Effect of benzo(a)pyrene on the morphometric characteristics of tomato plants (Solanum Lycopersicum) under the conditions of a model experiment

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds of the benzene series, which differ in the number of benzene rings. Due to their carcinogenic and mutagenic properties, they have been included in the list of priority pollutants by the US Environmental Protection Agency and the European Community. Among all PAHs, there is a mutagen and a carcinogen of the 1st hazard class - benzo (a) pyrene (BaP), which is most often used as a marker of environmental pollution with PAHs. Up to 95% of the emitted pollutants are accumulated by the soil in various chemical forms. Since plants are inextricably linked with the soil, it becomes necessary to study the behaviour of PAHs in the formed plant-soil system. The aim of the study was to evaluate the effect of BaP on the morphometric characteristics of tomato plants under the conditions of a model experiment.

The studies were carried out under the conditions of a vegetation experiment. The soil was sifted through a sieve with a diameter of 1 mm and placed in 2 kg pots in 4 L pots. A BaP solution in acetonitrile was added to the soil surface based on the creation of a pollutant concentration in the soil of 400 and 1200 ng / g, which corresponds to 20 and 60 MPC of BaP. The original uncontaminated soil was used as a control. The soil was sown with tomato plants (Solánum lycopérsicum) of the early maturing variety White filling 241. The experiment was repeated three times. We analyzed such morphometric parameters as root length and stem height, as well as dry biomass of plants.

The root length and stem height in the control sample is set at 32 and 63 cm, respectively. In the samples contaminated with 20 MPC BaP, these indicators were lower, so the root length was 19 cm, and the stem height was 40 cm. In the samples with the introduction of 60 MPC BaP, the root length decreased to 14 cm and the stem height - to 27 cm.

In the control sample, the dry biomass of the roots was 10.3 g and the vegetative part was 80.2 g. When 20 MPC BaP was applied, these parameters decreased to 6.8 g of roots and 67 g of the vegetative part. In the samples with the introduction of 60 MPC BaP, the biomass of the roots was 3.1 g and the biomass of the vegetative part was 44 g, which is lower than the control values.

Thus, a decrease in the length of roots and the height of plant stems, as well as a decrease in their biomass relative to the control values, was established, which indicates that tomato plants are quite susceptible to soil pollution with BaP.

The research was financially supported by the Ministry of Science and Higher Education of the Russian Federation project on the development of the Young Scientist Laboratory (no. LabNOTs-21-01AB).