The color will change. Modern problems of science and education. Universal indicator paper

Humans and all animals (insects, inhabitants of the seas and oceans, even the simplest microorganisms) have vision of varying degrees of resolution, and in many cases color vision.

As a result of the interaction of light rays of a certain length (380–700 nm), corresponding to the visible part of the solar spectrum, with transparent and opaque objects containing inorganic and organic substances of a certain chemical structure (dyes and pigments) or objects with a strictly organized structure of nanoparticles (structural coloring) selective absorption of rays of a certain wavelength occurs and, accordingly, the remaining (less absorbed) rays are reflected (opaque object) or transmitted (transparent object). These rays enter the eye of an animal with color vision, onto biosensors and cause a chemical impulse corresponding to the energy of the quanta of light rays hitting the retina, and nervous system transmitted to a specific part of the brain responsible for visual perception, and there a feeling of a color picture of the surrounding world is formed.

In order for each of us to see the world as beautiful in all its diversity of colors, a combination of certain physical, chemical, biochemical, and physiological conditions that are met on our planet is necessary. Or maybe on some others?

• The presence in the solar spectrum of rays (visible part of the spectrum) reaching the Earth's surface with a wavelength of 380–700 nm. Not all rays of the solar spectrum reach the surface of the earth. So the ozone layer absorbs hard (high energy that kills living organisms) ultraviolet radiation (< 290 нм), благодаря чему на планете Земля существует жизнь.
• Nature, and then man, created many substances and materials, thanks to their chemical structure and physical structure capable of selectively absorbing rays of the visible part of the spectrum. We call such substances and materials colored and colored.
• The evolution (many millions of years) of living matter has endowed living beings with biosensors (“biospectrophotometers”) - vision, capable of selectively responding to quanta of visible rays, a nervous system and brain structure (higher animals), transforming photoimpulses into biochemical ones, which create a color picture in our brain.

Traditionally, for a long time (many thousands of years), imitating nature (in the daytime, almost everything is colored, colored, all the colors of the rainbow), learned to produce colored and dyed materials, and succeeded in many ways. In the middle of the century before last (1854), William Perkin, a 3rd year student at King's College (England, London), synthesized the first synthetic dye - mauvais. This began the formation of the aniline dye industry (the first industrial Revolution). Before this, for many thousands of years, people used natural colored substances (dyes, pigments).

But in nature, dyes and pigments not only perform a very important and multi-purpose function of coloring natural objects, but also a number of other tasks: protection from harmful microorganisms (in plants), converting light energy into biochemical energy (chlorophyll, rhodopsin), etc.

Chromium dyes and coloring (dyes, pigments, nanostructures)

Once again, it should be emphasized that there are two mechanisms for the appearance of color:

1. Due to the presence in the substrate of colored (dyes, pigments) substances of a certain chemical structure;
2. Due to physical structure ordered nanolayers, nanocells, nanoparticles (molecules, supramolecules, crystals, liquid crystals), on which the phenomena of interference, diffraction, multiple reflection, refraction, etc. occur.

For the coloration of the first and second mechanisms of its formation, chromium may be observed. What is chromium, which an ordinary person encounters quite often, and a color chemist not only constantly encounters this phenomenon, but is also forced to fight it, or in any case is obliged to take it into account, and even better, use it (this remains to be discussed).

Chromia- This reversible change in color (color, shade, intensity) under the influence of some external physical, chemical and physico-chemical impulses.

Chromia should not be confused with irreversible changes when destruction of the colored system occurs. These irreversible changes in color are scored as color stability to various factors.

The following types of chromium are distinguished depending on which factor or impulse causes a reversible color change: photo-, thermo-, chemo-, solvato-, mechano-, electro-, magnetochromia.

Photochromia(reversible change in color or light transmission) - under the influence of electromagnetic radiation, including natural (sunlight) or artificial radiation sources. Color chemists encounter this negative phenomenon when they use dyes with a high tendency to photochromia. Products made from material painted with such dyes when exposed to bright sunlight noticeably changes its color shade, but it is reversible, and in the dark (in a closet, at night) the color returns to its original color. However, this phenomenon is hysteretic and after a certain number of cycles the color loses its intensity (photodestruction). As a rule, dyes prone to photochromia do not have high enough light fastness.

The tendency of dyes to photochromia is assessed according to the ISO standard.

Thermochromia– a reversible change in color (color, shade) when a painted object is heated. We observe this phenomenon in everyday life when we iron dyed textiles; Thermochromia is especially pronounced if the products are moistened before ironing. After a certain time after cooling, the color returns to its original color. Each dye has a different tendency to thermochromia; on fabrics made of synthetic fibers it is more pronounced.

Chemochromia– reversible color change under the action of chemical reagents (change in pH, action of oxidizing agents and reducing agents).

Which chemist did not use color reactions of indicator dyes to determine the pH of a medium? All indicator dyes are chemochromes.

The technology of coloring with vat pigments (usually called dyes) is based on reversible redox processes: first, the conversion of an insoluble colored pigment into a weaker colored leuco form using reducing agents in an alkaline medium, and then again into a colored pigment by oxidation.

Solvatochromia– reversible color change when changing the solvent (polar to non-polar and vice versa).

Mechanochromia– reversible change in color (color) under deformation loads on the painted material.

Electrochromia and magnetochromia– a reversible change in color when passing various types of current and the action of a magnetic field on a painted object.

General mechanisms of chromia

All these types of chromium have a common mechanism, but specific features associated with the nature (physics, chemistry, physical chemistry) of the impulse itself are also obvious.

As was said earlier, coloring, color with all other necessary conditions(we have already talked about them) are caused by the chemical structure of a substance or the physical nanostructure that makes a substance, object, material colored and colored. In the case of coloring, the formation of which involves colored substances (dyes, pigments), the molecules of these substances must have a specific structure responsible for the selective absorption of rays of the visible part of the spectrum. In the case of organic dyes and pigments, the part of their molecule that determines this property is called a chromophore. According to the theory of color, a chromophore in organic substances is a structure with a fairly extended system of conjugated double bonds (conjugation).

The longer the chain of conjugations, the deeper the color of substances built from such molecules.

The conjugated bond system is characterized by a certain density of π- and d-electrons and, as a result, when interacting with rays of sunlight (its visible part), the substance is able to selectively absorb some of them.

Consequently, the phenomenon of chromism is necessarily associated with the reversible formation or change of the chromophore structure. If coloring is due to the presence of a strictly organized nanostructure (structural coloring), then chromism is associated with the reversible organization or disorganization of this structure under the influence of external impulses. Under the influence of external factors, reversible chemical modification molecules, but very often this is associated with spatial isomerism (for example, cis-trans isomerism of azo dyes), the transition from an amorphous state to a crystalline state (pots at the stage of soaping with boiling surfactant solutions), etc.

The specifics of the mechanism of chromia, depending on the nature and type of impulses causing it, will be outlined when considering each type of chromia.

Photochromia

The most studied type of chromia. Photophysical and photochemical transformations of dyes became objects of study by outstanding physicists and chemists of the last few hundred years, as soon as the foundations of physical and chemical ideas about the world began to form (I. Newton, A. Einstein, N. Vavilov, N. Terenin, etc.).

Photochromia, as part of a broader scientific and practical direction - photonics, underlies the properties of many natural and man-made phenomena and materials.

So rhodopsin– a natural visual pigment (chromoprotein), a highly chromic photoactive substance contained in the retinal rods of mammals and humans. It is essentially a visual photosensor. If its photoactivity were irreversible, then it would not be able to perform this function. The evolution of living nature created and selected this substance for effective vision at the very beginning of evolution (~ 2.8 billion years ago). This dye, rhodopsin, is present in archaic (original), primitive bacteria Halobacterium halolium, which convert light energy into biochemical energy.

The mechanism of rhodopsin photochromy involves very complex biochemical transformations.

In the case of photochromia during the transition from a colorless compound to a colored one, the transition diagram can be represented as follows:

Figure 1. On the absorption spectra, the reversible transition will be reflected in the shape of curves A and B.

Colorless substance A intensively absorbs light in the near UV (~ 300 nm), passes into a photoexcited state, the energy of which is spent on photochemical transformations of substance A into substance B with a chromophore that absorbs in the visible part of the spectrum. The reverse transformation can occur in the dark or when heated. Return to the original state occurs either spontaneously (due to the supply of heat) or under the influence of light (hυ2). When moving from compound A to B, its electron density changes and molecule B acquires the ability to absorb photons of lower energy, that is, absorb rays of the visible part of the spectrum. From the photoexcited state, molecule B is able to return again to the colorless state A. As a rule, forward reaction 1 proceeds much faster than reverse reaction 2.

It is necessary to distinguish between physical and chemical mechanisms photochromia. Physical photochromia is based on the transition of a molecule of a substance for some time to a photoexcited state, which has an absorption spectrum different from the initial state. Chemical photochromia is based on deep intramolecular rearrangements under the influence of light, passing through the stages of photoexcitation.

The chemical photochromia of colored substances is based on the following transformations caused by the absorption of light quanta by the molecule and its transition to a photoexcited state:

• redox reactions;
• tautomeric prototropic transformations;
• cis-trans isomerism;
• photo rearrangements;
• photolysis covalent bonds;
• photodimerization.

Currently, many photochromic substances of inorganic and organic nature are known and studied. Inorganic photochromes: metal oxides, compounds of titanium, copper, mercury, some minerals, compounds of transition metals.

These interesting photochromes are unfortunately not very suitable for fixation on textile materials due to the lack of affinity for fibers. But they are successfully used as such or on substrates of various natures.

Organic photochromes are more suitable for fixation on textiles (they have affinity) and are less environmentally harmful.

These are mainly spiropyrans and their derivatives, spirooxazines, diarylethanes, triarylmethane dyes, stylenes, and quinones. Let us give an example of photoinitiated photochromic transformations of spiropyran, as the most studied photochrome. The photochromism of spiropyrans and their derivatives is based on reversible reactions: the rupture of covalent bonds in the molecule under the influence of UV and their restoration under the influence of rays of quanta of the visible part of the spectrum or due to heating. Figure 2 shows a diagram of the photochromic transformations of spiropyrans and their derivatives.

As can be seen, the original form of spiropyran does not have a conjugated double bond system and, accordingly, these compounds are colorless. Photoexcitation initiates the cleavage of the weak spiro-(C-O) bond, as a result of which the new two forms (cis- and trans-) cyanine derivatives acquire a conjugated system of double bonds and, accordingly, color.

Thermochromia– reversible color change when heated; When cooled, the color returns to its original color. As in the case of photochromia, this is associated with reversible changes in the structure of the molecule and, accordingly, with changes in the absorption spectrum and color.

Thermochromes can be, as in the case of photochromes, inorganic and organic.

Among the inorganic thermochromes are indium and zinc oxides, complexes of chromium and aluminum oxides, etc. The mechanism of thermochromia is a change in the state of aggregation or geometry of the ligand in a metal complex under the influence of temperature.

Inorganic complexes are not suitable for textiles, since they require high temperatures to change color, at which the textile material is thermally degraded.

Organic thermochromes can reversibly change color by two mechanisms: direct or sensitized. Direct mechanisms usually require relatively high temperatures (not suitable for textiles) leading to rupture chemical bonds or to the conformations of molecules. Both lead to the appearance or change of color. When heated, structural, phase changes can also occur, for example, a transition to a liquid crystalline state and, as a consequence, the appearance of structural color due to purely physical, optical phenomena (interference, refraction, diffraction, etc.).

The breaking of chemical bonds, leading to the reversible appearance of color, as in the case of photochromia, is associated with the formation of a chain of conjugated double bonds. This is how spiropyran derivatives behave (60° – red, 70° – blue).

Stereoisomerization when heated requires relatively high temperatures (>100°C). When ironing textiles based on synthetic fibers dyed with azo dyes, the consumer often observes a reversible change in color shade, as a result of cis-trans isomerism of azo compounds.

Another reason for direct thermochromia may be isomerism associated with the transition from a planar (coplanar) form of a molecule to a volumetric one.

Particular attention should be paid to thermochromia crystal structures, reversible transition to liquid crystalline form. Liquid crystals: an intermediate state of matter between solid crystalline and liquid; the transition between which occurs with a change in temperature. A certain degree of ordering of molecules in the liquid crystalline state causes them to display a structural color that depends on temperature. Coloring in liquid crystal form depends on the refractive index, which in turn depends on the specifics of this structure (the orientation and thickness of the layers, the distance between them). Similar behavior (structural coloring) is demonstrated by certain structures of living and inanimate nature: opals, the color of the plumage of birds, sea creatures, butterflies, etc. True, this is not always a liquid crystalline form, but more often photonic crystals. Liquid crystal structures change color in the range of –30 – +120°C and are sensitive to very small temperature changes (Δ 0.2°C), which makes them potentially interesting in various areas technology.

These were all examples of the direct thermochromic mechanism, requiring high temperatures and therefore of little use for textiles.

The mechanism of indirect (sensitized) thermochromia is that substances that do not have thermochromic properties are capable of triggering the chromium mechanism of other substances when heated. Of interest are systems with a negative thermochromic effect, when the color appears at room temperature or lower, and when heated, the color disappears reversibly.

This thermochromic system consists of 3 components:

1. A dye or pigment sensitive to changes in pH (indicator dye), for example, spiropyrans;
2. Hydrogen donors (weak acids, phenols);
3. Polar, non-volatile solvent for dye and hydrogen donor (hydrocarbons, fatty acids, amides, alcohols).

In such a 3-component system at low temperatures, the dye and the hydrogen donor are in close contact in the solid state and the color appears. When heated, the system melts, and the interaction between the main partners disappears along with the color.

Electrochromia occurs due to the addition or donation of electrons by molecules (redox reactions). The initiation of these reactions and the development of color can be achieved using a low current (just a few volts, ordinary batteries will do). In this case, depending on the strength of the current, the color changes color and shade (a find for fashionable clothes– “chameleon”)

Electrochromes (of course, they must be conductive conductors): metal oxides of transition valency (iridium, ruthenium, cobalt, tungsten, magnesium, rhodium), metal phthalocyanines, dipyridine compounds, fullerenes with the addition of alkali metal anions, electrically conductive polymers with a conjugated chain of double bonds (polypyrrole, polyaniline, polythiophenes, polyfurans).

The main areas of application of electrochromic materials are: fashionable clothing that changes color; camouflage, completely matching color environment(morning, afternoon, twilight, night); devices that measure current strength by color intensity.

Solvatochromia– reversible color change when replacing the solvent (polar to non-polar and vice versa). The mechanism of solvatochromy is the difference in solvation energy of the ground and excited states in different solvents. Depending on the nature of the solvents being replaced, bathochromic or hypsochromic shifts occur in the absorption spectra and, accordingly, a change in color shade

Most solvatochromes are metal complex compounds.

Mechanochromia– manifests itself in the presence of deformation loads (pressure, tension, friction). This is most clearly evident in the case of colored polymers, the main chain of which is a long chain of conjugated double π bonds. For them to exhibit mechanochromia, the combined action of mechanical impulses, heating and changes in the pH of the environment is often required.

For example, polydiacetylenes, when cooled without mechanical loads, have a blue color (λ ~ 640 nm), in a stressed state at 45 ° C, the material soaked in acetone becomes red (λ ~ 540 nm). By chemically modifying mechanochromic polymers, it is possible to change the color spectrum under mechanical loads.

By carrying out graft polymerization of polydiacetylene with polyurethane, an elastomeric polymer is obtained, which can be used in various fields to assess mechanical stress by color change, as well as in fashionable “stretch” clothing made from fibers of this structure. In places of bends (knees, elbows, pelvis) coloring will appear.

The most striking examples of the use of chromium in practice at present

Photochromia. Coloristic effects: change or appearance of color when irradiated with UV rays: fabrics, shoes, jewelry, cosmetics, toys, furniture; protection of banknotes, documents, brands, camouflage, actinometers, dosimeters, windows, sunglass lenses, facades made of glass and other materials, optical memory, photo switches, filters, shorthand.

Thermochromia. Temperature measurement (thermometers), indicator packaging of food products, document protection, liquid crystal thermochromic systems for decorating various materials, cosmetics, skin temperature measurement.

Chromia in fashionable clothes. Microcapsules with photochromic dyes (spiropyran derivatives) are introduced into printing ink and applied to the fabric using printing technology. When illuminated by sunlight (contains near UV ~ 350–400 nm), a reversible color appears (blue - dark blue).

The Japanese company Tory Ind Inc has developed a technology for the production of thermochromic fabrics using a microencapsulated mixture of 4 thermochromic pigments. In the temperature range –40 – +80°С (thermal sensitivity step ~ 5°С) the color changes, covering almost the entire color spectrum (64 shades). This technology is used for winter sportswear, fashionable women's clothing, and for window curtains.

An interesting technology is proposed for combining conductive yarn dyed with thermochromic dyes (incorporation of metal threads). Applying a weak current causes the yarn to heat up and color it. If fabric with conductive threads is printed with thermochromic dyes, then by changing the weave and current strength, you can not only develop and change the color, but also create a variety of patterns. Mollusks are capable of such a change in pattern with the help of chromatophores (organelles containing mechanochromic pigments). Such fabrics can and are used for camouflage; the color and pattern change to suit the type of surrounding area (desert, forest, field) and time of day. Using this principle, a flexible display is made on a textile basis, which is mounted on outerwear. When a low current is applied to such a display (for example, from a battery), animation can be shown.

Clothes made from stretch (elastomer) fibers dyed with mechanochromic dyes look very impressive. Places of clothing with greater extensibility (knees, elbows, pelvis) have a different color from other parts of clothing.

Chrome dyes make it possible to produce camouflage textiles and clothing. If textiles are printed with a mixture of conventional textile and photochromic dyes, camouflage can be achieved in any lighting conditions and environmental conditions.

Chameleon camouflage fabrics can be produced by printing with electrochromic dyes. By applying a weak current, you can achieve complete fusion of color and pattern with the environment.

The problem of protecting banknotes, business papers, and the fight against counterfeit products is successfully solved with the help of chromium dyes and pigments and, above all, photo- and thermochromic ones. The application of colorless chromium substances to the material allows them to be detected under UV illumination or heating.

Further prospects for the use of chromium dyes (substances)

Along with the use of chromium (thermo-, photo-, electro-, mechanical) dyes in the creation of fashionable clothing and shoes with interesting color effects, their use is expanding in technical purposes: optics, photonics, computer science, detection of harmful substances.

When using chromium dyes on textiles, the following problems arise:

• high price;
• problems of fixing and ensuring the permanent effect under the operating conditions of the product (washing, dry cleaning, light fastness);
• limited number of color reversibility cycles;
• toxicity.

The advantage that attracts the phenomenon of chromium is the ability to give materials and products special properties (functionality) that cannot be imparted to them by any other means.

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13. G.E. Krichevsky. The man who created a colorful tomorrow. "Chemistry and Life", 2007, p. 44–47.
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Municipal government educational institution average comprehensive school village of FilippovoKirovo – Chepetsky district, Kirov region

Research project

Change in leaf color and leaf fall of Norway maple in autumn

Completed by: Lyskova Vera,

4th grade student

MCOU secondary school in the village of Filippovo

Head: Kozminykh N.V.,

teacher primary classes

Filippovo

Project passport……...………….……………………………………… 3-5

Stage reports………………………………………………………6

1. Preparatory stage. ……………………………………………6-9

   Practical stage. . …………………………………………………………10-12

   Control and evaluation stage. ……………………………………13-14

Conclusion………………………….……………………………………………………15

List of sources used….............................................. .........16

Appendix……………………………………………………………………………….17-27

Project passport

Project name: Study of leaf color and leaf fall of Norway maple in autumn

Project participant: Vera Lyskova, 4th grade student of the MKOU secondary school in the village of Filippovo

Head: Nina Vladimirovna Kozminykh, primary school teacher

Project type: long-term, individual, research, intended for younger children school age.

Project duration: 7 months

Educational area: educational and research (biology, ecology)

Problem: How, when and why does the color of maple leaves change in autumn?

Why do leaves change color?

Why are the leaves colored differently in autumn?

How does the process of changing the color of maple leaves occur?

How long does maple leaf fall last?

Purpose: to study the color of leaves and leaf fall of Norway maple in autumn to create a video film

Explore scientific literature about Norway maple, changes in the color of maple leaves, leaf fall in the summer - autumn period.

Conduct phenological observations of changes in leaf color from mid-August to the end of leaf fall and weather conditions.

Draw a conclusion about the seasonal changes that occur with the leaves of Norway maple.

Collect material for the herbarium and video film.

Object: Norway maple

Subject: change in leaf color and leaf fall of Norway maple in the summer-autumn period

Study and analysis of literature and performance results.

Observation.

Comparison.

Generalization.

Photography, video shooting.

Expert review.

Planned results

While working on the project I will learn:

Search for information (independently and together with adults) in literature and Internet sources;

Collect, record, compare, summarize and evaluate the results of observations, formulate conclusions and express one’s own point of view;

Work in programs Microsoft Office Word and Film Studio for creating a video film;

Speaking publicly, answering questions on the topic of the project.

annotation

The project examines the phenological change in leaf color of Norway maple in the period from August 12 to the end of September 2015. The object of observation was a lonely maple tree growing near house No. 16 on M. Zlobina Street in the village of Filippovo, and the area where the maple was located was described. Also, to obtain reliable results, changes were recorded in maple trees along M. Zlobin and Zaev streets. Observations showed that the coloring of the maple leaf occurs from the edge to the center of the leaf, and the tree itself - from the top to the lower branches, the shedding of leaves began on September 2, the end of leaf fall is September 25. During the study it was noted weather(air temperature, wind, precipitation). The progress of observations was also recorded by video filming and photography. A scientific justification for the project about autumn seasonal changes occurring in tree leaves and leaf fall is given. One of the main sources of information was tutorial V.A. Koposov, professor at Voronezh State Pedagogical University, “Phenological observations in nature,” which examines the periods of autumn characteristic of our region.

An important place in the preparation of the project was occupied by practical work on processing scientific information into information accessible to children primary school, as well as the labor-intensive process of working with collected photo and video material at the stage of preparation for the presentation. Practical significance of the project: a textbook has been created for classes on the surrounding world.

Product project activities: video film

Equipment and materials: camera, computer (Microsoft office Word, Film Studio programs), projector, color printer, paper.

Report by stages

Preparatory stage:

Select and study scientific and educational literature on the topic of the project.

Prepare the necessary equipment and materials.

Make an observation plan.

Report on the results of studying scientific literature

Introduction

The gradual decline of summer in our region begins on August 16. There is a gradual reduction in daylight hours, a decrease in the amount of solar heat entering the Earth, and a change in the color of plants. To replace the summer colors in mixed forests golden autumn is coming to our region. The voices of the birds fall silent, the smell of leaves and mushrooms, the air is clean and transparent. September is called the “thoughtful” month. The silence in nature is broken only by the rustle of leaves falling from the treetops and the noise of the rushing cold wind. Nature is preparing for the coming changes. Autumn is difficult period in plant life. Perennial grasses, shrubs and trees begin to actively prepare for overwintering in the autumn. Most trees shed their leaves for the winter. Leaf fall is preceded by autumn leaf color.

The science of phenology studies the laws of seasonal development of nature. Periodic natural phenomena on our planet depend primarily on changes in the amount of radiant energy that the Earth receives from the Sun. Autumn, according to phenologists, is divided into four periods: first autumn, golden autumn, deep autumn and pre-winter.

Autumn leaf color

Autumn leaf color changes occur with the green foliage of deciduous trees and shrubs, resulting in one or more colors ranging from golden flaxen, almost white to purple with brown veins. The color of the leaves is determined by pigments. A green leaf has this color due to the presence of the pigment chlorophyll when it is in large quantities contained in cells. This occurs during the plant's growth period. In summer, the green color of chlorophyll predominates, eclipsing the colors of other pigments.

In late summer, the veins that carry juices into and out of the leaf gradually close and the amount of water and minerals entering the leaf decreases. The amount of chlorophyll also begins to decrease. Often the veins remain green even after the leaf has long since completely changed color. The color of the leaf changes due to other pigments.

Carotenoids are predominantly yellow or orange in color. They are always present in the leaves, but are obscured by the green color of the chlorophyll.

Anthocyanins are responsible for the red colors in leaves and are not present in leaves until chlorophyll levels begin to decline.

The brown color of the leaves is not due to the action of any pigment, but due to the cell walls, which become noticeable when there are no visible color pigments.

The color of autumn leaves is determined genetically in each plant species. But whether this color will be dull or bright depends on the weather.
The brightest and richest colors of leaves occur when the weather lasts for a long time: days are clear, nights are cold, autumn is dry and sunny. At temperatures from 0 to 7 degrees Celsius, the formation of anthocyanin increases, and the red color of the leaves becomes more intense. The yellow or red coloration of the leaves may persist for several weeks after they have fallen to the ground.
2.1.2. Deciduous fall of trees and shrubs

What causes leaf fall? If you examine the leaves of trees during leaf fall, it is easy to detect a separating layer of cork cells at the base of the leaf petiole. After the formation of the separating layer, the access of moisture to the sheet stops, and they easily crumble even under their own weight and from the action of the wind. In shady, damp places, leaf fall occurs later, since the roots of plants there absorb more moisture and transfer it to the stem and leaves. At higher elevations, leaves fall off earlier due to lack of moisture. By shedding their leaves, the plants have adapted to life in the harsh winter conditions. Leaf fall helps trees and shrubs to withstand not only prolonged cold, but also drought. As you know, plant roots are not able to absorb cold water, and the leaves constantly evaporate moisture through the stomata, and this could lead to the plants drying out and dying. Thanks to leaf fall, trees get rid of harmful metabolic products, and plants retain beneficial substances in the trunk and roots. Leaf fall protects trees and shrubs from snowbreakers during winter.

Characteristics of the observed object

Norway maple, or Sycamore maple, or Platanifolia maple (lat. Acer platanoides) is a species of maple, widespread in Europe and South-West Asia.

Deciduous tree 12-28 m high with a beautiful, wide, dense spherical crown. The bark of young trees is smooth, gray-brown, darkens with age and is covered with long, narrow, longitudinal cracks. The branches are strong, wide, and directed upward. The leaves are simple, opposite, up to 18 cm in length. The leaves are dark green at the top and paler at the bottom. In autumn they turn yellow or orange and then fall off.

The flowers are fragrant, yellowish-green, collected together in 15-30 flowers. Appear in the first half of May before and during leaf bloom. Pollinated by insects.

The fruit is a lionfish; the wings are capable of carrying the seed over a long distance. The seeds are bare and can remain on the tree throughout the winter. Norway maple bears fruit annually, in Russia - in September.

During the first 3 years, maple grows quite quickly, the annual growth of a young tree can reach 1 meter, and it begins to bear fruit after 17 years. In nature, it lives up to 150 years.

Observation plan:

1. Every week, come to the maple tree and note the weather conditions, describe the appearance of the maple, noting the change in color of the leaves. During periods of intense foliage coloring and leaf fall, increase the frequency of visits.

2. Record the results of observations using photographs, videos and written notes.

3. Enter the results into the table:

	weather condition	Observation of an object	Observing other maples

4. Prepare a video film and herbarium based on observational material.

5.Draw a conclusion about the seasonal changes that occur with Norway maple from the end of summer until the end of leaf fall.

Practical stage:

Describe the location of the observation object.

Carry out observations and record the results

Prepare the project product.

Draw a conclusion (conclusion)

Description of the location of the maple

The object of our observation is growing in the courtyard of an apartment brick building No. 16 on M. Zlobina street. Filippovo Kirovo - Chepetsky district. The plot is located on the opposite side of the asphalt road from the house, adjacent to the vegetable garden, and there is a children's playground nearby. The soil is loamy, quite dense, the surface is smooth. In this area, in addition to maple, birches grow nearby, the distance between the trees is 3 meters. The maple is well lit on the southern and western sides, grows on the edge of the site, the distance to the road is about 3 meters.

Observations on changes in leaf color and leaf fall of Norway maple

Our observation began on August 12. The decline of summer in our area begins on August 16 and continues until the end of the month. Average daily temperatures are gradually decreasing. The first yellow leaves appear. The days are getting shorter. Fog falls on the ground, dew falls on the grass.

The beginning of autumn coloring of leaves is marked on the day when colored leaves appear on plants, and new ones are added to them every day. The beginning of leaf fall is marked on the day when 3-5 leaves fall off when the branches are shaken. Full autumn coloring of leaves is observed on the day when the leaves on most plants of the observed species change color. The end of leaf fall is celebrated on the day when most specimens of a given species have completely lost their leaves.

	weather condition	Observation of an object	Observing other maples
	Sunny, clear, warm +21, light wind	The leaves are bright green, firmly attached to the branch.	All maples are green
	Cloudy, cold + 12, windy, raining	Without changes	Without changes
	Partly cloudy, warm +20	The maple began to change the color of the leaves at the top of the tree. The leaves along the edges became orange, individual leaves were completely colored	The color of the foliage changes from the top of the tree to the lower leaves. Maples illuminated by the sun from all sides are more actively colored than in the shade.
	Partly cloudy, air temperature +16, windy	The top of the tree became orange-gold, the lower branches were completely green. The leaves are actively changing color. The first leaves appeared on the ground	The leaves are actively changing from green to orange and yellow.
	Mainly cloudy, 14, dry, light wind	The upper leaves have changed color. The leaves close to the tree trunk and the lower leaves are still green. Leaf fall.	The beginning of leaf fall
	Sunny, warm +20, dry, weak wind, warm	The maple has changed its color. The tree became all orange and yellow. The leaves on the lower branches are partially green. Massive leaf fall is underway. Leaves carpet the ground around the maple tree.	Complete change in leaf color. Massive leaf fall.
	Partly cloudy, warm +20, dry, windy	The tree has almost completely fallen off; there is some foliage on some of the lower branches.	Some of the trees are bare, but most of the maples are still losing their leaves.
	Sunny, warm +22, dry, light wind	The leaf fall is over. The leaves on the ground began to dry out.	Tall, large maples have leaves in the center and on the lower branches. The leaf fall continues there. But for most trees, leaf fall has ended.

Thus, the coloring of the maple leaf occurs from the edge to the center of the leaf, from the top to the lower branches, the color of the leaves is orange, yellow. The shedding of the first leaves began on September 2, mass leaf fall began on September 16, and the end of leaf fall began on September 25. Favorable weather conditions for coloring foliage in bright colors: nights are quite cold and days are warm, sunny and dry. For comparison, observations were made of other trees that grow along the street. M. Zlobina and st. Zaev, the timing of changes in the color of foliage on maples and the time of leaf fall coincided.

2.3. Control and evaluation stage:

1. Conduct a presentation of the project and answer questions on the topic.

2. Get an expert assessment of the project.

3. Give self-evaluation of the work done.

2.3.1. Expert assessment (review)

The project is presented on 17 pages with a 10-page appendix, contains 1 table, 16 photographs.

The project examines issues related to observations in nature according to the seasons. Each season has its own characteristics, its own laws of seasonal development of nature. Project work 4th grade students is relevant in connection with the personal awareness of the beauty and uniqueness of nature and understanding of the relationships between living and inanimate nature. The author chose an interesting and accessible research topic, formulated the problem, and set goals and objectives. To solve the set tasks, 5 literary sources were studied, including Internet resources, observations were planned and carried out, and the results of the work were presented in a variety of ways at the stages of the project. The text corresponds to the stated objectives, is well designed and illustrated with its own photographs. In conclusion, fairly clear and logical conclusions are given. The product of the project - a video film - clearly demonstrates how seasonal changes occur in wildlife using the example of Norway maple. Work on the project product showed the student’s capabilities in the field of ICT. The phenological autumn nature calendar contained in the appendix indicates the prospects of this project for the study of wildlife. Wishes to the author: continue work on the project, expanding it with phenological observations for the spring and summer period.

The project work of Vera Lyskova, a 4th grade student of the Municipal Municipal Educational Institution Secondary School in the village of Filippovo, can be submitted to environmental and biological competitions.

Reviewer: Shchekleina N.G., biology teacher of the Municipal Educational Institution Secondary School in the village of Filippovo

Self-esteem

I, a 4th grade student at the Municipal Municipal Educational Institution Secondary School in the village of Filippovo Lyskova Vera, back in the 3rd grade, began to be interested in what colors the sorceress - autumn decorates the trees with. The most beautiful tree is maple. It has a lush crown and large carved leaves that can be collected into bouquets. I conveyed the beauty of maple with paints on paper and took photographs. And by the new autumn, under the guidance of my teacher, I began research project“Changes in leaf color and leaf fall of Norway maple in autumn.”

I learned why leaves change color and fall from trees in autumn. It was interesting for me to observe this natural phenomenon, record my observations, explain the changes taking place, and then create a film that clearly shows how this miracle of nature occurs.

I had difficulties when I came across previously unfamiliar terms that I found in the literature (chlorophyll, pigments, carotenoids, etc.), but gradually I remembered these names.

I would like to continue working on the project.

Conclusion

While working on the project:

studied the literature about autumn changes occurring with Norway maple leaves and leaf fall;

described the appearance of the leaf, the change in its color;

gave a description of the location of the observation object;

carried out observations of the object and compared it with other maples, based on the results they compiled a table indicating weather conditions;

created a video to show to elementary school students.

Observations have shown that the coloring of a maple leaf occurs from the edge to the center of the leaf, and the tree itself - from the top to the lower branches, the color of the leaves - from orange to bright yellow. The shedding of the first leaves began on September 2, mass leaf fall began on September 16, and the end of leaf fall began on September 25. There were favorable weather conditions for the foliage to turn bright colors: the nights were quite cold and the days were warm, sunny and dry. For comparison, observations were made of other trees that grow along the street. M. Zlobina and st. Zaev, the timing of changes in the color of foliage on maples and the time of leaf fall coincided.

Thus, answers were found to the problematic questions posed at the beginning of the project. Knowledge about seasonal phenomena in the life of trees has expanded. Using Norway maple as an example, it was established how inanimate nature(solar heat, daylight hours, precipitation, wind) affects a living organism: the tree adapts to new conditions, first the color of the leaves changes, then the leaves are shed. Prospects for the project: with the help of adults, plant young maples in the spring to green the streets of our village; this is a very beautiful and fast-growing plant.

List of sources used

Kurt - Gilsenbach.H. Trees [Text]. Encyclopedia “What is what” - Word, 1997. - 48 p.

Kopysov, V.A. Phenological observations in nature [Text]: textbook. - Kirov, 2009. - 135 p.

Nature, economy, ecology of the Kirov region [Text]: [Sb. articles] – Kirov: Kirov Regional Committee for Nature Protection, 1996. – 490 p.

Website of the ecological center "Ecosystem", http://www.ecosystema.ru/. (last access date: 12/07/15.)

World Encyclopedia website, https://ru.wikipedia.org/wiki/Colors_of_autumn_leaves (last access date: 12/14/15.

Annex 1

Norway maple

Photo 1. Norway maple Photo 2. Leaf

Photo 3. Flowers Photo 4. Fruits

Photo materials from http://yandex.ru (last access date 08/12/15)

Appendix 2

Photographic observations of leaf color and leaf fall

Norway maple

Photo 6. Maple leaves begin to change color.

Photo10. Autumn excursion.

Photo 16. Completion of the practical stage of the project

Appendix 3

Phenological calendar of autumn changes in nature

First autumn

The last storm.

Departure of barn swallows.

The last calls of swifts.

The first ripe lingonberry fruits.

The first yellow leaves on birch trees.

The first yellow leaves on linden trees.

The first yellow leaves on the bird cherry.

The first yellow leaves on rowan trees.

The first yellow leaves on the aspens.

The first flocks of cranes on migration.

Transition of average daily temperature through +10° C.

Ripening of acorns near an oak tree.

The appearance of yellow leaves on most trees and shrubs.

The beginning of leaf fall at the linden tree.

The appearance of a flying web.

The beginning of leaf fall in the bird cherry tree.

The leaves have begun to fall at the birch tree.

The leaves have begun to fall on the aspen tree.

The first flocks of geese on migration.

The appearance of waxwings.

The leaves have begun to fall at the poplar tree.

The leaves have begun to fall on the rowan tree.

The first frost in the air.

Full autumn color of linden leaves.

Appearance of magpies near dwellings.

The first flocks of ducks on autumn migration.

Full autumn color of rowan foliage.

Full color of bird cherry leaves.

29.Full color of poplar leaves.

30. Full autumn color of aspen leaves.

Golden autumn

Full autumn color in most trees and shrubs (except lilac and alder).

The beginning of yellowing of larch needles.

The end of leaf fall at the linden tree.

The end of leaf fall in the bird cherry tree.

The end of leaf fall at the aspen.

The end of leaf fall for rowan and birch.

deep autumn

1. The end of mass leaf fall for most trees and shrubs

2. The last rooks flew away.

The beginning of leaf fall in larch.

Full autumn color of larch needles.

The last flock of geese.

First snow cover.

The beginning of leaf fall in lilacs.

The last flock of ducks

The end of leaf fall for lilacs.

The end of leaf fall in larch.

Pre-winter

1.Temperatures dropped below 0°C.

2. Establishment of permanent snow cover.

3.The rivers were covered with ice.

4. Establishment of a sleigh path.

1

The color fastness of clothing materials is an important indicator of the preservation of the aesthetic properties of clothing. Existing methods Assessments of the color fastness of clothing materials to various influences do not allow us to quantify and indicate the degree of significance of color changes in materials from the point of view of human perception. The paper proposes a method for assessing the color change of clothing materials, based on the processing of scanned photographic images of samples before and after exposure. Based on the obtained Lab characteristics of the CIE Lab color space, the color difference index ΔE is calculated. The assessment of the color change of semi-finished sheepskin leather fabric showed that the proposed method makes it possible to quantitatively assess changes in color characteristics, is a sensitive and more accurate assessment, and makes it possible to evaluate color changes that are significant for human perception. It was revealed that various influences (dry cleaning, light weather, dry and wet friction) lead to various changes in color characteristics (lightness, saturation, hue), which is assessed by the magnitude and sign of these characteristics.

impact

sheepskin semi-finished product

lightness

saturation

color difference

sustainability

1. Barashkova N.N., Shalomin O.A., Gusev B.N., Matrokhin A.Yu. A method for computer determination of changes in the color of textile fabrics when assessing its resistance to physical and chemical influences: Russian Patent No. 2439560.2012.

2. Borisova E.N., Koitova Zh.Yu., Shapochka N.N. Assessment of color fastness of sheepskin at various types impact // Bulletin of Kostroma State Technological University. - 2012. - No. 1. - P. 43-45.

3. Borisova E.N., Koitova Zh.Yu., Shapochka N.N. The influence of dry cleaning on the consumer properties of sheepskin products // Bulletin of the Kostroma State Technological University. - 2011. - No. 2. - P. 37-38.

4. GOST 9733.0-83. Textile materials. General requirements to methods for testing color fastness to physical and chemical influences. - Enter. 01/01/1986//Publishing house of standards. - M., 1992. - P. 10.

5. GOST R 53015-2008. Fur skins and dyed sheepskins. Method for determining color fastness to friction. – Enter. 11.27.2008//Publishing house of standards. – M., 2009. – P. 7.

6. GOST R ISO 105-J03-99. Textile materials. Determination of color fastness. Part J03. Method for calculating color differences. – Enter. 12/29/1999 // Publishing house of standards. – M., 2000. – P. 11.

7. Dolgova E.Yu., Koitova Zh.Yu., Borisova E.N. Development of an instrumental method for assessing the color fastness of clothing materials // News of universities. Textile industry technology. - 2008. - No. 6C. - pp. 15-17.

8. Domasev M.V. Color, color management, color calculations and measurements / M.V. Domasev, S.P. Gnatyuk. - St. Petersburg: Peter, 2009. - P.224.

The color stability of clothing materials during use largely determines their quality, since the constancy of the original color characteristics ensures the preservation of the aesthetic characteristics of clothing, which is one of the main consumer preferences.

The color stability of clothing materials to various types of exposure is determined in accordance with standards. New methods have also been developed and new indicators have been proposed for assessing color characteristics. However, these methods do not allow us to assess how significant color changes under operational impacts are from the point of view of human perception, because There is no quantitative assessment of color changes corresponding to the peculiarities of color perception by the human eye.

To quantify color changes, it is proposed to use the method of calculating color differences. To obtain the color characteristics of the test samples, their scanned photographic image is used, followed by processing in the Adobe Photoshop graphic editor (Fig. 1), in which it is possible to obtain the Lab color characteristics.

Figure 1 - Adobe Photoshop window with photographs of samples before and after exposure

To assess color change, the characteristic ΔE is used - color difference - which is defined as the difference between two colors in one of the equal-contrast color spaces. This characteristic takes into account the difference between the L, a and b color coordinates of the CIE Lab color space and the difference between the H° chromaticity and C saturation coordinates of the CIE LCH color space. The Lab characteristic is hardware-independent and corresponds to the peculiarities of color perception by the human eye, giving a more accurate assessment of the color change of the material.

The color difference ΔE is calculated using formula (1):

∆E = [()2 + ()2 + ()2]1/2 , (1)

where ∆L, ∆C, ∆H - the difference between the sample before and after exposure in lightness, saturation and hue, respectively, calculated using formulas (2), (4.5) and (6.7);

KL, KC, KH - weighting coefficients, which are equal to one by default;

SL, SC, SH - lengths of the semi-axes of the ellipsoid, called weight functions, allowing you to adjust their corresponding components, following the location of the color sample in the Lab color space, determined by formulas (7.8), (9.10) and (11-13) respectively .

Detection of lightness changes (2)

∆L = L1 - L2, (2)

where L1 is the lightness of the color of the sample before testing;

L2 - lightness of the color of the sample after testing.

Determination of sample color saturation (3):

C = 1/2, (3)

where a is the ratio of red and green colors in a given color;

b is the ratio of blue and yellow.

Detecting changes in saturation (4)

∆C = C1 - C2, (4)

where C1 is the color saturation of the sample before testing;

C2 - color saturation of the sample after testing.

Definition of color tone (5):

H = arctan,(5)

Detection of color tone change (6)

∆H = 2sin, (6)

where H1 is the color tone of the sample before testing;

H2 - color tone of the sample after testing (5).

Determination of the average lightness value of samples before and after testing (7.8):

= (L1+ L2)/2 (7)

where K2 = 0.014 is the weighting coefficient.

Determination of the average saturation value of samples before and after testing (9.10):

C12 = (C1 + C2)/2 (9)

SC= 1 +K1C12, (10)

where K1 = 0.048 is the weighting coefficient.

Determination of the average color tone of samples before and after testing (11-13):

T= 1-0.17cos(H12 - 30°)+0.24cos(2H12)+0.32cos(2H12 + 6°)-0.2cos(4H12 - 64°)(12)

SH= 1 + K2C12T(13)

When calculating H12, it should be taken into account that if the chromaticities of the samples fall into different quadrants, then 360° must be subtracted from the chromaticity value that is the largest and then the average must be determined.

By the magnitude of the color difference, one can judge the degree of change in the color of materials after various influences. ΔE value< 2 соответствует минимально различимому на глаз порогу цветоразличия, величина в пределах ΔE = 2—6 приемлемо различимая разница в цвете. Величина ΔE >6 will correspond to a noticeable difference between the two colors. By the sign of changes in lightness, saturation and color tone, one can judge the degree of change in these characteristics of the material.

Currently produced semi-finished sheepskin products are distinguished by a wide variety of colors, types of finishing of leather fabric and hair. During wear and care, products experience a complex set of various influences that lead to deterioration. appearance products. Therefore, to test the proposed method, an assessment was made of the color change of a semi-finished sheepskin product with different color characteristics of leather fabric and under different types of exposure (dry cleaning, light weather, dry and wet friction) (Table 1).

Table 1 - Assessment of color fastness of semi-finished sheepskin leather fabric under various types of influences

Type of impact

Sample of semi-finished product

Before exposure

After exposure

Dry cleaning

Sheepskin fur, black leather fabric

Light weather

Sheepskin coat, black leather fabric

Sheepskin fur with polymer film coating, light brown leather fabric

Fur velor, dark green leather fabric

Dry friction

Sheepskin coat, brown leather fabric

Fur velor, brown leather fabric

Sheepskin fur, dark gray leather fabric

Wet friction

Fur velor, brown leather fabric

Fur velor, brown leather fabric

Fur velor, light gray leather fabric

Analysis of the data obtained shows that the greatest color changes occur during dry cleaning. The color difference values ​​reach 12.7, which is a significant indicator of color change. At the same time, the color of the material becomes less saturated and lighter. During wet friction, the material darkens, as evidenced by positive values ​​of the ∆L - lightness indicator, while with other types of exposure this indicator has negative values, which indicates that the material becomes lighter under this type of exposure. External influences lead to changes in the indicator ∆H - light tone. When this value is exceeded by 4 units, the tone of the material changes significantly.

Thus, the proposed method for assessing changes in color characteristics makes it possible to obtain quantitative indicators of color changes, is sensitive and makes it possible to evaluate color changes that are significant for human perception, and to study the kinetics of changes under the influence of a certain operating factor. It can be used to assess color stability at the dyeing stage semi-finished sheepskin product, at the preparatory stage when selecting skins for the product in order to exclude different shades, during dry cleaning to assess its degree of influence on color changes.

Reviewers:

Sokova G.G., Doctor of Technical Sciences, Professor, Acting Head of the Department of Technology and Design of Fabrics and Knitwear, Kostroma State Technological University, Kostroma.

Galanin S.I., Doctor of Technical Sciences, Professor, Head of the Department of Technology, Artistic Processing of Materials, Artistic Design, Arts and Technical Services, Kostroma State Technological University, Kostroma.

Bibliographic link

Borisova E.N., Koitova Zh.Yu. USING THE METHOD OF CALCULATING COLOR DIFFERENCES TO EVALUATE CHANGES IN COLOR OF SHEEPSHIP SEMI-FINISHED PRODUCT // Contemporary issues science and education. – 2013. – No. 5.;
URL: http://science-education.ru/ru/article/view?id=10468 (access date: 06/15/2019). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

Khakhalina Daria

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Municipal budgetary educational institution Strochkovskaya sosh

Research work on the topic:

“Study of changes in leaf color and patterns of leaf fall in woody deciduous plants”

Work completed by: Daria Khakhalina

11th grade student

Scientific supervisor: Petrova L.G.

2015

1. Introduction __________________________________________________________

2. Literature review ___________________________________________________

2.1.Causes of leaf fall

2.2 The significance of leaf fall

2.3 Leaf fall mechanism

2.4. Leaf pigments

2.4.1. Plant pigments

2.4.2. Yellow pigments

2.4.3. Red pigments

2.4.4. Green pigments

3. Practical part__________________________________________________________

3.2 . Detection of violations in the timing of leaf fall under the influence of artificial lighting

3.3.1. Experiments with pigments

• Decolorization of anthocyanins by sulfur dioxide
• Study of the indicator properties of anthocyanins
• Separation of a mixture of alcohol-soluble pigments
• Release of water-soluble pigments (anthocyanin)

3.3.2 Distribution of pigments in leaf blades of autumn leaves

4. Results and their discussion_______________________________________________

5. Conclusion _____________________________________________________

6. List of references and online sources_____________________________________________

Applications

1. Introduction

Seasonal changes in surrounding nature- this is probably the first thing that a reasonable person thought about. The study of the phenomena of the awakening of nature and its transition to a state of rest was sung by poets and artists. Scientists have also thoroughly studied this issue. But there are still many contradictions and unanswered questions. Our own observations of the phenomenon of leaf fall raised a number of questions for us, the answers to which we wanted to obtain as a result of a detailed study of this topic.

Relevance

Green spaces in an urban environment are the few things that connect a person in an alien urban environment with nature. The selection of plant species used in landscaping is of great importance in creating a high-quality environment. Studying the mechanism of leaf shedding in the studied plants reveals an understanding of how it works in other plants, and can also help control the timing of leaf fall. Understanding the patterns of leaf fall finds practical application in nature conservation, urban gardening and settlements, selection for landscaping species and varieties with longer growing seasons, long-term preservation of a beautiful tree crown in the autumn.

Target

To study changes in leaf color and patterns of leaf fall in woody deciduous plants

Tasks

1. Identify the relationship between the timing of leaf coloring, the timing of leaf fall and the ecological and phytocenotic conditions of their growth.

2. Study the mechanism of leaf blade separation using a digital microscope

3. Experimentally isolate the pigments of autumn leaves and study their properties

4. Investigate the distribution of pigments in autumn leaves using a photo scanner and a digital microscope

5. During phenological observations, determine the plants with the longest and shortest leaf fall periods

6. Master the device and methods of working with the Altami digital microscope and Altami VideoKit software

Hypothesis .1 The timing of leaf coloring and leaf fall depends on the stage of plant development, ecological and phytocenotic conditions of their growth

2. Plants with a predominance of red pigments are more resistant to low temperatures, they have a longer deciduous period and later leaf fall

2. Literature review

2.1.Causes of leaf fall

Leaf fall developed during the long evolution of plants and entered into the rhythm of life. Following this rhythm, plants prepare for winter in advance. As autumn approaches, the temperature drops, life processes (photosynthesis, transpiration) weaken, and the destruction of pigments in the leaf begins. The green pigment - chlorophyll - is destroyed first, masking other pigments - carotene, xanthophyll, anthocyanin, which are more persistent and last longer. The leaves become golden yellow, purple or crimson red, and “golden autumn” begins. At the same time, and even earlier, a separating layer appears at the base of the petiole, the leaf breaks off and falls under the weight of its own blade. The wound is closed with a cork, forming a leaf scar with cut leaf marks. Leaf fall begins, which not only saves the tree from winter drought, but is also useful in other respects.”

Trees growing near street lights take the longest to shed their leaves in the fall. This was first noticed at the beginning of this century by the Austrian physiologist G. Molisch. He tried to explain this phenomenon by the peculiarities of water evaporation by leaves. In fact, the late leaf fall in these plants is explained precisely by the artificial extension of daylight hours.

2.2 The significance of leaf fall

1) “leaf fall helps remove substances accumulated in the leaves during the growing season. In this regard, it can be considered as a complex and extremely important process of excretion by plants. various substances. Before the leaves fall, not only an increased content of harmful substances is found in them, but also a significant decrease in beneficial elements (nitrogen, phosphorus, potassium, etc.). Carbohydrates and nitrogen-containing compounds move from leaves to the internal parts of plants. Some of these substances rush to the roots, where they are stored in reserve until spring. »

2) “Fallen leaves are a very valuable fertilizer. Thanks to them, the soil in the forest is annually enriched with humus, acquiring a number of important properties. We know, for example, that the soil of a broad-leaved forest does not freeze in winter due to its significant humus content, and this allows spring plants to develop under the snow. One hectare of oak forest receives more than 5000 kg of waste (dry weight of leaves, brushwood, etc.), which produces approximately 520 kg of ash."

2.3.Mechanism of leaf fall

The petioles of green leaves are firmly connected to the branch. Nutrients pass through them. In autumn, changes occur in the leaf petioles.
Cells of the separating layer are laid perpendicular to the longitudinal axis of the petiole near the stem.A transverse layer of parenchyma thin-walled cells formed at the base of the petiole several days (weeks) before the leaf falls. parenchyma cells begin to rapidly divide. As they round, they form large intercellular spaces, so that the tissue in this place becomes loose and fragile.The intercellular substance connecting these cells becomes mucus, and the cells separate from each other. At the site where the leaf separates from the side of the stem, by this time layers of cells are formed, the shells of which become suberized. The resulting layer of cork protects the internal tissues of the stem in place of the separated leaf.
After the formation of the separating layer and the disruption of communication between cells, the leaf continues to remain on the tree for some time thanks to the conducting bundles connecting the leaf to the stem.
The leaf remains hanging on the tree only thanks to vascular bundles, which, like tiny “water pipes,” connect the leaf to the rest of the plant. Vascular bundles can easily be seen with the naked eye on leaf scars in the form of large dots. They serve to conduct water and mineral salts from the root to the leaves and nutrients. However, there comes a time when this last connection between the leaf petiole and the mother plant is broken. Often the most insignificant gust of wind is enough for this, but sometimes leaves fall even in completely calm weather as a result of sharp fluctuations in temperature, freezing or thawing, or directly under the influence of gravity of the leaf blade, aggravated by settled dew. The leaves do not fall off the branches, but are separated in a certain place - where the petiole is attached to the branch and where a cork layer forms in the fall. The fallen leaves of different trees have the same smooth, rounded edge of the petiole. After the leaf falls, there is no living “wound” left on the stem.

: 1 – conductive fabrics ; 2 – periderm stem;

3 – cork under the base of the leaf; 4 – separating layer).

At the site where the fallen leaf is attached to the stem, a leaf scar (1) remains, which looks like a more or less sharply defined print-like spot or depression.
Leaf scars can be narrow or wide depending on the size of the petiole. The leaf scar is usually placed under the bud on a raised area called the leaf cushion (2). On the leaf scar, leaf traces (3) are noticeable in the form of more or less large dots or tubercles, which are traces of vascular bundles passing from the stem to the leaf petiole. There can be a different number of leaf traces: one, three, five or many. Sometimes leaf marks are not clearly visible, then you should make a thin section from the leaf scar (no more than 0.1-0.2 mm thick) and examine them with a magnifying glass. Since leaf scars and leaf marks are quite characteristic of each species, they are of great importance in identifying woody plants in a leafless state.

2.4. Pigments of leaf fall

2.4.1. Plant pigments- these are large organic molecules, absorbing light of a certain wavelength. In most cases, “responsible” for the appearance of color are certain parts of these molecules, called chromophores . Typically, a chromophore fragment consists of a group of atoms united in chains or rings with alternating single and double bonds (–C=C–C=C–). The more such alternating bonds, the deeper the color. In addition, light absorption is enhanced by the presence of ring structures in the molecule. IN plant cells The most common pigments are green chlorophylls, red and blue anthocyanins, yellow flavones and flavonols, yellow-orange carotenoids and dark melanins. Each of these groups is represented by several pigments that differ in chemical structure, and therefore in light absorption and color.

2.4.2.Yellow pigments

“Yellow pigments are as widespread in the plant world as red ones, but in some cases they are masked by anthocyanins and chlorophyll and are therefore less noticeable.”

The group of pigments that can give a cell a yellow, yellow-orange color is the most numerous: these are carotenoids, flavones, as well as flavonols and some others.
Carotenoids are very widespread in the plant world. Plants usually contain not one, but several different carotenoids.” “The most common pigments in this group are carotene, xanthophyll and lycopene.
Carotenoids absorb light in the blue region of the spectrum. The color of a pigment is determined both by the number of conjugated double bonds in the molecule and by its concentration in solution.” “It is impossible to identify any one characteristic chromophore fragment in carotenoids, because their molecules include chains of atoms with alternating single and double bonds of different lengths; each type of chain has its own individual chromophore. As the chain lengthens, the color of the pigments changes from yellow to red and even red-violet.”

“Carotenoids that are resistant to low temperatures When chlorophyll is depleted during the cold season, the leaves acquire a noticeable yellow or orange color due to the prolonged action of the carotenoid pigment. Carotenoids protect plants from the harmful effects of sunlight by absorbing UV radiation from the sun, transforming it into energy and transferring it to chlorophyll. With the help of this transmission, chlorophyll regulates the processes of photosynthesis.”
“Carotenoids, unlike other yellow pigments,insoluble in water. To extract them, organic solvents (gasoline, alcohol) are used.
In plants, carotenoids are contained in almost all organs: flowers (petals, ovaries, stamens), leaves, fruits and seeds. In leaves and green fruits, carotenoids are found in chloroplasts, where they are masked by chlorophyll, and in chromoplasts. In petals and seeds, they can also be in an extraplastidal state as a coloring component of oil droplets.”

“The practical use of carotenoids is based on their medicinal properties: they are used as an anesthetic for burns and frostbite, as a source of vitamin A, and for the treatment of difficult-to-heal wounds. Carotenoids are excellent yellow food colors. Carotene isolated from plants is used to color candies, butter, cheese, ice cream and other products.
_____________

3.Practical part

The study was conductedon the territory of the Gorodetsky district

Object of study:deciduous woody plants

Subject of study:patterns of leaf coloring and leaf fall

Research deadlines:August - November 2015

3.1. Phenological observations of the process of leaf coloring and leaf fall

Methodology.

We used a technique for measuring leaf fall parameters (Bukhvalov et al., 1995), adapted to our purposes.20 trees were marked for each speciesThe phases of leaf coloring and leaf fall were recorded at weekly intervals.

View	Coloring			Timing of leaf coloring	Start date of leaf fall
Ash maple	yellow (Cadmium lemon)	5.09	18.09.	13 days	10.09.	10.10	30 day
	orange-red
	yellow (Cadmium yellow medium)	4.09	19.09.	15 days	10.09	25.10	45 days
Snowberry white(Symphoricarpos albus)	yellow (Cadmium lemon)	10.10	17.10	7 days	15.10	5.11	21 day
Sycamore maple(Acer platanoides L)	yellow (Cadmium yellow medium)	6.09	20.09.	14 days	12.09	12.10.	30 days
	Red
Common hazel (Corylus avellana)	yellow (Cadmium lemon)	7.09	25.9	18 days	11.09	16.10.	36days
Serviceberry (A. ovalis Me)	Red. dark crimson	12.09.	22.09.	10 days	18.09	15.10	27days
	yellow (Yellow ocher)	10.09	20.09.	10 days	17.09	13.10.	26days
	brown (Mars is brown)
Mountain ash(Sorbus aucuparia)	Yellow (Golden dark)	6.09	17.09.	11 days	15.09	14.10.	29days
	red (Ferric oxide light red)
Linden heart-shaped ( Tilia cordata)	Yellow (Yellow Ocher)	10.09	17.09.	7 days	10.09.	17.10	37days
	yellow (Yellow ocher)	7.09	18.09.	11 days	15.09.	5.10	20 days
Willow tristamen ( Salix triandra)	Yellow (Yellow ocher)	15.09.	5.10.	20 days	20.09.	23.10	33 days
Goat willow (Sálix cáprea)	Yellow (Yellow Ocher)	15.09.	10.10.	25days	5.10.	26.10	11 days
Rosehip May ( Rosa majalis)	Red. scarlet	10.09.	20.09.	10 days	18.09.	3.11	46 days
Common bird cherry ( Prúnus padus)	Yellow (Cadmium yellow medium)	6.09	19.09.	13 days	10.09	10.10.	30 days
Common lilac (siringa vulgaris)	Yellow (Cadmium lemon)	5.10.	____		28.09.	26.10	28days 37days
						6.11
	Blue-purple
	Red-purple	11.09.	21.09.		17.09	25.10	38days
Larch	yellow (Cadmium yellow medium)	18.09.	3.10.	16days	20.09.	27.10	37days
Common aspen ( Populus tremula)	Yellow (Yellow ocher)	5.09	20.09.		8.09	19.10.	41days
	Red (Iron oxide light red)			15 days

Conclusions from the table:

1. The longest deciduous period is for cinnamon rose (46 days), silver birch (45 days) and common aspen (41 days)

2. Goat willow has the shortest deciduous period (11 days)

3. The longest periods of leaf coloring are for goat willow (25 days) and three-stamen willow (20 days)

4.The most short term leaf color (7 days) was detected in white snowberry and heart-shaped linden.

5. Plants with the most early dates beginning of leaf fall

6. Plants with the latest dates for the onset of leaf fall

7. Plants with the earliest dates for the beginning of leaf coloring

8. Plants with the latest start of leaf coloring

9. Plants with the earliest dates

10. Plants with the latest datescompletely leafless state

11.Plants with several pigments: ash maple, sycamore maple, pedunculate oak, rowan, common lilac, common aspen

12. Different shades of red are found: ash maple, sycamore maple, mountain ash, common aspen

3.2. Detection of violations in the timing of leaf fall under the influence of artificial lighting

1) For several years, students at our school have been observing an amazing feature in the silver birch (Betula pendula), growing at the entrance to the Strochkovskaya sosh. The age of the tree is reliably known - 39 years. Since 1993, a lantern with a fluorescent lamp has been installed near the tree. Gradually, the crown of the tree grew and practically surrounded the lantern.

Since 2004, every year we have observed an interesting phenomenon, which we have documented in our work.

1.The timing of coloring of the leaves of this tree is 5-10 days later than that of most other trees of this species.

2. The timing of leaf fall is also 10-15 days later than most other trees of this species.

2. The area of ​​the crown located below the lantern and in its immediate vicinity does not change its color or partially changes color before the onset of frost, when the rest of the crown is already completely colored.

3. In the area of ​​the crown located below the lantern and in its immediate vicinity, part of the leaves remain, which are preserved when the rest of the crown is already without leaves; even after frost, some of the leaves remain on the tree.

4. This year, the start date for painting on this tree is September 15 (September 4, 2015); Deadline for full coloring of leaves - September 29 (19.09.) , the dates for the beginning of leaf fall are 10.09 (10.09), the dates for the end of leaf fall are November 2 (25.10). Note Data on average terms for the type are indicated in parenthesesSilver birch Betula pendula

2) In the process of studying the phenomenon of leaf fall, we identified other amazing facts. We found plants of several species in the generative phase of development, growing under normal living conditions (no factors contributing to a shift in the timing of leaf fall were identified); the timing of leaf coloring and leaf fall was significantly shifted compared to the average established for this species.

We observed these plants:

View	Place of growth	Leaf coloring start date	Date of full leaf coloring	Timing of leaf coloring	Start date of leaf fall	Date of complete leafless state	Deciduous period (number of days)
Silver birch Betula pendula	With. Strochkovo, side of the road on the village of Vysoka Ramen	15.09 (4.09)	2.10.10 (19.09.)	17 days 15 days	15.09 (10.09)	4.11 (25.10)	51 days 45 days
English oak (Quercus róbur)	With. Strochkovo st. Anniversary house No. 7	10.09	20.09.	10 days	17.09	13.10.	26days
Linden heart-shaped ( Tilia cordata)	With. Strochkovo st. Anniversary house No. 12	10.09	17.09.	7 days	10.09.	17.10	37days
Black poplar (Populus nígra)	Gorodets Chernyshe-vskogo st. (shop)	7.09	18.09.	11 days	15.09.	5.10	20 days
Willow tristamen ( Salix triandra)	village Kunorino	15.09.	5.10.	20 days	20.09.	23.10	33 days
Larch	Gorodets Cenotaph	18.09.	3.10.	16days	20.09.	27.10	37days
Common aspen ( Populus tremula)	Green zone on the eastern border of the village of Strochkovo (football field)	5.09	20.09.		8.09	19.10.	41days
				15 days

3.3.Study of pigments in autumn leaves

3.3.1.Experiments with pigments

1) Decolorization of anthocyanins by sulfur dioxide

1. Materials: For the experiment, I used leaves with red and crimson colors (Fig. 3.1), a glass cap suitable for treating leaves with sulfur dioxide in it, a piece of sulfur, a spoon for burning substances. The experiment was carried out in a fume hood, since sulfur dioxide irritates the human respiratory system (Fig. 3.2).

2. Work progress:

• I placed 2 cinnamon rose leaves (without water) under a glass cover
• Filled the space inside the cap with sulfur dioxide. To do this, I lit a piece of sulfur in a spoon and brought it into the flask where the leaves were (Fig. 3.3-3.4). Afterwards, I closed the flask.
• Within 15-30 minutes, I observed discoloration of the leaves.
• As soon as the petals were completely discolored, I took the leaves out of the flask (Fig. 3.5),
• I compared the resulting leaf color with the initial color (Fig. 3.6)
• I put the leaves in a glass of water (Fig. 3.7). I left the leaves in the water so that the sulfur dioxide evaporates and the leaves take on their previous color (Fig. 3.8)Conclusion based on the results of the experiment
• sulfur dioxide (S0 2 ) has an amazing effect on anthocyanins - they become discolored: red and purple leaves turn into white.

Sulfur dioxide causes the transition of anthocyanins into a colorless, so-called leuco form. Under certain conditions they are capable of transforming into colored forms;

• the time it took for leaves to restore color was 21 hours;
• complete restoration of color did not occur

2) Study of the indicator properties of anthocyanins

1. Materials: ethyl alcohol for extracting, gasoline, acid (1% HCl solution), alkali (weak NaOH solution), test tubes.

2. Work progress:

• I obtained an alcoholic extract of anthocyanins from the leaves of cinnamon rose and common lilac (with scarlet-purple color scheme). To do this, I placed the leaves of one plant in a mortar, crushed them, added 5 ml of ethyl alcohol, and filtered the resulting solution into a test tube. I did the same with another plant (Fig. 3.9).
• Next, I added gasoline to the test tubes so that the pigments were distributed among the layers (Fig. 3.10).
• I added a solution of hydrochloric acid to one test tube and alkali to the other.
• Next, I observed a change in the color of the extract caused by a change in the acidity of the medium (Fig. 3.11). The extract with acid acquired a scarlet tint, and the extract with alkali turned purple.

Conclusion from the experience:anthocyanins change color depending on the pH of the environment; their alcohol solutions can be used as acid-base indicators.

3) Separation of a mixture of alcohol-soluble pigments

1.Materials: Ethyl alcohol, gasoline, yellow and green leaves.

2.Process of work:

• I prepared an alcohol extract of leaf pigments. To do this, I placed the leaves in a mortar, crushed them, added 5 ml of ethyl alcohol, and filtered the resulting solution into two 3 ml test tubes.
• Then I added 3 ml of gasoline to one (Fig. 3.12) so that the pigments were distributed among the layers (Fig. 3.13)
• Observations have shown that the lower layer of alcohol is yellow in color and contains the yellow pigment xanthophyll. The top gasoline layer is green and contains chlorophyll and carotene. The orange-red color of plants is given by the pigment carotene, and the yellow color by xanthophyll.
• This experiment was done several times with leaves of different shades.

3. Conclusion from the experience:

• The alcohol extract of the leaf contains chlorophyll and two yellow pigments - carotene and xanthophyll.
• The color of a plant leaf primarily depends on the quantitative ratio of these pigments, as well as on the possible presence of anthocyanin group pigments.

4) Release of water-soluble pigments (anthocyanins)

1.Materials: gas stove, saucepan, red leaves (rich in anthocyanins) (Fig. 3.14)

2.Process of work:

• I poured water into the pan
• Bring the water to a boil (Fig. 3.15)
• I dipped the leaves into the water (Fig. 3.16)
• Boiled for 15 minutes (Fig. 3.17)
• I laid out the leaves from the pan and took pictures (Fig. 3.18-3.20)
• I poured the resulting anthocyanin solution into a transparent glass. (Fig. 3.21-3.22)

3. Conclusion from the experience:

• Anthocyanins are soluble in water and form a red-orange solution with water.
• After the experiment, the leaves acquired a gray-orange hue. Since chlorophyll has been destroyed, we can conclude that the pigments carotene and xanthophyll remain in the leaves.

1. Distribution of pigments in leaf blades of autumn leaves

1) Scanned image of shoots and leaves

During the period from October 2 to October 29, 2015, we collected and scanned. shoots and individual leaves of deciduous trees. The work was carried out using a photo scannerEPSON Scan 2580 PHOTO in the biology room of the Strochkovskaya sosh. Scanning took place immediately after collecting the material, so that the structure of the leaves did not have time to change.

1. Scanned image of shoots and leavesCommon hazel (Corylus avellana) (18.10.2015)

In mature leaves, decaying chlorophyll was preserved only in the central part of the leaf. Only yellow pigments remained on the periphery (Figure 3.23)

At the same moment, on the same plant, on younger shoots the leaves are completely green (Figure 3.24)

2. Scanned image of shoots and leavesRosehip May ( Rósa majális) (15.10.2015)

On one complex leaf, individual leaves can have different colors (yellow, greenish and red), contain different pigments (Figure 3.25)

3.Scanned image of leavesServiceberry (A. ovalis Me)(15.10.2015)

In an old serviceberry leaf, the petiole and veins are initially colored (Figure 3.26), then anthocyanins begin to appear in the main tissue of the leaf blade (Figure 3.27, 3.28)

4. Common aspen ( Populus tremula)

Leaves with different colors and different pigments are formed on one plant (Figure 3.29)

5. Chokeberry (Aronia melanocárpa)

The intensity of coloring on the outer surface of the leaf blade is higher than on the lower surface of the leaf. Pigments in leaves are located closer to the outer surface (Figure 3.30); Fig 3.31 - bottom surface of the sheet.

6. Common lilac (siringa vulgaris)

A fact was established: 23% of the examined siringa vulgaris plants change the color of their leaves from green to blue-purple; by the end of October, anthocyanins accumulate in the leaves (Figure 3.32). In 28% of plants, by this time the leaves had acquired a yellow color (carotenoids and flavonoids) (Fig. 3.33)

7.Interesting fact was established as a result of leaf examination

2) Microscopic examination of leaves using a digital microscope

Before starting the research, I mastered the device and methods of working with a digital microscope, as well as studied and applied the software for it.

The work was carried out using an Altami digital microscope and Altami VideoKit software in the biology classroom of the Strochkovskaya Secondary School. The study took place immediately after collecting the material so that the structure of the leaves did not have time to change.

1. Microscopic examination of leavesRosehip May(Rósa majális) was held on October 16, 2015.

Leaves Rose hips may be bright red and yellow. The former contain many anthocyanins, the latter carotenoidsand flavanoids. We've looked at both

Leaves rose hips containing anthocyanins. The photograph shows how pigments fill the leaf cells, some of them are contained in the intercellular substance(Fig. 3.35). Vascular-fibrous bundles are colored yellow, that is, they are devoid of anthocyanin and contain carotenoids or flavanoids (Fig. 3.36)

Leaves rose hips containing yellow pigments.

2. Microscopic examination of leavesPlane maple (Acer platanoides L) was carried out on 10.10.15

The leaves of the sycamore maple are uniformly colored with yellow pigments, both the vascular-fibrous bundles and the main part of the leaf. The photo shows the cells of the leaf skin; they are transparent and do not interfere with the viewing of pigments; only their cell walls with bends are clearly visible (Fig. 3.37)

4. Results and their discussion.

1 The timing of leaf fall in one plant of one species has a very wide range.

2. For plants living in similar living conditions and belonging to the same age group, the timing of leaf fall varies greatly.

3. It is certain that if the coloring of leaves and leaf fall begin earlier, then the complete coloring of the leaves and the onset of a complete leafless state occurs earlier.

4 Plants in a depressed state (weakened, diseased, growing in unfavorable conditions) enter the leaf fall stage earlier.

5. In plants in the immature and virginal stages of development, later the leaves become colored and the complete leafless state occurs.

6. In plants subjected to pruning, the leaves later become colored and a complete leafless state occurs.

7. Plants with a predominance of red pigments are more resistant to low temperatures, they have a longer deciduous period and later leaf fall

8. A fact was established: 23% of the examined siringa vulgaris plants change the color of their leaves from green to blue-purple; by the end of October, anthocyanins accumulate in the leaves. In 28% of plants, by this time, the leaves had acquired a yellow color (carotenoids and flavonoids). Moreover, most sources express the opinion that the leaves of siringa vulgaris do not change their color in the fall.

9. An interesting fact was established as a result of studying the leafPlatan maple (Acer platanoides L) (Figure 3.34): damage to the leaf conductive system (vascular-fibrous bundles) slowed down the process of changing leaf color.

10. Intraspecific polymorphism of some species was revealed according to the timing of leaf fall -

11. The transition of plants into a state of dormancy is also influenced by temperature: for some species (mainly of southern origin - ash, horse chestnut, lilac, cherry) a decrease in night temperatures is the main signal for dormancy.

Conclusion

Summing up research work, I can conclude that the goal I set has been achieved. I studied leaf color changes and leaf fall patterns in woody deciduous plants and compared evidence-based and scientifically proven findings with research on the topic.

We confirmed the hypotheses put forward at the beginning of the study and established the relationship between the timing of leaf coloring, the timing of leaf fall and the ecological and phytocoenotic conditions of their growth; It was also confirmed that plants with a predominance of red pigments have a longer deciduous period and later leaf fall.

I was able to isolate the pigments of autumn leaves and study their properties. Using a photo scanner and a digital microscope, I examined the distribution of pigments in autumn leaves. In the course of our work, we obtained some data that contradict what was found in the literature studied; they require further consideration.

6. List of references and Internet sources

1. Bukhvalov V.N., Bogdanova L.V., Cooper L.Z. methods of environmental research. M., 1995, 168 p.
2. Detari L., Kartsagi V., Biorhythms. M., Mir, 160 p.
3. Chernova I.M., Bylova A.M. Ecology. M., Education, 255 p.
4. Yakovlev A.S., Yakovlev I.A. Selection and genetic fund for reforestation in oak forests Chuvash Republic.// Ecological Bulletin of Chuvashia, vol. 13, Cheboksary, 1996, pp. 20-26.
5. Artamonov V.I. Interesting plant physiology. – M.: Agropromizdat, 1991.
   Berdonosov S.S., Berdonosov P.S. Guide to general chemistry. – M.: AST Astrel, 2002.
6. Baturitskaya N.V., Fenchuk T.D. Amazing experiences with plants. Book for students
   Golovko T.K. Plant respiration (physiological aspects). – St. Petersburg: Nauka, 1999.
   Children's encyclopedia. – M.: Academy of Pedagogical Sciences of the RSFSR, 1959.
   Zalensky O.V. Ecological and physiological aspects of the study of photosynthesis / Timiryazev Readings. – L.: Nauka, 1977. Vol. 37. 57 p.
   Lebedeva T.S., Sytnik K.M. Pigments flora. – Kyiv: Naukova Dumka, 1986.
   Olgin O. Experiments without explosion. – M.: Chemistry, 1986.
   Pchelov A.M. Nature and its life. – L.: Life, 1990.
   Atkins P. Molecules. – M.: Mir, 1991.
7. http://www.donnaflora.ru/viewtopic.php?p=32844 PIGMENTS, LEAF OPTICS AND STATE OF PLANTS (MERZLYAK M. N., 1998), BIOLOGY Moscow State University them. M. V. Lomonosova
8. Alexander Vladimirovich Kozhevnikov “Spring and autumn in the life of plants” Publisher: Moscow. Publishing house of the Moscow Society of Natural Scientists Year: 1950
9. http://zooflora.ru/rasteniya/listopad/
10. PLANT LIFE ed. Academician A. L. Takhtadzhyan

Glossary

• Age groups of trees: p – seedlings; j – juveniles; im – immature individuals; v – virgin individuals; g – generative individuals; s – senile individuals.RAL 1012 Lemon yellow

  RAL 1013 Oyster white

  RAL 1014 Ivory

  RAL 1015 Light ivory

  RAL 1016 Cadmium lemon

  RAL 1017 Saffron yellow

  RAL 1018 Cadmium yellow medium

  RAL 1019 Grey-beige

  RAL 1020 Olive yellow

  RAL 1021 Golden

  RAL 1023 Deep yellow

  RAL 1024 Yellow ocher

  RAL 1027 Yellow curry

  RAL 1028 Yellow ocher

  RAL 1032 Egg yellow

  RAL 1033 Dahlia yellow

  RAL 1034 Pastel yellow

  RAL 2000 Yellow-orange

  RAL 2001 Red-orange

  RAL 2002 Bright red

  RAL 2003 Orange pastel

  RAL 2004 Pure orange

  RAL 2008 Bright red-orange

  RAL 2009 Deep orange

  RAL 2010 Pale orange

  RAL 2011 Deep orange

  RAL 2012 Salmon orange

  RAL 3000 Red flame

  RAL 3001 Deep red

  RAL 3002 Magenta red

  RAL 3003

  Dark crimson

  RAL 3004 Violet-red

  RAL 3005 Wine red

  RAL 3007 Black-red

  RAL 3009 Oxide red

  RAL 3011 mars brown

  RAL 3012 Beige-red

  RAL 3013 Tomato red

  RAL 3014 Old rose

  RAL 3015 Light pink

  RAL 3016 Coral red

  RAL 3017 Rose

  RAL 3018 Strawberry red

  RAL 3020 Iron oxide light red

  RAL 3022 Salmon red

  RAL 3027 Raspberry red

  RAL 3031 Oriental red

  RAL 4001 Lilac red

  RAL 4002 Violet-red

  RAL 4003 Heather violet

  RAL 4004 Claret violet

  RAL 4005 Lilac blue

  RAL 4006 Deep violet

  RAL 4007 Blue-purple

  RAL 4008 Violet

  RAL 4009 Violet pastel

  RAL 5000 Violet blue

  RAL 5001 Green-blue

  RAL 5002 Ultramarine

  RAL 5003 Sapphire blue

  RAL 5004 Black-blue

  RAL 5005 Deep blue

  RAL 5007 Diamond blue

  RAL 5008 Gray blue

  RAL 5009 Blue

  RAL 5010 Blue

  RAL 5011 Blue steel

  RAL 5012 Light blue

  RAL 5013 Cobalt blue

  RAL 5014 Bluebird

  RAL 5015 Sky blue

  RAL 5017 Pale blue

  RAL 5018 Turquoise blue

  RAL 5019 Capri blue

  RAL 5020 Ocean Blue

  RAL 5021 Water blue

  RAL 5022 Night Blue

  RAL 5023 Deep blue

  RAL 5024 Pastel blue

  RAL 6000 Green wax

  RAL 6001 Emerald green

  RAL 6002 Green sheet

  RAL 6003 Olive green

  RAL 6004 Blue-green

  RAL 6005 Moss green

  RAL 6006 Olive gray

  RAL 6007 Bottle green

  RAL 6008 Brown-green

  RAL 6009 Spruce green

  RAL 6010 Grass green

  RAL 6011 Mignonette green

  RAL 6012 Black-green

  RAL 6013 Reed green

  RAL 6014 Olive yellow

  RAL 6015 Olive black

  RAL 6016 Turquoise green

  RAL 6017 Spring green

  RAL 6018 Yellow-green

  RAL 6019 Pastel green

  RAL 6020 Green chrome

  RAL 6021 Pale green

  RAL 6022 Olive gray

  RAL 6024 Green rich

After heat treatment, the color of food products may remain or change, and most often these changes are undesirable. The technology for processing products involves preserving their native color or imparting the desired shade in various ways.

An example of the formation of a desired color in culinary products can be the gray-brown color of meat, which it acquires during heat treatment.

A pinkish color is desirable for sausage products. It is obtained due to the fact that when pre-salting meat, sodium (or potassium) nitrates and nitrites are added, which, when interacting with meat pigments, form nitrosomyoglobin, which gives the sausages a persistent pinkish-red color.

A pinkish color or individual reddish spots in the finished culinary product reduce its organoleptic evaluation.

When analyzing the reasons for the appearance of abnormal coloring in meat products, it is first necessary to exclude violations of the heat treatment regime of the product. If the heat treatment is carried out carefully, then an abnormal color that does not correspond to the traditional one can be caused by two reasons: the questionable freshness of the meat or broth.

In meat of questionable freshness (especially when stored packaged with limited air access), primary, secondary, tertiary amines and ammonia accumulate. These compounds behave similarly to nitrates and nitrites when salting meat products, since during heat treatment they form stable pinkish-red hemochromogens.

The second reason for the abnormal coloring is the staleness of the broth in which benign meat products are heated. It is known that when storing broths, the pH of the medium changes to the acidic (acidification) or alkaline (action of putrefactive microflora) side. In an alkaline environment, the heme of denatured myoglobin has a red color (this can be easily checked by boiling a piece of meat with the addition of baking soda).

For more information on how to process products to maintain or change color in the desired direction, see the processing sections for each group of raw materials.

Consequently, the appearance of an abnormal color both during the accumulation of amines and ammonia, and when the environment changes to the alkaline side, is a kind of “indicator of trouble” and requires the elimination of the causes that caused it.

Acids are often used to give products the desired shade. For example, when poaching chicken fillets, lemon juice or citric acid is added, which lightens the product and gives it a creamy tint. For the same purpose, brains are boiled in water acidified with vinegar.

An acidic environment improves and intensifies the color of anthocyanins (which determine the color of cherries, plums, raspberries, etc.) and beet pigments. At the same time, the chlorophyll of green vegetables in an acidic environment becomes brown, which is undesirable.

The metal from which the cookware is made affects the color of the finished product. For example, green vegetables and beets should not be processed in aluminum containers; it is preferable to use stainless steel containers.

The change in color may be due to the hydrolytic breakdown of compounds and the release of coloring substances (for example, flavones when cooking onions, potatoes, white cabbage).

Great importance to change color, it comes into contact with air oxygen of peeled products containing polyphenolic compounds (potatoes, mushrooms, apples). In this case, enzymatic darkening of the product occurs.