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Studying the dynamics of tree growth using annual rings. Research work “Studying the dynamics of tree growth using tree rings. Studying the dynamics of tree growth using tree rings.

Studying the dynamics of tree growth using tree rings

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MUNICIPAL STATE EDUCATIONAL INSTITUTION

ZYUZINSKAYA SECONDARY

GENERAL EDUCATION SCHOOL

Research

“DETERMINING THE AGE OF A TREE

BY ITS TREE RINGS"

Completed by: 4th grade student

Snegirev Dmitry

Supervisor:

primary school teacher

Snegireva Natalya Vladimirovna

Zyuzya 2015

CONTENT

    Introduction………………………………………………………………………………2 page.

    Theoretical part…………………………………………….4 p.

    Practical part of the study. ………………………………5 pp.

    Conclusion…………………………………………………….…...7 pages.

    References………………………..……………………….8 pp.

    Application.

Introduction

I want to start my research work with the fact that in 1969 a new building of the Zyuzinsky secondary school was built. Then, during school cleanup days, students from grades 1 to 10, together with their teachers, planted tree seedlings around the school. The seedlings grew, turned green and, thanks to their care, turned into huge trees. The poplar growing at the entrance to the school was especially slender and powerful. But in 2011 this tree was forced to be cut down because... it began to threaten the safety of the school. We decided to investigate the cut of this tree. I tried to independently determine the age of the tree and clarify in what year it was planted.

So I chose the topic:"Determining the age of a poplar by its growth rings."

Goal of the work:

Determine the age of the poplar and establish a connection between age and conditions of its growth.

Tasks :

1. Study the literature on the topic;

2. Determine the age of the tree based on the specifically selected tree cut;

3. Analyze the annual rings.

4 . Formulate conclusions to confirm the stated hypothesis.

Research hypothesis:

1.The age of the tree can be determined by the number of annual rings.

2. The width between the annual rings depends not only on the age of the tree, but also on the living conditions of the tree in different years.

The subject of the study is I cut down a poplar tree growing near the school.

Object of study factors influencing the width of tree rings.

Basic working methods:

    research;

    method of analysis and generalization.

    descriptive;

Theoretical part

Trees growing in climatic zones with a seasonal climate grow differently in summer and winter: the main growth occurs in the summer, but growth is very slow in winter. Differences in conditions lead to the fact that wood growing in winter and summer differs in its characteristics, including density and color. Visually, this is manifested in the fact that the tree trunk on a cross cut has a clearly visible structure in the form of a set of concentric rings. Each ring corresponds to one year of the tree’s life (the “winter” layer is thinner and visually simply separates one “summer” ring from the other). A well-known method for determining the age of a cut tree is by counting the number of growth rings on the cut. Depending on many factors operating in the summer (season length, temperature, precipitation, etc.), the thickness of the growth rings varies in different years of the tree’s life. The differences in the thickness of the rings in different years are quite significant. By taking into account the width of each ring and using mathematical statistics methods, the probability of error is significantly reduced.

Practical part

My job is to study the saw cuts. The study of poplar cuttings is based on the method of ring analysis, which is based on the property of a tree to grow annually by one annual ring.

Using the annual rings, I will try to determine the age of the tree and its growing conditions.

Description of the material being studied.

For the study, a tree from a felling was used; a cross-section of a poplar was taken. (Appendix No. 1)

By carefully examining the cut surface with the naked eye and by touch, you can be convinced that the wood cut has a different structure.

(Appendix No. 2)

Counting the width of the rings.

The most important procedure when performing this task is calculating the width of the growth rings.

First, with a thin pencil, I outline the line along which I will take measurements. The line should run exactly from the center of the cut to its outer edge (along the radius). For measurement, you should select the sector of the trunk with the least number of anomalies - cracks, non-concentric seals, remnants of knots, old closed wounds, etc. The counting line should run along the maximum “average” sector of wood.

(Appendix No. 3)

Then we apply a ruler with clearly visible millimeter divisions to the outer edge of the last (outer) ring. The zero of the ruler should coincide with the outer edge of the last ring.

(Appendix No. 4)

The study is carried out using a ruler (take a 30 cm ruler) and a magnifying glass

Barrel diameter D – 66 cm

R 1 = 1 cm R 2 = 1cm R 3 = 0.9cm R 4 = 1.2cm R 5 = 1.3cm R 6 = 0.8cm

R 7 = 0.5 cm R 8 = 0.5 cm R 9 =0.9 cm R 10 = 1cm R 11 =0.9cm R 12 =1cm R 13 =1cm R 14 =0.9cm R 15 =0.5cm R 16 = 0.6cm R 17 = 0.5cm R 18 = 0.7cm R 19 =0.8cm R 20 = 1cm R 21 =1.5cm R 22 =0.4cm R 23 =1cm R 24 = 1.5cm

R 25 = 1.8cm R 26 = 2cm R 27 = 1.5cm R 28 = 1cm R 29 = 1.4cm R 30 =1.5cm R 31 =1.4cm R 32 =1cm R 33 =0.8cm

R 34 = 2cm R 35 = 2cm R 36 = 2cm R 37 = 2.3cm R 38 = 2.5cm R 39 =0.6cm

R 40 = 0.5cm

Examination with a magnifying glass showed that the approximate radius of width between growth rings isR 1 = 1.5 cm(see Appendix 5)

The specimen has forty annual rings. In the center there is a looser core, clearly visible. The growth rings are wide, dark and light, barely distinguishable, not the same in width on different sides of the tree, the wood is durable.

While researching the ring count, I found out that the tree is 40 years old and was planted around 1971. 2011 (year when the tree was cut down) - 40 (number of annual rings) = 1971. This is confirmed by the recollections of eyewitnesses. The school was opened in 1970, trees were planted the following year in the spring.

The width of the distance between the annual rings is from 0.5 to 2.5 mm.

I also determined favorable and unfavorable years for tree growth, this is shown in the table. (Appendix 6)

Also, based on the distance between the growth rings, I found out where the south and north sides of the tree were. This can be seen from the growth rings. Where there are narrow rings and the width between the rings is from 0.2 mm to 1 cm, this is the north, and where there are wide rings and the width between the rings is from 1 cm to 2.5 cm, this is the south. (Appendix 7)

Conclusion: The tree is approximately forty years old. It grew in damp lands and ate well, as evidenced by the wide, light yellow rings and the condition of the wood. The tree grew in a well-lit place, which is why the width of the annual rings on different sides of the tree is approximately the same.

We can say for sure that such a plant could have become a long-liver if it had not been cut down.

Conclusion

After analyzing the obtained material, I came to the conclusion that by counting the number of growth rings using a ruler, you can determine the approximate age of the cut tree.

By the thickness of the growth rings you can find out in what conditions the tree grew in different years of its life. Narrow growth rings indicate a lack of moisture, shading of the tree and its poor nutrition. The cardinal directions can also be determined by the growth rings. Tree rings are usually wider on the side of the tree that faces south and narrower on the side that faces north.

Since the thickness of the trunk increases every year, it would seem that long-livers should be looked for among thick trees, but this was not the case - the growth of a tree in thickness mainly depends not on the age of the plant, but on the conditions of its growth.

One might ask: “Why know the age of a tree?”

The answer, in my opinion, is simple.A tree is a unique source of information from which a person can learn about weather conditions, the quality of the soil, and the ecological state of the area at different periods of time. The tree “can be read like a book.” Take a closer look and you will penetrate the secrets of the past and present!

Bibliography

1. B.N.Golovkin, M.T.Mazurenko. Encyclopedic edition

“I explore the world” - M.: Astrel Publishing House LLC, 2002.

2. V.A.Korchagina. Biology: Plants, bacteria, fungi, lichens: Textbook. for 6-7 grades.-M.: Education, 1990.

Appendix No. 6

Analysis of tree growth conditions

Favorable years

Unfavorable years

1-5 (1971-1975)

6-8 (1976-1978)

9-14 (1979-1984)

15-19 (1985-1989)

20,21 (1990-1991)

23-26 (1993-1996)

27-29 (1997-1999)

30-32 (2000-2002)

34-37 (2004-2008)


Municipal educational institution

“Secondary school named after. Novikova R.A.

With. Kovylino, Chernyansky district, Belgorod region"
Research

“Studying the dynamics of tree growth using tree rings”

Performed:

Sbitneva Svetlana,

10th grade student

Supervisor:

Grevtseva V.A.

biology teacher
Content.

1. Introduction.

2. Preparing the cut.

3. Counting tree rings.

4. Building a graph.

Purpose of work: to prepare cuts of tree trunks with subsequent

counting and measuring the width of tree rings (annual

increments).

Tree rings visible on the cross-section of a tree trunk growing in a temperate climate zone appear as a result of the fact that during one growing season the tree grows unequally in thickness. At the beginning of summer, the growth of the trunk in thickness occurs due to large loose cells, which subsequently have a light shade. At the end of the growing season - in autumn - the resulting wood cells are smaller and their shells are thicker than in spring and summer. The color of these cells is darker than those formed at the beginning of summer. Thus, the growth ring has a light and dark component, and as a result of this, we can see the boundaries of the growth rings on the cut tree.

Such visible tree rings form only in those areas of the Earth where there is a clear change of seasons. In areas without a clear change of seasons, for example on the equator, tree rings also form, but they are practically invisible - the wood is dark in color.

By the number of growth rings on the cut trunk, you can quite accurately determine the age of the tree. In addition, the width of one annual ring, that is, the annual growth of a tree, fluctuates from year to year. It depends on the condition of the tree in a given growing season, which, in turn, depends on the climatic conditions of the year, the health of the tree and many other factors.

Every year the tree grows an outer layer of wood in the form of a ring, which is why it is called annual. By counting the number of rings, we can accurately determine the age of the tree. But not all trees have annual rings, and they are not always exactly annual.

Each growth ring consists of two parts: light and loose (this is the inner part of the ring) and darker and denser (the outer part). These two parts of the same ring formed at different times: the lighter and looser part - in spring and summer; dark in autumn. In winter, in our climate, the tree does not grow. In tropical climates where there is no winter, the tree grows all the time, and most tropical trees do not have noticeable growth layers.

Between the wood and the tree bark there is a special tissue consisting of living cells capable of division and growth. This tissue is called cambium. It forms a very narrow ring around the wood, which can only be seen with a magnifying glass. When cambium cells divide, both wood cells and bark cells are formed. But the cells that produce the cambium are different. In one case, cells are created that make up conductive tissue, that is, one through which various tree juices and nutrients move; in the other, the fabrics are mechanical, giving strength to the trunk.

The emergence of conductive and mechanical tissue cells is not at all accidental.

In the spring, when the frosts stop and the ground thaws, the tree begins to live: the flow of juices opens, the leaves bloom, flowering takes place, and new shoots appear. At this time, the tree needs accelerated transfer of water and nutrients from the roots to the branches. Therefore, the cambium produces many cells to build conductive tissue, consisting of wide-lumen vessels that can accommodate a large amount of necessary juices. They create the inner, spring part of the annual ring. By autumn, narrow-lumen vessels are formed, which give strength to the trunk. The cells of the mechanical tissue have thickened walls, their cavities are much smaller. These cells create the outer, compacted, autumn part of the growth ring. The next year, cells of conductive tissue are formed again, and then mechanical ones.

Thus, the boundary between the wood of two adjacent years is the line of contact of cells formed in the fall of the previous year with cells deposited in the spring of the following year. On a cut tree it is visible to the naked eye. Better yet, the boundary between adjacent annual layers of wood is visible under a microscope.

In coniferous trees - pine, spruce, fir, cedar and larch - late (autumn) wood is darker in color than spring wood, and therefore their growth rings are always clearly visible. In deciduous trees, such as oak and ash, the growth rings are also clearly visible, because a large number of large vessels are concentrated in the spring part of the wood of these plants. In others, for example, aspen, birch, linden, and willow, the vessels are small and the growth rings are difficult to distinguish. In order for the boundary between the rings to appear sharper, such wood must be painted (for example, with a chemical pencil).

How does a tree trunk change with age?

Scientists, studying the course of tree growth, examine not only the thickness of the trunk, but also its height at different periods of life, as well as appearance, shape and volume.

Every year, the growing wood, like a cover, covers the tree trunk, and its outer parts are the youngest, and the inner parts, located closer to the core, are the oldest.

If we sawed a tree trunk lengthwise, we would see a whole series of cones covering one another. Each of these cones reflects the shape of the tree trunk at different periods of its life. In other words, a longitudinal section of the trunk shows how the height, thickness and shape of the tree trunk changes annually. Therefore, in such a longitudinal section, you can see and measure changes in wood thickness and height.

To saw a whole tree trunk lengthwise, and even through its very core, is quite a difficult task. Usually it's simpler. Circles are cut across the trunk of a felled tree every one or two meters. The bottom circle is cut out at the very root - it will be the largest. For example, a felled pine tree has 120 annual rings on the bottom circle, and on the next one, which was cut at a height of 2 m, there are fewer rings, on the next one - even fewer, and finally, on the last, fourteenth circle, located at a distance of 0.5 m from the top , there are very few rings - only 12.

What does it mean? If there are 120 growth rings on the bottom circle, i.e. the tree is now one hundred and twenty years old, and on the last circle there are 12 growth rings, then over the last 12 years the tree has grown by only 0.5 m, since from the last circle to the top it was only 0.5 m. The height of the tree at 108 years (120-12) was the one on which the last circle was cut. On the next circle from the top you can already count 26 rings. This means that a tree at the age of 94 years (120-26) had the height from which a circle with 26 growth rings was taken. And so on.

Consequently, we can always find out the age of the tree at the height of the circle we cut.

One more example. They cut down the tree. On the lowest circle (or on the stump) 62 rings were counted. This means that the tree was 62 years old.

The preparation was done.
In the forest we will find a fallen or standing dry tree, from which we can determine the year of death. If the tree still has needles, then it died recently and the current year can be considered the year of its death. If there are no needles, but the smallest branches are preserved, then it died last year. If there are no small branches and needles, but the bark is well preserved, then about two years ago. It is better not to use older trees, since it is impossible to accurately determine the year of death of the tree; all further efforts will be negated by the lack of a “STARTING POINT” of the CHRONOLOGICAL SCALE.

Freshly fallen windfall trees can be considered an ideal option for preparing saw cuts. They die “not their own death,” i.e. not from diseases and pests, but under the influence of external forces.

We cut the trunk as close as possible to the base of the tree, since it is desirable to know the year of birth of the tree as accurately as possible. However, in any case, when subsequently calculating the year of birth of the tree, several years are added to the age of the trunk at the cut level until the tree has grown to the height of the cut. A distance of half a meter corresponds to approximately 5 - 7 years, about a meter - 10-12.

We make the cut using a mechanical saw.

To make a training cut (that is, not a one-time study, but for storage and subsequent repeated study by schoolchildren), we prepare a disk, that is, we cut the cut twice, making two parallel cuts at a distance of approximately 10 cm from each other.
Counting the width of the rings.
The most important procedure when performing this task is calculating the width of the growth rings.

First, use a thin pencil to mark the line along which the measurements will be taken. The line should run exactly from the center of the cut to its outer edge (along the radius). For measurement, you should select the sector of the trunk with the least number of anomalies - cracks, non-concentric seals, remnants of knots, old closed wounds, etc. The counting line should run along the maximum “average” sector of wood.

Then we apply a ruler with clearly visible millimeter divisions to the outer edge of the last (outer) ring. The zero of the ruler should coincide with the outer edge of the last ring.

Conclusion: The width of the growth rings on the illuminated side of the tree is greater than on the shadow side, therefore, from the stumps remaining from lonely trees, you can determine where north and south are. While the young tree lives in the shade, the rings are narrow; when more light begins to reach, they become wider. It should be noted the years with minimum and maximum growth, periods of slow and accelerated tree growth. The width of the growth rings also depends on the climatic and weather conditions of growth.

1

This article provides a detailed analysis of existing research in the field of studying the biological basis of tree-ring variability, and outlines modern ideas and the history of the issue. The prospects for improving the methods of dendroclimatic reconstructions and the methodology for using dendrochronological information in forest genetics and breeding are discussed. Currently, there are no studies analyzing the possibility of adaptive modification variability in the anatomical structure of tree rings in response to climatic influences. Also, many issues of intrapopulation variability of woody plant species based on the anatomical structure of tree rings and the time dynamics of tree ring width have been poorly studied. Research in this direction may be of practical importance from the point of view of improving methods for reconstructing and forecasting the frequency of droughts, as well as for improving methods of forensic botanical examination using dendrochronology.

annual ring

phytohormones

dendrochronology

dendroclimatology

1. Byusgen M. The structure and life of our forest trees // Translation with permission of the author A. Bitrikh. Ed. L.I. Yashnova. – St. Petersburg: Printing house St. Petersburg. city ​​administration, 1906. – 376 p.

2. Vaganov E.A., Terskov A.I. Analysis of tree growth based on the structure of tree rings. – Novosibirsk: Nauka, 1977. – 94 p.

3. Vikhrov V.E. Study of the structure and technical properties of wood in connection with forest types // Questions of forestry and forestry. – M.: USSR Academy of Sciences, 1954. – P. 317−325.

4. Gopius Yu.A., Kazantseva E.V., Korovin V.V., Korchagov S.A., Laur N.V., Melekhov V.I., Nikolaeva N.V., Pogiba S.P., Robakidze E.A., Romanovsky M.G., Rumyantsev D.E., Tarkhanov S.N., Torlopova N.V., Tsarev A.P., Shchekalev R.V. Production process and structure of trees, timber and forest stands. Deposited manuscript No. 792 – B2006, VINITI, 2006. – 106 p.

5. Lear H., Polster G., Fiedler G.-I. Physiology of woody plants. – M.: Timber Industry, 1974. – 421 p.

6. Korovin V.V., Novitskaya L.L., Kurnosov G.A. Structural anomalies of the stem of woody plants. Second edition, corrected and expanded. – M.: MGUL, 2003. – 280 p.

7. Korovin V.V., Rumyantsev D.E. Natural selection and prospects for artificial selection on growth rate in conifer populations // Bulletin of the Moscow State Forest University. Forest Herald. – 2007. – No. 5 (54). – P. 50–54.

8. Kosichenko N.E. The influence of genotype - environment on the formation of stem microstructure and diagnostics of technical properties, growth and stability of woody plants. Author's abstract. dis. doc. biol. Sci. – Voronezh, 1999. – 40 p.

9. Lobzhanidze E.D. Cambium and the formation of tree rings. – Tbilisi: AN GSSR, 1961. – 159 p.

10. Menyailo L.N. Hormonal regulation of xylogenesis in conifers. – Novosibirsk: Nauka, 1987. – 184 p.

11. Moskaleva V.E. The structure of wood and its changes under physical and mechanical influences. – M.: USSR Academy of Sciences, 1957. – 166 p.

12. Perelygin A.M. Wood Science // Second edition, revised and expanded Assoc. B.N. Ugolev. – M.: Timber Industry, 1969. – 318 p.

13. Razdorsky V.F. Architectonics of plants. – M.: Soviet Science, 1955. – 431 p.

14. Rumyantsev D.E. Diagnostics of the growth characteristics of pine and spruce in southern Karelia using dendrochronological methods: dis... cand. biol. Sci. – M., 2004. – 115 p.

15. Rumyantsev D.E. Potential for the use of dendrochronological information in forestry science and practice: dis... doc. biol. Sci. – M. 2011. – 354 p.

16. Rumyantsev D.E., Melnik P.G., Aleksandrova M.S. Genotypic components of variability in radial growth // Bulletin of the Moscow State Forest University. Forest Herald. – 2006. – No. 5 (47). – pp. 124–128.

17. Rumyantsev D.E., Melnik P.G., Stepanova O.V. Dendrochronologically reconstructed dynamics of ranks in terms of productivity and wood quality in different provinces of spruce in geographical cultures // Bulletin of the Moscow State Forest University - Forest Bulletin. – 2007. – No. 5 (54). – pp. 109–113.

18. Rumyantsev D.E., Aleksandrova M.S., Nikolaev D.K. Conjugation in short-term variability of the width of early and late wood in the annual rings of larch trees in the Moscow region // Bulletin of the Moscow State Forest University - Forest Bulletin. – 2009. – No. 1. – P. 56–60.

19. Rumyantsev D.E., Epishkov A.A., Cherakshev A.V. Frequency of occurrence of the coefficient of synchrony in coenopopulations of Scots pine from the Vologda, Vladimir and Nizhny Novgorod regions // Biological aspects of propagation, adaptation and stability of plants: materials of the All-Russian Federation. (with international participation) scientific conference. (Saransk, November 20–22, 2014). – Saransk, 2014. – pp. 175–177.

20. Sanaev V.G. Anisotropy of physical and mechanical properties of wood surface // Proceedings of the II International Symposium “Structure, properties and quality of wood - 96”, - M.: MSUL, 1996. - P. 219–223.

21. Serebryakov V.K. Essays on the history of botany. Part one. – M.: State educational and pedagogical publishing house of the People's Commissariat of Education of the RSFSR, 1941. – 247 p.

22. Sudachkova N.E. Cambial activity of conifers and its regulation // Scientific research for forests of the future. – M.: Nauka, 1981. – P. 165–167

23. Timiryazev K.A. Plant life: Ten public lectures // Academician. Sciences of the USSR. – M.: Publishing house Acad. Sciences of the USSR, 1962. – 290 p.

24. Chavchavadze E.S. Coniferous wood. – L.: Nauka, 1979. – 192 p.

25. Zimmermann M.H., Brown C.L. Trees: structure and function. Berlin-Heidelberg-New-York: Springer-Verlag, 1989. – 336 p.

The first researcher to become seriously interested in the processes of differentiation of growth ring cells into early and late wood was Julius Sachs. In 1868, he suggested that the formation of autumn wood with its thick shells and narrow cell cavities is a consequence of the mechanical pressure of the bark increasing towards autumn on the cambium and the young wood cells newly formed from it. The increase in bark pressure seemed to Sachs a natural consequence of the constant increase in the diameter of the wood cylinder during the summer. K.A. To Timiryazev, this hypothesis seemed completely justified, and he summarized it briefly in his book “The Life of a Plant,” published in 1878. Ten public lectures".

The discussion that erupted in the scientific community, as a result of which Sachs’s hypothesis was rejected, is described in detail in the work of M. Busgen. Wanting to confirm Sax's hypothesis, Hugo de Vries conducted a series of experiments. In the fall, he made cuts on the tree bark to relieve its pressure. Despite the late season, fibers that were less compacted and equipped with larger vessels appeared in the deposited wood. Conversely, by applying tightening or pressure bandages to tree branches in the spring, Frieze was able to artificially cause the formation of autumn wood with more flattened fibers and with fewer narrow vessels.

The next stage in testing Sachs's hypothesis was the experiments of Crabbe, who in 1882 showed that the increased bark pressure on wood assumed during the experiments of Sachs and de Vries did not exist at all. Krabbe showed that a ring of bark, removed from a branch or trunk, naturally contracts so much that when it is applied again to the old place, its ends no longer meet. The ring has to be pulled out to get a proper fit. The force required for stretching serves as a measure of the contraction of the cortex, in other words, it expresses the amount of pressure it produces in an intact state. The degree of contraction, or the amount of tangential tension, divided by the radius of the tree gives the amount of bark pressure on the wood in the radial direction. In other words: the radial pressure is equal to the tangential tension divided by the radius.

Krabbe determined the tangential tension of the bark using weights that stretched strips of bark to their original sizes. Stretching was carried out on wooden stumps, the cross-section of which was equal to the cross-section of the trunk or branch that was ringed. Krabbe's experiments showed that the tangential tension of the bark actually increases with increasing diameter of the cut under study, provided that the bark is clean and there is no crust. However, further experiments established that the contraction of the bark, although it increases with the diameter of the trunk, is far from proportional, i.e. bark tension does not yet cause an increase in pressure on the wood in the radial direction.

Measurements systematically carried out by Krabbe in spring and autumn on the same trees also showed that the magnitude of fluctuations in bark pressure in one direction or another during the growing season is so insignificant that it cannot have a significant effect on the activity of the cambium. The difference in bark pressures, taken into account simultaneously at different heights of a trunk or branch, turned out to be more significant in these experiments than insignificant fluctuations in bark pressure for only one cross section over the entire growing season. In addition, as Krabbe notes, there are examples of such a sharp transition from early wood to late wood that it is completely unclear where the sudden pressure that caused such a sharp instant compaction of cells could have come from.

In a later work, published in 1884, Crabbe sets out the results of experiments in which he was able to achieve a reduction in the radial size of xylem elements at a pressure of no less than three or five atmospheres. However, under natural conditions, the values ​​of bark pressure measured by Krabbe varied among different species and during the growing season only within the range of 0.227−1.7 atmospheres.

After the publication of Krabbe's works, de Vries' experiments lost their evidential power for the scientific community. In contrast to Sachs's theory, at the end of the 19th century, several theories of the formation of annual layers were created (theories of R. Gatrig, Wheeler, Lutz, Stassburger, Jost, de Maire, Haberland). Scientists such as R. Hartig, Wheeler, Lutz, Strassburger, Haberland relied on the idea that the reason for the formation of tree rings is a change in the nutritional conditions of the cambium and the water content in it, but they differed in the details of the interpretation of these processes. Only in the light of the study of plant hormones did the process of regulation of cambium activity receive a consistent explanation.

The forerunner of the hormonal theory of cambium activity should be considered the German forester Theodor Hartig, who in 1853 noted that radial growth usually begins to form at the base of a bud that has begun to grow and spreads downward into the branches and trunk. In the 30s. In the 20th century, based on a generalization of a number of experimental observations, Zimmermann formulated a theory according to which indolyl-acetic acid (auxin), produced by growing buds and elongating shoots, spreads basipetally and stimulates the activation of the cambium in the spring. It is now believed that in addition to auxin, other substances are involved in this process, such as cytokinins and gibberellins, raffinose and galactose.

In the monograph by L.N. Menyailo provides detailed data on the hormonal metabolism of conifers in connection with the formation of wood. Her conclusions are based both on a generalization of a wide range of literary sources available to the author, and on the results of her own experiments with Scots pine seedlings. Summing up his research, Menyailo notes that the timing and intensity of cambial activity and cytodifferentiation of tracheids are determined by the specificity of the seasonal supply and dynamics of phytohormones in the cambial zone of the trunk of conifers. This process is influenced by the different timing of the functioning of the apical meristems of the shoot and roots, the growth of young needles and the presence of old needles. There is a gradient of phytohormones along the height of the tree, which causes differences in the timing and intensity of cambial activity and tracheid ontogenesis and determines the specific structure of growth rings in different parts of the trunk.

Research shows that this process is determined by changes in auxin concentration. A detailed review of works on this topic is given in the monograph by H. Lear, G. Polster, G.-I. Fiedler. It is especially important to mention the results of studies showing photoperiodic control of the transition of cambium to latewood formation. Referring to the data of Tselawski (Zelawski, 1958), Larson (Larson, 1960), Tselawski and Wodiziki (Zelawski, Wodiziki, 1960), it is noted (Lear et al., 1974) that European larch, resinous pine and Scots spruce form early wood, and with short days late wood. The authors note that photoperiod acts in this case, probably only indirectly, by controlling the formation of auxins and growth inhibitors in leaves.

Research by E.A. Vaganova and I.A. Terskova found that in spruce the duration of the formation of early tracheids in annual rings coincides with the period of increase in the fresh mass of needles, the formation of transitional tracheids coincides in time with the decline in the growth of the main shoot and the end of its growth. In pine, early tracheids are formed while the main shoot is growing and while the increase in fresh needle mass, expressed as a percentage of the final value, exceeds the increase in dry mass.

It should be added that in the experiments of V.P. Malchevsky [according to 13], in pine trees cultivated under constant conditions of temperature, lighting and soil moisture, growth layers with zones of early and late type wood were still formed. This was considered by V.F. Razdorsky as undoubted evidence that histological differentiation into zones of one growth layer is partly the result of periodic changes in the influence of the environment on a given tree, and partly a hereditary property that occurred to some extent independently of periodic changes in environmental conditions.

Annual layering, according to Jeffrey, is absent in the wood of Paleozoic and Triassic conifers; it appears in the Jurassic. The differentiation of annual layers into early and late wood in conifers has been clearly noted since the Mesozoic. The appearance of annual layering is associated with the occurrence of warm and cold periods during the year and, therefore, with the need for seasonal periodicity, the activity of the meristem increases.

In the dissertation of N.E. Kosichenko paid considerable attention to the analysis of the fact that in conifers the width of the late wood layer in the annual ring remains practically constant during ontogenesis, while in deciduous ring-vascular species the width of the early part is constant. These differences, from the author’s point of view, have a deep biological and evolutionary meaning. The width of the late wood in conifers and the width of the early wood layer in ring-shaped trees are strictly genotypically determined characters that are weakly dependent on environmental conditions. Particularly important in Kosichenko’s conclusions is the fact that late wood of conifers and late wood of ring-vascular are characters with different genetic manifestations. This is a serious argument in favor of the hypothesis of the independent occurrence of pinoxylity in dicotyledons.

In Chavchavadze’s monograph, the issues of the evolution of pinoxylity are considered in more detail; we will allow ourselves only a brief retelling of the facts and views presented there.

First of all, most fossil plants, such as lepidodendrons, seed ferns, bennettites, as well as tree ferns and cycads that have survived to this day, belong to manoxyl plants, i.e. to those in whom the bulk of the trunk is occupied by parenchymal tissues. Pinoxyl plants include cordaite and coniferous plants; the bulk of their trunk is occupied by xylem, which, in addition to conducting water, also performs the mechanical function of supporting the crown. It is believed that in dicotyledons the pinoxyl type of organization appeared independently of conifers. The cambium in manoskil plants is active for a short time; over time, its elements are completely differentiated. In pinoxylaceae, on the contrary, the cambium is active throughout the life of the tree, which, of course, opens up greater opportunities for adaptive reactions during ontogenesis.

Without going into the details of phylogeny, well outlined by E.S. Chavchavadze, we would like to once again focus the reader’s attention on the fact that pinoxylity, and then periodicity in the activity of the cambium and its consequence - annual layering in different groups of plants arose independently. This should speak, first of all, of the great adaptive value of this trait.

What is the biological meaning of dividing the annual layer into early wood (the cells of which have large cavities, but thin cell walls) and late wood (the cells of which have small cavities and thick cell walls)? It is generally accepted that early wood is well adapted for transporting water along a tree trunk, while late wood provides mechanical strength to the trunk. In conifers, the cells of early and late wood differ not only in the thickness of their walls, but also in the number and size of the bordered pores. Early tracheids have a large number of large bordered pores on their radial walls; late tracheids contain smaller bordered pores and in much smaller quantities. In general, late wood in pine, larch and spruce is 2.5-3 times higher than early wood in terms of density and elastic modulus. In deciduous species, the differences between early and late wood in terms of physical and mechanical properties are not so pronounced; an indicator such as the excess of the density of the early zone over the late zone varies from 1.1 in hornbeam to 1.4 in alder.

It is well known that the existence of growth rings in wood in its geographical aspect is associated with the presence of a cold season throughout the year. In mild tropical and subtropical climates, they are almost not expressed; they are only single rows of thick-walled tracheids, appearing in the mass of thin-walled xylem elements, such as in conifers such as many representatives of the family Araucariaceae, Podocarpaceae, Cupressaceae.

It is likely that the first stage in the evolution of this trait in conifers was the pattern according to which the cambium, when its activity slowed down, deposited a single-row layer of thick-walled cells that played the role of reinforcement. This feature determined the appearance of the so-called false tree rings, which are still widespread today in breeds growing in subtropical climates.

At the same time, as the climate divided into temperate and cold seasons of the year, the work of the cambium required synchronization with the course of climate change throughout the year. Photoperiodic mechanisms apparently played an important role in this process. It can be assumed that the cold winter placed increased demands on selection for trunk strength due to factors such as frost and snow, which required woody plants to form wide layers of late wood. The difficulty in transporting water through such wood, in turn, probably determined selection for the formation of a pronounced layer of early wood.

The presence of a pronounced genotypic component in the variability of tree rings allows the use of dendrochronological information in research in the field of forest genetics, breeding and dendrology. In our works we have repeatedly touched upon these issues. To summarize, it should be noted that the annual ring of woody plants is characterized by strong variability in the anatomical structure depending on the year of its formation. It is observed both by quantitative (width of the growth ring, ratio of early and late wood, optical density of the late wood layer) and qualitative characteristics (“light rings”, “rings with intrazonal thickenings”). The genotype of a tree remains the same from year to year, and therefore the analysis of the variability of tree rings in connection with the variability of environmental conditions in different years makes it possible to study the adaptive polygenic systems of woody plants, the age-related dynamics of hereditary characteristics of wood structure, and the ecophysiological causes of the pathological work of the cambium.

The data obtained in such studies determine the possibility of solving practical problems of forest selection and dendrology - assessing the heritability of wood structure traits; identification of valuable genotypes differentiated for different economic tasks of forest use; diagnostics of factors that adversely affect the growth of tree introduced species in a particular region; forecasting the response of different species and intraspecific forms of woody plants to global climate change; studies of micro- and macroevolution processes.

A separate scientific problem of theoretical and practical interest is the analysis of the polymorphism of cenopopulations of woody plants based on quantitative characteristics of the dynamics of time series of radial growth and series derived from them, for example, by the synchronicity indicator. There are different ways to calculate coefficients that give estimates of similarity between series. The similarity between dendrochronological series is an integral indicator of the similarity of the plant groups they characterize in terms of hereditary ecological properties; this information is valuable for studying the spatial genetic structure of forest phytocenoses. On the other hand, the development of this direction will improve the methods of dendrochronological examination of the place of origin of felled wood.

In general, it is also important that taking into account the biological expediency of tree-ring variability can help detail the methods used for reconstructing climates of past eras. Currently, there are no works attempting to analyze the adaptive meaning of the modification variability of the anatomical parameters of the growth ring from year to year. It is likely that in addition to the teratological structure of tree rings associated with disruption of the normal functioning of the cambium, there are also tree rings whose anatomical structure is an adaptive response of the plant to certain environmental conditions during the growing season. The study of this issue and the search for the possibility of recognizing these two groups of cases are of fundamental interest for the further development of dendroclimatic reconstruction methods.

The work was carried out with the financial support of the Russian Science Foundation (grant 14-17-00645) at the Moscow State Forestry University within the framework of scientific cooperation with the Institute of Geography of the Russian Academy of Sciences.

Reviewers:

Korovin V.V., Doctor of Biological Sciences, Professor, Professor of the Department of Breeding, Genetics and Dendrology, Moscow State University of Forestry, Mytishchi;

Chernyshenko O.V., Doctor of Biological Sciences, Professor, Head of the Department of Botany and Plant Physiology, Moscow State University of Forestry, Mytishchi.

The work was received by the editor on February 12, 2015.

Bibliographic link

Rumyantsev D.E., Epishkov A.A. BIOLOGICAL BASES OF VARIABILITY IN TREE RINGS // Fundamental Research. – 2015. – No. 2-3. – P. 481-486;
URL: http://fundamental-research.ru/ru/article/view?id=36838 (access date: 06/16/2019). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

Municipal Educational Institution "Center for Additional Education of Children"
Georgievsky district"
Children's Association "Nature Explorers"

Determination of plant resistance
to soil and air salinity

Introduction


Goal: to study the resistance of some plants growing in the village of Novozavedennoye to soil and air salinity.
Tasks:
Assess the sensitivity of plants to soil and air salinity;
Determine the influence of chloride and carbonate salinity;
Identify species that are relatively resistant to the adverse effects of salts.

The practical significance of the research work lies in the fact that it can be used by the housing and communal services service when carrying out landscaping activities, in ecology lessons when studying anthropogenic influence on the soil, as well as when conducting classes in the elective course “Plant Physiology”.

Effect of salinity on plant organisms.
Plants adapted to exist in conditions of excessive salinity are called halophytes (from the Greek “galos” salt, “phyton” plant). These are salt-tolerant plants that grow on various soils along the shores of salt lakes and seas, and especially on saline soils in steppe and desert areas. All halophytes can be divided into three groups:
1) True halophytes (euhalophytes) are the most salt-tolerant plants, accumulating significant concentrations of salts in vacuoles.
2) Salt-secreting halophytes (crinohalophytes), absorbing salts, do not accumulate them inside the tissues, but remove them from the cells using secretory glands (hydathodes) located on the leaves.
3) Salt-impermeable halophytes (glycohalophytes) adapt to growing on saline soils due to the accumulation of organic substances in their tissues. High osmotic pressure in their cells is maintained by the products of photosynthesis, and not by mineral salts. The cells of these plants are poorly permeable to salts. (Sergeeva, 1971) Salinity leads to the creation of low water potential in the soil, so the flow of water into the plant is very difficult. The most important aspect of the harmful effects of salts is also the disruption of metabolic processes. The work of physiologist B.P. Stroganov shows that under the influence of salts in plants, nitrogen metabolism is disrupted, which leads to intensive breakdown of proteins, resulting in the accumulation of intermediate metabolic products that have a toxic effect on the plant, such as ammonia and other highly toxic products. Under the influence of salts, disturbances in the ultrastructure of cells occur, in particular changes in the structure of chloroplasts. (Strogonov, 1967)
A decrease in plant productivity under conditions of chloride salinity is determined by the inhibition of their growth, which is an integral characteristic of the plant response to environmental changes. The degree of plant inhibition and biomass reduction is directly correlated with the salt concentration in the substrate and the duration of salinity. The question of the indirect effect of salts on plant growth is unclear. (Waring, Phillips, 1984) Some authors argue that the main reason for the slowdown in plant growth under salinity conditions should be considered not the direct effect of excess salts in their tissues, but the weakening of the ability of the roots to supply metabolic products necessary for their growth to the shoots, i.e. slowdown the supply of nutrients from the substrate, inhibition of their metabolization in the roots and transport to the shoots. (Udovenko, 1977)
Of particular interest is the question of differences in the level of salt tolerance of different plant organs. The negative effect of high salt concentrations primarily affects the root system of plants. In this case, the outer cells in the roots that are in direct contact with the salt solution suffer. A characteristic feature of root systems on soils with deep salinity is their surface distribution. A sudden increase in NaCl concentrations in the medium leads to a sudden increase in the ionic permeability of the root system. When there is an excess of salts, plant roots lose turgor, die and, becoming slimy, acquire a dark color. Studies have shown that roots are more sensitive to salinity than above-ground organs. However, there are also known facts of the positive effect of substrate salinity on the accumulation of root mass with slow shoot growth. In the stem, the cells of the conducting system, through which the salt solution rises to the above-ground organs, are most susceptible to the action of salts. With sodium-chloride salinity, the shoots are short and quickly finish growing. The leaves are also highly sensitive to salinity. A common reaction for many crops is the death of the lower leaves, drying out of the tips of the leaves, and a change in leaf color from dark green to light green with a yellow tint - a clear sign of salt damage. (Genkel, 1982)
With increasing salt concentration, there is a tendency for plant succulence to decrease, which indicates a suppression of the ability to osmoregulate. With an increase in the concentration of sodium chloride, plants lose the ability to maintain hydration of their organs and this negatively affects their salt tolerance. But at the same time, different plant species have different abilities to regulate the water content in their tissues. Thus, C3 of a plant regulates the water content in its organs worse than C4. (Goryshina, 1979)
As a result of generalizing data on the influence of environmental salinity, the following factors of plant inhibition during salinity were identified:
1) It is difficult to supply water to the whole plant and, consequently, negative changes in the functioning of osmoregulation mechanisms;
2) Imbalance of the mineral composition of the environment, as a result of which disturbances in the mineral nutrition of plants occur;
3) Stress due to severe salinity;
4) Toxication. (Prokofiev, 1978)
In agricultural production, the main method of combating salinity is the reclamation of saline soils, the creation of reliable drainage and leaching of soils after harvesting. On solonetzes (soils containing a lot of sodium), reclamation is carried out using gypsum, which leads to the displacement of sodium from the soil absorption complex and its replacement with calcium. Adding microelements to the soil improves the ion exchange of plants under salinity conditions. The salt tolerance of plants increases after pre-sowing seed hardening. For cotton seeds, wheat, and sugar beets, treatment for an hour with a 3% NaCl solution followed by washing with water (1.5 hours) is sufficient. With such “hardening”, the permeability of protoplasm to salts decreases, the threshold for its coagulation by salts increases, the nature of metabolism changes - plants grown from such seeds are characterized by a lower intensity of metabolism, but are more resistant to chloride salinity. To harden to sulfate salinity, seeds are soaked for 24 hours in a 0.2% solution of magnesium sulfate. (Volodko, 1983)

Physiographic characteristics of the study site
Georgievsky district is located in the south of the Stavropol Territory. The village of Novozavedennoye is located in the east of the Georgievsky district, on the left bank of the Kuma River, at an altitude of 245 meters above sea level. Geographical location – 44o N. w. and 43o in. d., this is south of the temperate zone. The climate of the village is temperate continental. Summer is hot, the average temperature in July is +26 0C, the maximum temperature in July is +420C. Winters have little snow, the average temperature in January is -40C, the minimum temperature in January is -320C. The village is located in a zone of insufficient moisture; 400-500 mm of precipitation falls annually. (Savelyeva, 2003)
Eastern, northeastern, and western winds predominate. Natural phenomena such as fog are associated with climate. Every year, in the last five years, hail falls. The topography of the village is a hilly plain, to the north of the village the Prikumsky heights begin, up to 260 m, to the southeast are the Tersko-Kuma lowlands. The natural area is the steppe. The village is located in the transition zone - from chernozem to chestnut soils; in the Kuma River valley the soils are alluvial. (Vishnyakova, 2000)

3. Place, material, research methodology
When performing the work, the methodology proposed by A. I. Fedorova was used (Workshop on ecology.., 2001). This work was carried out in three versions.
Objects of study: black mulberry (Morus nigra), small-leaved elm (Ulmus laevis), common pear (Pyrus communis), sweet cherry (Cerasus avium), garden cherry (Cerasus vulgaris), common apricot (Armeniaca vulgaris), common lilac (Syringa vulgaris) , snowberry (Symphoricarpos albus), willow spirea (Spiraea salicifolia), common privet (Ligustrum vulgaris), fragrant mock orange (Philadelphus coronarius).
Equipment, reagents, materials: 100 ml cylinders; test tube racks; measuring tubes; scales; weights; sharp razor; salts Na2CO3, NaCl; water; twigs of different plants with 3-4 identical small leaves.
Option 1. The effect of dusting plants with salts on their stability (illustrates the effect of wind deposits on plants).
Work progress: Branches of different woody plants were weighed and leveled (by pruning) to the same weight, kept in water for 15 minutes until they were saturated with moisture, removed, dried with filter paper, and treated with a wetting agent (1% solution of green soap). The role of a wetting agent in a natural environment is performed by solutions of certain salts that form a gel, humic and fulvic acids contained in aeolian transfers, and most importantly, the secretions of the plants themselves. After this, the cut of the branch was quickly renewed with a razor and a large test tube with a strictly dosed amount of settled tap water was placed in the vessel. The opening of the vessel was tightly closed with a piece of staniol, and the test tubes were labeled. Salts (NaCI, Na2C03) were ground in a mortar until finely dispersed. Pieces of cotton wool were loosely wound onto a stick, tightened with thread and used as a brush, which was used to evenly dust the leaves, petioles, and experimental plants with salts. Control - plants without dusting. The branches were exposed to diffused light for 1 week, avoiding strong heating. Then, such signs as loss of turgor, the appearance of infiltration translucent spots, the appearance of necrosis (dead tissue), drying of leaf edges, their curling, etc. were taken into account. At the same time, water absorption from the test tubes was measured using a measuring tube.
Option 2. The effect of salt precipitation on plant leaves (simulates the effect of salt precipitation on a leaf or dew on the salt cover of a leaf, i.e. the effect of a salt solution on a leaf).
Work progress: Branches of different types of woody plants with the same number of leaves were aligned by weighing, as in the previous experiment, and kept by complete immersion in 5% salt solutions (NaCI, Na2C03) for 15 minutes. Control branches were kept in water. At least four branches of each species were used for the experiment. After this, the sections were quickly renewed with a razor and the branches were placed in water (the same amount in all experiments and control variants). Evaporation of water from the test tubes was prevented by isolating with foil. After 1 week, the condition of the plants was assessed and measured
water absorption.
Option 3. Absorption of solutions from saline soils by plants (the experiment simulates the state of plants and their absorption of solutions from saline soils, which is caused by saline groundwater lying close to the surface).
Work progress: Prepared 5% salt solutions (NaCI, Na2C03). Equal amounts of these solutions were poured into large test tubes. Control - water. Plant branches were weighed and leveled by pruning. The vessels were insulated from water evaporation with foil. After 1 week, the plant condition was assessed and water uptake was measured.

Research results
The effect of dusting plants with salts on their stability. In this variant, we observed the effect on plants of wind deposits, which contain various salts and are carried by the wind. The effect of salinity was assessed by visual observations of the appearance of plants and compared with control plants. The observation results are presented in Table 1. Table 1
Damage to plant leaves when dusted with salts.
Name
plants
Nature of leaf damage

Na2CO3
NaCl

Small-leaved elm
The appearance of dark spots along the edges of the leaf blade
The leaves turned yellow and brown spots appeared

Mulberry
Loss of turgor, leaf blade completely turns brown
Loss of turgor, leaves curled and dried out

Common pear
The leaf blade has darkened
Dark and brown spots

Cherries
Yellowing along the midrib
Part of the leaf blade has turned brown

Cherry
The color of the leaves has not changed
Dark stripes appeared between the veins

Apricot
Loss of turgor, drying of the lower leaves and falling
Loss of turgor, appearance of spots, drying of leaves

Lilac
The leaves become dirty brown.
Loss of turgor, leaves become ugly, dry out and fall off.

Snowy berry white
Yellow-brown leaves
Brown spots appear that turn into “holes”

Privet
Slight darkening of leaves
Darkening of leaf veins

Spirea
The appearance of dark spots on leaves and stems, drying out of the lower leaves.
The appearance of necrotic spots

Chubushnik
Loss of turgor, browning and drying of the lower leaves
Leaves lose turgor, droop, dry out

Loss of turgor in plants is observed on the second day after dusting with NaCl and Na2CO3. Signs of toxicity appear on the leaves on days 3-5 when dusted with Na2CO3, and on days 2-3 with NaCl. Necrotic spots appear on the leaf blades, leaves curl and dry out, darkening in the vein area, loss of necrotic spots and the formation of “holes” are observed. Changes in leaf blades are observed to a greater extent in mock orange, mulberry, elm, and lilac. The leaf blades of cherry and privet have undergone fewer changes. Comparing the degree of damage to leaves under the influence of NaCl and Na2CO3, we can say that chloride salinity has a stronger effect on plant leaves than carbonate salinity. The process of water absorption by plants is disrupted when dusted with salts. The observation results are presented in Figure 1.

Fig. 1 Water absorption by plants when they are dusted with salts

From the data presented in the figure it is clear that when dusting with salts, the process of water absorption in most experimental plants is disrupted. The high intensity of water absorption during chloride salinity is retained in pear, while in mulberry the absorption process does not occur at all. An excess of the control values ​​by 13% is observed in pears with carbonate salinity; in mulberries and cherries they are lower than the control values ​​and amount to 12% and 13%, respectively.
Comparing the data obtained on changes in the appearance of leaves and water absorption, the plants most resistant to air salinity were determined to be cherry, pear, sweet cherry and privet; mulberry, apricot, elm, mock orange, and lilac are less resistant.
The effect of saline solutions on plant leaves. In this variant, the effect of salt precipitation on the leaf or dew on the leaf cover was studied, i.e. action of a salt solution on a sheet. The results of observations of changes in the appearance of plants are presented in Table 2.
table 2
Damage to leaves by salt solutions
Plant name
Nature of leaf damage

Na2CO3
NaCl

Small-leaved elm
The leaves lose turgor and droop.
Curling and drying of leaves

Mulberry
A narrow stripe appears along the edges of the leaves, and yellowish-green spots appear between the veins.
Leaf discoloration

Common pear
Leaves take on a dark color
The appearance of through stains

Cherries
The appearance of dark stripes along the leaf veins
A small number of small, dark spots

Cherry
The appearance of dark brown borders along the edge of the leaf
The appearance of dots along the edges of the leaf, browning of the upper leaves

Apricot
The appearance of yellow and white spots, drying of the leaf
Loss of turgor, lightening and drying of leaves

lilac
Dirty purple leaves
Dark stripes along the veins

Snowy berry white
Brown spots on leaves
Necrotic spots fall out, leaving “holes” in the leaves

Privet
The appearance of brown spots
The appearance of dark stripes along the veins

Spirea
Yellow border around the edges of the leaves
Darkening of leaves

Chubushnik
Loss of turgor, drying out
Rapid drying out, curling and falling of leaves

A change in leaf color and loss of turgor in most plants occurs the next day after the shoots are treated with salt solutions. Light green spots appear along the edges of the leaves. Necrosis quickly grows within days. The color of the leaves becomes brown, the edges bend, the tips of the shoots droop down, and the upper part of the shoot quickly dries out. On the 5-7th day, leaves fall off. According to the degree of damage to the leaf blade, sweet cherry, sour cherry, and spirea are relatively resistant to sodium carbonate solution; mock orange, mulberry, and elm are not resistant. Cherry and privet are resistant to sodium chloride. In this option, as in the first, the effect of sodium chloride on the experimental plants is manifested to a greater extent, which is noticeable by morphological changes on the leaf blades.
The results of water absorption by plants after their treatment with salt solutions are presented in Figure 2.

Fig. 2 Water absorption by plants when leaves are exposed to 5% salt solutions
The measurements showed that the intensity of water absorption in most plants is higher when they are treated with a NaCl solution. Consequently, under conditions of carbonate salinity, a decrease in the process of water absorption is more pronounced in plants. Water absorption decreased to a greater extent in mock orange and spirea; in cherries, snow berries, and pears, water absorption decreased to a lesser extent.
Comparing the data obtained, we can say that the most resistant to the influence of salt solutions are cherry, snowberry, and pear plants.
Absorption of salt solutions from saline soils by plants
This experiment simulates the state of plants and their absorption of solutions from saline soils, which is caused by saline groundwater lying close to the surface. The results of leaf damage when absorbing NaCl and Na2CO3 solutions are presented in Table 3.
Table 3
Damage to leaves due to absorption of solutions
NaCl and Na2CO3 5% concentration
Plant name
Nature of leaf damage

5% NaCl
5% Na2CO3

Small-leaved elm
Loss of turgor, leaves turned yellow
Loss of turgor, appearance of dark spots

Mulberry
Loss of turgor, drying of leaves
Loss of turgor, curling and drying of leaves

Common pear
Loss of turgor
Loss of turgor, appearance of white stripes in the lower parts of the leaves

Cherries
Loss of turgor
along the midrib

Cherry
Loss of turgor
Loss of turgor, browning of leaves along the central vein

Apricot
Loss of turgor, darkening of veins, folding of leaf edges
Loss of turgor, loss of necrotic spots

lilac
Loss of turgor, browning of leaves
Loss of turgor, appearance of large black spots

Snowy berry white
Loss of turgor, browning of leaves
Loss of turgor, browning of leaves, appearance of large black spots

Privet
Loss of turgor, white salt coating appears
Loss of turgor, appearance of salt spots, loss of necrotic spots

Spirea
Loss of turgor, partial browning of leaves

Chubushnik
Loss of turgor, few necrotic spots
Loss of turgor, appearance of salt spots

When plants absorb NaCl and Na2CO3 solutions of 5% concentration, loss of turgor occurs the next day after the start of the experiment in all plants except spirea. Changes on the leaves in a 5% sodium chloride solution appear on the 3-5th day, in a sodium carbonate solution the next day. The stronger effect of sodium carbonate can be explained by the fact that soda breaks down to form a strong alkali (sodium hydroxide). (Aleshin, 1985) The petioles and veins of the leaves of experimental plants become brown. To a lesser extent, changes in the leaves are observed in spirea, cherry, cherry, pear; in other plants, more significant damage is noticeable; in privet, a white salt coating has appeared on the leaves.
The absorption of salt solutions by plants not only causes changes in leaf blades, but also disrupts the process of water absorption in plants. The results of water absorption by plants in this experiment are presented in Figure 3.

Rice. 3 Water absorption by plants from salt solutions of 5% concentration
When absorbing solutions, plants lose their ability to absorb water to a greater extent, and this negatively affects salt tolerance. From the data presented in the figure it can be seen that the absorption of water by plants is influenced to a greater extent by a 5% solution of Na2CO3, at the same time, different types of plants have different abilities to absorb water under salinity conditions. Elm, cherry, and snowberry absorb more water, therefore they are more salt tolerant.
Thus, the salinity factor negatively affects the life of plants. Salinity leads to changes in the anatomical and morphological structure of leaves and a decrease in water absorption. Salt tolerance of plants is associated with their ability to accumulate mineral salts or mobile organic compounds in cells and tissues

conclusions

After analyzing the results obtained during the study, the following conclusions can be drawn:
The sensitivity of different plants to salinity is not the same, it does not coincide when assessing different indicators; when the air is salinized, the leaf blades are most sensitive; when the soil is salinized, water absorption is more impaired;
When the air is salinized, the effect of chloride salinity is more pronounced, and when the soil is salinized, carbonate salinity;
Among the experimental plants we can distinguish species that are relatively resistant to soil salinity: spirea, cherry, snowberry, elm;
Cherry, pear, cherry, privet, lilac, apricot, and snowberry are relatively resistant to air salinity.

Literature
Aleshin E.P. Plant physiology. - M.: Agropromizdat, 1985
Volodko I.K. Microelements and plant resistance to unfavorable conditions. - Minsk: Science and Technology, 1983
Vishnyakova V.F. Ecology of the Stavropol Territory. – Stavropol, 2000.
Goryshina T.K. Plant ecology. uch. A manual for universities, - M.: V. school, 1979
Genkel P.A. Physiology of heat and drought resistance of plants. - M.:, Science, 1982
Prokofiev A.A. Problems of drought resistance of plants. - M.: Nauka, 1978
Savelyeva V.V. Geography of the Stavropol Territory. – Stavropol, 2003.
Sergeeva K.A. Physiological and biochemical bases of winter hardiness of woody plants. - M.: Nauka, 1971
Strogonov B.P. Physiology of agricultural plants. t. 3, - M.; 1967
10. Waring F., Phillips I. Plant growth and differentiation. - M.: Mir, 1984
11. Udovenko G.V., Salt tolerance of cultivated plants. - L.; 1977
12. Fedorova A.I., Nikolskaya A.N. Workshop on ecology and environmental protection. – M.: Vlados, 2001.