Analysis of chlorophyll “a”, “b”, and carotenoids in leaves of oriental maple, biota, common oak, and chestnut trees resistant to harmful substances emitted by motor vehicles in Tashkent city

2 Methods 
Each leaf was diluted to 50 milligrams to determine the amount of chlorophyll "a", 
chlorophyll "b" and carotenoids in plant leaves. Each leaf specimen was homogenized in 5 
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, 02032 (2023)
CONMECHYDRO - 2023
https://doi.org/10.1051/e3sconf/202340102032
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to 100% acetone solution. The homogenate was centrifuged at 10,000 mph at a rate of 
5,000. Chlorophyll "a", chlorophyll "b", and carotenoid light absorption values were 
determined at 662, 645, and 470 nm (Agilent Cary 60 UV-Vis spectrophotometer). Based 
on this index, chlorophyll "a", chlorophyll "b" and carotenoid content in leaves of 
ornamental trees were calculated using the equation Lichtentaler and Wellburn (1985): 
Statistical analysis of experimentally obtained plant chlorophyll a and chlorophyll b and 
carotenoid levels was performed in EXCEL 2016, Stat View 5.0 by anova. 
One of the main environmental problems of Tashkent city is the negative impact on the 
environment of various harmful gases emitted by vehicles. More than 70 percent of air 
pollution in Tashkent is caused by various gases emitted by motor vehicles. As a result of 
the growth of the population in Tashkent and the expansion of the city territory, the number 
of motor vehicles in the city is also increasing. As of January 1, 2022, motor vehicles 
belonging to individuals in our Republic totaled 3.6 million units, which are 10.6% more 
than last year's figures. Of these, the number of motor vehicles belonging to the residents of 
Tashkent city is more than 450 thousand, and on average, more than 23 thousand motor 
transport vehicles from the region enter the city and move on the city streets. 60% of motor 
vehicles in the capital run on gasoline and diesel, and 40% run on gas. 
Table 1.
Classification of motor vehicles moving in Tashkent by types of fuel (2022 year) 
Total number of 
vehicles 
Gasoline 
Diesel 
Compressed 
gas 
Liquefied gas 
3.6 mln. 
piece 
911.0 
thousand 
piece 
135.3 
thousand 
piece 
2.3 mln. piece 
294.2 
thousand 
piece 
Fig. 1.
Process of nitrogen dioxide production during high-temperature combustion of 
various fuels (natural gas, gasoline) in car engines 
Effect on a person - reduces the normal function of the lungs and has an adverse effect on 
the respiratory system. As a solution to this problem, it is necessary to increase the number 
of green spaces in the city; that is, as a result of scientific principles, it is necessary to study 
the city's climatic and soil conditions. It is desirable to selectively plant and maintain tree 
species that are resistant to various gases emitted by motor vehicles in urban areas [13-18]. 
Planting and cultivating landscape trees can achieve enormous economic and social 
benefits. Because plants are designed to meet the natural and vital needs of the population, 
which plays an important role in human health, trees prevent various infectious diseases. 
Ionization of the air under the influence of needles and broad-leaved trees and shrubs from 
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, 02032 (2023)
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https://doi.org/10.1051/e3sconf/202340102032
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the types of decorative trees recommended based on scientific principles is of great 
importance for the health of the natural environment in cities. The level of air pollution is 
determined due to the effect of atmospheric air quality on the positive charge of light and 
heavy ions. For example, the number of light ions present in 1 cm3 of atmospheric air: - up 
to 2000-3000 in forests - up to 800 in urban parks - up to 200-400 in industrial zones - up to 
25-100 in densely populated buildings by influencing, it ensures the harmony of 
cardiovascular, respiratory and circulatory systems, strengthens brain activity, lowers the 
amount of sugar and phosphorus in the blood, improves mood, reduces headaches and 
fatigue, and ensures people live longer. This, in turn, increases the economic efficiency of 
citizens living and working in the area. The better a person's physiological and 
psychological condition is, the more effective he will be in his work [15-18]. Currently, 
satellite imagery monitoring of tree stands is also being conducted to study emissions and 
reduce damage. 
3 streets and 1 park with ornamental trees were selected as the research object of 
Tashkent city. These objects are Sergeli district along Nyi Sergeli Street, Ukhtapa district 
along Farkhod Street, Sheikhontohur district along Abdulla Qadiri (Ganga) Street, and 
Yunusabad district along the botanical garden. Experiments were conducted to determine 
the amount of pigment in the leaves of eastern sycamore, eastern biota, common oak, and 
chestnut trees planted on these objects.