Why autumn leaves yellow and fall

The country season ends with the last fallen leaves from trees and shrubs. Many people have bare plants cause despondency and longing to fly. But autumn is beautiful! No wonder so many poetic strings is devoted to this time of year. Why are the leaves of some plants blush, and others are yellow? And why leave the leaves?

The leaf fall is the brightest sign of autumn. These plants adapt to the unfavorable conditions of the season. Seasonal variability of plants begins with northern latitudes and is gradually moving south. The leafflower is repeated every year and always leads us to delight with its bright colors - from yellow and orange to pink and purple. Leaves are flying even from evergreen plants in subtropics and tropics. Only there they fall not all at once, but gradually throughout the year, and it is not so noticeable.

In the fall, it becomes colder, and the water in the plant comes from the roots to the leaves in the slow motion. But this is not the main reason for the leaf fall. The onset of unfavorable conditions is a signal for the transition of plants into a new cycle of life, which is laid in the genetic code. This indicates us that the autumn dropping leaves is not a direct consequence of adverse conditions. It, together with the winter period, the rest is included in the most cycle of plant development. There is also a way to make sure that the leaf fall is the physiological process. Why is the sheet separated from the branch? It turns out that with the onset of colds at the base of the stuff, where the sheet is attached to the "sheet pad" to the branch, a cork layer is formed. The cells of this layer have smooth walls and are easily separated from each other. It is worth blowing the wind a little stronger, and the sheet is separated from the cork layer.

The green color of the leaves is due to the large number of chlorophyll pigment contained in them. This pigment "feeds" plants, since it is with its help on the light plant from carbon dioxide and water synthesizes organic substances and primarily the main sugar - glucose, and from it all other nutrients. The composition of chlorophyll includes iron, and when it is destruction, oxides are formed that have brown-yellow colors. The destruction of chlorophyll intensively occurs in the light, that is, in sunny weather. That is why in a cloudy rainy autumn leaves retain their green coloring longer. At the autumn of sunny days, the leaves acquire golden-red.

However, along with chlorophyll, green leaves contain other pigments - yellow xanthofill and orange carotene (it determines the color of carrot roots). In the summer, these pigments are invisible, as they are disassembled by a large number of chlorophyll. In the fall, as the livelihoods at the leaf, chlorophyll gradually collapses. Here, they are manifested in the sheet of yellow and red shades of xanthophyll and carotene.

In addition to the golden, autumn trees do the buggy shades. This color determines the pigment called Anthocian. In contrast to chlorophyll, anthocian is not connected inside the cell with plastic formations (grains), but dissolved in cellular juice. With a decrease in temperature, as well as in bright light, the amount of anthocian in cellular juice increases. In addition, the stop or delay of nutrient synthesis in the foliage also stimulate the synthesis of anthocyanins.

The fallen leaves can still save the form and color, and then they begin to dying and acquire brown is not very pleasant for the eye color. Part of the leaves remains in place under the trees and shrubs, and part of the wind takes out the site. The gardener from aesthetic considerations often occurs temptation to clear the soil from fallen leaves. Do I need? After all, the leaves contain the same chemical compounds that were taken by plants from the soil. True, they acquired a somewhat different chemical composition and entered the organic substance formed by the plant. Once on the surface of the soil, the leaves become "mining" of a great set of different living organisms. Among them, the most important role in the disposal of leaves belongs to the rainworms. Products of their livelihoods (excrement of worms are called caprolines) contain the entire set of power elements for plants almost in the finished form. So the leaves, hitting the biological cycle of substances, returned the soil, what was once received in the plant.

And now decide for yourself - to remove the foliage from under the trees or not? There are two ways to preserve the beneficial properties of false foliage. The first is to leave in place until spring, followed by perplex. In this case, the leaves will insulate the upper layer of the soil. The second path will be somewhat more complicated, and last longer. Collect the leaves to the compost pit and in a year or two to return under the trees in the rim.

V. A. Rossis , Professor Agau

Valentine Chrome
Abstract Node "Why yellow leaves?" In the preparatory group

Goal:

1. Teach children correlate the description of nature in verses at a certain time of the year:

Develop auditory attention, speed of thinking.

2. give children knowledge about why With the onset of autumn yellow leaves on trees; ideas about the beginning of the fall, about the dependence of the brightness color leaves from the weather.

3. Develop the ideas of children about signs of autumn, concepts: bush, tree.

4. Exercise in the preparation of descriptive stories about trees and the ability to determine the name of the tree by description.

Activation of the dictionary: chlorophyll, crimson, shrub.

5. To educate the desire to study nature, take it up.

Material: boxes with fruits and leaves Tula edge trees, familiar children, book Georgy Grauin « Why fall fall falls» .

Children, I will read you excerpts from poems, and you carefully listen and tell me what time we are talking about. AND why? (I read):

"We go to the courtyard in the yard

Leaves Rain with rain,

Under the legs rustle

And fly, fly, fly ... "

"I carry yields. Fields again sowing

I send the birds to the south, the trees undress,

But do not touch the pines and Christmas trees

I ... autumn. (children's responses)

Children, how do you determine that autumn has come? (children's responses). That's right, birds fly into warm edges, the day slowly decreases, insects disappear, yellow and fall leavesIn the fields, gardens and gardens collect harvest. - When does autumn comes? (children's responses)

The autumn calendar comes on September 1, when the first autumn month begins, schoolchildren go to school. Astronomer scientists consider the beginning of autumn the day of autumn equinox-September 23, when the day is equal to the night. The beginning of the autumn in the wildlife is considered to appear yellow leaves on birch.

Do you know, why yellow leaves? Would you like to know this mystery? (children's responses) Then listen. (I read a story from the book of Grand « Why autumn leaf falling» « Why yellow leaves» .

Fall. Far from frosts, and the trees are already starting to dump foliage. Not immediately trees are exempt from leaves. Gone preparation for leaf fall. IN leaves Amazing transformations occur.

at first the leaves begin to yellowAlthough no one adds paint to juices. Yellow paint is always in leaves. Only in summer yellow colorless. It is clogged with stronger color green. Green color leaves Special substance-chlorophyll comes. What is the name of the green substance? (children's responses) Chlorophyll B. leaves Gradually destroys and regenerates under the influence of the Sun. Summer the sun shines for a long time and chlorophyl is very quickly restored and leaf all the time green. But autumn comes, the nights are becoming longer, the plants get less light. Chlorophyll destroys and does not have time to recover. Green color decreases in foliage And noticeable becomes yellow: sheet yellow. Why does the sheet yellow? (children's responses)

But in the fall leaves become not only yellow, a and red, crimson, purple. It depends on how the coloring substance is in the worst sheet.

Autumn forest is rich in their paints. Brightness of autumn leaves depends onWhat weather is worth it.

If autumn is protracted, rainy - color leaves From excess water and lack of light will be dim, inexpressive.

If the cold nights alternate with clear days, then the paints will be juicy, bright.

But Olhi, Lilac the foliage will fall green, regardless of the weather. In them leaves except chlorophyllThere are no other substances.

That's what secret did you know about coloring leaves on the trees.

And now we will rest a little and play.

Fizkultminutka.

And now, tell me, how does a tree differ from the bush? (children's responses). Correctly at the tree one thick trunk and many branches, and the shrub has several thin trunks.

i suggest you sorry "Who will name more trees?" (children answer and get a chip for the correct answer). And now, name shrubs. (children also get chips). Well done, everyone tried to help their team.

I offer you another game. In my boxes lie leaves And the fruits of different trees. You choose yourself any box and you will need to describe a tree without calling it. The one who will correctly describe the tree and who first recognizes it will receive on one chicken. (play).

And now, count the chips and determine what the team today was more active and won.

What have we learned about today? That's right, we learned: why yellow leaveswhen autumn comes, the brightness of the color depends leaves, I remembered what trees differ from shrubs and very well described them. Have you been interested? In the next lesson, I will tell you why and how fall leaves.

Do you know ...

Why leaves yellow? Green leaves give a special substance - chlorophyll. Chlorophyll in a lively sheet is constantly destroyed and reappeared. But it happens only in the light.

Summer the sun shines for a long time. Chlorophyl is destroyed and immediately restored. Therefore, the leaf remains green all the time.

Yellow paint is always in the leaves. Only in the summer yellow color is immeasured. It is clogged stronger - green.

Autumn comes, the nights are lengthened. Lights plants get less. Chlorophyl is destroyed, and does not have time to recover. The green color decreases in the sheet, and the yellow becomes noticeable - the sheet turns yellow.

From alder and lilac foliage falls green. In their leaves, in addition to chlorophyll, there are no other coloring substances.

In Grübin

Why leaves on one aspen yellow, and on the other - red?

It turns out that the substance that gives the red leaves is formed in those plants that store more sugar. In plants that could not do it, the leaves of yellow color.

Why do leaves fly off from plants?

In winter strules, the roots of plants almost can not get water from the ground.

In the fall, a lot of water, but it is cold. Therefore, the roots of the plants can not suck it.

Leaves continuously evaporate water. So there are plants to reset them, so as not to dry in the winter.

In winter, the leaves would only damage the plant. Snow piles, lowned on them, would break the branches and bunches. In addition, harmful substances accumulate in the leaves for spring and summer. Resetting foliage, the plant is cleared of them.

How is spruce free from unnecessary substances?

It turns out that Eli also goes leaf fall. But her leaves are not falling away, but gradually and constantly. In their place they grow new. Some fall apart, others grow. This happens imperceptibly for our eyes, and it seems to us that the same needles are always the same.

Why fir does not drop the leaves for the winter?

The leaves of the needles ate small, rigid, resinous. Water they evaporate less than ordinary leaves. Winter drought ate is not terrible.

Branches of trees and under the weight of snow why? Because they grow sloping down and spring. Snow is easily clenched with branches from the slightest shock, blowing the wind, from excessive gravity of wet snow. In addition, due to the waxing nails, the snow does not stick to them firmly.

Why on branches from fallen leaves there is no wound?

The thing is that the leaves do not break down from the branches, but fall into a strictly defined place - where the petiole is attached.

In the summer, the leaves of the leaves are firmly connected to the branches. In the fall in stiffs there are amazing changes.

In the place where the petiole is attached to the branch, gradually grows a special cork layer. He, as if partition, separates the stiff from the branch.

Now the sheet with a branch connects several thin fibers. The gravity of the leaf itself, the impact of the rain drop, the branches of the breeze, so that the sheet is easily separated from the plant.

Leaf fall

Previously, everyone is losing the leaves of Lipa, Birza and Elm.

The linden and poplars are the first to leave the leaves of large lower branches, then the middle is exposed, and the latter takes place the macushkin of the tree. But Elm, Oshness, ash, the leaf fall starts with the upper branches. The foliage gradually melts, opening a dark trunk of a tree.

With the first frosts, the leaves of the Osine are tremended, then - Clean. Only alder yes willow on the shores of rivers are thick and green to the first snow. And then frozen, blackened, crispy leaves are falling.

In V.Krabelnikov

Sometimes autumn appears in front of us in gray. Gloomy lead sky, gray rain wall - easy to fall into the despondency. But there is a bright stain to raise the mood! Autumn color of trees always admire and pleases the eye.

Why leaves green

Green leaves are obliged by a chlorophyll pigment. It is this substance that provides plants in the light of oxygen synthesis and other important substances from carbon dioxide and water. Chlorophyll is actively produced in the warm season, when the trees get enough nutrients and moisture from the soil.

The oxygen obtained in the synthesis is given to the atmosphere, and the remaining substances absorb themselves. With the onset of autumn, trees activity decreases, they get less nutrition from the soil. The foliage to continue the photosynthesis process continues to pull nutrients from the barrel. In turn, the tree to maintain the reserves of substances for the wintering time, begins to take the magnesium leaves, which leads to the destruction of chlorophyll. As soon as the green pigment begins to collapse, other shades appear. Why is one piece of red, the other is yellow, and the third is a motley, like the artist's palette? It turns out, the case in the chemical composition.

What depends color leaves

• Yellow we can see thanks to the pigment Xantofilla.
• For orange color is the carotene.
• The crumbs and red leaves are influenced by Anthocian. It is dissolved in the sheet cellular juice, and the amount of pigment increases with bright light and decrease the temperature.

Pigments of all these colors are present in the cells of the plant always, but during the actively generating chlorophyll green color overlaps all the others. But the brown or brown leaf is becoming when it completely loses the coloring pigments. At this time, empty cell walls that have brown color become visible.

When leaves can change color

As a rule, the color of foliage changes in the fall, because at this time of the year the level of vital activity of plants is reduced. On the street it becomes colder, and the trees get more and less nutrients from the soil. Chlorophyll begins to collapse.
At the same time, its destruction is more active in the light. If the weather on the street is cloudy and rainy, then oaks, maples, birch will remain green longer. If there are clear sunny days on the street, the trees will replace their color much faster.

In the roast and dry summer, when plants lack moisture, and the sunlight in excess, the leaves can also lose the chlorophyll and green.

What happens in the fall with coniferous trees

Save green color with the onset of the year of the year, representatives of conifers: spruce, pines, fir, juniper. This is explained by the fact that the area of \u200b\u200btheir "foliage" is small, and they need some nutrients to maintain vital activity.

But even coniferous losing needles, just happening it gradually. The needles are not replaced simultaneously, and parts.

Catch and save bright moments of autumn

The painted foliage is preserved in the forests and parks at all, not long, the activity of the plants is reduced and gradually comes off, they "fall asleep". A special cork layer appears between the sheet and the trunk, and the sheet is separated from the branch. It will take quite a bit of time, and the trees will already stand completely naked.

Bright paints and beauty of autumn fleeting. Hurry up to enjoy these moments and capture them in memory. Pleasant autumn pastime is a walk through a colorful forest or the park, when the soft leafles of juicy shades are rustled under his feet. Only at this time the year in the forest can be causing a special silence when the rustling of foliage is clearly audible.

An unforgettable feeling will give a jump with a scatter into a soft bunch of multicolored freshly oxid leaves, the main thing is to hear more! Such entertainment will have to do with adults and children.

Painted in different colors of leaves look very picturesque. Collect a beautiful bouquet of dried foliage: it will just justify you and will delight you, bringing a sunny mood to the house.

Of the recently fallen, still juicy leaves can be collected a colorful album with herbarium. Put motley leaves between album pages or books. They will soon dry, and later, spilling album, you can breathe autumn fragrances.

Creating such an album can be turned into an interesting and cognitive game for children. Collect different leaves, spread them between pages, and sign, which tree which leaflet belongs.

Any time of year is fine. Autumn gives us a rainbow of paints in parks, alles and forests. Be open for gifts and divide them with your loved ones!

Sasha K. (Belogorsk)

What period starts and ends with leaves of Linden and birch?

With the onset of September, the trees gradually begin to replace the summer emerald green leaves on the autumn yellow. It will take some time and all the gold foliage rushes to the ground. Watching the nature, people often wonder - and when the leisure falls from the birch, limes, maples and other favorite yellowing trees ends? Let's try to answer this question.

The foliage begins to change the color long until the first frost. As a rule, this happens at the end of August, when the day was already noticeably reduced and a little colded, and lasts for 14-20 days. Initially, only single gray-yellow sections can be seen on the branches, but the day after day they are becoming more and more.

Autumn Bereza

By mid-September, birch leaves become oath-gold and gradually begin to fall. No less beautiful at this time of the maple branch. The crowns of the tree covers the foliage of yellow, brick-red, red and even purple shades. Linden foliage is noticeably allocated, which is only half yellow.

Start of leaf fall

Many trees leisure falls unevenly, that is, at different times. For example, after the first strong frost, leaf falling in linden and maples begins. Birch for this time has already dropped most of the leaves. Sheets starts in the first decade of September and lasts 15-20 days.

Important! The beginning of the leaf fall depends on the weather. Dry solar weather and windless days delay the golden decoration of trees.

A particularly abundant leaf fall occurs after the third frost. The leaves fall on the ground very thick, forming a thick litter on the ground. Birch drops in autumn about 30 kg of leaves. In an adult linden and maple, this amount reaches 40-50 kg.

End of leaf fall

The end of the leaf fall, as a rule, is accompanied by a significant cooling, deterioration of weather conditions, frequent rains and strong wind gusts. By October 7-10, Linden and Birch are losing the latter yellow leaves. Males are offended much later, only by October 20. Single leaves can be held on the branches until mid-November, reminding passersby about the last year of the year.

Autumn Maple

Observations of nature during leaf fall

The period of active leaf fall is accompanied by significant cooling and arrival of night frosts. Summer white clouds replaces a solid gray peel. In the morning there is often fog. The first flocks of migratory birds rush into the sky.

The end of the leaf fall on the linden and maples is accompanied by a gloomy rainy weather, hoarflash on another green grass and thin frost on the puddles. Grachics are knocked in flocks and fly south. Gradually cools the earth and falls asleep nature.

Autumn leaves: video