Bats and angiosperms. Insectivorous bats are the best pollinators of cactus flowers. Pollinated by bats

Introduction

Each organism, including plants, has the ability to reproduce its own kind, which ensures the existence of a species in space and time, sometimes for a very long time. With the loss of the ability to reproduce, species die out, which has repeatedly occurred in the course of the evolution of the plant world.

Plants reproduce both sexually and asexually. Sexual reproduction consists in the fact that two cells, called gametes, merge, and, in addition to the fusion of protoplasms, the fusion of nuclei is necessary for sexual reproduction. Thus, the fusion of nuclei is the most important stage of the sexual process, otherwise called fertilization.

Pollination plays a major role in plant reproduction. Pollination is the process of transferring pollen grains from the stamens to the stigma of the pistil. This process can occur with the help of various factors, both biotic and abiotic.

In this paper, we will consider the definition of pollination, its types. Cross-pollination and morphological adaptations of plants to it will be considered and studied in more detail.

The purpose of the course work is to consider and study the morphological adaptations of angiosperms to cross-pollination.

1. Review the definition of pollination.

2. Study the types of pollination.

3. Consider cross-pollination in more detail.

4. Consider the morphological adaptations of plants to cross-pollination.

Chapter 1. Pollination as a way of reproduction of angiosperms

1.1 Pollination as a mode of reproduction

Pollination is the process of transferring pollen grains from the stamen to the stigma of the pistil. This process can occur with the help of various factors, both biotic and abiotic.

In classical works on the ecology of pollination, two concepts are distinguished: autogamy, or self-pollination, in which pollen from the same flower falls on the stigma. If the flowers are on the same plant, pollination is called heitenogamy, if on different plants - xenogamy.

There are no sharp differences between these variants of pollination. Geitenogamy is genetically equivalent to autogamy, but requires the participation of certain pollinators, depending on the structure of the flower. In this respect, it is similar to xenogamy. In turn, xenogamy can be identical to autogamy if the pollinated plants belong to the same clone, i.e. arose as a result of vegetative reproduction of one maternal individual.

In this regard, pollination is reduced to two types: autogamy, or self-pollination, and cross-pollination.

1.2 Autogamy, or self-pollination

This type of pollination is characteristic only of bisexual flowers. Autogamy can be random or regular.

Random autogamy is not uncommon. It is difficult to enumerate all the factors contributing to its implementation. It is only important that there is a physiological compatibility of pollen grains and the stigma of the pistil.

Regular autogamy can be gravitational if the pollen grain, due to its gravity, falls on the stigma from the anther located above it. The carriers of pollen grains inside the flower can be raindrops, small insects - thrips, which settle in the flower. The most common is contact autogamy, in which the opening anther comes into contact with the stigma of the pistil (hoof). Autogamy is closely related to the time factor and environmental conditions. In Dortmann's lobelia (Lobelia dortmanna) (see Fig. 1), it occurs before flowering, although it develops chasmogamous flowers with external attributes to attract pollinators.

Figure 1 - Lobelia Dortmann (Lobelia dortmanna)

In the small mousetail (Myosurus minimus L.) (see Fig. 2), self-pollination occurs in the first half of flowering, later it is impossible. In flowers in which self-pollination occurs before flowering, certain elements are often reduced. The extreme degree of such reduction is represented by cleistogamous flowers.

Figure 2 - Small mousetail (Myosurus minimus L.)

In oxalis (Oxalis) (see Fig. 3), about a month after flowering, when seeds are already developing in their ovaries, small (up to 3 mm) cleistogamous flowers appear with perianth in the form of small scales. An important feature of the cleistogamous flower is that anthers never open in it, but pollen tubes grow from the pollen grains in them, piercing the anther wall and growing towards the stigma, often bending at the same time. The stigma is often located at the top of the ovary, there is no style.

Figure 3 - Common Oxalis (Oxalisacetosella)

Often, cleistogamy is optional and appears in plants only under certain weather conditions. This is found in plantain chastukha (Alismaplantago-aguatica), sundew, feather grass, in which cleistogamous flowers develop during soil drought and low temperatures. In wheat, chasmogamous flowers are formed in warm, humid weather, and cleistogamous in dry and hot weather.

In most cases, cleistogamy occurs in unstable habitat conditions unfavorable for cross-pollination.

1.3 Cross-pollination

Cross-pollination, or allogamy, is a type of pollination in angiosperms in which pollen from the androecium of one flower is transferred to the stigma of the pistil of another flower.

There are two forms of cross-pollination:

1. Geitonogamy (adjacent pollination) - pollination in which pollen from a flower of one plant is transferred to the stigma of the pistil of another flower on the same plant;

2. Xenogamy - cross-pollination, in which pollen from the flower of one plant is transferred to the stigma of the pistil in the flower of another plant.

With the help of cross-pollination, genes are exchanged, which maintains a high level of heterozygosity in the population, determines the unity and integrity of the species. With cross-pollination, the possibilities of recombination of genetic material increase, more diverse genotypes of offspring are formed as a result of the combination of hereditarily diverse gametes, therefore, more viable than with self-pollination, offspring with a greater amplitude of variability and adaptability to various conditions of existence. Thus, cross-pollination is biologically more beneficial than self-pollination, so it was fixed by natural selection and became dominant in the plant world. Cross-pollination exists in over 90% of plant species.

Cross-pollination can be carried out both biotically (with the help of living organisms) and abiotic (through air or water currents).

Cross-pollination is carried out in the following ways:

a) Anemophily (pollination by wind)

b) Hydrophilia (pollination with water)

c) Ornithophilia (pollination by birds)

d) Chiropterophilia (pollination by bats)

e) Entomophily (pollination by insects)

Chapter 2. Morphological adaptations of plants to cross-pollination.

2.1 Anemophily or wind pollination

Wind-pollinated plants often grow in large clusters, for example, hazel thickets, birch groves. A person sows rye and corn on hundreds of hectares, and sometimes thousands of hectares of land.

In summer, flower pollen rises above the rye field in a cloud. Wind pollinated plants produce a lot of pollen. Part of the dry and light pollen necessarily falls on the stigmas. But most of the pollen is wasted without pollinating the flowers. The same can be seen in spring when hazel, birch and other wind-pollinated trees and shrubs bloom. Poplar, alder, rye, corn and other plants with inconspicuous flowers are pollinated by the wind.

Most wind-pollinated trees bloom in early spring, before the leaves appear. This ensures that the pollen gets to the stigma better.

Plants pollinated by the wind do not have bright and fragrant flowers. Inconspicuous, usually small flowers, anthers on long hanging threads, very small, light, dry pollen - all these are adaptations for wind pollination.

2.2 Hydrophilia or water pollination

Hydrophilia is of more ancient origin, since it is believed that the first higher plants appeared in water. However, most aquatic plants are air-pollinated, just like their terrestrial relatives. Plants such as Nymphaea, Alisma, and Hottonia are entomophilous, Potamogeton or Myriophyllum anemophilous, and Lobelia dortman self-pollinating. But for pollination of some aquatic plants, an aquatic environment is necessary.

Hydrophilia can occur both on the surface of the water (ephidrophilia) and in the water (hyphydrophilia). These two types of pollination represent a further development of anemophily or entomophily. Many small, self-pollinating land plants can flower while submerged in water; at the same time, the self-pollination mechanism functions, usually enclosed in an air sac inside the flower. Cleistogamous flowers represent the highest stage of such development.

Ephydrophily is a unique type of abiotic pollination, since in this case pollination occurs in a two-dimensional environment. Compared to the three-dimensional environment in which anemophily or hyphydrophilia occurs, this type of pollination provides a greater economy of pollen. In epihydrophilia, pollen is released from the anthers in the water and floats to the surface where the stigmas (Ruppia, Callitriche autumnalis) are found. Pollen grains quickly spread over the surface film of water. This is easy to see when watching Ruppia in bloom: small yellow drops appear on the surface of the water and spread quickly, like drops of fat; this is facilitated by an oily layer covering the shell of the pollen grain.

An interesting case of pollination in Vallisneria is widely known, in which, instead of individual pollen grains, the entire male flower comes to the surface of the water; therefore, the pollen does not even touch the surface of the water. Small funnels form around the emerging female flowers; male flowers floating nearby slide from the edge of such a funnel to its center; while the anthers touch the stigmas. Due to this efficient method of pollination, the number of pollen grains in male flowers is greatly reduced. Vallisneria-type mechanisms are also found in various representatives of the Hydrocharitaceae, sometimes, as in Hydrilla, along with exploding anthers. A similar mechanism of pollination is also observed in Lemna trisulca, only the entire plant rises to the surface of the water; and in Elodea, with a similar mechanism of pollination, staminate flowers are brought to the surface of the water, which are partly attached and partly free-floating.

Hyphydrophilia has been described in a very few plants, such as Najas, Halophila, Callitriche hamulata and Ceratophyllum. So far, they are treated simply as separate cases, since there is probably little in common between them, except for the extreme reduction of the exine. In Najas, the slowly descending pollen grains are "caught" by the stigma.

The dispersing pollen unit in Zostera is 2500 µm long and much more like a pollen tube than a pollen grain. Being very mobile, it quickly wraps itself around any object encountered on the way, for example, around a stigma. However, this reaction is completely passive. The pollen grain morphology of Zostera can be seen as an extreme case of a trend that seems to be shared by other hyphydrophilic plants: a rapidly growing pollen tube ensures that the pollen grains spread rapidly. In Cymodoceae, even more elongated pollen grains (5000-6000 µm) have been described.

2.3 Ornithophily or bird pollination

Since the birds fly well and the surface of their body is not smooth, they have good external conditions for pollination. No one is surprised that insects get food from flowers, but the corresponding actions of birds cause great surprise and reflection on how they got the “idea” to use the nectar of flowers. One of the ideas put forward was the idea that pollination arose as a result of the eating of flowers by birds, and that food may have been primarily fruits. It has also been suggested that woodpeckers or sap-eating woodpeckers (Sphyrapicus) sometimes change their diet and switch to juices flowing from hollows (some of them also peck fruits; Dendrocopus analis - fruits of Cassia grandis). A third group of "explanations" suggests that the birds pursued insects in flowers and happened to find nectar or pierce succulent tissues; or at first they drank water collected in flowers to quench their thirst, since in tropical forests water is difficult to access for animals living in the crowns of trees. The fact that hummingbirds originally pursued insects in flowers can be seen even today. The rapid absorption of nectar makes it difficult to identify it in the stomach of birds, while indigestible remains of insects are easily recognized. However, in the ornithological literature there is a large amount of data indicating that the digestive systems of birds are filled with nectar. Extraction of nectar by piercing the base of the corolla is further evidence that all this is done for the sake of extracting nectar. Insects cannot obtain nectar in this way. Some hummingbirds are addicted to piercing flowers, like some hymenoptera. None of the insects get nectar from the closed flowers of the Loranthaceae from Java, which open only when struck by nectar-seeking birds. The fact that birds visit flowers can be confirmed even on very old museum preparations by the presence of pollen grains in feathers or on the beak.

Hummingbirds need a large amount of energy, especially when hovering. It is precisely such a large expenditure of energy for soaring and flying that can explain the small size of these birds. After a period of fasting, nutrient stores can be severely reduced despite low metabolic rates during sleep.

In pollinators with different energy budgets, the efficiency of nectar uptake and its metabolism are different. The presence of flowers with a large amount of nectar is a signal forcing hummingbirds to seize and defend territories. One could refer to the migration of hummingbirds to those places where these flowers are numerous, especially during the breeding season.

From a pollination point of view, it didn't really matter whether the birds visited the flowers for nectar or to catch insects, until these visits became regular. Whether nectar or insect is the reason for the visit is a problem of adaptation, not function. In Java, Zosterops visits the non-ornithophilous Elaeocarpus ganitrus to collect mites, which are in abundance in the flowers.

There is no doubt that birds perched on flowers for all the reasons mentioned above. Even if, from the gardener's point of view, the flowers were damaged, they were successfully pollinated. Damage to the flower itself is of little consequence as long as the pistil is not damaged. After all, explosive flowers are also destroyed themselves.

Other similar occasional flower visits by dystrophic birds have recently been recorded in birds migrating to England from more southerly areas. Campbell observed various birds in England chasing insects in flowers while landing very small amounts of pollen.

From these examples of dystropic visits to flowers, it appears that there is a gradual transition through certain allotropic birds with a mixed diet, in which nectar is one of the ingredients, to eutropic ones, as a result of which true ornithophily is established.

For a long time, observations were made of visits to hummingbird flowers. Ornithophilia as a scientifically recognized phenomenon was established by Treleese at the end of the last century, and Johaw, Freese, and chiefly Werth studied it in more detail. However, it was only when Porsche in the 1920s collected a huge amount of data and made convincing conclusions about the now well-known phenomena that ornithophilia was unanimously recognized, even if its origin is still a matter of controversy.

The habit of collecting nectar is obviously polyphyletic, having arisen in different groups of birds in different regions. The best-known example of high adaptation are the hummingbirds (Trochilidae) of North and South America. Hummingbirds were probably originally insectivorous, but later switched to nectar; their chicks still eat insects in addition to nectar. The same is observed in insects.

Another American group of more or less eutropic flower-eating birds are the much less important sugar-eating birds (Coerebidae). In the Old World, other families have developed the same characteristics as hummingbirds, even if their adaptations are usually less significant. In Africa and Asia live nectaries (Nectarinidae), in Hawaii - Hawaiian flower girls (Drepanididae), closely related to local lobelia, in the Indo-Australian region - honey badgers (Meliphagidae) and brush-tongued honey parrots or small loris parrots (Trichoglossidaei).

Less specialized pollinators of flowers with a mixed diet (allotropic pollinators) are also active, but as pollinators to a much lesser extent, especially in simpler bird-pollinated flowers (Bombax, Spathodea); this shows that flowers and their birds may have evolved in parallel, influencing each other. Pollinators are found in many other families, such as some tropical nightingales (Pycnonotidae), starlings (Sturnidae), orioles (Oriolidae), and even among tropical woodpeckers (Picidae), where the fringe at the tip of the tongue is the first sign of morphological adaptation.

The flower-suckers (Dicaeidae) visit a variety of flowers, while showing a curious "specialization" to one group of plants, namely the tropical Loranthoideae, in which they not only visit ornithophilous flowers, but also adapt to the digestion of fruits and the dispersal of seeds. The oldest observations of bird pollination in the New World were made by Catesby and Ramphius in the Old World.

The areas in which any type of ornithophilia is found practically cover the American continent and Australia and further tropical Asia and the deserts of South Africa. According to Werth, Israel is the northern limit of this area, with Cinnyris visiting the flowers of the red Loranthus as well. Galil recently reported on the abundance of these birds on plants growing in gardens.

In the mountains of Central and South America, the number of ornithophilous species is unusually high. If bees are present in the high elevations of Mexico, they are just as effective as pollinators as birds, except that birds are more efficient under adverse conditions. However, Bombus species are not very sensitive to climate. Their presence can completely change the picture, as shown by van Leeuwen. Stevens points out similar results of Rhododendron pollination in the mountains of Papua.

Obviously, in Australia and New Zealand, the number of eutropic pollinating insects is also low, and the function of higher bees performed by them on other continents is taken over by birds.

Individual cases of feeding on flowers in various groups of birds, their geographical distribution and single cases of ornithophilous types of flowers in many groups of plants - all this indicates that ornithophily arose relatively recently.

The ability to soar, well developed in hummingbirds, is rare in other groups of birds; it is observed, for example, in the honey-eating Acanthorhynchus, and is poorly developed in the Asiatic Arachnothera. Some birds can soar in strong headwinds.

The brightness of the plumage, leading to a significant similarity in the color of birds and flowers, may seem rather strange. We have reason to consider this fact from the point of view of protective coloration. Van der Pale observed that a highly visible flock of red-green Loriculus (brightly colored hanging parrots) becomes invisible when landing on a flowering Erythrina. Obviously, these animals are largely vulnerable when they are immobile while eating.

Grant argued that "persistence" to flowers is poorly developed in birds and that their feeding habits are too complex. Information about the evolution of constancy to flowers is different for different authors. Snow and Snow suggest a very close relationship - monotropic, in our current terminology - between Passijloramixta and Ensiferaensifera. Obviously, the relationship between different species of hummingbirds and the plants that provide them with food varies greatly, ranging from strict territoriality to a highly inefficient strategy of successive visits, when birds use any available source of nectar. It is also necessary to take into account the possibility of learning in birds. If diversity is allowed, then impermanence may be due to the lack of a proper distinction between deceit and preferred constancy. Birds feed on any kind of food, so it is natural that if there is a profuse bloom and a large amount of nectar is available, the apparent preference of the birds in this case will simply be a matter of statistics and will not depend on the food itself. If there is no such flowering, then they can fly from one species to another or even use other food. Any observed consistency will be impressive even though flower tube length, beak length, nectar composition, etc. may play a role in flower selection. In emergencies, birds eat flowers. Johow noticed in Chile that hummingbirds can even switch to European fruit trees or Citrus species. Hemitropic birds switch to fruits more frequently. In the tropics, birds especially prefer fresh flowering trees. The ecological significance of this, of course, is not absolute, but relative and can be of selective significance.

The phylogenetic development of tropical plant species and the most highly developed groups of pollinators has led to a distinct and easily recognizable bird pollination syndrome that excludes other pollinators. Any random combinations in this case are impossible. The mutual dependence is well seen in the example of the Hawaiian flower girls Drepanididae and the flowers pollinated by them, which, when the birds were exterminated, became autogamous.

For the differential diagnosis of classes of ornithophilous flowers and flowers pollinated by diurnal Lepidoptera. The differences are rather indistinct, especially in American plants.

Some bird-pollinated flowers are brush-like (Eucalyptus, heads of Proteaceae and Compositae), others are slanted-mouthed (Epiphyllum) or tubular (Fuchsiafulgens). Some moths are typically ornithophilous.

The fact that various types of flowers are ornithophilous indicates a recent development of ornithophily, which is on top of the previous ecomorphological organizations that determine the types of structure, etc., but leading to a secondary convergence of the style. Isolated instances of resemblance between unrelated flowers, regarded by some morphologists as a mysterious "repeated pair" and by others as orthogenetic, probably represent a parallel adaptation in the field of pollination.

The effectiveness of this syndrome is shown by the fact that typical bird-pollinated flowers growing in European gardens attract the attention of short-beaked, unadapted dystrophic birds, and also by the fact that flower-pollinating birds immediately recognize and then try to use the flowers of introduced bird-pollinated plants. Flower size is not included in the syndrome. Many flowers pollinated by birds are relatively small. The flowers pollinated by birds are usually deep, not belonging to any one particular class, but brush-like and tubular are the most characteristic among them.

Sensitivity to different regions of the spectrum in different species of birds varies. In one species of hummingbird (Huth), a shift to the short-wavelength region of the spectrum was found compared to the human visible spectrum.

In Columneaflorida birds are attracted by red spots on the leaves, while the flowers themselves are hidden. Since this spot does not reproduce the shape of the flower, a high degree of mental integration can be assumed in birds pollinating Columneaflorida.

Flowers with a bright, contrasting color should include flowers in the species Aloe, Strelitzia and many bromeliads.

The transition to ornithophily is mostly recent, but in some groups the ornithophily appears to be older. Porsche identified a suprageneric group in Cactaceae (Andine Loxantocerei), in which, apparently, ornithophily in the tribe was fixed. Snow and Snow give other examples of the coevolution of ornithophilous flowers and their pollinators.

Among Euphorbiaceae with dense cyathium, Poinsettia has large glands and red bracts that attract hummingbirds. The genus Pedilanthus is characterized by an even higher specialization, which appeared from the beginning of the Tertiary period, and in this genus the glands are in spurs, the flowers are erect and zygomorphic.

Even among orchids, which have excellent pollinators - bees, some species have switched to ornithophily in an endless search for new pollinators typical of this family. In the South African genus Disa, some species have probably become ornithophilous. Therefore, the flowers of this genus pollinated by butterflies are already red, with a spur and with a reduced upper lip. The same occurs in Cattleyaaurantiaca and in some species of Dendrobium in the mountains of New Guinea. Birds visiting the flowers of Elleanthuscapitatus and Masdevalliarosea were observed by Dodson.

2.4 Chiropterophilia or bat pollination

Like birds, bats' body surfaces are not smooth, so they have a great ability to retain pollen. They also fly fast and can travel long distances. Pollen from plants located at a distance of 30 km was found in the faeces of bats. Therefore, it is not surprising that bats are good pollinators.

The first conscious observations of bats visiting flowers were made by Bürk in the Biitenzorg (now Bogor) Botanical Garden. He observed that fruit-eating bats (probably Cynopterus) visited the inflorescences of Freycinetia insignis, a plant now known to be entirely chiropterophilic, in contrast to its closely related ornithophilous species.

Later, some authors described other cases, and the example of Kigelia (Kigelia) has become a classic. As early as 1922, Porsche was expressing certain considerations regarding chiropterophilia, noting its characteristic features and predicting many possible examples.

Thanks to the work of van der Piel in Java, Vogel in South America, Jaeger, and Baker and Harris in Africa, bat pollination has now been identified in many plant families. It turned out that some plants, previously considered ornithophilous, are pollinated by bats (for example, species of Marcgravia).

Bats are generally insectivorous, but herbivorous bats independently appeared in both the Old and New Worlds. Perhaps the evolution went through frugivorousness to the use of flowers for food. Fruit-eating bats are known in two suborders inhabiting different continents, while African Pteropinae are characterized by a mixed diet. Like hummingbirds, nectar feeding is thought to have evolved from hunting insects in flowers.

Hart's observations in Trinidad in 1897 on Bauhiniamegalandra and Eperuafalcata are often mentioned in the literature, confusingly with incorrect conclusions.

Relationships between fruit and flower feeding Megalochiroptera are still partly dystropic. In Java, Cynopterus has been found to eat Durio flowers and parts of Parkia inflorescences.

In eastern Indonesia and Australia, Cynopterus and Pteropus destroy many Eucalyptus flowers, indicating hitherto unbalanced pollination conditions.

Macroglossinae are more adapted to the flower than even hummingbirds. In the stomachs of these animals caught in Java, only nectar and pollen were found, the latter in such large quantities that its accidental use is completely excluded. Obviously, pollen is in this case a source of protein, which their ancestors received from fruit juice. In the Glossophaginae, the use of pollen, although found, seems to be less significant.

Howell is of the opinion that Leptonycteris satisfies its protein requirements from pollen, and the protein in the pollen is not only of high quality, but also in sufficient quantity. She also states that the chemical composition of the pollen of flowers pollinated by bats is adapted to the use of it by these animals and differs from the composition of the pollen of related species that are pollinated by other animals. This can be seen as a floral part of the co-evolution of the chiropterophilia syndrome. Until now, the issue of African fruit-eating bats that swallow pollen has not been clarified.

The class of flowers pollinated by bats has been found to have an early side branch of evolution, forming its own subclass, for which the only pollinator is Pteropineae. In these flowers, solid food (with a characteristic odor) is represented only by specialized structures. There is neither nectar nor large masses of pollen. Freycinetiainsignis has a sweet bract, the Bassia species is a very sweet and easily separating corolla. Perhaps another species of Sapotaceae, namely the African Dumoriaheckelii, also belongs to this subclass.

The possibility of bat pollination of the white-flowered tree strelitzia (Strelitzianicolai) in the eastern region of Cape Cod needs to be investigated.

Nectar-eating New World bats are typically found in the tropics, but some migrate to the southern US during the summer, visiting cacti and agaves in Arizona. There is no record of bat pollination in Africa from the north of the Sahara, while Ipomoeaalbivena in South Pansbergen in South Africa just grows in the tropics. In Asia, the northern limit of bat pollination is in the northern Philippines and Hainan Island, with a small

Pteropinae extends beyond the latitude of Canton. The Eastern Pacific border runs in a sharp ridge through the Caroline Islands to Fiji. Macroglossinae are known to have visited flowers in Northern Australia (introduced by Agave), but the native Adansoniagregorii has all the characteristics of chiropterophilia; therefore, chiropterophilia must also exist on this continent.

Knowing the characteristics of pollination by bats can help in solving the mysteries of the origin of plants. The chiropterophilic flower of Musafehi is evidence that the species was introduced to Hawaii, where there are no bats. Chiropterophilia could have taken place in his homeland, New Caledonia, from where, as established by several botanists, he comes from.

Nectar-eating bats are characterized by a variety of adaptations. Thus, the Macroglossinae of the Old World have adapted to life on flowers, namely, they have decreased in size (the mass of Macroglossus minimus is 20–25 g), they have reduced molars, a long muzzle, and a very elongated tongue with long soft papillae at the end.

Similarly, some species of the New World Glossophaginae have a longer snout and tongue than their insectivorous relatives. Musonycterisharrisonii has a tongue length of 76 mm and a body length of 80 mm. Vogel believes that the hairs of the Glossophaga's coat are particularly well adapted to carrying pollen, since they are equipped with scales similar in size to those on the hairs that cover the belly of a bumblebee.

The physiology of Megachiroptera's sense organs deviates from what we usually see in bats. The eyes are large, sometimes with a folded retina (allowing rapid accommodation), with many rods but no cones (causing color blindness). In night photographs, fruit-eating Epomopsfranqueti show huge eyes, almost the same as those of a lemur. Smell perception probably plays a more important role than usual (large nasal cavities separated by septa), and the sonar (hearing) apparatus is less developed. According to Novik, sonar location organs are present in Leptonycteris and other pollinating Microchiroptera. In American bats with a mixed diet - nectar, fruits and insects - the sonar apparatus is intact. They make long flights with very short visits to sometimes rather poor flowers with a less rigid corolla (in this case, soaring visits are more often observed).

Macroglossinae have a powerful flight, which at first glance resembles the flight of swallows. Some species can hover in much the same way as hummingbirds. Similar data have been obtained for the Glossophaginae.

The presence of a certain harmony between the flower and animals in structure and physiology allows you to create the concept of the existence of a special type of flower pollinated by bats. Secondary self-pollination in Ceiba, or even parthenocarpy, as in cultivated Musa, can only cause harm.

It is noteworthy that although the development of chiropterophilia in America occurred independently and probably much later than elsewhere, and although the bats in question developed as an independent lineage rather late, the basic features that make up the syndrome of chiropterophilia are the same throughout the world. In all regions, bat-pollinated flowers and flower-pollinating bats are mutually adapted. This indicates common features in the physiology of all the bats under consideration. Sometimes, the development of chiropterophilia in different lines may also be based on common features of plant families.

Many flowers open shortly before dark and fall off in the early morning. Since the times of activity of diurnal birds and dusky bats, as well as the opening times of flowers pollinated by birds and bats, overlap, it is not surprising that some chiropterophilous plants are visited by birds. Werth apparently never made nocturnal observations and therefore lists Ceiba and Kigelia in the list of ornithophilous plants, although birds only plunder these flowers.

Flowers pollinated by bats are similar in appearance to flowers pollinated by hummingbirds, but only more pronounced. Flagellifloria (pendulifloria) is often observed, with flowers hanging freely on long hanging stems (Adansonia, Parkia, Marcgravia, Kigelia, Musa, Eperua). This is most evident in some species of Misipa, in which shoots up to 10 m long or more bring attraction elements out of the foliage.

In Markhamia, Oroxylum there is also a pincushion type with tight stems that lift the flowers up. The giant agave blossom speaks for itself. Favorable is also the pagoda-like structure of some Bombacaceae.

The phenomenon of chiropterophilia also explains why caulifloria, best adapted to visiting bats, is practically limited to the tropics, with only 1,000 cases found. Good examples are Cres "centia, Parmentiera, Durio and Amphitecna. In many genera (Kigelia, Misipa), flagellifloria and caulifloria are observed simultaneously in the same species; in other cases, these signs occur in different species.

Caulifloria is a secondary phenomenon. Its ecological nature is consistent with the results of studies of its morphological basis. Numerous cases had no taxonomic morphological, anatomical and physiological commonality.

In most examples of cauliflory where the flower was not chiropterophilous, another connection with bats was found, namely chiropterochory, the dispersal of seeds by fruit-eating bats. In this case, bats had an earlier and more widespread effect on tropical fruit, including color, position, and smell. This older syndrome corresponds exactly to the newer chiropterophilia syndrome. Basicaulicarpy may also be related to saurochory syndrome (seed dispersal by reptiles), a phenomenon older than angiosperms.

The sequence of flowering periods is necessary for both the plant and the bats. In Java, on large plantations of Ceiba, which has a certain flowering period, bats visited the flowers only in places close to gardens with Musa, Parkia, etc., where they could feed when Ceiba was not in bloom.

In general, the relatively young nature of chiropterophily is reflected in the distribution of bat-pollinated flowers among plant families. So, in Ranales, bats eat fruits, but do not visit flowers. Pollination of flowers by bats occurs in highly evolutionarily advanced families ranging from the Capparidaceae and Cactaceae, and is concentrated mainly in the Bignoniaceae, Bombacaceae and Sapotaceae. Many cases are completely isolated.

Some families (Bombacaceae and Bignoniaceae), characterized by chiropterophilia, apparently developed independently of each other in the Old and New Worlds, probably on the basis of some kind of preadaptations. It may also have happened in some genera, such as Misipa and especially Parkia, which Baker and Harris considered from the point of view of the noted representations.

Similarly, Bignoniacae and Bombacaceae, like Misipa and Musa, are characterized by some intermediate types which are pollinated by both birds and bats. Bombaxmalabaricum (Gossampinusheptaphylla) is ornithophilous, but not completely so it has open red cup-shaped daytime flowers. The flowers of this plant, however, have a bat-smell, which is characteristic of the chiropterophilic related species valetonii. In Java, malabaricum flowers are neglected by bats, but in the tropical regions of southern China they are eaten by Pteropinae. Chiropterophilia appears to have evolved from ornithophilia in the Bignoniaceae; Bombacaceae and Musa have probably reverted and subtropical species are being pollinated by birds. The transition from hawk-pollinated flowers in Cactaceae has already been considered.

It is still too early to try to quantify the links and their genetic implications. Sometimes bats (especially the slow Pteropinae) confine themselves to a single tree, resulting in self-pollination. Macroglossinae, characterized by rapid flight, make circles around trees, and apparently remember spatial relationships very well. However, in the study of pollen on wool and especially large accumulations of pollen in the stomachs, it was found that they are not characterized by constancy to flowers. It is also not clear how genetic purity is maintained in related chiropterophilic species, such as the wild species Musa, or whether it is maintained at all.

2.5 Entomophily or insect pollination

Insects in the flowers are attracted to pollen and the sweet juice of nectar. It is secreted by special glands - nectaries. They are located inside the flower, often at the base of the petals. Pollen and sweet nectar are the food of many insects.

Here a bee sat on the inflorescence. She quickly makes her way to the nectar stores hidden in the depths of the flower. Squeezing among the anthers and touching the stigma, the bee sucks nectar with its proboscis. Her furry body was covered with yellow pollen. In addition, the bee collected pollen in special baskets on its hind legs. A few seconds pass, and the bee leaves one flower, flies to another, third, etc.

Large single flowers, small flowers collected in inflorescences, bright color of petals or tepals, nectar and aroma are signs of insect pollinated plants. Fragrant tobacco flowers open only at dusk. They smell a lot. By night, the aroma intensifies, and white large flowers still attract night butterflies from afar.

Large, brightly colored poppy petals and an abundance of pollen in the flower are a good bait for beautiful golden-green bronze beetles. They feed on pollen. Smeared with pollen, bronzes fly from one plant to another and transfer the dust particles adhering to the body to the stigmas of the pistils of neighboring flowers.

There are plants whose flowers are pollinated only by certain insects. For example, snapdragons are pollinated by bumblebees. During flowering, hives with bees are brought to the gardens. Bees in search of food pollinate the flowers of fruit trees, and the yield of fruits increases.

The flowers, relying on insects for such an important matter, amaze with a variety of shapes and shades, and almost all of them are brightly colored. However, in all this diversity, one can trace the structure common to all. A typical flower is a receptacle surrounded by leaves that have taken the form of petals and stamens.

Some resemblance to the leaves was retained only by the calyx, formed from green sepals and forming the outer circle of the perianth. The sepals hiding the bud in poppies fall off when the flower blooms, while in tomatoes or strawberries they remain until the fruit is fully ripe.

Above the calyx are larger and brightly colored petals, although wind-pollinated flowers such as the single-flowered coastal (Littorella unijlora) do not have them at all. Hidden within some of the modified petals are nectaries, groups of cells that produce sweet nectar to attract insects. Nectaries may be pouches at the base of the petals, like buttercups, or long spurs, like violets. Spurs usually attract pollinators with long proboscises - hawks and butterflies.

The sepals and petals together form a perianth, although gardeners more often use this term to designate fused perianths, as in daffodils. The totality of all the petals is called the corolla. The reproductive organs of the flower are also located here. The female organ - pistil - consists of an ovary, a style and a stigma, on which pollen settles. The column is surrounded by male organs (stamens), each of which is a thin stalked filament with an anther at the top.

Depending on the position of the ovary, the upper one is distinguished when the petals and sepals are located below it, and the lower one, when parts of the flower are above the ovary. In some flowers - for example, in buttercups - several pistils are collected in one corolla, containing all the female organs; others may have fused pistils, sometimes with one style for all, sometimes with several.

Most flowering plants are bisexual, but some of them have chosen a different path of development. Almost all species of sedge (all wind-pollinated) have male and female flowers on the same plant, while the insect-pollinated holly has same-sex flowers on separate male and female plants.

If a tulip throws out only one flower, then, for example, lily of the valley flowers are collected in an inflorescence on one pedicel, attracting insects with their appearance and delicate fragrance. Some inconspicuous flowering plants lure pollinators by surrounding the flowers with brightly colored leaves. The fiery red "petals" of the poinsettia (Euphorbia pulcherti) are actually modified leaves, or bracts. No one, except for insects, usually notices real flowers.

Conclusion

Having done this work, we found out that pollination is the main method of reproduction of angiosperms, there are 2 types of pollination: autogamy (self-pollination) and cross-pollination.

In the work, morphological adaptations of flowering plants to cross-pollination, such as wind, water, bird, insect and bat pollination, have been considered and studied.

In this work, the goal was achieved and all tasks were disclosed.

pollination angiosperm plant morphological

Bibliography

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Pollination of flowers by bats

"Talking" flowers. N.Yu. FEOKTISTOV

As you know, pollinators of flowers can be not only various insects, but also birds, and even mammals - you can read more about this in No. 20 of our newspaper for 1998. And plants, as a rule, to attract their pollinators, have certain adaptations that make it easier for them to perform their task. In particular, flowers pollinated by tropical bats are distinguished by a soft (greenish-yellow, brown, purple) color, strong large perianth, and the release of significant amounts of slimy nectar and pollen. Such flowers open in the evening and at night and emit a peculiar, often unpleasant for humans (but probably attractive for representatives of the order of bats) smell.

But that is not all. Researchers from the University of Irlangen (Germany) drew attention to the specific shape of one of the flower petals of the Mucuna holtonii liana, from the legume family, which grows in the tropical forests of Central America. This petal has a concave shape and rises in a certain way when the flower is ready for pollination. After that, the flower becomes very attractive to bats. When scientists placed cotton swabs in the recess of this petal, the bats stopped paying attention to the flowers.

As you know, one of the characteristic features of bats is the widespread use of echolocation for orientation in flight and obtaining information about surrounding objects. The researchers suggested that a certain form of concavity in the petal of the liana is a specific adaptation of the flower, aimed at “exploiting” this particular ability of bats.

Additional experiments carried out in the acoustic laboratory confirmed this assumption. It turned out that the concave lobe concentrates and then reflects the signal emitted by bats that have gone in search of food. As a result, a flower ready for pollination, as it were, “talks” with its pollinators, informing them of its readiness to “feed” them, and at the same time use their services in the process of pollination.

Based on Australia Nature magazine. 2000, V 26. No 8.

PLANTS WHICH ARE POLLINATED BY BATS: Couroupita guianensis; Cephalocereus (Cephalocereus senilis); African Baobab (Adansonia digitata); Sausage tree (Kigelia pinnata); Trianea (Trianea); Breadfruit (Artocarpus altilis); Liana Mucuna holtonii; Blue agave (Аgave tequilana weber azul); Cocoa (Theobroma cacao); Orchids from the genus Dracula; Chorisia is magnificent (Chorisia speciosa); Durian zibethinus (Durio zibethinus); this is not the whole list.

Scientists believe that bats follow ultraviolet radiation in search of nectar.

Reflected ultraviolet light has been observed to attract bats to the juicy treat. These bats live in the tropical forests of Central and South America.

Rainforest flowers that reflect ultraviolet light can help direct color-blind bats, Glossophaga soricina, to nectar, according to research by scientists in Germany and Guatemala.

Bats' sensitivity to ultraviolet light is just one side of the symbiotic relationship between bats and flowers. The flowers provide the animals with food in the form of nectar, while the bats themselves help pollinate the flowers, allowing the plants to reproduce just like the honey bee does.

“Many flowers that depend on bats for pollination are known to be pale in color. It was believed that this was necessary in order to make the flowers appear more contrasting among the surrounding vegetation and be more accessible to mice. And since darkness hides colors and contrasts, it's possible that mice can pick up UV light to find flowers," said Elizabeth Dumont, a biologist at the University of Massachusetts.

Unlike many fish, reptiles, birds, and insects, most modern mammals, including primates such as humans, have lost the ability to see ultraviolet through evolution.

Most mammals are bicolor, ie. they use only two types of visual cells to distinguish colors. These cells allow them to distinguish only two of the four primary colors.

Primates, including humans, have three cell types and can distinguish between three primary colors, giving tricolor vision or high color resolution.

The ability to see ultraviolet in mammals was discovered only 10 years ago. Some rodents and marsupials, for example, can detect ultraviolet light using special visual cells. Nocturnal bats have lost the functions of such cells completely. Instead, they have special rods in the retina of their eyes that are responsible for seeing in a dark place. There are such sticks in the human organs of vision for black and white vision in dim light.

Because bats have lost cells that other UV-sensitive mammals have retained, they use this single receptor to pick up light emission in the 310-600 nanometer wavelength spectrum.

Ultraviolet radiation ranges from 100-400 nanometers, and visible radiation 380-770 nanometers, so the Glossophaga soricina receptor is sensitive to both the ultraviolet spectrum and the visible spectrum.

Scientists suggest that this unique visual system is designed to help these animals find flowers that reflect ultraviolet at dusk, when the light spectrum shifts to short wavelengths.

All plants are capable of reflecting full spectrum light. This makes plants visible to humans because we can see all the colors in the visible spectrum.

But because we have a strong UV filter in the lens, we cannot see the UV rays. Mice, on the other hand, do not have these filters, so they can see most of the spectrum.

The researchers concluded that these bats could see ultraviolet and visible light with a single receptor through several so-called psychophysical experiments that included behavioral research.

The animals were placed in a computer controlled environment. They have been trained for several months that only flowers with a low light signal will give them food. The scientists then changed the wavelength and intensity of the light and watched the animals' reactions.

Based on these observations, the scientists concluded that bats can see well in the UV spectrum, but cannot distinguish colors.

In another experiment, the researchers made the background color of the environment uniform. At the same time, they lowered the light intensity on the artificial flowers and measured at what intensity the mice could still see the lights. This experiment was repeated with other background colors.

The results showed that regardless of the background color, the decreasing visual sensitivity of the animals was constant across all wavelength spectra. This is the case when only one visual photoreceptor is active.

Scientists have suggested that larger mammals are not able to distinguish between ultraviolet light, with a larger eye, ultraviolet light may be more diffuse, making clear, focused vision difficult.

And also bats pollinate bananas, for the same reason there are a huge number of bananas on Samal Island. Although bananas are not only pollinators, they help a lot in this process.

By the way, bats eat only sweet fruits and nothing else.

We arrived at the Bat Cave at 6 pm, specifically to see how they fly out, and it was a very interesting picture, how they circled and scattered in different directions. And the last time we were here in the afternoon, the bats sat quietly along the edges of the gorge. Entrance during the day before 5 o'clock is 100 pesos per person (65 rubles), and in the evening after 5 o'clock 130 pesos per person, but this is a group entrance and there should be 6 people. There were five of us and had to pay for the 6th person to be able to enter. Those. it's 780 pesos for 6 people. We called tricycle drivers with us, still paid one entrance ticket.

This is the only thing that we managed to capture on video, because. it was very dark

I would love to arrange holidays in goa I have been interested in India for a long time. There are such different reviews about it, someone says that there are almost no fruits there, and someone is delighted with this country.

Pollination is the transfer of pollen from the stamen to the stigma of the pistil. Precedes fertilization. There are cross-pollination and self-pollination. Cross-pollination can be carried out by wind, insects, water, birds, bats.

When it rains during flowering orchards, conditions are created for a poor harvest. This is due to the fact that the conditions for pollination are not created, the bees did not fly in the rain. The formation of fruits in flowering plants is preceded by pollination - the transfer of pollen grains (pollen) from the stamens to the stigmas of the pistils.

Christian Sprengel, rector of the gymnasium in the German city of Spandau, devoted every free minute to the study of plant life. For about a year, he observed the “live communication” of flowers and insects in the fields and meadows and came to the conclusion that insects carry pollen and pollinate plants. In 1793, Sprengel published the book "The Open Secret of Nature in the Structure and Fertilization of Flowers", in which he convincingly proved that pollination is an obligatory process in plant reproduction.

There are self-pollination and cross-pollination.

self pollination

During self-pollination, pollen from the anthers falls on the stigma of the pistil of the same flower (Fig. 157). Self-pollination often occurs even in a closed flower - a bud. Self-pollination is characteristic of peanuts, peas, nectarines, wheat, rice, beans, cotton and other plants.

Biologically, self-pollination is less "profitable" than cross-pollination, since the future plant, which develops after the fusion of gametes, repeats the mother plant. At the same time, the possibility of the emergence of new devices is reduced. At the same time, the process of self-pollination does not depend on weather conditions and mediators, and, therefore, is carried out under any conditions, often even in unblown flowers, and ensures the emergence of new offspring.

cross pollination

In cross-pollination, pollen from one flower is transferred to the stigma of another flower. Pollen carriers during cross-pollination can be insects, wind, water (Fig. 158). Insects pollinate flowers of apple, plum, cherry, poppy, tulip and other plants.

Wind pollinated are sedge, couch grass, ryegrass, alder, hazel, oak, birch. In aquatic plants (elodea, vallisneria), pollination is carried out with the help of water (see Fig. 158).

In tropical latitudes, small birds (hummingbirds) and bats can carry pollen from flower to flower (Fig. 159, p. 178). Birds, for example, pollinate eucalyptus, acacia, fuchsia, aloe and other plants.

Cross-pollination is biologically more valuable. Male gametes are formed in the pollen grain, and female gametes are formed in the ovary. When they merge, a zygote is formed, from which a new organism develops. During cross-pollination, the zygote is formed from gametes belonging to different plants, so the new organism will have the characteristics of two plants, and hence a wider set of adaptive characteristics.

artificial pollination

When breeding new varieties of plants to increase productivity, a person carries out artificial pollination - he himself transfers pollen from the stamens to the stigma of the flower. In calm weather, a person pollinates wind-pollinated crops (corn, rye), and in cold or wet weather, insect-pollinated plants (sunflower).

Pollen

Plants have certain adaptations for pollination by different pollinators. Insect pollinated plants produce a lot of pollen - it serves as food for insects. The surface of pollen grains is sticky or rough, so it attaches well to insects.

bright flower

Many plants have brightly colored flowers that are clearly visible against the background of green leaves. Single-night flowers are usually large. Small flowers, as a rule, are collected in inflorescences.

Nectar

The flowers of many plants secrete a sugary liquid - nectar, which also attracts pollinators. Nectar is formed in nectaries - special glands that are located deep in the flowers. Nectar is consumed by butterflies, bees, bumblebees, hummingbirds, some species of parrots and bats.

Smell

Many flowers emit a pleasant aroma that also attracts insects (white acacia, rose, some types of lilies, lily of the valley, bird cherry, etc.). The smell of flowers can be not only pleasant, like most ornamental plants, but also unpleasant (for humans) - like the smell of rotten meat, manure. Such smells attract beetles, flies. material from the site

Some plants are pollinated only by certain types of insects. For example, clover flowers, which are characterized by a tubular structure, are pollinated only by bumblebees with a long proboscis. Bumblebees also pollinate sage flowers. As soon as the bumblebee climbs inside the flower for nectar, immediately two stamens on long stamen filaments protrude from under the upper petal and touch the back of the bumblebee, sprinkling it with pollen. Then the bumblebee flies to another flower, climbs inside, and pollen from its back falls on the stigma of the pistil.

The special structure of the inflorescence

In wind-pollinated plants, the flowers are numerous, small and inconspicuous, collected in small inconspicuous inflorescences. The perianth is absent or poorly developed and does not obstruct the movement of air. The stamens have long filaments on which anthers hang, as, for example, in rye flowers (Fig. 160).