Biology at the Lyceum. Pollination, its types Pollination of gymnosperms

Pollination

What is pollination? Bloom- this is the state of plants from the beginning of the opening of flowers to the drying of their stamens and petals ... During flowering, pollination of plants occurs.

Pollinationcalled the transfer of pollen from the stamens to the stigma of the pistil. If pollen is transferred from the stamens of one flower to the stigma of the pistil of another flower, then cross-pollination ... If pollen gets on the stigma of the pistil of the same flower, it is self-pollination .

Cross-pollination. With cross-pollination, two options are possible: the pollen is transferred to flowers on the same plant, the pollen is transferred to the flowers of another plant. In the latter case, it must be borne in mind that pollination occurs only between individuals of the same species!

Cross-pollination can be carried out by wind, water (these plants grow in water or near water: hornwort, naiad, vallisneria, elodea ), insects, and in tropical countries also birds and bats.

Cross-pollination is biologically more expedient, because the offspring, combining the characteristics of both parents, can better adapt to the environment. Self-pollination has its advantages: it does not depend on external conditions, and the offspring stably retains parental characteristics. For example, if yellow tomatoes are grown, then the next year, using their seeds, you can again get the same yellow tomatoes ( tomatoes, as a rule, self-pollinators). Most plants are cross-pollinated, although there are few strictly cross-pollinated plants (e.g. rye), more often cross-pollination is combined with self-pollination, which further increases the adaptability of plants to survival.

Types of flower pollination: self-pollination, cross-pollination

Wind-pollinated plants. Plants whose flowers are pollinated by the wind are called wind-pollinated ... Usually their nondescript flowers are collected in compact inflorescences, for example, in a complex ear, or in panicles. They form a huge amount of small, light pollen. Wind-pollinated plants usually grow in large groups. Among them there are herbs (timothy, bluegrass, sedge) , and shrubs and trees (hazel, alder, oak, poplar, birch) ... Moreover, these trees and shrubs bloom simultaneously with the opening of the leaves (or even earlier).

In wind-pollinated plants, the stamens usually have a long filament and carry the anther outside the flower. The stigmas of the pistils are also long, "shaggy" - to catch the dust particles flying in the air. These plants have some adaptations to ensure that the pollen is not wasted, but preferably falls on the stigmas of flowers of their own species. Many of them bloom by the hour: some bloom early in the morning, others in the afternoon.

Insect pollinated plants. Insects (bees, bumblebees, flies, butterflies, beetles) are attracted by sweet juice - nectar, which is secreted by special glands - nectaries. Moreover, they are located in such a way that the insect, getting to the nectaries, necessarily touches the anthers and stigma of the pistil. Insects feed on nectar and pollen. And some (bees) even store them for the winter.

Consequently, the presence of nectaries is an important feature of an insect pollinated plant. In addition, their flowers are usually bisexual, their pollen is sticky with outgrowths on the shell to catch hold of the insect's body. Insect flowers are found by a strong odor, by bright color, by large flowers or inflorescences.

In a number of plants, nectar, which attracts insects, is available to many of them. So on blooming poppy, jasmine, buzulnik, nivyanike you can see bees, and bumblebees, and butterflies, and beetles.

But there are plants that have adapted to a particular pollinator. Moreover, they can have a special flower structure. The carnation, with its long corolla, is pollinated only by butterflies, whose long proboscis can reach the nectar. Only bumblebees can pollinate flaxseed, snapdragon : under their weight, the lower petals of the flowers bend back and the insect, reaching the nectar, collects pollen with its shaggy body. The stigma of the pistil is located so that the pollen brought by the bumblebee from another flower must remain on it.

Flowers can smell attractive to different insects or smell especially strong at different times of the day. Many white or light-colored flowers smell especially strong in the evening and at night - they are pollinated by moths. Bees are attracted by sweet, "honey" smells, and flies are often not very pleasant smells for us: this is how many umbrella plants smell (runny, hogweed, kupyr) .

Scientists have conducted studies that have shown that insects see colors in a special way and that each species has its own preferences. It is not for nothing that in nature, among daytime flowers, all shades of red reign (but in the dark, the red color is almost invisible), and there is much less blue and white.

Why are there so many adaptations? In order to have a better chance that the pollen will not be wasted, but will fall on the pistil of a flower of a plant of the same species.

Having studied the structure and features of a flower, one can assume which animals will pollinate it. So, flowers of fragrant tobacco have a very long tube of accrete petals. Therefore, only insects with a long proboscis can reach the nectar. Flowers - white, clearly visible in the dark. It smells especially strong in the evening and at night. Pollinators are hawk moths, moths, which have a proboscis up to 25 cm long.

The largest flower in the world - rafflesia - painted red with dark spots. It smells like rotten meat. But there is no scent more pleasant for flies. They pollinate this wonderful, rare flower.

Self-pollination. Majority self-pollinating plants are agricultural crops (peas, flax, oats, wheat, tomato) , although there are self-pollinating plants among the wild ones.

Some of the flowers are already pollinated in the buds. If you open a pea bud, you can see that the pistil is covered with orange pollen. In flax, pollination takes place in an open flower. The flower blooms early in the morning and after a few hours the petals fall off. During the day, the air temperature rises and the filaments twist, the anthers touch the stigma, burst, and the pollen spills out on the stigma. Self-pollinating plants, including linen, can also be cross-pollinated. Conversely, under unfavorable conditions, self-pollination can also occur in cross-pollinated plants.

Cross-pollinated plants in a flower have adaptations that prevent self-pollination: anthers ripen and pour out pollen before the pistil develops; stigma located above anthers; pistils and stamens can develop in different flowers and even on different plants (dioecious).

Artificial pollination. In certain cases, a person carries out artificial pollination, that is, he himself transfers pollen from the stamens to the stigma of pistils. Artificial pollination is carried out for different purposes: to develop new varieties, to increase the productivity of some plants. In calm weather, a person pollinates wind-pollinated crops (corn), and in cold or wet weather - insect pollinated plants (sunflower) ... Both wind and insect pollinated plants are artificially pollinated; and cross-and self-pollinated.

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POLLINATION

in plants, the process of transferring pollen by wind, insects, or human hands. from the stamens of the flower on the stigma of the pistil. O. precedes fertilization. Depending on the structure flower, its separate parts and their physiological characteristics O. occurs differently. Distinguish between self-pollination and cross A. In nature, cross O. prevails. Method O. plays a very important role in the life of rast. and in the practice of collective and state farms, sowing pure-grade seeds, and especially. v breeding and seed production. The nature of O. determines the method and technique of selection of individual plants. and agrotechnical measures to ensure the preservation of cleanliness during reproduction and cultivation of pure-sorts of crops (see. Spatial isolation). O. pollen at the choice of the breeder, depending on the task and on the culture with which they are working, is called artificial O.

O. is of great importance for fruit trees. Here it is carried out by Ch. arr. bees. According to the characteristics of O., the varieties of fruit trees are divided into self-fertile and self-fertile varieties. Self-infertile varieties under O. pollen from trees of the same variety do not produce normally developed fruits (most varieties of apple, pear, cherry, plum, all studied varieties of sweet cherry). Such varieties should be planted in orchards with mixed plantings in combinations that ensure mutual A.. Self-fertile varieties, capable of producing a normal harvest of fruits with their own pollen (part of plums and cherries, most of apricots, almost all peaches), can be planted in pure plantings after appropriate indications of local experimental stations. Cm. Bee pollination.

Agricultural dictionary reference. - Moscow - Leningrad: State publishing house of collective and state farm literature "Selkhozgiz". Editor-in-chief: A. I. Geister. 1934 .

Synonyms:

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From the time of Charles Darwin to the present day, pollination of orchids has not ceased to attract the attention of researchers. I. I. Mechnikov in his book "Studies on Human Nature" (1903) calls the mechanism of pollination of orchids one of the most amazing examples ... Biological encyclopedia

In plants, the transfer of pollen from the anthers to the stigma of the pistil (in flowering plants) or to the ovule (in gymnosperms). After O., a pollen tube develops from a speck of dust, grows towards the ovary towards paradise and is delivered by the husband. germ cells of spermatozoa to ... ... Biological encyclopedic dictionary

POLLINATION, the transfer of pollen (containing male HAMETS) from the ANTEN to the RYNEL in POTATO-SEED (flowering) plants, or from the male cone to the female in HOSE (pine-bearing) plants, leading to FERTILIZATION. Pollination occurs, mainly ... ... Scientific and technical encyclopedic dictionary

Pollination- the process of transfer of plant pollen from the anthers to the stigma of the pistils (in angiosperms) or to the ovule (in gymnosperms). Most plant species are cross-pollinated by insects (entomophilia), birds (ornithophilia), wind ... ... Ecological Dictionary

Modern encyclopedia

Transfer of pollen from the anther to the stigma of the pistil in flowering plants or to the ovule in gymnosperms. Precedes fertilization. Pollination within one flower or one plant is called self-pollination, when pollen is transferred to the flowers of others ... Big Encyclopedic Dictionary

Pollination Dictionary of Russian synonyms. pollination n., number of synonyms: 21 aerial pollination (2) ... Synonym dictionary

Pollination- POLLINATION, transfer of pollen from the anthers to the stigma of the pistil in flowering plants or to the ovule in gymnosperms. It is carried out mainly with the help of wind, insects, sometimes birds (hummingbirds), bats, water. Precedes fertilization. ... ... Illustrated Encyclopedic Dictionary

POLLINATION, pollination, many others. no, cf. 1. Fertilization in plants by transferring flower pollen from the stamens to the stigma of the pistil or to the ovule (bot.). 2. The same as pollination (agricultural). Ushakov's explanatory dictionary. D.N. Ushakov. 1935 1940 ... Ushakov's Explanatory Dictionary

POLLINATE, liu, only; lazy (yon, yena); sov. that. Ozhegov's Explanatory Dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Ozhegov's Explanatory Dictionary

POLLINATION- POLLINATION, transfer of fertilizing flower pollen from the place of its formation (stamen) to the receiving part of the female organ (on the stigma of the pistil). O.'s consequence is fertilization and development of the seed of the plant. Distinguish between: 1) with a mo-pollination ... ... Great medical encyclopedia

Books

Cross-pollination, Sharov V.A. .. The last book of the outstanding Russian writer Vladimir Sharov (07.04. 1952-17.08.2018) was compiled and completed by him in between two attacks of the disease. It is dedicated to those people and ...
Cross-pollination (time, place, people). Collection of essays, Sharov Vladimir Alexandrovich. The last book of the outstanding Russian writer Vladimir Sharov (07.04.1952-17.08.2018) was compiled and completed by him in between two attacks of the disease. It is dedicated to those people and ...

Under pollination in plants it is usually understood transfer of pollen from the anthers of the stamens to the stigma of the pistil... Since only angiosperms have flowers, it is appropriate to talk only about their pollination. However, for example, gymnosperms have wind pollination.

Most often, the transfer of pollen from plants occurs with the help of insects or wind. There is also self-pollination in the flower bud, artificial pollination (carried out by humans), and the transfer of pollen by water.

Cross-pollination is widespread in nature, when the flowers of another plant are pollinated with the pollen of one plant. But self-pollination is found not only in self-pollinated plants, it happens that the plant self-pollinates with the help of insects or wind.

Pollination by insects

Many flowering plants are pollinated by insects. This adaptation was developed in plants in the course of evolution. They attract pollinating insects with their sweet nectar and pollen. The insect sits on a flower and gets dirty with pollen. Then it flies to a flower of another plant of the same species and leaves there part of the pollen from the first plant. Thus, the second flower is pollinated by the pollen of the first. The pollen of the second flower may end up on the stigma of the flower of the third plant, etc.

Insect plants usually have either bright large flowers or inflorescences. In any case, they are clearly visible. Flowers often give off a pleasant or not very pleasant smell that attracts insects. Insects feed not only on pollen, but also on nectar, which is secreted by nectaries, which are usually found at the bases of flower petals.

In the process of evolution, not only plants have adapted to pollination by insects, but insects have also adapted to certain flowers of plants. Therefore, in nature, a phenomenon often occurs when one type of plant is pollinated by only one of its kind of insect. For example, snapdragons are only pollinated by bumblebees. (But that doesn't mean bumblebees only pollinate snapdragons.)

Insect pollination is considered to be more effective than wind pollination. Therefore, when pollinated by insects, plants do not need to produce huge amounts of pollen.

Wind pollination

Aetomopoly angiosperms apparently evolved earlier than inseminated ones. When pollinated by the wind, large, smelling flowers or inflorescences are not needed. However, much more pollen is required to be produced, since most of it does not reach the target, falls to the ground and is carried away by the flowers.

Wind pollination is most effective when plants of the same species grow in groups rather than one at a time. So pollination will almost certainly happen in a corn field, but if you plant several corn plants in the garden, then by autumn you will get half-empty cobs, since little pollen got on the stigmas of the flowers.

Many trees are wind-pollinated. Their pollen is light and dry. Such trees grow in thickets (birch grove, hazel) and bloom even before the foliage blooms, so that it does not interfere with the transfer of pollen.

Plants that specialize in wind pollination have small nondescript flowers, since they do not need bright and large flowers. On the other hand, long filaments and large anthers are often observed. Such stamens hang from the flower, the wind flutters them, as a result of which pollen easily spills out of them and is carried away by the wind.

Pollination types

There are two main types of pollination: self-pollination - when a plant is pollinated with its own pollen - and cross-pollination.

With cross-pollination, plants can produce two main types of plants: monoecious and dioecious.

Cross-pollination requires an intermediary to transport the pollen from the stamen to the stigma of the pistil; depending on this, the following types of pollination are distinguished:

Pollination of some plants from the pondweed family is sometimes carried out with the help of snails.

Animals that carry out pollination are called pollinators.

Abiotic pollination
- Anemophilia - wind pollination, very common in grasses, most conifers and many deciduous trees.
- Hydrophilia - pollination with water, common in aquatic plants.

Some examples of different types of pollination

Tomatoes (optional self-pollination) - flowers have both pistils and stamens. The stamens have grown together so that in most cases the pistil is fertilized with its own pollen.

Poplar and sea buckthorn are dioecious plants: on male trees there are only flowers with pollen, and female trees give fruit (in the poplar in the form of fluff). If only male poplars are grown from cuttings, then you can get rid of the fluff.

In the case of sea buckthorn, you need to pay attention to the fact that only female bushes give fruits, but if there is no male sea buckthorn bush nearby, then the female plant will not be able to bear fruit. Usually one male is enough for 10 female bushes.

Corn is a monoecious plant with unisexual flowers. Male flowers are collected at the top with a panicle, female flowers on the trunk by cobs. Also monoecious plants with unisexual flowers are pumpkin plants - cucumbers, pumpkin, etc. They have flowers of different types on the same plant, although outwardly and not so much different. But male flowers die off and fall off after pollination. Fruits grow from women.

Notes (edit)

Literature

Grinfeld E.K.,. The origin and development of anthophilia in insects... - L .: Publishing house of Leningrad State University. - 203 p.
Biology. Textbook for grades 6-7. 1993.
Chub V. Pollination of plants and self-incompatibility in plants // Floriculture... - 2008. - No. 4. - S. 18-21.

Links

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Modern encyclopedia

Pollination Dictionary of Russian synonyms. pollination n., number of synonyms: 21 aerial pollination (2) ... Synonym dictionary

POLLINATE, liu, only; lazy (yon, yena); sov. that. Ozhegov's Explanatory Dictionary. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Ozhegov's Explanatory Dictionary

The ultimate task of a typical flower is the formation of fruits and seeds. This requires two processes. The first is. After it, fertilization itself takes place - fruits and seeds appear. Consider further which ones exist.

General information

Pollination of plants - stage, on which the transfer of small grains from the stamens to the stigma is carried out. It is closely related to another stage in the development of cultures - the formation of the reproductive organ. Scientists have established two types of pollination: allogamy and autogamy. In this case, the first can be carried out in two ways: geitonogamy and xenogamy.

Specifications

Autogamy - by transferring grains from the stamens to the stigma of one reproductive organ. In other words, one system independently carries out the necessary process. Allogamy is the cross transfer of grains from the stamens of one organ to the stigma of another. Geitonogamy involves pollination between flowers of one, and xenogamy - of different individuals. The first is genetically similar to autogamy. In this case, there is only a recombination of gametes in one individual. As a rule, such pollination is typical for multi-flowered inflorescences.

Xenogamy is considered to be the most favorable in terms of its genetic effect. Such pollination of flowering plants helps to increase the possibilities of recombining genetic data. This, in turn, provides an increase in intraspecific diversity and subsequent adaptive evolution. Meanwhile, autogamy is of no small importance for the stabilization of species characteristics.

The ways

The pollination method depends on the seed transfer agents and the flower structure. Allogamy and autogamy can be accomplished using the same factors. They, in particular, are the wind, animals, man, water. Methods for allogamy differ in the greatest variety. There are the following groups:

Biological - carried out with the help of living organisms. Several subgroups are distinguished in this group. Classification is carried out depending on the vector. So, it is carried out (entomophilia), birds (ornithophilia), bats (chiropterophilia). There are other methods - with the help of mollusks, mammals, etc. However, they are rarely detected in nature.
Abiotic - associated with the influence of non-biological factors. In this group, grain transfer is distinguished by wind (anemophilia), water (hydrophilia).

The ways in which it is carried out are considered adaptations to specific environmental conditions. They are genetically less important than types.

Adaptation of plants to pollination

Let's consider the first group of methods. Entomophilia is usually found in nature. Plants and pollen carriers evolved in parallel. Entomophilous individuals are easily distinguished from others. Plants and vectors have mutual adaptations. In some cases, they are so narrow that the culture is not able to exist independently without its agent (or vice versa). Insects are attracted to:

Colour.
Food.
Smell.

In addition, some insects use flowers as a refuge. For example, they hide there at night. The temperature in the flower is several degrees higher than that of the external environment. There are insects that reproduce themselves in crops. For example, chalcid wasps use flowers for this.

Ornithophilia

Pollination by birds is observed mainly in tropical regions. In rare cases, ornithophilia occurs in the subtropics. Signs of flowers that attract birds include:

No smell. Birds have a rather weak sense of smell.
The corolla is mostly orange or red in color. In rare cases, a blue or purple color is noted. It should be said that birds can easily distinguish these colors.
Large amount of low-concentration nectar.

Birds often do not sit on a flower, but pollinate by hovering next to it.

Chiropterophilia

Bats mainly pollinate tropical shrubs and trees. In rare cases, they are involved in the transfer of seeds to herbs. Bats pollinate flowers at night. Traits of crops that attract these animals include:

Fluorescent white or yellow-green color. It can also be brownish, in rare cases purple.
The presence of a specific smell. It resembles the secretions and secretions of mice.
Flowers bloom at night or in the evening.
Large parts hang from branches on long pedicels (baobab) or develop directly on the trunks

Anemophilia

Pollination of about 20% of plants in the temperate zone is carried out by wind. In open areas (in steppes, deserts, polar territories), this figure is much higher. Anemophilic cultures have the following characteristics:

Anemophilous cultures often form large clusters. This greatly increases the chances of pollination. Examples are birch groves, oak groves, bamboo thickets.

Hydrophilia

Such pollination is quite rare in nature. This is due to the fact that water is not the usual habitat for crops. For many, they are above the surface and are pollinated mainly by insects or with the help of the wind. The signs of hydrophilic crops include:

Autogamy

75% of plants have bisexual flowers. This enables self-transfer of grains without external media. Autogamy is often accidental. This is especially the case under unfavorable conditions for the vectors.

Autogamy is based on the principle that self-pollination is better than none at all. This type of grain transfer is known in many cultures. As a rule, they develop in unfavorable conditions, in areas where it is very cold (tundra, mountains) or very hot (desert) and there are no vectors.

In nature, meanwhile, there is also regular autogamy. It is constant and extremely important for cultures. For example, plants such as peas, peanuts, wheat, flax, cotton and others are self-pollinated.

Subtypes

Autogamy can be:

Cleistogamy is found in different taxonomic groups of crops (in some cereals, for example).