According to the research results, bioaccumulation of lead element was determined in tomato plant bodies

Аннотация

According to the research results, bioaccumulation of lead element was determined in tomato plant bodies. The highest accumulation in tomato roots was observed in the 5-fold contaminated version and was 4.44 mg/kg, 8.88 times higher than the MPC. 1.16 mg/kg, 2.31 times higher than MPC, 1.38 mg/kg, 2.77 times higher than MPC, 3.18 mg/kg, 6.35 times higher than MPC, with 5 times contamination in stem. When tomatoes are grown in soil contaminated with lead, the mass of the root and fruit increases compared to the stem and leaves, resulting in a decrease in the fruit's suitability for consumption. Key words: soil, mineral fertilizer, lead, tomato. Introduction. Lead (Pb) is one of the heavy metals that cause serious environmental problems in soil and plants. Lead remains in the soil for a long time and damages ecological stability. It can fall to the ground in the following ways: Fall from the atmosphere (waste from factories, cars). Industrial waste (batteries, paints, metal smelting processes). Through pesticides and fertilizers. The mobility of lead in soil is low, and it usually binds to clay minerals and organic matter. As a result, the biological activity of the soil decreases, the composition of microorganisms deteriorates, and the fertility of the soil decreases. The physico-chemical characteristics of the soil deteriorate, for example, the pH balance of the soil may change. Lead is absorbed by the root system of plants through the soil and has a negative effect on their growth and development. The process of photosynthesis is disturbed, because Pb prevents the production of chlorophyll. The growth and development of plants slows down, deformations are observed in the growth of roots and leaves. As a result, metabolic processes slow down. Transport of water and nutrients deteriorates, absorption through the roots decreases. Review of literature. The concentration of lead (Pb) observed in tomatoes was higher than that of similar food products in Great Britain, where 0.02 mg/kg was found for each crop [4; 391–403]. The concentration of Pb and Cr observed in tomatoes was high and exceeded the maximum allowed concentration (0.30 34 ACADEMIC RESEARCH IN MODERN SCIENCE International scientific-online conference mg/kg) in fresh vegetables established by some countries such as Hungary [5; 530–532]. As a result of the experiments conducted by Nitu Mihaela and others, as a result of the accumulation of three heavy metals in tomato fruit, the highest concentration of alcohol was observed, followed by copper and the least lead, and it was concluded that all concentrations of the mixture of copper, lead and alcohol showed a low risk for human consumption [3]. The concentration of lead (Pb) is associated with automobile exhaust gases as the main source of heavy metal contamination of roadside tomatoes [2; S. 1- 11]. Research results. Researches were conducted on the basis of field and laboratory experiments, the field experiment was carried out in the Khromiddin Nurillaevich farm field, located in the Kislyk massif, Kitob district, in 2 options (option 1 without control fertilizer, option 2 with fertilizer N160P120K80), and laboratory experiments were conducted at the Institute of Soil Science and Agrochemical Research. Laboratory experiments were carried out on field soils in two variants (variant 1 without control fertilizer, variant 2 with fertilizer N160P120K80) and artificially polluted soils of the institute courtyard (variant 1 without control fertilizer, variant 2 with fertilizer N160P120K80, variant 3 with 3-fold contamination, variant 4 with 5-fold polluted, option 5 complex with seven types of heavy metal is polluted 3 times, option 6 complex with seven types of heavy metal is polluted 5 times) was carried out in options. The permissible limit of lead in soil is 6 mg/kg, and the permissible limit in tomato plant bodies is 0.5 mg/kg [1]. Bioaccumulation of lead (Pb) ions in tomato roots was observed in all variants. All of the selected typical gray soils have lead (Pb) content above the MPC (Figure 1). During the experiments, in the tomato roots of the control version, their amount decreased to 0.85 mg/kg in the first year of the experiment, and to 0.75 and 0.52 mg/kg in the other years, and an increase of 1.71-1.50-1.04 times was observed from the MPC. In option 2, where mineral fertilizers were given, in tomato, from 1.19 mg/kg in 2021 to 0.66 mg/kg in 2023, an increase of 2.38-1.33 times the MPC was observed. Bioaccumulation of 0.62-0.55 and 0.63-0.71 mg/kg was observed in tomato roots in soils selected for laboratory experiments from the Kitab district and in the 7-8 variants taken from the experimental field under field conditions. 35 ACADEMIC RESEARCH IN MODERN SCIENCE International scientific-online conference 8 8 ,8 9,00 8 7 8,00 ,74 2 ,7 7,00 3 1 8 6,00 2 6 ,5 ,5 6 1 2 3 4 5 , , , , , 0 0 0 0 0 0 0 0 0 0 5 8 ,0 1 7 ,1 5 7 ,0 0 5 ,1 2 5 ,0 4 0 ,1 9 1 ,1 8 3 ,2 1 1 ,1 3 2 ,2 6 6 ,0 3 3 ,1 9 9 ,1 7 9