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2UDK: 633. 581.1:581.5.
SPECTROPHOTOMETRIC ANALYSIS OF PHOTOSYNTHETIC PIGMENTS IN AFRO-ASIAN COTTON SPECIES
Sh.Sh.Normurodov, Kh.A.Muminov
Faculty of Natural Sciences, Chirchik State Pedagogical University, Chirchik, Uzbekistan * Corresponding author email: [email protected]
Abstract. This article presents the light absorption analysis of the concentration of chlorophyll "a", chlorophyll "b", total chlorophyll and carotenoid pigments in the samples belonging to the subspecies G.herbaceum L. and G.arboreum L. When the light absorption was analyzed for the concentration of chlorophyll "a", chlorophyll "b", total chlorophyll and carotenoid pigments in the samples belonging to the subspecies of G.herbaceum L. and G.arboreum L., during the flowering period, G.herbaceum subsp. pseudoarboreum f. harga, G.arboreum subsp. neglectum f. sanguineum samples showed the low levels of chlorophyll "a", chlorophyll "b", total chlorophyll and carotenoid pigments, while G.herbaceum subsp. frutescens, G.arboreum subsp. obtusifolium var. indicum showed the high values in the samples. These high indicators have a positive effect on the process of photosynthesis in cotton leaves and lead to an increase in productivity.
Keywords: cotton, subspecies, photosynthetic pigment, spectrophotometric analysis, light absorption, chlorophyll "a", chlorophyll "b", total chlorophyll, carotenoid.
СПЕКТРОФОТОМЕТРИЧЕСКИЙ АНАЛИЗ ФОТОСИНТЕТИЧЕСКИХ
ПИГМЕНТОВ В АФРО-АЗИАТИЧЕСКИЙ ВИДОВ ХЛОПЧАТНИКА
Ш.Ш.Нормуродов, Х.А.Муминов
Факультет естественных наук, Чирчикский государственный педагогический
университет, Чирчик, Узбекистан Соответствующий автор email: [email protected]
Аннотация. В данной статье представлен анализ поглощения света на концентрацию хлорофилла "а", хлорофилла "Ь", общего хлорофилла и каротиноидных пигментов в образцах, принадлежащих к подвидам G.herbaceum L. и G.arboreum L. При анализе поглощения света на концентрацию хлорофилла "а", хлорофилла "Ь", общего хлорофилла и каротиноидных пигментов в образцах, принадлежащих к подвидам G.herbaceum L. и G.arboreum L., в период цветения образцы G.herbaceum subsp. pseudoarboreum f. harga, G.arboreum subsp. neglectum f. sanguineum показали низкие уровни хлорофилла "а", хлорофилла "Ь", общего хлорофилла и каротиноидных пигментов, в то время как G.herbaceum subsp .frutescens, G.arboreum subsp. obtusifolium var. indicum показали высокие значения в образцах. Эти высокие показатели
положительно влияют на процесс фотосинтеза в листьях хлопчатника и приводят к повышению урожайности.
Ключевые слова: хлопок, подвиды, фотосинтетический пигмент, спектрофотометрический анализ, светопоглощение, хлорофилл "а", хлорофилл "Ь", общий хлорофилл, каротиноид.
Introduction
Humanity used cotton fiber even in primitive society. In general, people must have used cotton fiber for 15-30 thousand years or even 0 cultivation in China started somewhat late compared to India. According to historical data, cotton cultivation existed in Iran and Arabia in the 6th century BC, and in Egypt in the 7th century. There is enough information that cotton was grown in the territory of Central Asia 2200-2400 years ago and the fiber was widely used at the beginning of our era. The northern border of the cotton growing area on the earth is 38-44° degrees north latitude and the southern border corresponds to 35° degrees south latitude. At this latitude, cotton is grown on an area of more than 32-33 million hectares in more than 90 countries, and 19-20 million tons of fiber are produced annually. China, the United States, India, Pakistan, Uzbekistan, Brazil, Turkey, Egypt, and Mexico are the countries that grow the most cotton in the world, accounting for more than 80% of the total cotton grown in the world [4, 8].
Cotton flower is bisexual; the organs are arranged in five circles. The structure has three large bulwarks outside; then the calyx; in the calyx a
leaf of petal is connected to each other; there is a paternity ring (androecium) inside the petal. The calyx consists of a tube of paternal threads, many paternal pollinators are located on the surface: in the center of the flower there is a maternal, which consists of a pistil and a mouth. The cotton flower has a separate nectarine [6, 7, 9].
It is known that photosynthesis takes place in the leaves of green plants. The cellular structure of the leaf is adapted to photosynthesis, respiration and transpiration. Its upper and lower sides are covered with skin. The covering tissue, the epidermis, is composed of a series of dense cells that transmit the light well. In the middle of the bark there are leaf mouths and they are mostly under the leaf plate. Gas exchange takes place through mouths. Rod-shaped, densely located forming cells (mesophyll) are located under the upper skin. They have a lot of chloroplasts. At the base of these, round cells are scattered and form cavities, which participate in the exchange of gases and water [1-2].
There are mainly three types of pigments in the chloroplasts of plant leaves: 1) chlorophylls; 2) carotenoids; 3) phycobilins. Chlorophylls were isolated in 1817 by the French chemists Pelte and
Cavantu as a free pigment from green leaves. Chlorophyll "a" of the German scientist Wilstetter chlorophyll C55H7205H4Mg; studied the chemical composition of chlorophyll "b" C55H7o06H4Mg:
Chlorophyll "a" is dark green, while chlorophyll "b" is yellow-green. The amount of chlorophyll "a" in green leaves is 20-40% more than the amount of chlorophyll "b". Chlorophylls are bound to proteins in the cell, so they form a colloidal solution with the aqueous extract of the leaf. Acetone and alcohol easily separate chlorophyll from the leaf. The chlorophyll-protein complex is strong and performs its function without breaking even under various adverse conditions. Chlorophyll "a" absorbs 660-663 nm from the red spectrum, 428-430 nm from the blue spectrum, and chlorophyll "b" absorbs 642-644 nm from the red spectrum and 452-455 nm from the blue spectrum. They do not absorb green and infrared light. In the spectroscope, the light absorbed by chlorophyll appears dark. One of the optical properties of chlorophyll is fluorescence, that is, it also has the property of reflecting absorbed light. Chlorophyll appears red in the reflected light.
Chlorophyll is produced in the plants grown in the light, but not in the plants grown in the dark. Therefore, the grasses grown in the dark are yellow or colorless and are called etiolated plants.
Etiolated plants turn green when exposed to the light.
Organic compounds formed in the photosynthesis are the main source of the life for all living organisms. In photosynthesis, oxygen, necessary for the respiration of all living organisms, is released into the atmosphere [1, 10, 11]. Photosynthetic pigments are the substances with very diverse chemical structures; they are porphyrin pigments chlorophyll "a", "b" and "c", carotenoids [5].
Object and methods of research
In the research, G.herbaceum L. ruderal subsp. pseudoarboreum, subsp. pseudoarboreum f. harga; tropical subsp. frutescens; and G.arboreum L. wild subsp. obtusifolium var. indicum; ruderal subsp. perenne; tropical subsp. neglectum, subsp. neglectum f. sanguineum, subsp. nanking (white fiber) forms were used as the primary source [4].
To carry out the research, the amounts of chlorophyll "a", chlorophyll "b" and carotenoids in plant leaves were determined. In this case, the samples were taken from the 3-4 leaves, counting from the growing point of the plant in the field conditions. 50 milligrams of each leaf was placed in a test tube. Each leaf sample was homogenized in 5 ml of 95% ethyl alcohol solution [3]. The homogenate was centrifuged at a speed of 5000 for 12 minutes. The amounts of chlorophyll "a", chlorophyll "b" and carotenoids in the resulting extract were determined by an Agilent Cary 60 UV-
82
Vis spectrophotometer at 664, 649 and 470 nm. Based on this indicator, the amounts of chlorophyll "a", chlorophyll "b" and carotenoids in plant leaves were calculated using the following equation [8].
Chlorophyll-"a" [mg/g] =13.36A664-5.19* A649
Chlorophyll-"b" [mg/g] =27.43A649-8.12* A664
Carotenoid [mg/g] = (1000A470 -2.13*Xlo "a"- 97.63 Xlo "b")/209
F (Mg/g)=(V*S)/P.
Research results
According to the results of the research, the average amount of chlorophyll "a" in the representatives of
the species G.herbaceum L. and G.arboreum L. was 13.8-20.0 mg/g. It was observed that the average amount of chlorophyll "b" is 8.5-14.7 mg/g. The average amount of total chlorophyll was 20.1-34.8 mg/g. It was also shown that the carotenoid content of G.herbaceum L. and G.arboreum L. was on average 9.4-16.6 mg/g. The average amount of chlorophyll "a" in representatives of G.herbaceum L. species is 14.0-20.0 mg/g, and the highest index is subsp. frutescens subspecies, the average amount of chlorophyll "a" was 20.0 ± 0.01 mg/g, the coefficient of variation was 0.09%. The low indicator 14.0 ± 0.01 mg/g was observed in the sample of subsp. pseudoarboreum f. harga, and its coefficient of variation was 0.12% (Table 1).
Table 1
The analysis of chlorophyll "a", chlorophyll "b" and carotenoids in the budding
Chlorophyll content (mg/g) Carotenoid content (mg/g)
Chlorophyll "a" V% Chlorophyll" ß" V% Total chlorophyll V% x±Sx V%
G.herbaceum subsp. pseudoarboreum
16.1 ± 0.02 0.27 11.5 ±0.05 0.76 27.7 ±0.06 0.36 13.7 ±0.03 0.43
G.herbaceum subsp. pseudoarboreum f. harga
14.0 ± 0.01 0.12 10.9 ± 0.02 0.35 25.0 ± 0.03 0.21 11.8 ±0.01 0.19
G.herbaceum subsp .frutescens
20.0 ± 0.01 0.09 14.7 ±0.02 0.20 34.8 ± 0.01 0.05 16.6 ± 0.01 0.15
G.arboreum subsp. obtusifolium var. indicum
15.5 ± 0.05 0.57 13.2 ±0.11 1.44 28.5 ± 0.16 0.96 13.7 ±0.07 0.90
G.arboreum subsp. perenne
15.4 ± 0.05 0.55 12.9 ± 0.07 0.91 28.3 ± 0.11 0.68 13.4 ± 0.06 0.74
G.arboreum subsp. neglectum
14.3 ± 0.03 0.32 12.6 ± 0.04 0.55 26.9 ± 0.06 0.36 12.7 ±0.03 0.35
G.arboreum subsp. neglectum f. sanguineum
13.8 ± 0.05 0.62 8.5 ± 0.02 0.32 20.1 ± 0.02 0.16 9.4 ± 0.01 0.10
G.arboreum subsp. nanking (white fiber)
14.3 ± 0.03 0.34 11.5 ± 0.04 0.58 25.8 ± 0.07 0.44 12.2 ± 0.02 0.27
The average amount of chlorophyll "a" in the representatives of G.arboreum L. is 13.8-15.5 mg/g, and the highest index is subsp. obtusifolium var. indicum subspecies, the average amount of chlorophyll "a" was 15.5 ± 0.05 mg/g, the coefficient of variation was 0.57%. The low indicator is subsp. neglectum f. sanguineum sample was 13.8 ± 0.05 mg/g, and its coefficient of variation was 0.62%.
The average amount of chlorophyll "b" in the representatives of G.herbaceum L. is 10.9-14.7 mg/g, and the highest indicator is subsp. frutescens subspecies, the average amount of chlorophyll "b" was 14.7 ± 0.02 mg/g, the coefficient of variation was 0.20%. The low indicator is subsp. pseudoarboreum f. harga 10.9 ± 0.02 mg/g was observed in the sample, and its coefficient of variation was 0.35%.
The amount of chlorophyll "b" in the representatives of G.arboreum L. is 8.5-13.2 mg/g on average, and the highest index is subsp. obtusifolium var. indicum subspecies, the average amount of chlorophyll "b" was 13.2 ± 0.11 mg/g, the coefficient of variation was 1.44%. The low indicator is subsp. neglectum f. sanguineum sample was 8.5 ± 0.02 mg/g, and its coefficient of variation was 0.32%.
The total amount of chlorophyll in the representatives belonging to the species G.herbaceum L. is on average
25.0-34.8 mg/g, and the highest indicator is subsp. frutescens subspecies, the average total chlorophyll content was 34.8 ± 0.01 mg/g, the coefficient of variation was 0.05%. The low indicator is subsp. pseudo-doorboreum f. 25.0 ± 0.03 mg/g was observed in the harga sample, and its coefficient of variation was 0.21%.
The total amount of chlorophyll in the representatives of G.arboreum L. is
20.1-28.5 mg/g on average, and the highest indicator is subsp. obtusifolium var. indicum subspecies, the average total chlorophyll content was 28.5 ± 0.16 mg/g, the coefficient of variation was 0.96%. The low indicator is subsp. neglectum f. sanguineum sample was 20.1 ± 0.02 mg/g, and its coefficient of variation was 0.16%.
The average carotenoid content of G.herbaceum L. is 11.8-16.6 mg/g, and the highest value is found in subsp. frutescens subspecies, the average carotenoid content was 16.6 ± 0.01 mg/g, the coefficient of variation was 0.15%. The low indicator is subsp. pseudoarboreum f. harga 11.8 ± 0.01 mg/g was observed in the sample, and its coefficient of variation was 0.19%.
The average carotenoid content of G.arboreum L. is 9.4-13.7 mg/g, and the highest value is found in subsp. obtusifolium var. indicum subspecies, the average carotenoid content was 13.7 ± 0.07 mg/g, the coefficient of variation was 0.90%. The low indicator is subsp. neglectum f. sanguineum sample was 9.4 ± 0.01 mg/g, and its coefficient of variation was 0.10%.
Conclusion
When the light absorption was analyzed for the concentration of chlorophyll "a", chlorophyll "b", the total chlorophyll and carotenoid pigments in References
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