seeds (Vicia sativa L., Sinapis alba L., and Avena sativa L.) in the presence of Rhodoccocus-biosurfactants was studied.

Evaluation of the Phytotoxicity of Leachate from a Municipal Solid Waste Landfill: The Case Study of Bukov Landfill

Municipal solid waste landfilling, landfilling process and landfill reclamation result in leachate, which may be dangerous to the environment. Municipal solid waste leachate phytotoxicity tests were performed using the toxicity test and a subchronic toxicity pot experiment by direct application of leachate to reference soil in 5, 25, and 50% concentration for a period of 28 days. White mustard (Sinapis alba L.) seeds were exposed to different leachate dilution. Leachate were collected monthly in 2018 in the period from April to September. Furthermore, pH, conductivity, and dissolved oxygen were measured. The inhibition results on Sinapis alba L. seeds in the tested leachate samples ranged from −18.02 to 39.03%. Lower concentration of leachate showed a stimulating effect (only for Sample 1 and Sample 2 at 5% concentration). It was found out that leachate taken at the landfill is phytotoxic. The results of measurements are based on rainfall which affects the quantity and quality of the leachate. The values of germinated seeds/growing plants from the subchronic toxicity pot experiment ranged from 80 to 104%; therefore, the leachate is considered phytotoxic. However, it was confirmed that leachate may be used for landfill irrigation.

Effect of Morus alba L. leaf extracts on seeds germination and the seedlings growth of Sinapis alba L. and Cucumis sativus L.

Plant growth and development can be modified, including modification by chemical processes that result from neighbouring plants. If interactions in the natural environment between one plant and another are of a chemical nature, then this phenomenon is called allelopathy. The aim of the study was to determine the effect of aqueous extracts of Morus alba L., at concentrations of 3%, 5% and 10%, on the germination and growth of Sinapis alba L. (mustard) and Cucumis sativus L. (cucumber). It was found that allelopathins contained in the extracts slowed the germination of both species. The highest, 10%, extracts significantly inhibited germination. It was found that with an increase in allelopathin concentration, there was a significant inhibition of the growth of underground and above-ground plant organs. A complete lack of growth was observed for mustard plants grown from seeds watered with extracts during germination for 48 hours. Compared to the control plants, a differences in the growth of fresh and dry mass in plants watered with extracts during the germination and growth phases were found. Depending on the timing of treatment and the type of organ tested, aqueous mulberry leaf extracts at lower concentrations had a positive effect on the growth and development of the analysed species. Extracts with a higher concentration of chemical compounds had a negative impact on both mustard and cucumber.

Behavior of Cd Accumulation in Sinapis alba L. in the Presence of Essential Elements (Ca, Mg, Fe, Zn, Mn, Cu, Ni)

Heavy metal toxicity in plants is well known due to their severe phytotoxic effects and also because of their capability to accumulate in vegetables. The use of aromatic plants in remediation techniques has increased in the context of environmental pollution issues, including metal soil contamination. Cadmium is knowed as a toxic and bio accumulative element provided by natural or anthropic sources. In this context, the paper presents a laboratory experimental study aiming to evaluate the accumulating and transfer behavior of Cd in the plant organs of Sinapis alba L. (white mustard) and in the presence of essential elements (Ca, Mg, Fe, Zn, Mn, Cu, Ni). The study involves a comparison between white mustard cultivated in unpolluted soil and in two Cd polluted soils at values above the alert (2.8 mg/Kg), respectively intervention threshold for soils with sensitive use (5.6 mg/kg) according to the legislation in force in Romania. While Cd accumulated predominantly in roots (TC values 1.46 and 2.22), its transfer to the stem and leaves was observed too, the TF values for the aerial part of the plant being greater than 1. Moreover, the study showed that certain elements (Zn, Ca, Mg, Mn) were found in higher concentrations in plants subjected to Cd pollution than in the control sample indicating antagonistic effects and Cd toxicity limiting. Other essential metals, such as Cu, Fe and Ni were found in lower concentrations in intoxicated plants compared to control plants. Their translocation from soil in plant organs could be reduced by the Cd toxicity. Contrariwise, the mobility of these elements from roots to leaves could support the tolerance effect of plants to Cd stress. The study allows us to consider that Sinapis alba L. aromatic plants are suitable for soil phytoremediation technologies used in Cd decontamination.