The spread of plants throughout the planet is a process that is constantly being improved by nature. All plant cultures that are found on Earth have their own methods of reproduction, in which other plants, animals, natural phenomena, etc. may participate. Some methods of propagation of plants by fruits and seeds are especially interesting. Such methods may seem almost miraculous even to the most persistent skeptics. Let's talk about the possibilities of nature in this matter in a little more detail.

After seeds or fruit are formed on the culture, they ripen and separate from the parent plant. Botanists argue that the farther away such planting material is, the less likely competition from the parent will be. In addition, with a wide distribution, plants have a chance to colonize new territories and increase the size of the population.

Distribution of fruits and seeds of plants

Distribution by animals

It is believed that the distribution of fruits and seeds by animals is quite reliable, since different animals actively visit areas with high fertility, where seeds will grow well. Many fruits have thorns or special hooks that cling to the skin or fur of animals that are nearby, which contributes to their transfer to a considerable distance, after which they "sooner or later" fall into the ground or will be torn off, but still fall into him.

Vivid examples of such plants include burdock, tenacious bedstraw, carrots, succession, ranunculus, gravel, and also agrimony.

So gravilat has special hooks on the column, and burdock fruits are surrounded by hook-like leaves of the wrapper, they also have small, fairly stiff hairs that can penetrate the skin and provoke irritation (this leads to combing and subsequent falling off of the fruit). Bedstraw, carrots and buttercups have a pericarp surrounded by outgrowths that look like trailers. And the series has a fly on the fruit, like a dandelion, but with fairly strong spikes.

This group of plants can also include crops with juicy fruits, for example, blackberries, plums, tomatoes, apple trees and strawberries. After being eaten by animals, the seeds pass through the digestive tract and are excreted in the feces. After falling on fertile soil, such planting material germinates without difficulty.

wind spread

Those plants whose fruits and seeds are carried by the wind have special devices that facilitate this process. These include flyers, they can be seen on the seeds of willow, fireweed, dandelion, cotton. In addition, such a device is also characteristic of maple, hornbeam, ash, etc.

In certain cultures, the fruit looks like a box, which is located on a leg and sways in the wind, which leads to scattering of numerous small seeds. Such plants are represented by poppy, nigella, foxglove, etc.

In some representatives of the flora, the seeds are so small and light that they can be carried by the wind without having any additional devices for this. This group includes orchids. In such plants, the seeds fall out after cracking the seam between the carpels. In this case, the planting material is ejected from them with a sufficiently strong push. Additionally, some plants may have wind-carrying devices on their seeds, as an example, fireweed.

Spread by water

Few plants have fruits or seeds that are specially adapted for aquatic dispersal. Such planting material contains small air cavities that keep it on the surface of the reservoir. An example is a coconut, which is a drupe with a fibrous cover and a significant number of air cavities. This group of plants also includes the water lily, whose seed has a spongy membrane that comes from the stalk of the ovule.

random spreads

Botanists do not strictly divide seeds and fruits into categories depending on the method of their distribution. Many crops can be propagated by some of the above methods, if not all of them. The most important factor of accidental spread is a person, because the seeds can be easily carried on clothes, cling to loads and thus fall at a significant distance from the parent plant. Many grain crops become littered with weed seeds. In addition, planting material can be accidentally spread by hurricanes, floods, etc.

The most interesting ways to distribute plant seeds

One of the curious examples of such a distribution is the process of scattering seeds by an amazing plant, mad cucumber. Its fruit is similar in appearance to an ordinary cucumber, and after reaching full maturity, its fleshy tissues surrounding the seeds become a slimy mass. After the fruit is separated from the peduncle, there is pressure on its contents, comparable to the principle jet thrust, due to which the seeds are scattered over a large area. It happens like a cannon shot. Common oxalis also has a similar method of seed dispersal.

Legumes are able to push the seeds to a fairly large distance, and the escholcia throws the entire fruit away from itself along with the ripened seeds.

So, there are quite a few ways to ensure the reproduction and spread of plants around our planet.

Municipal state educational institution

Secondary School No. 7 of the village of Velichayevsky

Levokumsky district of the Stavropol Territory

Biology lesson summary
in 6th grade

"Spreading Fruits and Seeds"

prepared

biology teacher

Kraeva Maria Alexandrovna

Velichaevskoe 2012

Topic : Distribution of fruits and seeds.

Lesson form: combined.

Equipment: table "Distribution of fruits and seeds"; plant herbariums; drawings of plants; photographs, dummies of fruits and seeds, natural fruits; coconut;

table "Classification of fruits".

Target: To acquaint students with the features of the distribution of fruits and seeds in nature, biological significance distribution devices. Formation of the ability to work with visual material, the ability to explain biological phenomena, analyze, draw conclusions. Education of interest in the subject, biological thinking, respect for nature.

1. Organizational moment.

2. Actualization of students' knowledge.

Front poll:

1. What is the structure of a seed?

(seed peel, stock nutrients, embryo: germinal root, germinal stalk, germinal kidney)

1. What is the importance of seeds in plant life?

(reproduction, distribution)

1. How are fruits formed?

(after the flower fades, a fruit is formed, a seed is formed from the ovules, and a pericarp is formed from the overgrown and modified ovary wall)

1. What is the structure of fruits?

(the fruit consists of seeds and pericarp)

Recall the classification of fruits:

Didactic game "Collect fruits in a basket."

(There are natural fruits, photographs of fruits, dummies of fruits on the tables; there are baskets in which you need to collect fruits. The one who copes raises his hand.)

Task number 1: collect juicy one-seeded fruits in a basket

(drupe: apricot, cherry, plum, peach….)

Task number 2: collect dry one-seeded fruits in a basket.

(nut, acorn, caryopsis (wheat, corn, rye), achene (sunflower)…)

Task number 3: collect juicy multi-seeded fruits in a basket.

(berry: currant, tomato, grape; apple: apple tree, pear, quince; pumpkin: watermelon, pumpkin, cucumber; polydrupe: raspberry, ......)

Task number 4: collect dry multi-seeded fruits in a basket.

(bean: beans, peas; box: poppy, dope; pod: cabbage, radish ....)

3. Formation of new knowledge.

? How do you think fruits and seeds can spread?

(wind, water, animals, man…)

Most plants have adaptations for dispersing their seeds.

One helps the wind. Their seeds are covered with hairs or fluff, or are equipped with pterygoid outgrowths (elm, spruce). All summer long, sunny dandelion flowers turn yellow in fields and meadows, along roads and fences, in squares and gardens. Who does not know how their seeds are distributed! The feather grass seeds are also spread by the wind, and they are also capable of self-burrowing. Grass grains are pointed at one end, and at the other they have a fleecy thread curled into a corkscrew and bent at a right angle - a characteristic feature of this plant. The wind carries the feather grass seeds across the steppe, while the fleecy thread acts as a parachute and stabilizer. Thanks to her, the grains always fall on the ground with a sharp end and pierce into the soil. Then, swollen with moisture, the spine begins to unwind. The upper part of the awn, bent at a right angle, catches on objects on the surface of the soil, and the sharp grain, like a corkscrew, is screwed into the ground.

In autumn, thrushes and waxwings are hosting in the crown of curly mountain ash, pecking at juicy fruits. But for rowan seeds you can be calm - they will not be digested and the birds will scatter them with droppings throughout the area. Juicy fruits, intended to attract animals - seed dispersers, are often brightly colored - remember the same mountain ash, cranberries, blueberries.

Often they turn out to be the food of birds and animals and such large and nutritious fruits as acorns and nuts. Of course, if a bird eats a nut, it will not germinate. But often the bird does not eat it immediately, but hides it somewhere in a secluded place in reserve. And then for some reason does not return to the cache.

Animals settle not only those plants whose fruits attract them with their gastronomic qualities. Many herbs have adapted to use their services for free. Fruits with thorns in a string, burdock, they can firmly cling to the fur of animals, bird feathers, our clothes.

Seeds and fruits of some aquatic and coastal plants can stick to the paws of waterfowl and move with them from water to water. Or make independent trips on the water, going with the flow. Fruits can be considered record holders for the range of water travel coconut tree- coconuts.

The coconut palm grows on the coasts of tropical seas, on islands and atolls. Its tall smooth trunks are usually inclined towards the sea. The fruits of the palm tree are fibrous drupes (the contents of the immature drupe are completely yellow at first, thickening as they ripen - the famous coconut milk), weighing 1.5-2 kg. Outside, they are covered with a fibrous, air-containing tissue, covered with another smooth shell. Ripe and fallen nuts are picked up by waves and sea currents and carried to nearby islands. But their journeys are also longer. Sprouted coconuts have been found on islands 4,800 km away. from the place of their maturation! Even after 100 days of sailing on the sea waves, these amazing fruits do not lose their germination.

Once, in the end, on the shore, the fruits of the coconut often find themselves in conditions that are not very suitable for the growth of the plant - on bare sand. A large supply of nutrients helps the palm to survive in this situation - the seedling uses them for more than a year, even when the young palm forms 3-4 large leaves.

In the Crimea and the Caucasus, there is a large pubescent grass with large heart-shaped leaves - the common mad cucumber. No wonder she has such a sonorous name. For those who have weak nerves, it is better not to approach this plant when fruits similar to small cucumbers ripen on it. Even a light touch on a ripe fruit causes an amazing effect! In an instant, the “cucumber” breaks away from the stalk, and a strong stream of mucus is thrown out of the hole formed at the base of the fruit, dragging the seeds with it. Cucumber can "spit" in the face or on clothes. The fetus itself, like a rocket, moves in the opposite direction. Crazy cucumber seeds disperse up to 10 meters!

No less interesting is the ordinary touchy, which grows everywhere near human dwellings or along forest ravines. When yellow tubular flowers hang on the juicy, tender stems of the touchy, you can walk nearby without paying attention to it. But then, in their place, long green pod-shaped fruits ripen, which are already more difficult not to notice. A light touch on them causes a real shot!

? What do you think is the importance of the distribution of fruits and seeds in plant life?

(for plant propagation)

? How do the fruits and seeds of plants growing near your home spread?

(wind, animals, man)

Physical minute:

Moved by the flower

All four petals

I wanted to rip it off

He fluttered and flew away

4. Reflection

1. What topic did we cover in class today?

(distribution of fruits and seeds)

1. What did you learn in class today?

(how do fruits and seeds spread, what adaptations do seeds have for spreading by wind, animals, water)

Puzzles: (you need to guess not only the plant, but also name the method of distribution of its fruits and seeds, adaptation to distribution)

The green house is cramped:

Narrow, long, smooth.

Sitting side by side in the house

Round kids.

Trouble came in autumn

The smooth house cracked,

Who jumped where

Round kids.(peas, self-spreading,

shutters dry and open)

Planted a seed

Raised the sun.

We'll tear this sun -

We will collect a lot of grains,

We'll fry them, we'll gnaw them,

And the guests will come

We'll give them a handful.(sunflower, animals,

human)

On a green fragile leg

The ball has grown by the track.

The breeze rustled

And scattered this ball. (dandelion, blown,

parachutes)

Autumn has come to our garden

The red torch was lit.

Here thrushes, starlings scurry

And, noisily, they peck at him.(rowan, birds and animals,

Seeds are not digested) elimination. a strong stream of mucus is thrown out, dragging the seeds along with it.

Who does not touch

It clings to it.

Affectionate and prickly,

Needles stick out all around.(burdock, animals

And the person

sharp teeth cling to wool

animal or human clothing)

3) Filling in the table:

Filling example:

Methods of distribution of fruits and seeds

5. Homework:study paragraph 31, answer the questions on page 139.

Bibliography:

1. Biology: Botany: Grade 6: A book for a teacher.-M .: "First of September", 2002 (I'm going to class).
2. Biology. 6-9 grades. Lesson notes: seminars. Conferences, the formation of key competencies / ed. I.N. Fasevich and others - Volgograd: Teacher, 2009.
3. Biology. Living organism: reference notes, Moscow: Classics Style, 2003.
4. Biology in tables and diagrams. Edition 2 St. Petersburg, Victoria Plus LLC, 2004.
5. Biology. Bacteria, fungi, plants. Grade 6: Thematic and lesson planning To the textbook by V.V. Pasechnik "Biology. Bacteria, fungi, plants ": A guide for the teacher / N.V. Dubinina, V.V. Pasechnik, - M.: Bustard, 2002.
6. Biology. bacteria. Mushrooms. Plants. Grade 6: Lesson plans according to the textbook by V.V. Pasechnik / author-comp. N.I. Galushkov. - Volgograd: Teacher, 2005.
7. Pasechnik V.V. Biology. 6th grade. Bacteria, fungi, plants: Proc. for general education institutions. - M.: Bustard, 2009.
8. Pasechnik V.V. Biology: bacteria, fungi, plants. 6th grade.: workbook/ V.V. Pasechnik, T.A. Snisarenko - M.: Bustard, 2005.

flora provided not only the development and adaptation to environment plants, but also developed an adaptation for efficient seed dispersal. The dispersal of seeds and fruits is necessary for plants so that they do not compete for resources.

Example 1

For example, if a shoot appears under the mother plant, then most likely it dies due to lack of sunlight, or is underdeveloped.

The varied structure of fruits provides various ways distribution. Distribution is carried out with the help of anthropogenic, biotic and abiotic factors. Based on this, there are four ways to distribute fruits and seeds:

1. Animals and man;
2. Wind;
3. Water;
4. Self-propagation.

Many fruits are able to spread in more than one way.

Distribution of fruits and seeds by animals

Remark 1

It is believed that the animal method of dispersal of seeds is the most effective, since humans and animals are able to carry them far enough from the parent site of the plant. Man distributes many plant species to all continents of the world.

Four variants of seed distribution are known.

One of the options is dry fruits spread. With the help of small hooks, hooks, thorns, the seeds are attached to animal hair and fall on human clothing. Thus, the seeds migrate along with animals and humans. Seeds of plants, being in a new place and under favorable conditions, germinate. For example, string, bedstraw, burdock, camel thorn and other tenacious plants.

The second distribution option is juicy fruits. Animals, eating juicy fruits, do not process the seeds of the fruits, and thus the seeds end up in a different place. For example, plants that form juicy edible fruits, berries, apples, cherries, mountain ash, elderberry, etc.

The third option is due to stocks of rodent fruits. Forgotten or lost uneaten rodent fruits are spreading. For example, nuts, acorns, cereals.

Fourth option human. Moving over long distances, a person transports large loads and, along with them, seeds and small fruits of plants are accidentally transported from one continent to another. Also, a person can specially transfer the fruit or seed of plants to their homeland for its further cultivation. So, for example, potatoes and tobacco were brought to Europe from other continents. There are many examples of such distribution.

Wind dispersal of fruits and seeds

Seeds and fruits are adapted for flight due to their lightness. The flight distance of the seed or fruit depends on this ability. In addition to their mass, the distance is overcome with the help of flying formations that increase the area of ​​\u200b\u200bthe fetus. From the large volume of the surface of the fetus and its small mass, its ease of flight depends.

Flying formations are represented by bats and lionfish. Flyers include fruits with fluffy formations or parachutes. For example, poplar, willow, cotton, dandelion, and other lionfish have membranous outgrowths, they are large enough that the fruit can easily fly. Lionfish fruits are characteristic of trees, for example, maple, birch, ash.

Dispersal of fruits and seeds by water

Water spreads respectively aquatic plants, as well as those plants that grow above the water along the coast. The fruit is adapted for buoyancy by the formation of air cavities inside it. For example, there is a lot of air in the fibrous part of the coconut, so the coconuts do not sink and reach neighboring islands. Spongy fruits surround water lily seeds, which prevents them from drowning. Sedge and alder also spread with the help of water.

Self-propagation of seeds by fruits

This method is typical for drop-down dry fruits; when ripe, they themselves provide a scatter of seeds. In some cases, the seeds are pushed out with force. So the wind, from a ripe box, which opens and sways, scattering seeds, spreads plants, for example, violets, poppies. It is the box that is adapted for self-propagation, and the wind plays only a secondary role.

Propagation of bean-bean plants is accomplished by ripening, drying out, twisting and eventually cracking along the seam, which promotes seed dispersal. This is how acacia, lupine, mad cucumber, touchy spread.

Remark 2

Self-propagation in relation to other methods is considered ineffective. Since seeds do not fly off from the parent plant.

Sexual reproduction in seed plants, which include flowering and gymnosperms, is carried out using seeds. In this case, it is usually important that the seeds are at a sufficiently remote distance from the parent plant. In this case, it is more likely that young plants will not have to compete for light and water both among themselves and with an adult plant.

Angiosperms (they are flowering) plants in the process of evolution of the plant world solved the problem of seed distribution most successfully. They "invented" such an organ as the fetus.

Fruits serve as an adaptation to a certain method of dispersal of seeds. In fact, most often the fruits are distributed, and the seeds along with them. Since there are a lot of ways to distribute fruits, there are many varieties of fruits. The main methods of distribution of fruits and seeds are as follows:

with the help of the wind

animals (including birds and humans),

self-spreading,

with the help of water.

The fruits of plants that are dispersed by the wind have special devices that increase their area, but do not increase their mass. These are various fluffy hairs (for example, poplar and dandelion fruits) or pterygoid outgrowths (like maple fruits). Thanks to such formations, the seeds soar in the air for a long time, and the wind carries them farther and farther from the parent plant.

In the steppe and semi-desert, plants often dry up, and the wind breaks them off at the root. Rolled by the wind, withered plants scatter their seeds over the area. Such "tumbleweed" plants, one might say, do not even need fruits to spread seeds, since the plant itself spreads them with the help of wind.

With the help of water, the seeds of aquatic and semi-aquatic plants are distributed. The fruits of such plants do not sink, but are carried away by the current (for example, in alder growing along the banks). And it doesn't have to be small fruits. In the coconut palm, they are large, but light, so they do not sink.

Adaptations of plant fruits to distribution by animals are more diverse. After all, animals, birds and humans can distribute fruits and seeds in different ways.

The fruits of some angiosperms are adapted to cling to the fur of animals. If, for example, an animal or a person passes next to a burdock, then several prickly fruits will catch on to it. Sooner or later, the animal will drop them, but the burdock seeds will already be relatively far from their original place. In addition to burdock, an example of a plant with hook fruits is a string. Its fruits are of the achene type. However, these achenes have small spikes covered with denticles.

Succulent fruits allow plants to distribute their seeds with the help of animals and birds that eat these fruits. But how do they spread them if the fruit and seeds along with it are eaten and digested by the animal? The fact is that it is mainly the juicy part of the pericarp of the fetus that is digested, but the seeds are not. They come out of the digestive tract of the animal. The seeds are far from the parent plant and are surrounded by droppings, which, as you know, are a good fertilizer. Therefore, a juicy fruit can be considered one of the most successful achievements in the evolution of wildlife.

Man played a significant role in seed dispersal. So the fruits and seeds of many plants were accidentally or deliberately brought to other continents, where they could take root. As a result, now we can, for example, observe how plants characteristic of Africa grow in America, and in Africa - plants whose homeland is America.

There is a variant of seed distribution using spreading, or rather self-spreading. Of course, this is not the most effective method, since the seeds are still close to the mother plant. However, this method is often observed in nature. Usually seed scattering is characteristic of fruits of the pod, bean and box type. When a bean or pod dries out, its wings curl into different sides and the fruit cracks. Seeds fly out of it with little force. This is how peas, acacia and other legumes spread their seeds.

The fruit of the box (for example, in a poppy) sways in the wind, and seeds spill out of it.

However, self-spreading is not limited to dry seeds. For example, in a plant called mad cucumber, seeds fly out of their juicy fruit. It accumulates mucus, which, under pressure, is ejected along with the seeds.

Previously, potatoes, tobacco, corn grew only in America. And cucumbers are only in China. But it does not seem surprising to us at all that they are now growing with us. Just a man took and spread the seeds of these plants around the globe. But besides man, seeds are spread by wind, animals, and water. And some plants literally “shoot” with their seeds. In this lesson, we will learn how these processes take place.

In many plants, it is not the seeds themselves that propagate, but the fruits. Efficient seed dispersal is essential for the survival of a plant species. It can occur with the help of water, animals, wind, self-propagation.

Observation: Spreading the Seeds

Watch the spread of seeds and fruits from plants growing near your home. Try to find at least one example for all distribution methods. Give examples of plants that spread seeds in a similar way.

Anemochory is the dispersal of seeds and fruits by the wind.

The seeds of willow, poplar, aspen (see Fig. 1) are covered with white fluff and are distributed by the wind to long distances. The seeds of dandelions and feather grass are also distributed.

Rice. 1. Willow seeds

Only light, dry fruits can be dispersed by wind. To capture the wind, the fruits have outgrowths, these are the fruits of birch, ash, maple (see Fig. 2). A strong wind can pluck them from the tree only after the leaves have completely fallen, and so spread.

Rice. 2. Maple fruit

Linden fruits have characteristic sail-like leaves (see Fig. 3), which contributes to their picking up strong wind. They, rotating, are able to fly away from the tree for long distances.

Rice. 3. Sail-shaped leaves of the linden fruit

Hydrochory is the dispersal of seeds and fruits of a plant by water.

Anemogeochory

Some steppe plants form a branched stem, thin at the base, which dies off in autumn as the fruits ripen. The wind breaks off the plant at the root and rolls it over. Such plants are called perekatipole. Examples of plants: kachim, kermek.

Anemogeochory is a method of dispersing seeds by rolling the whole plant over the ground by the wind.

Alder fruits (see Fig. 4), falling into the water, do not sink and are carried by the current over short distances.

Rice. 4. Alder fruit

The fruits of the coconut palm are carried by sea currents from one island to another. Such fruits are resistant to salt water. So, the fruits of the Seychelles palm do not sink in water, but perish in sea water.

Autochory - dispersal of plant seeds by self-spreading (see Fig. 5). So, when the fruit of a touchy plant is touched, its valves twist sharply, scattering seeds. This is typical for peas, beans, and other legumes. Seeds are scattered over a not very long distance.

Rice. 5. Violet autochoria

Zoochory is the distribution of seeds and fruits of plants with the help of animals.

Squirting cucumber

On dry slopes and sea coasts, you can find a weed plant called mad cucumber. After the seeds ripen, mucus accumulates in its fruits, which, together with the seeds, can be shot out of the fruit. Such seeds can stick to a person or animal that touches the fruit.

Burdock fruits (see Fig. 6) or strings are equipped with sharp teeth or hooks. With their help, the fruits cling to the hair of animals or the clothes of people who carry them over long distances.

Rice. 6. Burdock fruit

Juicy fruits of cranberries (see Fig. 7), blueberries, elderberries, etc. are eaten by animals, mainly birds. Their seeds are protected by a hard shell and are not digested. Therefore, they are thrown away along with the litter.

Ornithochory is the dispersal of seeds by birds.

Rice. 7. Cowberry fruits

Acorns, chestnuts (see Fig. 8) fall directly under the parent plant. As a rule, such fruits are nutritious, and many animals make food supplies from them for the winter. Often the animal dies or is unable to find hidden supplies. In this case, the plant will germinate.

Rice. 8. Chestnut fruit

Anthropochory is the dispersal of plant seeds by humans.

When transporting various cargoes, seeds and fruits of plants may stick to bales or bags. When they are unloaded, the seeds can fall off and germinate. Also, the seeds can stick to the transport.

Seed transfer can occur between continents. So, from Europe to America was brought plantain. Ambrosia (see Fig. 9) and odorous chamomile were brought from America to Europe.

Rice. 9. Ambrosia

One type of plant can combine different kinds dispersal of fruits and seeds. So, violet seeds, in addition to self-scattering, are spread by ants (they have nutritional appendages that attract ants).

Elm fruits are spread by wind and water.

Myrmecochory is the dispersal of seeds by ants.

Bibliography

1. Biology. Bacteria, fungi, plants. Grade 6: textbook. for general education institutions / V.V. Beekeeper. - 14th ed., stereotype. - M.: Bustard, 2011. - 304 p.: ill.
2. Tikhonova E.T., Romanova N.I. Biology, 6. - M.: Russian word.
3. Isaeva T.A., Romanova N.I. Biology, 6. - M.: Russian word.

1. Biolicey2vrn.ucoz.ru ().
2. Cosmoschool.ru ().
3. School.xvatit.com().

Homework

1. Biology. Bacteria, fungi, plants. Grade 6: textbook. for general education institutions / V.V. Beekeeper. - 14th ed., stereotype. - M.: Bustard, 2011. - 304 p.: ill. - With. 151, assignments and questions 1, 5 ().
2. What adaptations do seeds have for wind dispersal?
3. What is zoochory? What plants does it belong to?
4. * Is there a most profitable way to distribute seeds? Which? Give reasons for both negative and positive answers.