From the life of our deciduous trees and shrubs in early spring - spring and autumn in the life of plants. What trees wake up first in spring What leaves appear on trees
In this article, we have collected material on the topic "tree leaves" and "tree structure". Acquaintance with the tree begins for the child in his earliest childhood.
Each yard has its own good-natured giant, who will gladly shelter from the scorching sun, rain, share fallen leaves and dry twigs for all kinds. However, many children perceive trees as nameless satellites, not thinking about the fact that each of them has its own name, has a complex structure and performs important tasks. Therefore, with a deeper study of trees, kids make many discoveries for themselves.
For example, children will be interested to know what parts a tree consists of. To do this, we use a schematic image of a tree and talk about each part of it:
- The roots of a tree are its foundation. They feed the tree by absorbing the nutrients dissolved in the water, and also keep it upright. The larger the tree, the richer its root system.
- The trunk of a tree is, as it were, its body. All the substances extracted by the roots pass up the trunk, while branches begin to depart from the trunk. It is important to note that a real tree has one trunk, but shrubs have several, even large, trunks.
- Tree branches - support for leaves; it is on the branches that buds are formed, from which leaves and flowers then appear. Nutrients also pass through them. Over time, the branches become wider and harder (woody), and new branches appear from them.
- The foliage of a tree is an organ that allows the tree to exchange substances with environment. Thanks to the leaves, the tree absorbs carbon dioxide harmful to humans from the air, here, under the action of sunlight, carbon dioxide is formed from it. organic matter, and through the leaves, the tree releases the oxygen we breathe out.
- All the leaves and branches of the tree form its crown - a lush hat that gives shade and shelters us from the rain.
Having studied the structure of a tree, you can proceed to the next stage - to find out how it comes into being. Where and how do trees grow? The answer to this question can be represented in the form of a circular diagram.
So, let's take it all apart life cycle fruit tree:
A seed is the source of life for every plant, including a tree. It contains small fetus and the initial supply of nutrients that the embryo needs in order to germinate through the seed coat. Once in the soil, the embryo begins to actively develop, pecks through the shell, grows and puts out roots, with which it absorbs the substances necessary for its growth from the ground.
After many years, the embryo turns into a tree, which, having reached a certain age, acquires the ability to reproduce its own kind.
In spring, buds form on the branches of a tree, in which an organ of amazing beauty and smell develops - a flower.
The flower of a fruit tree is arranged in such a way that when pollinated (by wind or insects), a small rudiment of the fruit is formed in it.
The beginning of its development and rapid growth occurs in the spring, when buds are actively formed on the branches, from which leaves and flowers subsequently appear. No wonder it is said that in spring the trees come to life after a winter sleep.
In summer, the trees appear before us in all their glory. They constantly interact with the outside world, feed, replenish the reserves of substances necessary for their life. The leaves of the trees are constantly working in the summer, turning into a real factory for processing carbon dioxide, and producing oxygen and nutrients from it.
All vital processes in the tree are on the decline: daylight hours become shorter, and the amount of sunlight is not enough to form new chlorophyll molecules in the leaves, so the foliage gradually changes its color and falls off. Leaf fall not only saves the tree's strength, which it will need to survive the harsh winter, but also saves tree branches from breaking off, which can occur under the weight of the fallen snow.
The tree seems to freeze. It economically spends the reserves accumulated over the summer and is looking forward to the arrival of the first spring warmth.
But not all trees go through such a cycle of transformations, but only those that have leaves, that is, deciduous ones. But the trees, whose branches are covered with needles - needles (coniferous) all winter look the same as in summer.
The most famous coniferous tree is. Of course, it became famous thanks to the Russian tradition of decorating spruce branches on New Year's Eve. Spruce reproduces with the help of cones that form during the summer.
But of the deciduous trees, the most common are:
- - a tree with bright berries and beautiful jagged foliage, which looks especially impressive in autumn. There is a version that it was called mountain ash because its leaves are quite small and, when the wind blows, they tremble, causing ripples in the eyes of the one who looks at it.
- Birch is a symbol of Russia, unique tree with white bark. Its very name comes from a Slavic word meaning "shine, turn white." The birch is also interesting for its flowers, which look like earrings, and the fact that its branches are very long and thin, they seem to hang down.
- Poplar is a frequent companion of human habitation. Poplars are planted near houses because they grow quickly - which means that they begin to purify the air early and absorb excess moisture well. In the wild, poplar is often found in wetlands, for which it got its name, which in translation from Slavic means "marshy place, swamp." Poplar fruits are boxes from which seeds are spilled, covered with many silky hairs - poplar fluff. This fluff gives people a lot of inconvenience, so poplars are often cut off, leaving only non-fruitful branches at the top.
- Oak - a tree - a giant, especially revered by our ancestors. Its fruits - acorns - were used to make a drink that replaces coffee, but oak bark and wood, which is distinguished by its strength and beautiful color, have found even greater use among people.
- Maple is the owner of the most beautiful leaves with sharp edges. A sweet aromatic maple syrup is obtained from its juice.
- Elm is a tree, wood, branches and bark of which people have used for the manufacture of furniture, tools and even weapons since ancient times. Elm bark (bast) is strong and flexible, it was tied various items for which the tree got its name. Shoes were woven from bast.
- Chestnut is a tree with unusual fruits, the core of which resembles a nut. It is believed that the word "chestnut" has the same root with the word "porridge", since chestnut fruits were often eaten.
- Willow is a tree with unusual long branches and narrow leaves. Its name comes from the word "twist", which is explained by the main use of willow branches - baskets were woven from them, furniture was woven.
In order to better remember the names of the trees, you can play a simple game: shuffle the cards with the image of the leaves and the trees themselves, and then match them and name them.
From the leaves you can make a very interesting visual aid for children. To do this, you need to collect leaves different types and laminate them.
Cut out the leaves slightly stepping back from the edge.
We get a living manual for the study of leaf types.
Print on a separate piece of paper the names of the trees from where you collected the leaves. The name of the tree is compared with the leaf itself, studying and memorizing its shape and structural features.
Images of leaves are more visible in coloring pages, where you can see their contour and give color depending on the expected season and shades characteristic of a particular tree.
birch coloring page Ilinov Dmitry
In the course of a theoretical study, the hypothesis that tree leaves are "living factories" for the production of food was confirmed. The nutrients produced in them give the trees the strength to grow. In autumn, leaf fall occurs, during which the tree gets rid of excess mineral salts that accumulate in the leaves throughout the summer, and saves itself from moisture loss.
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Municipal educational autonomous institution
secondary school №11
SCIENTIFIC SOCIETY OF STUDENTS "RODNIK"
Section name: natural - scientific
Research
Topic: Why do trees need leaves?
Ilinov Dmitry, 1 "B" class
Work manager:
Ignatieva Tatiana Valerievna,
Primary school teacher
Belogorsk, 2012
Introduction……………………………………………………………………………….3
1.1. The role of leaves in the life of a tree………………………………………………..…..4
1.2. Why do leaves turn yellow? ....................................5
1.3. Why do leaves fall? ....................................6
Conclusion…………………………………………………………………………….8
Bibliography
Applications
Introduction
They grow up in the summer, fall off in the fall. When they read this riddle to me, I immediately guessed that we were talking about the leaves of deciduous trees. Then I wondered why in spring the leaves appear on the trees, and all summer we admire their beauty, and in autumn the trees lose them. What is it connected with? Why do trees need leaves?
Purpose: to find out why trees need leaves and why they fall in autumn.
Tasks: - to get acquainted with the role of leaves for a tree,
Determine the life stages of leaves
Find out the cause of leaf fall.
Object of study: leaves of trees.
Subject of study: life cycle of tree leaves.
Research methods:
Think for yourself;
To study the literature on the research topic;
Ask other people;
Turn to a computer, look in the global computer network Internet;
Watch.
Hypothesis: Suppose the leaves give the tree the strength to grow.
Life cycle of tree leaves
- The role of leaves in the life of a tree
I observed the manifestation of the life of trees already in April, when they began
swell buds on birch, aspen and other deciduous trees. Then, in May
the buds burst and sticky leaves appeared on the tree. They straightened and grew so quickly that in June my birch, which I often watched, showed off in a pale green outfit (Appendix 5). Why do trees need leaves?
In a book for the curious, I found the answer.
It turns out that everything is very simple - the leaves of the trees produce juice, which is called resin or sucrose. This juice nourishes the tree itself and is involved in the ripening of fruits. Gum is made from the green sticky substance, chlorophyll, contained in the leaves. Entering all parts of the plant, it nourishes it and gives strength for growth (4).
Interesting fact.
Caterpillars really like the juice of fresh plants, which is why they eat leaves with such pleasure (4).
- Why do leaves turn yellow?
All summer the trees delight us with their greenery. Poets and writers sing in their works the beauty of the Russian birch, the elegance of the young mountain ash, the graceful fragility of the aspen (Appendix 2). Admiring the beauty of trees, the variability of their outfits is also reflected in oral folk art, in particular in riddles (Appendix 1).
The chlorophyll contained in the leaves turns them green. In addition to green chlorophyll, the leaves also contain other substances (pigments) of yellow and red color, but there are very few of them (3.3.). When the formation of chlorophyll ceases in autumn, only pigments become the main “dye” of the leaves, and therefore the leaves change color - turn yellow or redden (2) .
The autumn outfit of deciduous trees inspires the work of writers and poets (Appendix 2). I also like golden autumn: I drew my birch tree in a colorful outfit (Appendix 3).
1.3. Why are the leaves falling?
By autumn, the leaves accumulate many useful and harmful substances. Useful material the tree takes away, and gets rid of harmful ones by dropping foliage.This is how leaf fall begins (3.1).
It turns out that the leaves produce nutrients only in sunlight, taking carbon dioxide from the air, and water from the ground through the root system of the tree. At the same time, a chemical process (photosynthesis) takes place in the foliage, during which the leaves produce oxygen, which is very necessary for all living on Earth (1). That is why trees are called the "lungs of the planet" (2).
If the trees did not shed their leaves for the winter, they would die. There are several reasons:
Reason one. The leaves of the tree in their totality have a very large area, and water evaporates intensively from all this area. In summer, the tree is able to compensate for the loss of moisture by extracting water from the soil. But with a cold snap cold water from the soil is greatly reduced; in winter, it is completely difficult to extract moisture from frozen soil. Trees with deciduous cover in winter would die from lack of moisture, that is, they would dry out (3.4).
Reason two. Have you noticed that after heavy snowfalls, the branches of trees strongly lean towards the ground under the weight of snow? Some branches even break from it. If the leaves remained on the trees in winter, then much more snow would linger on the branches, since the leaf surface, as we said above, is large. Thus, by dropping their leaves in autumn, trees protect themselves from mechanical damage under the pressure of snow (3.4).
Reason three. During leaf fall, the tree gets rid of excess mineral salts that accumulate in the leaves throughout the summer. The sheet strongly evaporates water. To replace this evaporated water, new water constantly enters it, which is sucked in by the roots from the soil. But in the water that the roots get from the soil, various salts are dissolved. So the leaves don't get clean water and saline solutions. Part of the salts is used by the plant for nutrition, and the rest of the salts are deposited in the cells of the leaves. The more moisture the leaf evaporates, the more it mineralizes by autumn. As a result, by autumn, the leaves accumulate a lot of salts, becoming, as it were, mineralized. An excess of mineral salts disrupts the normal functioning of the leaves. Therefore, shedding old leaves is necessary condition to maintain the normal life of the plant (3.1).
Trees that lose their leaves in autumn are called deciduous or deciduous. In evergreen conifers, needles are also leaves, but they are small and hard, and calmly survive the winter (2)
Interesting fact.Evergreens also lose their leaves, but not all at once, but gradually (4).
After the leaf fall, I noticed that on my birch bare branches small but tight small buds are visible, from which new leaves will bloom in spring (Appendix 4).
In this way, shedding leaves helps the tree save energy, since there is very little sunlight in winter for photosynthesis in the leaves. In autumn, the trees go dormant. The movement of water and nutrients through the vessels inside the trees stops, as a result, the leaves dry up and fall off (2).
8 Conclusion
Now I know that the leaves of trees are "living factories" (4) for the production of food. The nutrients produced in them give the trees the strength to grow. In autumn, leaf fall occurs, during which the tree gets rid of excess mineral salts that accumulate in the leaves throughout the summer, and saves itself from moisture loss.
Thus, my hypothesis was confirmed - the leaves do produce organic substances to feed the tree during the process of photosynthesis.
Bibliography
- Great encyclopedia of the student / transl. from French Bogatyrevoy E., Zemtsova T., Lebedeva N. - M .: LLC Publishing House Astel: LLC Publishing House AST, 2003, p. 711;
- The Great Encyclopedia of the Erudite, - M: Makhaon, 2004, p. 487;
- Global computer network Internet:
3.1. www.razumniki.ru/stihi_pro_derevya.html;
3.2. www.playroom/content/view;
3.3. www.razvitierebenka.com
3.4. http://images.yandex.ru/yandsearch?
4. Why and why / encyclopedia for the curious, ed. Pokidayeva T., Frolova T., - M.: Makhaon, 2007, p. 255 ;
The tree that opens the flowering season is alder. Its inflorescences are inconspicuous, but nevertheless, during the period of mass flowering, they will certainly attract attention if we pass somewhere along the bank of a stream or near a ravine at this time, where alders are usually found. Even from a distance you can see the reddish tint of the tree crown. Coming closer, we will see a large number of drooping earrings, which, with the slightest tapping on the trunk or a breath of wind, will throw out whole clouds of yellow dust. In addition to these earrings, we will also find numerous black knobs on the alder. While the catkins are the male alder buds, these buds are last year's female buds that are still hanging on the tree and fall off only by early summer.
Almost simultaneously with alder in early spring, when snow drifts still lie in the depths of the forest, hazel, or hazel, a common and well-known shrub in our forests, blooms on the edge, on the slopes baked by the sun. However, hazel is popular only in autumn, when its fruits ripen; in the spring no one pays attention to him, especially when he stands in a leafless state. Meanwhile, just at this time, he is perhaps the most interesting in a biological sense. Hazel blossom is taken by some phenologists as the beginning of the third period of spring, which at this time finally comes into its own.
First flowering shrub 
Almost simultaneously with alder in early spring, when snowdrifts still lie in the depths of the forest, hazel, or hazel, a common and well-known shrub in our forests, blooms on the edge, on the sun-baked slopes. However, hazel is popular only in autumn, when its fruits ripen; in the spring no one pays attention to him, especially when he stands in a leafless state. Meanwhile, just at this time, he is perhaps the most interesting in a biological sense. Hazel blossom is taken by some phenologists as the beginning of the third period of spring, which at this time finally comes into its own. At this time, warm sunny days, snow quickly melts and awakening flora every day becomes more and more noticeable. If the birch and maple, with the beginning of their sap flow, seemed to catch the first glimpses of the coming spring, then the modest flowers of the hazel mark its complete reversal, the final victory over winter.
Early flowering of hazel, as well as alder, is possible only thanks to the advance preparation of its inflorescences. Throughout the winter, on its branches, we observe male earrings, in which there are fully formed flowers. They endure thirty-degree frosts, but as soon as they begin their development, they already become much more sensitive to lower temperatures and during the flowering period they often suffer from frost. The structure of male hazel earrings at first glance resembles the already familiar alder earrings.
The development of a flower earring in spring occurs with exceptional speed. As soon as the sun warms and the temperature rises, the earrings begin to crack, and the stem on which the flowers sit stretches and grows almost before our eyes. So, for example, on a cut branch of a hazel in a humid chamber, the stem of a male earring elongated by as much as 3 cm in a day. The rate of anther cracking is closely dependent on the degree of air humidity. In a humid atmosphere, the opening of the anthers is delayed for several days, but if the earring is moved to a dry place, it occurs in half an hour. This circumstance is of great importance in the life of the plant. It allows him, as it were, to wait out rainy weather and postpone flowering until a more favorable time. However, in rainy weather, the already opened gaps of the anthers have the ability to close again. It also significantly reduces waste of pollen. The amount of pollen released by hazel trees during the flowering period is enormous. One earring of it gives about 4 million pollen grains, and if we assume that there will be at least a hundred such earrings on an average bush, but in fact much more, then one can imagine what a colossal amount of tiny dust particles is carried in spring in the air in our forests. Let us now turn to the female hazel flowers. Unlike males, they are hidden in the kidney in winter and become noticeable only in spring, when purple tassels of stigmas appear from the scales.
Does the intense red color of the stigmas have any biological significance? Many probably paid attention to the fact that young leaves developing from buds in spring, or sprouts of herbaceous perennials are bright red in color. It is clearly visible on large sprouts of horse sorrel or on young leaves of maple, cherry or oak. This red color is due to the presence in plant tissues of a special pigment - anthocyanin, dissolved in cell sap. We will dwell on it in more detail in the chapter on leaf fall, and now we will point out that anthocyanin is currently attributed the role of an additional trap from the wind. By absorbing the green and blue rays of the spectrum, it contributes to an increase in the temperature in the cells, which in the cool spring time has great importance. It is believed that the intense pink color of the stigmas of hazel, as well as the purple color of the female alder inflorescences, thus accelerates the germination of pollen on the stigmas, which occurs more vigorously under conditions of elevated temperature.
When buds are laid at the hazel
Deployment of leaves in hazel occurs much later than its flowering. Only after the male earrings have dusted off, darken, dry up and begin to fall off the branches, the buds begin to bloom, covering the shrub with a delicate green haze. Why do leaf buds open much later than female flower buds or male catkins? Why is the development of our shrub proceeding with such a regular sequence, first opening its huge flowers, and then dressing in its green attire? It can be assumed that in hazel, as well as in most of our other trees and shrubs that bloom before leafing out, the development of flower and the development of vegetative buds are different stages, for the onset of which different temperature conditions are required. The deployment of vegetative buds requires much more heat than the development of flower buds. Hazel buds, having begun their development, subsequently bloom extremely quickly, since all the necessary parts have been laid in them since the previous year. This bud formation takes place much earlier than is usually imagined, and already in the middle of summer, in most of our trees and shrubs, fully formed buds can always be found on young shoots. So, for example, on May 25, buds consisting of 6-10 scales were observed on young growing shoots of hazel. On June 10, there were already 12-14 scales on these buds, but leaf primordia were not yet noticeable among them. They appeared in the buds in early July, first in the amount of one or two, and by August 11 the next 2-3 leaves had developed.
It is remarkable that already at that time in the axils of these tiny leaves, under strong magnification, small buds of two to four scales could be found. These bud primordia must therefore overwinter twice before they begin their development. This is how long the hazel buds go through before they become noticeable or we pay attention to them!
What are kidney scales 
In most plants, for example, in willow, hawthorn, wild rose, etc., in adult leaves, we can distinguish three main parts - the leaf blade, which serves for light nutrition of plants, the petiole, which supports the leaf blade and attaches it to the stem, and, finally, stipules. Stipules usually look like two small leaves located at the base of the leaf petiole, and their purpose is not always clear at first glance. However, the significant role that they play in plant life becomes clear in the spring, when the buds on the trees begin to develop. It turns out that in hazel, as in most of our trees and shrubs, the bud scales, which play such a significant role in the life of plants in winter, are nothing more than stipules, which in the bud significantly outstrip the corresponding leaves in their development. At the hazel, the stipules fall off, having fulfilled their purpose, immediately after the shoot develops, and in the summer it is no longer possible to find them on the shoots. In linden, this fall of stipules at the time of leafing out is so noticeable that in linden forests in spring all the soil under the trees is strewn with pinkish or slightly greenish bud scales. In other trees, stipules persist throughout the life of the plant. They turn green and take part in assimilation. However, one should not think that in all our trees and shrubs the kidney scales are formed by stipules. The currant is completely devoid of stipules, and in its buds the scales are expanded leaf petioles. In horse chestnut, bud scales are modified leaf blades. This is not difficult to verify at the moment of blooming of its large buds, where you can easily observe all the transitions between bud scales and true leaves. We now know what the bud scales of the hazel are. Let's see how they are arranged. There is one interesting detail here. If we make a transverse section through the kidney scale and look at it under a microscope, we will find a special cavity inside. This cavity is filled with air, which is known to be a very poor conductor of heat. As a result, the protective role of scales increases, which protect delicate leaf primordia from sudden temperature fluctuations.
After the shoot of the hazel finishes its development - flowering, deployment of growth buds, growth of shoots and the laying of new buds, we will not notice further significant changes. Nevertheless, important processes of seed maturation in fertilized ovaries and the deposition of reserve substances in leaf buds and flower male catkins take place in summer, which ensures their development next spring.
Seed ripening in hazel is extremely slow. Despite the fact that this shrub blooms extremely early, its fruits fully ripen only by September. In this it differs sharply from our other trees and shrubs, the fruiting period of which is much shorter. It is especially curious that the period of fruit ripening in willow and aspen usually does not exceed a month, while in hazel it averages four months. It is difficult to say what these features of the fruiting of various plants are connected with, however, in the future we will partially return to this issue.
Our willows in early spring
In early spring among our wind pollinated trees and bushes, hung with modest, nondescript catkins, flowering bushes of willows attract attention from afar. At this time, against the gray, still transparent background of the forest, bright yellow willow inflorescences stand out sharply, densely covered with sticky pollen and emitting a delicate and pleasant aroma. However, long before flowering, many willows, especially red willow, become quite noticeable due to their graceful fluffy inflorescences, known as "lambs". The sudden appearance of these "lambs" in the middle of winter, in January or February, is one of the most curious phenomena in the life of our spring nature. However, before getting acquainted with the vital characteristics of willows, it should be noted that we have a large number of species. In total, in the flora of the USSR, there are currently about 170 species of willows, and in the Moscow region alone, their number reaches 40. With such a variety of species, willows have the ability to give hybrids with each other, and often double and triple. At present, even five and six hybrids are known, which are extremely difficult to understand. We will have in mind only some of the most famous and common willows among those that bloom in early spring before the leaves bloom. This includes the well-known red willow, or red willow (Salix purpurea), common in the south of the European part of the USSR, reaching in the north to the southern border of the Moscow region and introduced into culture; goat willow, or bred willow (Salix caprea), ubiquitous in forests, and ash willow (S. cinerea), growing in damp places in most of the USSR. Other willows that are widespread in our country, such as the white willow (Salix alba) or the brittle willow (Salix fragilis), growing along the banks of ponds and near dwellings in the form of large weeping trees, bloom much later, simultaneously with the development of young leaves.
When willow flower buds awaken from their winter sleep 
The dormant period of our early willows lasts until mid-January. Until this time, their kidneys are densely scaled and do not show any noticeable changes. However, starting from the end of January, flower buds begin to show undoubted signs of incipient development. The caps crack at the very base and, not being able to embrace the swelling flower earring, gradually move towards its top or to the side, and then completely fall off. However, this process proceeds at an extremely slow pace and usually ends completely only by the second half of March.
The dropping of caps in our early willows is an extremely interesting phenomenon. In February, there are the lowest temperatures, twenty-degree frosts often crack and the soil freezes on maximum depth. Nevertheless, the swelling of flower catkins undoubtedly indicates the beginning of the development of plants, their exit from winter stupor. The life of our trees in winter has not yet been studied enough, but there is reason to believe that during periods of thaw and on warm sunny days, sap flow begins in individual branches of willows. In them, the transformation of spare substances takes place and they move to the kidneys from various parts of the crown and trunk.
Let us now follow further the development of flower catkins in the willow. Having thrown off their caps, they look like elegant, fluffy white balls, similar from a distance to small tufts of cotton wool. What do their numerous hairs represent? It is best to answer this question at the time of flowering willow. At this time, it is easy to see that willow inflorescences are of two varieties: both male and female, and they are located on different bushes in such a way that on one bush there are only male earrings, and on the other - female.
Male willow flowers are built very simply. They are devoid of perianth and are covered with only one scale in the axil, in which there are usually two (some willows have more) stamens. The scales are usually two-colored: yellowish-green below, blackish above. The upper part of the scale is covered with long numerous hairs, which give the unflowered earring a characteristic fluffy appearance. The significance of these hairs in the life of the plant is quite clear. Dressing the buds like a fur coat, they give them the opportunity to endure low temperatures and its sharp fluctuations without any harm at a time when the caps covering them fall off. Female willow flowers have a similar structure, except that instead of stamens there is an oblong ovary thickened downwards, resembling a bottle in shape. This ovary at the top passes into a style with a bifid stigma, the sticky surface of which catches the pollen that falls on it. In addition to scales, stamens and pistils, male and female willow flowers have special nectaries at the base of the covering scales that secrete sweet juice-nectar. Willows, unlike most of our other early-flowering trees and shrubs, are pollinated with the help of insects, which are attracted, on the one hand, by fragrant nectar, and on the other, by a large amount of pollen, densely sticking to flower earrings during the flowering period.
Such a simple structure of flowers in our willows, devoid of any trace of perianth, somehow does not fit with their method of pollination; in addition, all the rest, by the way, more ancient representatives of the willow family - various poplars and aspens - are typical wind-pollinated plants. Therefore, it is now believed that willows are secondarily adapted for pollination with the help of insects, and this adaptation could have arisen in relatively recent times. This is indicated, among other things, by the large number of species of insects that visit willow flowers, reaching up to eighty. Among them we will meet bumblebees, ordinary and earthen bees, butterflies and some flies. This diverse range of pollinators indicates that willows do not have a particular specialization in this direction, while the flowers of most other entomophilous plants are strictly adapted to a particular species or group of insects. We will explore some of these devices in the next chapter.
It is also interesting to note that at present there is reason to believe that the ancestors of our willows had bisexual flowers, as indicated by the not so rare appearance of special freaks in the goat willow in the form of flowers that have both a pistil and a stamen. It is possible that the transition to dioecy gave willows a number of advantages in terms of protection against self-pollination. However, all this still remains in the area of the most remote assumptions.
Seasons are seasons that differ in weather and temperature. They change with the annual cycle. Plants and animals adapt perfectly to these seasonal changes.
It is never very cold or very hot in the tropics, there are only two seasons: one is wet and rainy, the other is dry. At the equator (on the imaginary midline) it is hot and humid throughout the year.
In temperate zones (outside the lines of the tropics) there is spring, summer, autumn and winter.
Generally, the closer to the North or South Pole, the cooler the summer and the colder the winter.
For three spring months, nature has time to change beyond recognition. In March, she is just beginning to wake up from hibernation. The spring warmth is not enough to make the snow and ice blocks melt, but the air gradually warms up, preparing all living things for a gradual awakening, the first cumulus clouds appear, which are still very high.
Astronomers consider the beginning of spring to be March 21–22, the moment of the vernal equinox, when the day is equal to night, and the end, June 21–22, the longest days of the year.
For naturalists, spring begins with the arrival of rooks (March 19 on average) and the movement of sap near the Norway maple (March 25).
This season is conditionally divided into three periods: early spring - before the snow melts on the fields (until mid-April), middle spring - before bird cherry blossoms (until mid-May) and late spring - before apple and lilac trees bloom (until early June).
Phenomena in inanimate nature.
In the second half of March, the days noticeably lengthen, the nights decrease; the sun rises higher and higher at noon above the horizon, its rays fall more directly on the earth and warm it more strongly. The snow becomes loose, begins to melt, and on open places thaws are formed.
In the second half of March, the first cumulus clouds appear.
They are very beautiful, they look like snow-white, dome-shaped masses with even bases. Clouds usually arise in the morning or at noon due to the heating of the air adjacent to the earth; towards evening, when the ascending currents weaken, they begin to disappear, to melt.
In the first half of April come off the ground snow; streams formed during its melting run down to reservoirs.
Ice drift usually begins in mid-April. Shortly before this, rims appear near the shore - narrow strips of water. Under the influence of water and the sun, cracks form in the ice, it breaks up and starts to move. Ice floes, crowding and pushing, rush down the river, hitting the banks and piles of bridges. In the middle of the river, ice floes move faster than near the banks. They melt along the way. The river is freed from the ice cover, overflows its banks and overflows. The flood begins.
Usually in early May there is the first thunderstorm.
At this time and later, a sudden cold snap often occurs with frosts, from which plants suffer greatly, especially fruit and berry plants.
Spring awakening of trees. Soon after the appearance of thawed trees, trees wake up: they begin to flow sap. This phenomenon is revealed if the bark is pierced with a thick needle: a sweet transparent liquid flows out of the raki; in air, it oxidizes and acquires a reddish color.
Extraction of juice causes great harm to trees.
Sap flow is a complex physiological process. The roots begin to actively absorb water from the thawing soil, it dissolves the plant's winter nutrient reserves and moves in the form of a solution along the trunk and branches to the buds.
Swelling and bud break.
Top 16 primroses among shrubs and trees
Ten days after the start of sap flow, swelling of the buds becomes noticeable, in which, under the protective bud scales, there are rudimentary shoots.
Trees and shrubs, pollinated by the wind, bloom before they are covered with leaves, or at the very beginning of their deployment.
Alder and hazel are the first to bloom in the second half of April, and willow is among those pollinated by insects. Willow buds are densely tightened with brown scales that look like caps.
Having dropped them, the buds look like fluffy balls, consisting of hairs that protect the flowers from sharp fluctuations in temperature and rain.
In April, most of the trees are still bare, but the integumentary scales of the swollen buds are already moving apart, and the tailbones of the leaves are showing from them.
The appearance of leaves. The young leaves of some trees are covered with a sticky fragrant substance, while others have a fluff that protects them from the cold.
Gentle and transparent at this time is the light green outfit of the trees.
At the end of April, bird cherry and birch buds bloom; in the first half of May - buds of maple, yellow acacia, apple and pear, and then - oak and linden.
In late spring, in the second half of May, the real flowering of spring begins. Bird cherry blossoms, at the same time - blackcurrant, a little later - wild strawberries and fruit trees, lilac, mountain ash and most herbaceous plants.
In the last days of May, the fruits of aspen and willow ripen.
The petals of apple and lilac flowers fall off - spring ends, summer begins.
Biology Spring phenomena in plant life
Spring is the time for the awakening of nature. According to the calendar, spring begins on March 1. In nature, spring comes into its own with the beginning of sap flow in trees, earlier in the south, and later on March 1 in the north.
The spring movement of juices near trees and shrubs is the first sign of spring. It comes after the soil thaws and water from the roots begins to flow into all organs of the plant. At that time leaves not yet.
Water accumulating in cells plant stems, dissolves organic matter stored in them. These solutions move to the swollen and blooming kidneys. Already at the beginning of March, earlier than in other trees, the spring sap flow begins in the Norway maple, a little later in the birch.
The second sign of spring is the flowering of wind-pollinated trees and shrubs.
The gray alder blooms first in the middle zone of the European part of the USSR. Its flowers are inconspicuous, but the blossoming earrings of staminate flowers are clearly visible. 123
. One has only to touch an alder branch with catkins, as the wind picks up a whole cloud of yellow pollen. 
Pistillate alder flowers are collected in small grayish-green inflorescences. Next to them, dry, blackened cones of last year's inflorescences are usually clearly visible.
Almost simultaneously with the alder, the hazel, which you met in the fall, blooms.
Hazel staminate flowers develop in inflorescences - complex catkins, and reddish stigmas of pistillate flowers protrude from generative (flower) buds.
Early flowering of alder, hazel and other wind-pollinated plants- good adaptation to life in the forest.
Bare leafless branches do not impede pollination. Pollen, picked up by the wind, is freely transferred from one plant to another.
Flowering coltsfoot is also a sign of the coming spring. This perennial herbaceous plant grows in open, sunlit places, on railway embankments, river banks, steep slopes and cliffs.
As soon as the snow melts, its scaly stems already appear - flower stalks with bright yellow inflorescences, similar to dandelion inflorescences 124
. The large leaves of the coltsfoot grow after its fluffy fruitlets have ripened and scattered. 
The coltsfoot received its unusual name for the originality of the leaves. Their underside is covered with white, soft, like felt, hairs, and the upper side of the leaves is smooth and cold.
The coltsfoot blooms in early spring, before the leaves bloom, perhaps because its thick, long rhizomes have accumulated reserves of nutrients deposited in the summer of last year.
Feeding on these reserves, flower plants grow shoots and fruits are produced.
The third sign of spring is the flowering of perennial herbaceous plants of the deciduous forest. In the districts middle lane they bloom almost simultaneously with the coltsfoot. The first to bloom in the forest are the noble liverwort with azure flowers and the medicinal lungwort, then the oak anemone and buttercup 125 , Corydalis 119 , spring chistyak 126 , spring primrose 127 .
Flowering shrubs in spring
All of them are photophilous and bloom under the canopy of the forest, when there are no foliage on the trees and shrubs yet.
In the life of some early-flowering herbaceous plants of the forest, their growth under snow is very interesting. Plants such as the blueberry, or snowdrop, grow even in winter under the snow.
In the spring, many of them come out from under the snow with green leaves and with buds formed last fall.
Οʜᴎ often bloom before the snow melts 128 . That is why these plants are called snowdrops.
Plants that bloom in early spring always attract attention because they are beautiful and because after a long winter they are the first flowering plants. Unfortunately, they are often collected, making up large bouquets. Often they destroy entire plants, pulling them out with roots. Plants with flower-bearing shoots torn off do not produce fruits and seeds.
This makes it difficult for them to reproduce. Many of the plants have become very rare, for example, noble liverwort, sleep-grass. They cannot be allowed to disappear completely. We must take care of the preservation of plants, do not tear them in order to throw them away in a day, do not damage wild plants and actively protect nature.
Protection of Nature and rational use natural resources of the country are legalized by the Constitution of Russia, i.e.
e. obligatory for all citizens of our country.
Trees and shrubs pollinated by insects bloom later, after the leaves bloom. If you observe the course of spring from year to year, you will be able to establish the sequence of spring development of plants.
In the middle zone of the European part of the USSR, usually 8 days after the flowering of the coltsfoot, lungwort begins to bloom, after 21 days - dandelion and willow-rakita.
The pear blossoms on the 29th day, the yellow acacia on the 30th, and the linden on the 75th day after the start of flowering of the coltsfoot.
Every year the spring phenomena come in strict order. For example, lungwort always blooms later than coltsfoot, but before dandelion.
Observations of spring phenomena in the life of plants help to establish the best dates for agricultural work and to prepare for them in a timely manner.
For example, it is known: in the regions of the middle lane best harvest cucumbers are obtained by sowing their seeds during the flowering of lilac and yellow acacia, and the best crop of turnips and beets is obtained by sowing them during the flowering of aspen.
Knowing how many days after the coltsfoot blooms lilacs bloom, it is easy to set the time for sowing cucumbers and prepare for it.
Spring. Spring months. Spring phenomena of nature. Spring weather signs.
Answer left Guest
Signs of spring in inanimate nature:
1) The main sign of spring in inanimate nature is that the sun rises much higher above the horizon than in winter.
2) It shines brighter and warms more and more every day.
The days are getting longer.
3) The most noticeable sign of the onset of spring in inanimate nature is the melting of snow.
4) The ice starts to melt. Ice starts on the rivers.
5) It is very dangerous to walk on melted ice. You can not start games on the river during the ice drift.
6) When rivers and lakes overflow with water from melted snow, water fills meadows, forests, fields along the river.
This is called a flood.
7) The soil thaws from the spring heat. It accumulates a lot of moisture. This moisture is very necessary for plants.
8) It rains in spring, not snow. Not far from the first thunderstorm.
Signs of spring in wildlife:
a) in the life of birds with the advent of spring: migratory birds return, build nests, lay eggs, hatch chicks
Such changes have become possible because many birds feed on insects. And with the advent of spring, insects crawl out of their hiding places.
The birds got more food. The ice on the rivers and lakes has melted, so waterfowl are returning
b) in the life of animals: Animals shed - they change their winter coats for summer ones. Bears, badgers, hedgehogs, chipmunks wake up from winter sleep.
Many animals have cubs in the spring.
c) Buds swell on deciduous trees and shrubs; earrings, silvery lambs, flowers appear, then leaves appear. Coniferous trees change the color of the bark, needles.
The ground is covered with young grass, many plants begin to bloom. Usually, early-flowering herbaceous plants are called snowdrops.
if everything is short:
The sun is higher than in winter. The days got longer. It got warmer outside. The sky in spring is blue and high.
The clouds are white and light. Snow and ice are melting. On the rivers ice drift, flood. In the spring, in different months, it snows, then it rains. In May, the first thunderstorm rumbles. The soil thaws, buds appear on the trees, and then sticky leaves. Primroses bloom. Insects appear. The migratory birds are returning. Forest animals breed offspring.
- familiarization with the change in trees and shrubs, with the change in buds.
Lesson progress:
I. Organization of attention.
Updating what has already been learned.
- What are the mushrooms that we meet in the forest consist of?
What is the name of the underground part of the fungus?
- Do you need a fly agaric?
Who is it useful for?
- What mushrooms can not be collected?
What should be done to avoid damage to the mycelium?
- Is it possible to collect old mushrooms?
But someone important
On a white leg.
He is wearing a red hat
The hat has polka dots.
Learning new.
1. Communication of the topic and purpose of the lesson.
It is impossible to imagine our nature without the white-trunk beauty of the birch. How many fairy tales, poems, songs have been composed about her? It is interesting that birch is the only tree in Russia with white bark that lives
birch 100 - 120 years old. Yes, people love birch, but how often do they not take care of it. Losing in the spring through the fault of man a considerable part of the juice, birch
If you inflict wounds on her for several years in a row, she can
die completely. Remember that the sugar contained in the juice is needed to feed the tree!
The movement of sap from trees and shrubs is a sign of their spring
awakening.
Another sign is the flowering of some trees and shrubs. Of the trees, the alder is the first to bloom. It is easy to recognize it in winter and spring by the black bumps on the branches. In the spring, earrings appear on the alder.
Which trees wake up first in spring? Urgently give 100 points
Earrings are many small flowers gathered together.
Willow blooms early in spring. Bees and bumblebees curl around its flowers. They come here for sweet nectar.
Of the shrubs, hazel and wolf's bast are the first to bloom. On hazel, as well as on alder, earrings are visible. And the wolf's bast is a poisonous plant.
All these plants are early flowering. They bloom before blooming
Birch blooms later, when the leaves on it are already beginning to bloom.
Even later, the bird cherry blossoms.
Swelling of buds and blooming of leaves is a sign of spring
awakening trees and shrubs.
Guys, interesting changes occur in the spring with conifers.
The larch is fully dressed with new needles. But coniferous plants never bloom.
Rules of friends of nature: do not damage the bark of trees, do not cut on
her letters.
Do not collect birch sap. Take care of the trees! Do not break branches of flowering trees and shrubs. Without flowers, there will be no fruits!
IV. Fizminutka.
V. Practical work.
- Unravel the ball. (Circle around)
- Writing straight lines with a rounding at the bottom.
- Shade the tree.
(The material is taken from the book Psychological and Pedagogical Support for the Life of a Child in the Conditions of Preschool Education (Part II)) - N.
The opening of the kidneys is an annual spectacle arranged by nature, which we see at the beginning of spring. These often barely noticeable tubercles on deciduous trees and shrubs, sometimes a few millimeters in size, are pressed against bare branches and seem to be just waiting in the wings. Indeed, the opening time of the kidneys is a phenomenon dependent on natural factors designed to protect the plant from the consequences of waking up too early. Buds in woody plants are usually laid in summer, but become visible only in autumn, after leaf fall. And in order to open up in the spring, they must go through a stage of winter dormancy.
Relatively large mixed buds are distinguished, in which flowers and leaves are simultaneously laid (as, for example, in horse chestnut), as well as purely flower and pure leaf buds. Shrubs that bloom early in spring, such as dogwood and willow, have flowers in a protective shell of the bud so well formed that a few warm days are enough for them to fully open even before the first leaves appear.
With their nectar and pollen, fluffy “lambs” of inflorescences begin to attract bees as early as March, while the leaf buds of the shrub remain closed for some time:
On other woody plants, on the contrary, greenery appears first and flowers much later. These include, for example, forest beech, mountain ash.
At forest beech leaf buds are narrow and long. After the brownish scales part, within one to two days, corrugated green leaves will appear.
Most of our trees and shrubs climate zone have closed buds, the “inner world” of which is completely enclosed in a protective sheath of modified leaves, the so-called scales. This leathery material is often additionally covered with villi, a layer of resin or wax, which provide the kidney with protection from cold, drying out and damage. But there are also woody plants with bare () and half-naked (black elderberry) buds, from the outer visible scales of which real leaves develop.
By the way, if some of the buds did not open in the spring, they should not be considered dead. The so-called dormant buds can grow into the surrounding bark and lie dormant for several years before they open. At the same time, they grow just enough so as not to overgrow due to the thickening of the stem. If, during late frosts, the buds that have awakened on the same branch freeze, the dormant buds will come to the aid of the plant. So nature saves plants with severe damage from the cold.
It has relatively large kidneys, thanks to which the process of their deployment is clearly visible.
On a longitudinal section of a horse chestnut bud, one can clearly see 1
inflorescence bud. 2
The leaf primordia are compactly folded and 3
renal scales form a protective sheath. Under the large apical bud and smaller lateral ones, 4
scars left after the fall of autumn foliage. visible on the scars 5
conducting vessels through which the plant was supplied with water and minerals. 
1. When the kidney scales move apart, flowers and leaves are not yet visible. After a couple of days, cover leaves will unfold at the top of the stem and inflorescence buds will appear.
2. For some time, the inflorescence retains a compact shape, and the light green covering leaves droop gently.
3. But after a couple of weeks, the leaves will turn dark green, the flowers will fully bloom and long and lush inflorescences-candles will appear on the tree.
Throws out greenish-yellow umbels of inflorescences in late April.
They develop rapidly, while the leaves at the base of the peduncle remain small and shriveled.
The young leaves of the Norway maple (Acer platanoides) are orange-red, and in some green-leaved varieties, such as 'Cleveland' and 'Deborah', a pronounced rich red. Naturally, the same applies to the red and purplish red varieties ‘Royal Red’ and ‘Crimson Sentry’.
About flower color ordinary(Syringa vulgaris) can be judged already at the stage of bud opening. But it will take more than one week before all the flowers bloom completely.
5. Unlike most conifers, it is not an evergreen. The more spectacular its fresh light green looks every spring. The reddish spikelets that appeared a little earlier will later turn into cones.
6. Do
PHOTO: MSL/A1PIXYOUR PHOTO TODAY (2), AVENNE IMAGES/J. LILLY, IMAGO, F1 ONLINE, BERND SCHULZ, ANNETTE TIMMERMANN; DRAWING: SYLVIA BESPALUK
