Ways of spreading fruits and seeds. How seeds spread with the help of the wind. Methods for spreading fruits and seeds Plants that are spread by the wind

The seeds are quite rare, but germinate directly in the plant. For example, having cut a ripe pumpkin, we can observe already sprouted seeds in it. However, they generally do not germinate where they ripen, but in a completely different place. What are they - ways of spreading the fruits and seeds of plants? How does this happen and why? Let's find out!

What is a fetus

Before we consider in detail the methods of spreading fruits and seeds, these very concepts should be studied. Indeed, without basic knowledge, it will be difficult for us to understand the whole process and mechanism of the "travel" of seeds and fruits around the world. So, let's begin. It is no secret that pear, plum, apple, strawberry, cherry are fruits of fruit plants and trees, containing seeds. It is believed that they develop from ovaries and other parts of plants, but not all botanists agree with this.

Some of them are sure that only those that are formed exclusively on ovaries, for example, cherries, plums, tomatoes, poppies, etc., can be called real fruits. Fruits that develop from other parts of flowers and plants are usually called false. For example, strawberries are generally formed by an overgrown receptacle. What kind of ovary can we talk about here! As a result, scientists decided to consider the fruit as the result of the modification of the entire flower. Moreover, if at the beginning of their "life path" they can somehow retain some of the characteristics of a flower, then after ripening they completely lose or strongly modify them.

How plant fruits are arranged

Outside, each fruit is surrounded by the so-called pericarp, which protects the seeds ripening inside from damage and drying. In turn, the pericarp is divided into juicy and dry. For example, the pulp of a ripe watermelon, melon or peach can be called a juicy pericarp. Immature pericarp is astringent, bitter, sour, tasteless. During this period, he protects the fruit itself from untimely eating, and its still immature seeds from early damage.

Types of fruits

To understand how the seeds and fruits of certain plants and trees spread, you need to know that botany includes:

• polyspermous (pumpkin, berry, apple, pomegranate);
• single-seeded (peach, apricot, mango, cherry, bird cherry, prune).

As the name suggests, the single-seeded ones have one bone. They are also called drupes. However, there is an exception here: for example, a blackberry is a polystyrene, but it is a single-seeded fruit.

The distribution of fruits and seeds directly depends on their size, weight and shape. As mentioned above, the fruits are juicy and dry. Dry, in turn, are divided into opening and non-opening. For example, the pericarp of ripe beans, pods, and poppy pods are opened (burst) after their ripening. But, for example, the hazel pericarp is very hard and stiff. He himself would never be revealed. He has one single seed that we know perfectly well: the nut.

Another type of fruit is the capsule. It usually has 3 to 5 nests with seeds. When these seeds ripen, their "house" begins to burst. For example, boxes of St. John's wort or tobacco crack along their partitions, after which they disintegrate into separate parts. At the same time, at the "houses" of lilies, hyacinths, tulips and cotton plants, only the walls are cracked, and at the poplar and willow the boxes generally crack at the seams. The most famous capsule is the pod, which splits into two flaps during ripening.

Is a berry considered a fruit

Yes. This is a kind of fruit that has many seeds in its composition, but does not have seeds. If the berry is ripe, then it has a juicy and fleshy pericarp (grapes, strawberries, lingonberries, cranberries, blueberries). That is why, from the point of view of botanists, cherries are not a berry, but tomatoes are! This can also include citrus fruits, which are also berries:

• tangerines;
• oranges;
• lemons;
• oranges;
• grapefruits.

The fact is that the nests with seeds located inside the aforementioned fruits are filled with aromatic exotic juice. Fruits can also be called berries:

• melons;
• watermelons;
• cucumbers.

For a common man, this, of course, hurts the ear, but professional botanists have long got used to the idea that formally watermelon and cucumber are not only berries, but also relatives.

What does a seed look like from the inside

The dissemination of fruits and seeds (grade 2, acquaintance in biology lessons with students with one way or another of the "travel" of seeds and fruits of various plants) is unthinkable without the participation of humans, animals and, of course, water and wind. But to understand how such a small seed can "travel" around the world, you need to briefly familiarize yourself with its structure. So, any seed is covered with a skin. On smooth seeds, a scar is visible, which forms in those places where it separates from the seed stalk.

If you look closely, then next to such a scar you can see a micropolar hole, called in the scientific community a micropyle. There is also a root tip somewhere nearby. It is he who, when the seed germinates, is the very first to appear outside. The dense peel protects the seed from various damages and at the same time allows moisture to pass through without interfering with the germination of the embryo - the main part of all seeds. It is formed only after fertilization of the egg and usually consists of a stalk, root and kidney.

How plant seeds are distributed in nature

Well, here we come to the main point. As mentioned above, rarely germinated seeds give life to new plants, since in the vast majority of cases they do not grow where they ripened. Why is this happening? It's simple: they "travel" to new places through people, animals and Mother Nature herself! If the conditions for a new life turn out to be quite suitable, these seeds will begin to germinate, and if not, they will die.

1. An excellent way of their distribution is a cross, thanks to which new species of flora representatives can form. This is the minimum that gives life to new plants. Of course, the methods of spreading the fruits and seeds of plants are not limited to pollination.
2. Fruits and seeds that are unpleasant to humans or even poisonous are very attractive food for birds. At the same time, seeds that have a hard shell are simply not able to be digested in their stomachs. As a result, they, together with bird droppings (guano), are transferred to long distances from the place of their initial "birth". But the role of birds in the spread of new plant life is not limited to this!
3. Many birds, arranging for themselves stocks for the winter, drag seeds and fruits of various plants into their nests. Some of them are simply lost during the flights of birds, falling to new places. For example, they constantly stock up on acorns, some of which are lost and germinate over time.
4. Another helpers in the germination of seeds and fruits are ants. These small, but naturally useful creatures carry the seeds of various plants to their nests, especially those rich in essential oils (cornflower, celandine, lungwort, oxalis, violet). Like birds, ants lose the lion's share of the collected seeds along the way. By the way, it is grass seeds that are mostly available to these little weasels.

How else do the fruits and seeds of plants "travel"

They are mainly spread by the wind. At the same time, the seeds fly away much better than the already formed fruits. But more on that later. As you know, in nature there are also the so-called "live" fruits, which independently cling to the hair of animals that accidentally ran by, and also stick to human clothing. For example, these are the fruits of burdock, string, cocklebur and burdock.

Here, botanists especially note pyzonia, a shrub or tree that grows on the islands of the Pacific Ocean. The fruit of this is enclosed in a special cup, seated with rows of various sticky hairs. It is they who allow the fruits of pyzonia to easily stick to any animal or object. Often in nature you can see reptiles and small birds, completely covered with such fruits. Unfortunately, in this case, the animals cannot fully move and die.

"Traveling" by air

You know that fruits and seeds can be spread by the wind, i.e. by air? For example, this happens in high-mountainous steppes, in savannas and deserts, where strong winds are constantly walking. In this case, the seeds are simply scattered in different directions and over great distances. It is especially good for seeds that are flat and small in size (bell, hop, heather, broomrape, eucalyptus).

Winged seeds and fruits

It will be interesting to learn how the seeds with the so-called wings spread with the help of the wind. They appeared in those plants that grow exclusively in open areas. These "wings" are specific hairs that completely cover the seeds (for example, in the anemone). In poplars and willows, the seeds are generally provided with crests, consisting of the finest hairs.

In hazel, hornbeam, alder and birch, the fruits are small nuts with wings. Ash and maple fruits have one wing. Incidentally, this is why they spin when they fall. The seeds and fruits of swollen sedge, bladderwort, astragalus are spread with the help of the wind. Curiously, in these plants, they travel in balloons, which are formed by the air sacs that cover them.

Tumbleweed

Probably everyone has at least once heard of such a bizarre plant. The scientific name for him is swing paniculata. In autumn, it tends to completely break away from its root. Loose and globular bushes of this plant with ripe fruits are spread by the wind. The seeds of the paniculata kachim are hidden in boxes, the teeth of which have a curved shape. This allows the seeds to spill out only during fairly strong gusts of wind that carry them over long distances.

"Travel" on water

Fruits and seeds of plants are not always spread by the wind. Seeds often "travel" along streams and rivers, carried by sea currents and streams of rain. For example, a coconut can stay afloat on the high seas for years without losing its germination. Often, an entire piece of land with palm trees and shrubs growing on it, as well as animals living there, can break off the coast. Such islets begin to float with the flow, spreading the seeds of their trees for thousands of kilometers.

1. What is a seed?

The seed is the embryo of the future plant with a supply of nutrients and a reliable protective shell - the seed coat.

2. What is the role of seeds in plant life?

For plants, seeds play an important role; with the help of seeds, plants multiply and spread to other territories.

3. What is the role of fruits in plant life?

The fruit is essential for protecting and spreading seeds.

Questions

1. In what ways are fruits and seeds distributed in nature?

Fruits and seeds are spread by wind, water, animals, humans, and also by self-scattering.

2. What distribution devices do the fruits or seeds carry in the wind?

Fruits or seeds carried by the wind have white fluffy hairs, pterygoid outgrowths for distribution.

3. What adaptations do fruits or seeds spread by humans and animals?

The fruits of plants such as burdock or burdock have sharp teeth and hooks.

The seeds of the juicy fruits of mountain ash, elderberry, lingonberry, blueberry, bird cherry and other plants are protected by a hard shell, so they are not digested by eating animals.

4. What plants are spreading their seeds?

Impatiens, beans, peas, acacia, poppy, viola scatter their seeds.

Think

What is the significance in nature of the spread of fruits and seeds?

The biological role of the spread of fruits and seeds lies in the fact that plants thus expand their habitat.

Tasks

1. Find out how the fruits and seeds of plants growing near your home are distributed.

Wind-borne fruit or seeds: maple, dandelion.

Acacia scatters its seeds.

The seeds of the juicy fruits of mountain ash are distributed by animals.

2. Collect tree and shrub seeds. Sow some of them on the school site, and hand over the rest to the nearest nursery or forestry.

3. Collect seeds of ornamental cultivated and wild-growing plants, as well as seeds of medicinal and rare plants for sowing at the training and experimental plot.

Fruits and seeds are often very far from the plants on which they ripen. This is due to the fact that some fruits and seeds are carried by the wind, others are spread by animals, humans, water, and some by self-scattering, like the acacia and mad cucumber.

Spread by the wind poplar seeds and some other plants.

Poplar seeds, covered with white downy hairs, ripen in May. Falling from branches, they are carried by the wind, accumulate on the ground, resembling flakes of snow. Thanks to the fluffy hairs, the wind carries the poplar seeds over long distances. Dandelion fruits are also distributed.

Fig. 9 .: 1 - dandelion; 2 - mountain ash; 3 - burdock; 4 - turn.

Maple fruits have two winged outgrowths. Falling from the branches, the fruits quickly spin in the air. Therefore, they do not fall to the ground for a long time and are carried away far away from the tree. Some dried up steppe plants are easily broken off by the wind at the root, carried along the ground, rolling from place to place, and the seeds are scattered. Steppe plants, driven by the wind, are called tumbleweeds.

Water spread fruits and seeds of not only aquatic plants, but also terrestrial ones. For example, the fruits of alder, which often grows along the banks of rivers, fall into the water, and the current carries them away from the mother plants. The fruits of the coconut tree often fall into the sea and swim for a long time before landing and sprouting.

The seeds of many weeds sometimes involuntarily carried by animals and people. So, a basket of burdock with fruits, called compound fruits, clings to animal hair or human clothing, and the fruits are far from the plants on which they are ripe.

A series of weeds grows in ditches, near ponds and rivers. Its inflorescences are small yellow baskets, and the fruits are achenes with thorns covered with cloves, which are bent back. A dog will run through the thickets of a train, another animal or a person will pass - and small thorny fruits will tightly cling to wool or clothes, so much so that you cannot clean it with a brush, you have to choose with your hands. Plants come across not only with tenacious, but also with sticky fruits. Such fruits are in forget-me-not.

Seeds of plants with juicy fruits - mountain ash, elderberry, lingonberry, blueberry, bird cherry, lily of the valley - birds spread... They eat these fruits and, flying from place to place, together with the droppings, throw out the intact seeds of the eaten fruits.

Fig. ten. Distribution of fruits and seeds: 1 - birch; 2 - maple; 3 - mad cucumber; 4 - max.

Fruits and seeds of some plants stick or cling to bags and bales of cargo and end up in secluded corners of cars, cars, planes. When unloading, the seeds fall on the ground, germinate and often find themselves a new home. So, plantain was brought from Europe to America at one time, which is found on paths and roads. That is why the indigenous people of America - the Indians - call the plantain "the footprint of the white man."

Self-spreading seeds can be observed in many plants. For example, in summer, on a hot, sunny day, near the bushes of yellow acacia, you can hear a slight crackling - ripe acacia beans crack and scatter seeds.

Scatter their seeds and fruits of peas, beans, beans. Therefore, the fruits of these plants must be harvested without waiting for them to dry completely. Otherwise, they will open up, throw out the seeds, the crop will die.

Seeds that are spread by the wind can be recognized immediately. They are either very small or have special appendages that help them to float in the air. The appendages in the form of tuft of fluffy hairs have the fruits of dandelion, sow thistle, skerda. Birch and alder have flat and light fruits, so they glide easily when the wind blows. The fruits of the maple have two winged outgrowths, which, falling from the branches, rotate like a helicopter blade. Because of this, the fall slows down, and the wind carries it away from the parent plant.

Some steppe and desert plants have an interesting adaptation for spreading by the wind. They branch very strongly near the ground, forming a dense, spherical crown. When the seeds are ripe, their stem dries up and breaks off easily. The wind picks up these balls and drives them across the steppe from place to place, at this time the seeds are scattered over the ground. Such plants are called tumbleweeds.

Seeds and fruits that are spread by water are either very light and weightless, and therefore float well in the water, or have special swimming devices.

The seeds of many plants are sometimes unwittingly carried by animals and people. The dry fruits of some of them are equipped with various hooks. As soon as you walk along a vacant lot or the bank of a stream overgrown with weeds in the fall, you will definitely carry on your clothes a whole collection of tenacious fruits of burdock, gravilat, and a string. Also, the fruits of these plants cling to animal hair, bird feathers, gaining the ability to be transferred to new places.

Animals

The seeds contained in the juicy fruits are spread by the animals that feed on them. Bright, tasty fruits of bird cherry, raspberry, viburnum attract many birds. Eating the fruit along with the pulp, they swallow the seeds. The pulp in the stomach and intestines is digested, and the seeds, protected by a dense skin, pass undigested and are thrown away somewhere along with the droppings. So the seeds are sown and, moreover, together with fertilizers.

In addition, the seeds of many plants are carried by insects. For example, ants are attracted by seeds with juicy appendages, like celandine, violets. The spread of fruits and seeds is facilitated by animals (squirrels, chipmunks), storing them in reserve. Seeds that have not been eaten or lost often germinate under favorable conditions.

We sow, we sow

There are many plants in nature that can scatter their own seeds. When ripe, their fruits open, and the seeds fly in different directions.

With the help of animals, by wind or water, the seeds and fruits of plants are able to travel great distances. They cross deep rivers, mountain ranges, deserts and oceans. But the longest travels of plants are associated with humans.

During resettlements, wars or trade expeditions, a person certainly carried with him the seeds of cultivated plants. Merchants and conquerors always brought seeds of new cultures from overseas countries along with gold and jewelry. This is how potatoes, corn and sunflowers from America, oranges from Asia, coffee from Africa got to Europe. Together with cultivated plants, new lands and weeds were developed after man. Attaching to clothing or pet hair, adhering with dirt to shoes, the seeds and fruits of the weeds followed in their heels. Following the white settlers, the plantain mastered the vast expanses of America. The Indians called this plant the "white man's footprint".

Many plants have spread during the wars. After all, after the armies there were always carts with provisions and hay for horses. Seeds of field plants traveled along with the hay. A large number of foreign weeds got to a new place by sea, along with imported grain. Before threshing, it was cleaned of impurities in which there were many different seeds. As a result, new weeds appeared around the mills.

Many seeds were also brought with unprocessed wool. Thus, about 500 species of alien plants from Algeria, South America, Australia settled in the south of France.

Today, plants cover great distances thanks to humans: many exotic flowers grow in our homes, offices or on lawns.

2. Study of the flora of the village of Snezhnogorsk

The village of Snezhnogorsk is a part of the Norilsk industrial region and is located on the western slope of the Putorana mountains, on the bank of the Khantaysky reservoir. Vegetation is typical for the Taimyr Peninsula.

To study the flora of the village of Snezhnogorsk, I have collected a herbarium, numbering 77 plants from those blooming in July and August. To make it easier to determine their appearance, at the same time with the collection, he took pictures with a camera.

But there was a difficult job to determine the names of the collected flowers. For this he turned to the scientific literature, which turned out to be extremely small. The book "The Nature of the Khantai Hydrosystem" contains a list of plants growing in this area. With the help of plant reference books and Internet information systems, I began to determine the names of those found.

Based on the data of the website of the State Natural Biosphere Reserve "Taimyrsky", I learned that the plants in the territory of the village are poorly studied, while in the vicinity of Lake Khantaysky they are good. The data from these studies helped me identify plant species.

Simultaneously with the search for plant names, I conducted a survey. As a result, I found out which plants were familiar to the inhabitants of Snezhnogorsk, and which ones appeared relatively recently.

From the collected flowers, I selected the following plants for a more detailed study: feather grass, bearded gentian, garden chamomile.

So, I found out that feather grass does not grow in our region. It's amazing: how and when did he get to Snezhnogorsk?

Having conducted a survey of the inhabitants of the village, I learned that feather grass appeared only about 20 years ago. It grew only in one place (Khantayskaya Street - Naberezhnaya 2, corner of the house) and consisted of about 10-15 plants.

To date, the area of \u200b\u200bits distribution has increased many times. I presented her in the diagram.

I assume that the plant was brought from the mainland in the form of a bouquet. And thrown out as unnecessary.

However, it not only did not die in our harsh conditions, but also reproduces splendidly, spreading over vast territories.

The next plant I have chosen is the Bearded Gentian. So in the book by B. G. Ioganzen "The Nature of the Khantai Hydrosystem" there is a mention of the distribution of this plant along the coast of the Yenisei River, which is 60 kilometers from Snezhnogorsk. How did it end up on the territory of the village?

From my grandfather, a passionate fisherman who often visits the Yenisei, I learned that the bearded gentian was gradually spreading along the banks of the Khantayka River. And thus, this plant gradually expanded its growing territory. It can be assumed that this happened in connection with the construction of the Ust-Khantayskaya HPP, when a large area of \u200b\u200bland was flooded. The emergence of such a hydraulic system could not but affect the climate around the reservoir, and therefore on the plants and on the territory of their growth.

Garden chamomile is the next plant I have considered. (Family: Asteraceae. Distribution: widespread in Eurasia, America and South Africa, Australia)

In the summer of 2006, chamomiles were brought from the mainland to Snezhnogorsk for landscaping the territory, which were planted throughout the village, decorating flower beds. All summer, the flowers delighted the inhabitants with their beauty. However, the next year I saw that very few plants overwintered.

And this summer I could not find a single garden chamomile flower. How could this happen? Probably, the plant brought by man from a warmer climate could not adapt and survive in our northern conditions. Although her relative, the pharmacy chamomile in the territory of the village, grew successfully and is still growing.

Conclusion

Little travelers Who are they?

In the course of the study, these turned out to be plants that entered the territory of the village of Snezhnogorsk. Their path was not easy: some (such as garden chamomile) were artificially introduced by people and could not adapt to the harsh climatic conditions. Others (like feather grass) have successfully acclimatized in our northern latitudes. Still others, thanks to human economic activity, expand their territory. Who knows how many more new plants will eventually be introduced or brought to our area ?! This is unknown to anyone, but one thing is clear: new travelers will be welcome, because they make our life more beautiful and brighter.

The spread of seeds is a prerequisite for the existence and prosperity of plants. In the process of evolution, fruits and seeds have developed many adaptations for distribution.

Depending on the seed and fruit spreading agent, all plants are divided into 4 groups:

1) anemochoric - spread by the wind;

2)zoochoric – spread by animals;

3) hydrochloric - spread by water;

4)autochors - spread by self-spreading.

Most trees in the upper canopy of the deciduous forest spread their fruits and seeds through the wind.

The seeds of these trees are lightweight. For example, 50,000 aspen seeds have a mass of 4 g. And there are plants whose seeds are many times lighter: the mass of a broomrape seed is 0.000001 g; wintergreens - 0.000004 g. Winged birch fruits can fly 1.6 km away from the mother plant. Its seeds can move much further away from the spruce. Their wings are like a sail. And the seeds slide over the crust. Maple and ash lionfish travel near their native trees.

Some plants have parachutes, which consist of branched hairs that increase the sail surface of the parachute. The fruits are indicative in this respect. dandelion, goatbeard or sow thistle... Such fruits can fly away in the wind for a great distance.

In a number of plants, flying devices help not only the movement of seeds, but also, like a gimbal, burying them in the ground. Grain is often found in the steppes feather grass... The fruit is its sharp weevil with a long awn curved at a right angle. Part of the awn is pinnate. Its lower part, when dried, twists in a helical manner, when moistened, it unwinds. Having met during its movement along the steppe, any obstacle - a pebble, a lump of soil, a stem of a plant, a weevil is screwed into the ground with its sharp end.

In the steppes, the wind picks up whole plants, breaking them at the root, and carries them, rolling them from place to place. Tumbleweed - so called the people driven by the wind, jumping dry plants. Over a long journey across the tumbleweed steppe, the field carries its seeds over long distances.

Some of the fruits and seeds are spread by water. The ripe fruits of the coconut palm are dumped into the sea and carried away by the current. Carried by the water to new shores and thrown out on a sandbank, they sprout and form new coastal groves. Thus, even in very distant times, coconuts settled along the shores of continents and islands - wherever they were warm enough.

Hydrochoria is observed in plants growing in water or along the banks of water bodies (pondweed, water lily, arrowhead, sedge, alder). Their fruits, falling into the water, do not sink. The current carries them away from the mother plants.

Self-spreading can also be observed in many plants. For example, if you touch the fruit of a touch-me-not plant, then its shutters break, twist and forcefully scatter the seeds. The same thing happens with peas and beans. Therefore, they are harvested without waiting for the complete drying of the fruit valves, otherwise they will throw out the seeds and the crop will die.

Probably everyone heard on a clear day a slight crackling and clicking in the yellow acacia bushes. The pods heated by the sun crack, then curl, the seeds scatter in all directions.

In the Crimea and the Caucasus, on dry slopes and sea coasts, you can find the weed plant mad cucumber. After the seeds ripen, mucus accumulates in its fruits, which, together with the seeds, is forcefully thrown out of the fruits. It seems like a mad cucumber is shooting its fruits. In many plants, ripe fruits, when dried, burst violently and throw the seeds over a considerable distance, for example, in marsh geranium at a distance of 2.5 - 3 m, in a dog violet - by 4 - 5 m, in begonia - up to 15 m.

The seeds and fruits of many plants are sometimes unwittingly distributed by animals and people.

Many berry bushes grow under the forest canopy: wild rose, viburnum, elderberry, euonymus, wolfberry and others. There are also low trees: bird cherry, mountain ash and others.

The seeds of plants with juicy fruits are eaten by animals, mainly birds. They eat these fruits and, moving from place to place, together with the droppings, they throw out the intact seeds of the eaten fruit. During their autumn migrations, birds carry seeds adhered with dirt, especially of aquatic and coastal plants.

The fruits of plants such as burdock or burdock have sharp teeth and hooks. With their help, these fruits cling to the hair of animals or to the clothes of people, which carry them over considerable distances.

When transporting goods, the fruits and seeds of some plants may stick or cling to bags or bales. When unloading, they fall, and the plants that have grown from them often find good living conditions in new territories.

An interesting way of spreading fruit, associated with self-closure (peanuts). After flowering, the pedicels lengthen greatly, then bend to the ground and bury the young fruits at some distance from the mother plant. In the ground, the fruits ripen and germinate.

So plantain, a common plant of paths and roads, was brought from Europe to America at one time. The indigenous people of America - the Indians - call the plantain the trail of the white man. And the weed of our southern fields odorous chamomile was brought to us from America.