At great depths, up to 250 meters, they grow red algae, otherwise called crimson... In combination with corals and colorful fish, the variously colored crimson flowers create the unique beauty of the underwater world. These are predominantly large algae, but, for example, microscopic red algae also belong to the banguian class.
Why can red algae grow at such a significant depth? This question was asked in the Unified State Exam in Biology. Red pigment allows algae to grow at great depth phycoerythrin... Thanks to him, during photosynthesis, red algae absorb green, blue, blue-violet rays of the spectrum. It is these rays, unlike red ones, that are able to penetrate deep into the water column.
For red algae, spore asexual reproduction is characteristic, as well as sexual reproduction (oogamy), sometimes vegetative reproduction by parts of the thallus occurs.
The red algae include phyllophora, porphyry, gracillaria, poultry, chondrus, and there are about five thousand species in total.
Purple - a flat and thin oval plate up to half a meter in diameter. It is characterized only by sexual reproduction. Male reproductive cells do not have flagella (sperm). This is understandable, since at great depths under the water column it is difficult to move with the help of a flagellum.
The value of algae
Place in food chains, impact on nature
1. A huge mass of algae creates phytoplankton, and even in the Arctic seas there are 20-30 million individuals per 1 cubic meter of water. These are primary products that form the backbone of the food chain.
2. Phytoplankton serves as food for zooplankton (secondary production), which is eaten by large marine lifelike whales. Interestingly, Thor Heyerdahl tasted plankton soup during his expedition on the Kon-Tiki raft and found it quite tasty and nutritious.
3. Bottom algae provide shelter and food for fish and a variety of marine animals. Kelp, for example, is eaten with pleasure by a sea urchin.
4. Algae oxygenate the oceans and atmosphere.
5. However, during mass reproduction of algae (for example, Chlamydomonas) during the so-called "blooming" of water, the oxygen content in it drops and the water is saturated with toxins. River inhabitants die from lack of oxygen.
Meaning for a person
1. Algae have been used as food in many regions for thousands of years. Such brown and red algae as kelp, undaria, porphyra, hidziki (and generally sargassum) are especially popular.
2. Red algae is a source of iodine, especially some species rich in it.
3. Also red algae are a source of agar-agar - a gelling substance that is used in the confectionery industry, in the cultivation of bacteria, etc.
4.With the help of algae, wastewater is purified from fluorine, nitrogen, etc., as well as air from carbon dioxide (chlamydomonas, chlorella, euglena have succeeded in this).
5. Algae are food additives: spirulina, kelp, fucus, ulva, chlorella and others.
The department name comes from the Greek word rhodon ("Rodon") - pink. The coloration of red algae is due to different combinations of pigments. It ranges from gray and purple to almost black, and also includes all shades of red and pink. Red algae that live in highly illuminated areas are colored yellow, brown or black due to the presence of a large number of photoprotective carotenoids in the cells. Combines unicellular, colonial and multicellular organisms with coccoid, filamentous, pseudoparenchymal and parenchymal types of body structure. All representatives are characterized by the complete absence of flagellar stages in the life cycle. The shape of the thallus is varied: filamentous, bushy, cortical, lamellar, vesicular, saccular, etc. They live mainly in the seas and oceans (usually attached forms), are less common in fresh waters... About 4 thousand species are known.
Cell structure... The cell in red algae is eukaryotic: it has formed organelles with their own membranes: the nucleus, mitochondria, plastids, the Golgi apparatus, and others. From one to many plastids are found in the cells of red algae. There are pore connections between cells. In addition to the outer cell membrane, rhodophyte cells have a special formation - the cell wall.
The core is most often one, but there are also multi-core representatives. The red algae nuclei are small. For some species, endoreduplication, or replication of the nuclear genome without mitosis, is known. It leads to polyploidy, or a multiple increase in the set of chromosomes in cells. Mitochondria with flattened cristae.
Chloroplasts of red algae of various shapes, they are usually located along the cell walls, or parietally. These plastids are mainly disc-shaped and ribbon-shaped. The shape of chloroplasts can change depending on the age of the alga. Each chloroplast is surrounded by its own two-membranous membrane; the chloroplast endoplasmic reticulum is absent. Thylakoids in chloroplasts are single, not grouped, and are at the same distance from each other. One or two thylakoids are usually located along the periphery of the chloroplast, parallel to its membrane. Chloroplast DNA is in the form of small nucleoids scattered throughout the chloroplast stroma. Each nucleoid contains several circular chloroplast DNA molecules.
Of the chlorophylls, only chlorophyll is present in the plastids of red algae and, which is masked by additional pigments - phycobilins: red phycoerythrin, blue phycocyanin and allophycocyanin. These phycobilins are localized on the surface of thylakoids in special formations - phycobilisomes of hemispherical and semi-disc-shaped form.
The cell wall consists of a structural fibrillar fraction and an amorphous matrix. The strength of the cell wall is given by cellulose fibrils, which form an irregular network in red algae. The most important substances of the amorphous polysaccharide matrix are agar, agaroids, carrageenan. These substances are synthesized in the cisterns of the Golgi apparatus, then transported to the cell surface and incorporated into the wall. They account for up to 70% of the dry weight of the cell wall. A number of red algae may have a cuticle on top of the cell wall, consisting mainly of protein. Among the purple ones, there are species with calcified membranes: calcite or aragonite is deposited in them. Part of the thallus or the whole thallus can be encrusted.
General characteristics.
Almost all red algae are phototrophs and build their bodies through photosynthesis. The products of photosynthesis are a special crimson starch that is deposited in the cytoplasm, and not in the chloroplast, as in green algae. Purple starch gives a bright red color with iodine. An important reserve product is the low molecular weight hydrocarbon floridoside. Its content in the thalli of some representatives may exceed 10% of the dry weight. It performs an osmoregulatory function. In addition to red algae, floridoside is found in cyanobacteria and cryptomonads. Its concentration in cells increases with increasing salinity of the environment. Some purples can also store polyhydric alcohols.
Most species of red algae are multicellular complex organisms, the size of which can reach 1–2 meters, and only primitive representatives have a unicellular or colonial structure (Fig. 17). There are both annual and perennial species, which are usually 3–6 years old. The purplish body shape is extremely
Figure: 17 Appearance red algae: A - unicellular alga Porphyridium; B - multicellular alga Delesseria
varied. It can be: threadlike (hair-like or coarse), lamellar whole or complexly dissected with outgrowths along the edge, cylindrical, cortical (crusts, films pressed against the substrate), coral-like. The variety of external forms of red algae is reduced to several types of thallus differentiation: coccoid, filamentous, multi-filamentous, pseudo-tissue and tissue. The thalli of the rhodophyte are attached by the rhizoids or the sole.
The thalli of Florida algae are the most complex. Their thalli have signs of tissue differentiation with cell specialization. In their thallus, one can distinguish: the cortex, consisting of several layers of intensely colored cells; a pith, consisting of colorless cells, often gathered in threads. The core performs not only a transport function, but also a mechanical one, since it contains threads with thick longitudinal walls. Many red algae may have an intermediate layer of large, colorless cells between the bark and core. Thallus growth is most often intercalary (intercalated) and apical (apical), less often basal.
Reproduction.
Red algae have three methods of reproduction: vegetative, asexual, and sexual.
Asexual reproduction carried out through various disputes. Spores can be located in sporangia one, two and four at a time; they are called monospores, bispores and tetraspores, respectively. Tetraspores can be located in tetrasporangia in different ways: one above the other - linearly, or zonal, crosswise and in the corners of the tetrahedron (Fig. 18).
Figure: 18. Types of arrangement of tetraspores in tetrasprangia (after: S. Noek van den et al., 1995): A- cruciform; B- cruciform with a turn; IN- linear; G - tetrahedral
Sexual reproduction in red algae it is oogamous, it has a number of features that are not found in other groups of algae. Male reproductive cells - sperm, are devoid of flagella and are passively transferred with the flow of water to the female genital organs - carpogons... Carpogonum of red algae looks like a bulb and consists of an expanded lower part (abdomen) and an elongated upper part - trichogynes, which serves to trap sperm. In most red algae, carpogon forms at the end of a short branch called the carpogon branch. The cell that gives rise to the carpogonous branch is called the supporting cell.
Sperm form one at a time in the spermatangia, which in turn form on the mother's cells. Mature sperm cells are mononuclear and devoid of a rigid cell wall, surrounded by mucus, and may contain chloroplasts. Sperm is passively carried by currents of water, contacts with trichogina, which is located above the surface of the female gametophyte. The walls of the sperm and trichogyne at the point of contact dissolve, the male nucleus passes through the central canal in the trichogyne and merges with the haploid nucleus of the carpogon. Further development species of different orders have their own characteristics.
Life cycle.
In the majority of Rhodophyta, after the fertilization of female gametes - carpogons with male gametes - by spermations from the zygote, after multiple cell fusions, a multicellular filamentous-parenchymal formation, carposporophyte, appears (Fig. 19). He imagines
Figure: 19. Life cycle Batrachospermum (after: R. E. Lee, 1999)
myself gonimoblast,in which diploid cells develop - spores of sexual reproduction, or carpospores, growing into a new diploid plant - sporophyte. Gonimoblast,or cystocarp is a complex of the placenta, from which the threads of the gonimoblast depart with carposporangia at the ends and integuments of the gonimoblast - the wrapper. In gonimoblasts, all cells have a diploid set of chromosomes.
In a number of Florida, the gonimoblast is surrounded by a shell. In this case, this structure is called cystocarp (Fig. 20). In carposporangia
Figure: 20. Life cycle Polyphony (after: R. E. Lee, 1999)
carpospores are formed, which germinate into a diploid tetrasporophyte. Reduction division occurs on tetrasporophyte in tetrasporangia. Haploid tetraspores grow into a haploid gametophyte. This life cycle with alternating generations: one haploid - gametophyte and two diploid - carposporophyte and tetrasporophyte - is found in most red algae, but there are a number of deviations from it, depending on the variability of conditions in their environment.
The life cycle is not always rigidly fixed. If there are no conditions for the development of one of the phases, over and over again, until the environmental factors change, the same phase is resumed - either the gametophyte or the sporophyte. Such a cycle is called heteromorphic with an irregular change in developmental forms. It is noted by the Mastokarpovs. There are isomorphic cycles with a regular change in developmental forms, when sexual and asexual forms are externally represented by identical independent free-living generations. This development cycle is typical for Gracilaria, Hondrus, Mazella.
Taxonomy
The Rhodophyta department is traditionally divided into two classes: Bangiophyta - Bangiophyceae and Florida - Florideophyceae. The last class includes most genera and species of scarlet.
THE RED ALGAE DIVISION is almost exclusively seaweed. life cycle - complete absence of flagellar stages; a special form of oogamous sexual process. 2
Pigments chlorophyll "a" and "b", carotenoids (carotene, zeaxanthin, antheraxanthin, cryptoxanthin, lutein, neoxanthin) phycobilins: phycoerythrins (red) phycocyanins and allophycocyanin (blue) thallus coloration from raspberry-red to bluish-stale ) 3
Chloroplasts are a membrane of two membranes, single thylakoids, on the surface of the phycobilisome. A spare product is the polysaccharide "purple starch", which becomes brownish-red from iodine. The grains of crimson starch are always deposited in the cytoplasm without any connection with pyrenoids and chromatophores. 4
The structure of the thallus is unicellular coccoid forms (porphyridium), heterotrichous and in the form of branched filaments attached to the substrate using rhizoids. pseudoparenchymal thalli, interlacing of lateral branches Lamellar thalli of parenchymal structure (porphyry). five
The cell is covered with pectin - the hemicellulose components swell in the walls and lime is deposited. Cells are mono- and multinucleated. Chromatophores are parietal, numerous, in the form of grains or plates. 6
Asexual reproduction by means of immobile cells of a monospore - one in the sporangium of Tetraspor - four Tetraspores - on diploid asexual plants - sporophytes. In sporangia, before the formation of tetraspor, meiosis. 7
Sexual process Oogamous Female organ - carpogon in most - from the expanded basal part - the abdomen - the ovum, and the process - the trichogyne. Karpogon develops on a special short carpogonial branch. eight
Antheridia - small colorless cells contain flagellate sperm sperm are passively carried by currents of water and adhere to trichogyne. At the point of contact, the sperm and trichogynes of their walls dissolve the core of the sperm moves along the trichogyne in the abdominal part of the carpogon merges with 9
Formation of carpospores After fertilization, the basal part of the carpogon is separated by a septum from the trichogyne - dies off Development - formation of carpospores the contents of the zygote (fertilized carpogon) 1.Dividing directly to form motionless naked spores - carpospores, 10
Formation of carpospores 2. From a fertilized carpogon branching threads grow - gonimoblasts, their cells turn into carposporangia, producing one carpospore each. eleven
the formation of carpospores in most gonimoblasts do not develop directly from the abdomen of a fertilized carpogon from auscular cells. can be removed from the carpogon or are located on the thallus in the immediate vicinity when the auxilar cells are removed from the carpogon, from its abdomen after fertilization grows food, or about s e, threads. 12
cells of regional filaments contain diploid nuclei. Oregional filaments grow up to the auxilar cells, at the point of contact, the membranes dissolve and a message is established between the oregional filament cell and the auxilar cell. This fusion of cells is not accompanied by the fusion of their nuclei (the diploid nucleus of the cell with the oblast filament and the haploid nucleus of the auxilar). fusion with the auxilar cell stimulates the division of the diploid nucleus of the oregional filament cell and the development of gonimoblasts contain diploid nuclei and produce diploid carpospores Gonimoblasts - a special generation - 13
In the most highly organized red algae, auxilar cells develop only after fertilization of the carpogon and in its immediate vicinity. The collection of auxilar cells (or cells) with carpogon has a special name for procarpies. There is no need for the formation of long oregional filaments connecting carpogon and auxilar cells, the auxilar cell simply merges with the abdomen of a fertilized carpogon, after which gonimoblasts with carpospores develop from it. ... fourteen
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CLASS BANGIAN Cells often with a stellate chromatophore and a pyrenoid. Pores between cells are usually absent. Carpogon without trichogina, after fertilization, the contents of the carpogon are directly divided to form carpospores. Asexual reproduction - monospores 17
19
genus compsopogon Freshwater widespread in the tropics introduced with aquarium plants Heterotrichal thallus Reproduction by monospores. Monosporangia are detached by an oblique septum from any thallus cell and have contents granular from the abundance of purple starch, which turns into one motionless naked monospore 20
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CLASS FLORIDEA Cells mostly with parietal chromatophores without pyrenoids. There are pores between cells. Carpogon with trichogina. After fertilization, gonimoblasts develop either directly from the abdomen of a fertilized carpogon, or from auxilar cells after their fusion with oregional filaments. Asexual reproduction of most is tetrasporic. Gonimoblasts carrying carposporangia are considered as a special generation - carposporophyte. The details of the development of carposporophyte (from fertilized carpogon or from auxilar cells), as well as the time of differentiation of auxilar cells (before or after fertilization), their position on the thallus, etc., form the basis for the division of Florida into six orders of magnitude 23
Order non-malionic Representatives are characterized by the absence of auxilar cells; gonimoblasts develop directly from fertilized carpogon 24
The genus Lemanea is found in fast flowing rivers with cold water... Thallus, which looks like an unbranched setae 10-15 cm long and 1 mm thick, dark purple or olive brown in color with knotty swellings. Attaches to the substrate using a sole made of creeping threads. One thread of elongated colorless cells runs along the axis of the thallus. From the upper part of each cell of the central axis, a whorl departs for the most part of four branches diverging along the radii. The basal cells of each of these branches are large, elongated. Branches of the second order extend from their distal (morphologically upper) end, which in turn branch many times. The terminal branches grow together into a multilayered crust. Its outer cells are small and filled with chromatophores, 28
The order of kryptonemia contains auxilar cells that develop before fertilization of the carpogon and are scattered over the thallus at a certain distance from the carpogon. After fertilization, more or less long multicellular connecting, or oregional, threads grow from the carpogon to the auxilar cells. After the fusion of the auxilar cell with the cell of the oregional filament and the transition of the diploid nucleus of the filament cell into the auxilar cell, gonimoblasts arise. Carpospores developing on gonimoblasts (carposporophyte) contain a diploid nucleus and grow into diploid plants - tetrasporophytes, which produce only tetrasporophytes, which produce only tetrasporophytes. During the formation of tetraspores, meiosis occurs and haploid tetraspores germinate into haploid plants - gametophytes, bearing genitals. Gametophyte and tetrasporophyte do not differ externally (morphologically). isomorphic alternation of generations, complicated by diploid carposporophyte. 29
genus Durenea common in the southern seas. Thallus has the appearance of branched pink mucous bushes. thirty
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The order of ceramics is highly organized, many species of auxilar cells differentiate only after fertilization of the carpogon has taken place.Long oregional filaments are not formed: the abdomen of the carpogon either fuses directly with the adjacent auxilar cell (s), or through short outgrowths, forming cystocarpies 36
evolution within the department Bangui are more primitive. the carpogon has not yet developed a typical form, it differs little from ordinary vegetative cells. After fertilization, the contents of the carpogon are directly divided into carpospores. Florida is a more evolved group of Karpogon with trichogina. Of the Florida class, the simplest order is non-malionic, which do not have auxilar cells, and gonimoblasts, on which carposporangia develop, are formed directly from the ventral part of a fertilized carpogon. Kryptonemic are the next step in progressive evolution: they have auxilar cells that increase the production of carpospores, since not one cystocarp is formed, but many, according to the number of auxilar cells. With auxilar cells scattered randomly over the thallus, more or less long oregional filaments are required. The highest stage of evolution was reached by ceramiums, which have procarp and auxilar cells differentiate only after fertilization has occurred. The close proximity of carpogon and auxilar cell (s) in the procarp facilitates the formation of cpstocarpia. This order is the richest in species. 39
The oldest fossil identified as a red alga is also the oldest eukaryotic fossil belonging to a particular modern taxon. Bangiomorpha pubescens, a multicellular fossil found in Arctic Canada, differs only slightly from the modern red alga of the genus Bangia, despite being deposited in layers 1.2 billion years ago. 41
DEPARTMENT BROWN ALGAE RNAEORNUTA marine, especially in the cold waters of the northern and southern hemisphere. According to the morphological and anatomical differentiation of the thallus, it is at a higher level than the previously considered groups of algae. neither unicellular nor colonial forms, nor thalli in the form of a simple unbranched filament are known. the simplest are large heterotrichous thalli, false or true tissue structure.
strongly mucous cell walls one nucleus, one or many vacuoles, usually wall chromatophores of various shapes. chromatophores are surrounded by a complex system of membranes - in direct connection with the shell of the nucleus - the "chloroplast endoplasmic reticulum" The chloroplast matrix is \u200b\u200bcrossed by parallel three-thylakoid lamellae Thylakoid-free pyrenoid protrudes from the chloroplast in the form of a kidney
The chromatophore pigments are brown colored chlorophylls “a” and “c” (chlorophyll “b” is absent) b-carotene There are many brown xanthophylls, especially fucoxanthin. 44
Reserve polysaccharide - laminarin alcohol mannitol fat is deposited outside the chloroplast in the cytoplasm. Monad cells (zoospores and gametes) have an ocellus and flagella. The eye is a part of the plastid, connected with the flagellar apparatus. Flagella are heteromorphic. 45
Reproduction is vegetative, asexual and sexual. Vegetative propagation by portions of the thallus. Some have specialized branches (brood buds) that break off into new thalli. Asexual reproduction - zoospores formed in unilocular or unicameral sporangia on diploid plants (sporophytes) before the formation of zoospores, the nucleus is reductively divided. In protozoa, the sexual process is isogamous; gametes develop in multi-celled or multicameral sporangia. In the most highly organized brown algae, the sexual process is oogamous. In oogonia and antheridia, as a rule, one gamete is formed (egg and sperm, respectively). The ovum is fertilized always outside the oogony. A zygote without a dormant period grows into a diploid plant.
CLASS ISOGENERATE Order Ectocarp genus Ectocarpus are the most primitive brown algae. Distributed in all seas, especially cold ones, and grow on underwater objects and other larger algae. 50
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The order of Kutleria The order includes only two genera: Kutleria and Zanardinia Kutleria is distributed along the entire coast of Europe, Zanardinia - mainly in the Mediterranean Sea, as well as in the Black Sea. Both genera exhibit an alternation of generations: in Kutleria, the generation change is heteromorphic, in Zanardinia, isomorphic 55
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CLASS HETEROGENEATE Order Laminaria gametophytes differ little from each other and are represented by microscopic filamentous sprouts, often reduced to several cells, that carry the genitals. On male gametophytes, antheridia are formed in the form of small cells that develop one sperm cell each, on female gametophytes - oogonia, in which one egg cell is formed. Sporophytes of different genera differ sharply and represent the largest lower plants, reaching 60-100 m in length, with significant morphological dissection and complex anatomical structure. In most cases, laminaria sporophytes are dissected into a leaf-shaped blade, a "trunk" and rhizoids, with the help of which the whole plant is attached to pitfalls and rocks. At the point of transition of the leaf blade into the stem, there is an intercalary meristem, due to the activity of which it grows as leaf bladeand the barrel. genus of kelp, the species of which are widespread in the northern seas. 63
CLASS CYCLOSPORE The order of the fucus is characterized by - - apical growth of the thallus Absence of asexual reproduction by the oogamous sexual process the genitals are located in the depressions of the thallus - conceptacula, or scaphidia There is vegetative reproduction, leading in some parts of the ocean to the formation of huge accumulations of Sargasso thallus (Sargasso thallus) (can serve as an example).
The genus Sargassum, a complex morphological division of the thallus, is widespread in the southern hemisphere, especially in warm seas. The stem, attached to the substrate by the sole branches, carries flattened leaf-like formations, spherical air bubbles on special stems, branched fertile twigs 71
Brown algae are a natural group that differs well from the rest of the algae in their morphology. However, as already mentioned, according to a number of signs (the presence of chlorophylls "a" and "c", the absence of chlorophyll "b", the location of thylakoids in chloroplasts - threetylakoid lamellae, according to similar stock products - kelp, chrysolaminarin, according to the structure of monad cells with heterocontact and heteromorphic flagella) brown algae show similarities with golden, yellow-green, diatoms and pyrophytic algae. On this basis, some authors reduce the brown and other listed groups of algae to the rank of classes within one large division of Chlorop. Ly1 a. The existence of monad cells in the life cycle of brown algae allows them to be removed, like the rest of the listed groups, from some primary photosynthetic flagellates with a predominance of brown pigments. These flagellates evolved in several ways, one of which led to the emergence of brown algae. However, in brown algae, the connection with flagellates is more distant than in golden algae, common algae, diatoms, pyrophytes, similar to them in a number of characters, as well as in green algae, since there are no direct transitional forms here. Among brown algae, there is no consistent development of types of thallus organization from monadic to filamentous and lamellar, as is easily observed in green, yellow-green, golden and pyrofite algae. As already noted, among brown algae, only the highest stages of morphological differentiation of the thallus are represented - heterotrichal and lamellar. Perhaps more simple forms (monadic, coccoid, simple filamentous) are completely lost during the long evolution, which was done by brown algae - an ancient group already known; from the sediments of the Silurian and Devonian. There is no unanimous view regarding the relationship of orders within the division of brown algae and their location in the system. According to one of the phylogenetic schemes of brown algae, built taking into account the similarity of the structure of the thallus at the earliest stages of development, brown algae are a diphyletic group: one line of evolution combines (from those mentioned in the presentation) sphaceliaceae, dictyote and fucus, the other - ectocarp, cutleria, laminaria. Both 219``75
the groups of orders also differ in the way of thallus growth: the first is characterized by apical growth, the second by intercalary growth. Kilin (N. Ku 1 sh), whose system is most widespread at the present time, derives three evolutionary lineages from a common ancestor of brown algae, which are presented to him as isogenetic, heterogeneous and cyclosporous classes; they are based on differences in the life cycles and morphological structure of algae. Large brown algae are widely used in the human economy. Algin is extracted from them - an adhesive used in textile, food and a number of other industries. In the coastal countries, the emissions of seaweed, rich in potassium and nitrogen, are used as fertilizer and also used as feed for livestock. Some, like kelp ("seaweed"), are edible. 76
The biological meaning of the emergence of inflorescences is in the increasing probability of pollination of flowers of both entomophilous and anemophilous plants. There is no doubt that an insect will visit many more flowers per unit of time, if they are collected in inflorescences. In addition, flowers collected in inflorescences are more noticeable among the greenery of the leaves, not single flowers. Many drooping inflorescences are easily swayed by air movement, thereby dispersing pollen.
Inflorescences are characteristic of the vast majority of plant flowers. Usually, the inflorescences are grouped near the top of the plant at the ends of the branches, but sometimes, especially in tropical trees, they arise on the trunks and thick branches. This phenomenon is known as caulifloria... An example is the chocolate tree. It is believed that in a tropical forest, caulifloria makes flowers more accessible to pollinating insects. Another example of caulifloria is found in the legume plant carob cercis, which is widely cultivated in the Crimea and the Caucasus.
The inflorescence has a main axis, or inflorescence axis, and lateral axes, which can be branched to varying degrees or unbranched. Their final branches - pedicels - bear flowers.
Have simpleinflorescence lateral axes are not branched and are pedicels. Inflorescences, in which the lateral axes branch, are called complex... A complex inflorescence may have lateral axes of the first, second and subsequent orders.
The main and all terminal lateral axes may end with apical flowers, as a result of which their growth is limited. Such inflorescences are called closed ( sympodial), or certain. In closed inflorescences, the apical flowers usually open earlier than the underlying lateral ones, and therefore they are called vericolor.
In open inflorescences, the growth of the main axis is unrestricted (i.e., open), and the flowers are located on the side of the morphological top of the flowering shoot. The same may apply to the lateral axles. Such inflorescences are called open ( monopodial), or undefined. In open inflorescences, flowers bloom sequentially from bottom to top, therefore they are called side-flowered.
2. Monopodial, or botriodic inflorescences.
Monopodial (open or side-flowered) inflorescences have a main axis, which continues to grow all the time, and the lateral axes bear flowers. In such an inflorescence, the lower flowers bloom first, and later, the upper ones successively. Distinguish between simple and complex botrioid inflorescences
Simple botryoid inflorescences
K and s t - on the main axis, or the axis of the first order, pedicels are alternately located, which bear small flowers (lily of the valley, bird cherry, foxglove);
Gray - the main axis of the inflorescence, in contrast to the brush hangs down (birch);
K about l about s - on the main elongated axis there are sessile flowers (plantain);
Fat about - the main axis of the inflorescence is distinguished by great fleshiness, the arrangement of flowers is like that of an ear (corn);
Shch and to - the flowers are located in the same plane, the lower flowers have longer pedicels than the upper ones (pear, apple, plum);
Zon t and k - pedicels of individual flowers have the same length and extend from the upper part of the axis, like the spokes of an umbrella (onion, cherry);
To rzinka - numerous sessile flowers are located on a shortened and saucer-shaped thickened axis. Outside there is a wrapper of bracts (sunflower, chamomile);
Head - on the shortened and extended main axis, closely adjacent flowers (clover, burnet) sit.
Complex botryoid inflorescences
They are characterized by the fact that the flowers are located on the axes of the 2nd, 3rd, etc. orders.
1. Panicle - on the lateral axes there are simple brushes (lilac, grapes).
2. Compound spike - simple spikelets (wheat, rye, barley) are located on the main axis.
3. Composite umbrella - there are simple umbrellas on the lateral axles. Simple umbrellas usually have their own bracts (private envelopes), and the bracts at the base of the umbrella form a common envelope (dill, carrots, anise).
4. Complicated scutellum (corymbose panicle) - on the lateral axes there are small inflorescences-scutes (mountain ash).
In some cases, mixed inflorescences are observed. For example, oats have a panicle inflorescence, but instead of flowers there are small spikelets, so that two inflorescences are mixed: a panicle and an ear.
3. Sympodial, or cymoid inflorescences. Fruit morphology.
Sympodial (cymoid) inflorescences are those inflorescences in which the common peduncle (main axis) ends with a flower, and its growth continues with the upper lateral, or lateral shoots, which in turn continue their growth in the same way. Cymoid inflorescences include the following:
1. Razvilina, or dichasium. The main axis ends with a flower, the growth of the peduncle continues with opposite lateral lower buds, forming flowers, and so on (carnation, cockle, soapwort).
2. Pleiochasium, or false umbel, - the growth of the peduncle ends with a flower and continues whorly below the lateral buds, forming flowers (spurge).
3. Curl - the growth of the peduncle ends with a flower and continues with a lateral bud forming a flower, and so on repeatedly, with all the flowers directed in one direction (potatoes, forget-me-not, comfrey).
Fruit morphology.
After fertilization, the walls of the pistil ovary develop into the pericarp (pericarp). The pericarp refers to the walls of the fruit that surround the seeds that form at the same time as the pericarp. The pericarp usually has three layers:
1) external ( exocarp), sometimes covered with various outgrowths (lionfish in maple, attachments in burdock);
2) medium ( mesocarp), which constitutes a pulp in juicy fruits containing a lot of sugar (plum, cherry) or oil (olive);
3) internal ( endocarp), turning in juicy fruits often into a layer
stony cells (plum or cherry pits) or juicy pulp (lemon).
All three zones are clearly visible. For example, in cherry fruit there is a thin leathery outer layer - exocarp, edible juicy pulp of the fruit - mesocarp, hard stone of stony tissue surrounding the only seed - endocarp.
Immature fruits are usually green in color, cells of the exocarp and mesocarp contain chlorophyll and photosynthesize. As it ripens, the fruit loses its green color and often acquires a bright color, caused either by anthocyanin in the cell sap (in cherries, grapes, blueberries), or by chromoplasts (mountain ash, tomato).
In some plant species, the fruit is formed not only from the ovary of the pistil, but also from the receptacle or perianth. Such fruits are called false. For example, a berry-like false strawberry fruit is an overgrown juicy colored receptacle, on which there are small dry real fruits (achenes) formed from the ovaries of pistils. From the overgrown receptacle, the fruits of rose hips, apple trees, pears are formed.
In some plant species, the fruit is formed from several pistils. Such a fruit is called composite, or complex (composite fruit of raspberries, blackberries, buttercup).
4. Classification of fruits. All varieties of fruits are divided into the following types.
Non-expanding dry fruits
1. A nut, or nut, has a woody pericarp in which there is one free-lying seed. For example, hazel, oak, beech, hemp.
2. The achene has a leathery pericarp in which there is one free-lying seed. For example, in sunflower, dandelion, chamomile and other species from the Asteraceae family.
3. The caryopsis has a leathery pericarp, in which there is one seed fused with the pericarp. For example, in wheat, barley, and other species from the family of cereals.
4. The lionfish has a pericarp of the nut-like or hemicate type, which grows into one or more winged appendages. For example, maple, birch, elm, ash.
5. In some species, a dry, non-opening fruit has a fly - a tuft of hairs. For example, a dandelion.
Unfolding dry fruits
1. Leaflet is a box-shaped, unilocular, polyspermous fruit formed by one carpel, opening along the ventral suture from apex to the base.
For example, in cotton wool, species of the buttercup family and the Rosaceae family. A peony produces many leaflets from the pistils of one flower.
2. Bob is a box-shaped unilocular, often polyspermous fruit, formed by one carpel, opening along the ventral and dorsal sutures from apex to the base. For example, peas and other species of the legume family. In some species, when the bean valves open, they spirally twist and scatter seeds (for example, in yellow acacia). In some species, the beans are single-seeded (for example, in sainfoin) and then do not open.
3. The pod and the pod is a box-shaped two-celled polyspermous fruit formed by two carpels. In the middle of the fruit there is a membranous septum from top to bottom, to the edges of which seeds are attached. The fruit opens with two leaves along two seams from the base to the top. The leaves fall off, and the septum with seeds remains. A pod is called a long and narrow fruit - the length is 4 times or more wide (for example, in mustard), and a pod is short and wide (for example, in a shepherd's purse).
4. Boll is a multi-celled (rarely single-celled) multi-seeded fruit formed by several carpels. The bolls open differently, then with the shutters (for example, in cotton, dope, fiber flax, tea, lily, castor oil plant), then with cloves on the top of the box (for example, in many species of the carnation family), then in holes (for example, in some species of poppy and bell), then a lid on the top of the box (for example, in henbane), then side slits (for example, in okra).
In some species, dry polyspermous fruits (pods, beans), when ripe, break down laterally into single-seeded segments (for example, in wild radish). Such fruits are called articulate.
In other species, dry polyspermous fruits, when ripe, disintegrate longitudinally into separate single-seeded segments, for example, in maple and other species of the maple family, as well as in the families of umbrella, labiate, mallow and some others. Such fruits are called fractional.
Juicy fruits
1. Berry is a juicy, usually colored, polyspermous fruit formed by one or more carpels. The seeds in the berry are immersed in the juicy pulp. For example, in grapes, currants, gooseberries, belladonna, blueberries, cranberries, potatoes, tomato, cucumber, watermelon, melon, pumpkin, lemon, tangerine, orange (cucumber, pumpkin, watermelon, melon are false berries, since the outer part of the fleshy fruit they formed from a receptacle).
2. Drupe - usually juicy and colored, unilocular, single-seeded or multi-seeded fruit, formed by one or more carpels. The endocarp in the drupe looks like a bone. For example, plum, cherry, apricot, dogwood, olives. Multi-seed drupes - in elderberry, laxative buckthorn. The walnut fruit is a drupe, but its mesocarp is not juicy; the so-called nut itself is a fruit bone. In almond drupe, the mesocarp is also not juicy, while in coconut drupe it is fibrous.
The fertility of angiosperms is very high. So, one plant of white quinoa forms about 100,000 seeds per year, henbane - ≈ 500,000, walker ≈ 750,000,
poplar ≈ 27,000,000 seeds.
5. Fruit production. Distribution of fruits and seeds.
In some species, the fruit is formed from the inflorescence. This formation is called compound fruit. For example, beet fruit is a glomerulus, mulberry fruit is “berry”, and wine berry fruit is “berry”. Compound fruit in mulberry is accreted false fruits formed by overgrown perianths.
In some varieties of cultivated plants, fruits develop without pollination and fertilization, and therefore without seeds. This phenomenon of seedless fruit formation is called parthenocarp. Parthenocarp is observed in some varieties of apple, pear ("seedless"), grapes (raisins - dried grapes without seeds), gooseberries, tangerines, orange, lemon, figs, Japanese persimmon, etc. In some varieties, parthenocarp can be caused by irritating the stigma with alien pollen (pollinating pear with apple pollen, tomato - with potato pollen, eggplant - with tomato pollen), some chemicals, insect bites, burning with hot wire, etc. Seedless fruits are usually smaller than fruits with seeds and, therefore, they give lower yields. In practice, however, the seedless fruit is highly prized by the consumer. Seedless varieties can only reproduce vegetatively.
Distribution of fruits and seeds
The seeds and fruits of angiosperms have many different distribution adaptations. Most plant species have adapted to spreading seeds and fruits through the wind (anemochoria). Seeds of cotton, aspen, poplar, willow, dandelion fruits, etc. have peculiar long hairs and flies, which help to scatter them by the wind, often over long distances. Fruits of maple, birch, elm, ash, alder, pine seeds, spruce, etc. have winged outgrowths (which is why they are called lionfish), which contribute to their dispersal by the wind. It also contributes to the dispersion of the covering leaf by the wind during linden inflorescences. The seeds of many species from the families of heather, gentian, orchid and others are so small and light that they are carried by the wind, like dust, over very long distances. Plants of camel grass, kurai, bugs, etc., having a spherical shape, after ripening of the fruits, break off by the wind from the underground part and roll along the steppe for long distances, often forming whole moving ramparts, scattering their seeds along the way. These plants are collectively called tumbleweed.
The seeds and fruits of aquatic plants are spread by water (hydrochoria). Rainwater (especially after a rainstorm), water from streams and rivers plays a significant role in the transfer of seeds and fruits of plants grown on land.
Animals play an important role in the spread of seeds. Birds (ornitochoria) and to a lesser extent other animals (zoochoria) eat juicy fruits. Their seeds, passing through the digestive tract of the animal, are not damaged, do not lose their germination. Together with animal excrement, the seeds fall on the ground and germinate.
Thus, seeds often germinate at a considerable distance from the mother plant. In some plant species (burdock, carrot, burdock, Velcro), seeds and fruits have different attachments or sticky surfaces and cling to the wool of an animal passing by or stick to the feathers of birds and are thus transferred. Small seeds are spread by ants, and can also stick with dirt on the hooves of animals and thus be carried.
Some plant species have developed the ability to independently scatter their seeds (autochory). For example, in yellow acacia, the valves of ripe beans open and spirally twist with such force and speed that the seeds in the bean are scattered with force in all directions. This opening of the fruit in the yellow acacia is explained by the fact that when its bean ripens, the outer and inner layers of its valves contract unequally and tension arises and grows between them, which causes twisting and shaking of the valves when the bean opens.
In a "mad" cucumber, the ripe fruit of which breaks off the stalk, seeds are thrown into the hole formed along with the liquid contents. This happens with such force that the seeds usually fall several meters away. This ejection of liquid and seeds is explained by the fact that in the fetus, as it ripens, pressure increases and by the time the fruit ripens, it reaches a great tension.
LESSON TOPIC 27 : S-in buttercup (Ranunculaceae). Poppy (Papaveracea)
1. Buttercup family. 2. Poppy family. FROM. 379 – 383
Order Buttercup.Buttercup family (2.000)
About 2000 species. Species of the buttercup family are common in cold temperate and subtropical (mountain) regions. 32 species grow in the Smolensk region. In the tropics, plants of this family are found as an exception. Life forms are primarily perennial herbaceous plants; shrubs, shrubs and lianas are rare.
Leaves are simple, without stipules; the shape of the leaf plate is varied. The leaves can be either whole (spring chistyak) or dissected to varying degrees (oak anemone, noble liverwort, basil catchment). The leaf arrangement is next.
Many buttercups have modified underground shoots (rhizome in anemone and horse cones in spring cleaver).
Flowers can be single (genus anemone) and collected in inflorescences (genera buttercup, catchment, basil). Buttercup flowers are extremely varied in flower structure.
The diversity in the structure of flowers can be expressed by tracing several evolutionary series.
1. Flowers with an indefinite number of members (in an anemone, a simple oak perianth may have 5-8 leaves) → flowers with a certain clearly established number of members (genus wrestler).
2. Perianth simple (genus anemone, genus catchment) → double perianth (genus buttercup)
3.carpels from a large number to one
4.gynoecium from apocarpous to syncarpous
5.flowers from actinomorphic flowers to zygomorphic (genus wrestler, genus Aconite
6. the axis of the flower is elongated, therefore the members of the flower are arranged in a spiral → the axis of the flower is almost flat, therefore the members of the flower are located in a circle.
7. flowers are non-specialized, entomophilous (often pollinated by flies) → specialized flowers, entomophilous (genus wrestler, genus larkspur).
Many types of buttercup are characterized by staminodes - strongly reduced and modified petals (or stamens), which turn into nectaries. Only the basilist has no nectars.
Most species have many pistils, they are free and are located on an elongated axis (genera buttercup, liverwort, marigold). Less often, the number of pistils is limited: 3-1. The ovary is always unilocular and superior. There are usually many ovules, but there are species that have 1 ovule in the pistils. The fruits are leaflets or nuts.
There may be a different number of stamens. Most often, there are flowers with a large and indefinite number of stamens, in some types of stamens there may be from 3 to 1.
marsh marigold - * Р 5 А ¥ G ¥
Depending on the type of fruit, buttercups are divided into two subfamilies:
Wintering houses (childbirth swimsuit, wrestler, larkspur), having a fruit leaflet
Buttercup (genera buttercup, anemone, basil), having the fruit of a nut
Alkaloids are very common in all plants of this family. Buttercup plants are poisonous, they are not food plants, but due to the prevalence of alkaloids, plants are used as medicines. In morphologically unspecialized species (genus basil, marigold, buttercup), simple alkaloids are synthesized, while in advanced and specialized genera complex alkaloids are formed (plants from the genus Aconite and larkspur).
Of the different types of buttercups, 20 alkaloids are used in cardiological practice. Alkaloids of all types of buttercups are poisonous, the most poisonous belong to the aconitic ones.
Spring adonis, larkspur retina, wrestler (or aconite) are important medicinal plants.
Alkaloids of spring adonis produce a curariform effect and are used to relax muscles.
Alkaloids of retina larkspur is used in the nervous clinic for diseases associated with disorders of motor functions
Tincture of the herb Aconite Dzungarian, which is a part of the drug "Akofit", is recommended for radiculitis.
Rare and protected species: European swimsuit, spiked crow, northern wrestler.
Poppy order.Poppy family (250)
Plants of this family are distributed mainly in tropical and subtropical areas. They are rare in the temperate zone. Within the territory of Smolensk region 2 types - celandine large and poppy seed.
Poppy plants are herbaceous perennials, sometimes annuals. The presence of annuals is considered an evolutionarily young trait. The foliage is alternate, the leaves are simple, without stipules, can be either whole or dissected.
Poppy flowers are very often large, actinomorphic:
* Ca 2 Co 2 +2 A ¥ G ( ¥ )
As a rule, sepals fall off during the blooming of the flower. The gynoecium consists of several carpels that grow together to form a paracarpous gynoecium. The fruit is a dry capsule that is covered with cloves. There are many ovules, the fruits are small, and contain fats as a spare material.
A striking anatomical and biochemical feature of poppies is the presence of lactic acid plants, in which milk sap is synthesized complex structure... It contains various isoquinoline alkaloids. Milky sap and poppy alkaloids are widely used in medicine.
The genus poppy has acquired particular importance, the sleeping poppy species, the main raw material for obtaining opium. Opium contains more than 20 alkaloids, including morphine, codeine, narcotine, papaverine. Some alkaloids have a powerful anesthetic effect, but are addictive. Papaverine is used as an antispasmodic for angina pectoris and bronchial asthma. In our country, sleeping pills are not grown. A certain amount of narcotic alkaloids is also found in oil-bearing and ornamental varieties of hypnotic poppy.
Celandine large
The flowers are small, collected in an umbrella-shaped inflorescence: * Ca 2 Co 2 +2 A ¥ G (¥)
Its orange milky juice, along with alkaloids, contains flavonoids, tannins, saponins, organic acids, vitamins. The herb celandine is used as a choleretic and antibacterial agent for diseases of the liver and gallbladder. Greater celandine is a poisonous plant.
The drug "Sanguirithrin" is made from the herb of celandine for rinsing the mouth and throat in case of inflammation, as well as for washing purulent wounds.
For medicinal purposes, a yellow macula is used, from it is obtained notthe narcotic antitussive agent glaucine hydrochloride. Also, for medicinal purposes, small-fruited and heart-shaped makley are used.
LESSON 28: Family Rosaceae (Rosaceae).
1. Rosaceae family, general characteristics.
2. Subfamily Spireae. Subfamily pink.
3. Apple subfamily. Subfamily plum.
1. Family Rosaceae (3500)
Representatives of this family are distributed outside the tropical regions of the Northern Hemisphere and are found in various phytocenoses. 56 species of Rosaceae grow in the Smolensk region. Life form: trees, shrubs, grasses (annuals and perennials).
Leaves are both simple (whole or dissected) and complex (paired and pinnate, trifoliate), very often there are stipules. The foliage is alternate, rarely opposite. Some species have thorns (metamorphoses of the epidermis).
Biochemical features of Rosaceae:
· There is no non-specialized secondary metabolism. This is manifested in the complete absence of alkaloids and toxins. Essential oils are rarely formed, and they always have a simple composition and structure (except for the genus Rose)
The structure of Rosaceae flowers is not highly specialized in insect pollination. The flowers are single or collected in inflorescences of various types. The flowers are actinomorphic, the perianth is complex - there are usually five sepals and petals. Quite often the flower has a double number of sepals, in this case the first circle of sepals forms submission... There are many stamens, 2-4 times more than petals. The number of carpels is either indefinite or strictly fixed.
A characteristic feature of the flower is the presence hypantia - a special formation formed from an overgrown receptacle and the bases of sepals, petals and stamens that have grown together with it. The shape of the hypanthium can be convex, saucer-shaped, concave. Hypanthium protects the gynoecium from environmental factors. However, it plays an important role in the formation of fruits. It can grow and participate in the formation of the mesocarp and endocarp. So the juicy pulp of rose hips, apples, pears, plums is an overgrown hypanthium. In addition, hypanthium provides communication with animals - distributors of fruits (exo-and-endochoria).
Rosaceae fruits are very diverse in structure, which provides a variety of distribution methods. Improving distribution methods is one of the main directions of evolution within the family.
Very often, rosaceae develop false fruits (an apple in an apple tree and an apple in a mountain ash) and complex fruits (many-nuts in strawberries and polynuts in raspberries).
The Rosaceae family includes four subfamilies: spirea, pink, apple, plum.
2. Subfamily Spirea. Subfamily pink.
Subfamily Spirea (180)
This is the most primitive subfamily, represented by shrubs, less often trees, and very rarely perennial rhizome grasses. The flowers are small, collected either in panicles, or in racemose inflorescences, or in scutes. Corolla petals are white, less often light pink. Representatives of this family are characterized by a concave or almost flat receptacle (hypanthium), and the dry fruit is a multi-leaf (five-leaf). Gynoecium is apocarpous, usually of 2-5 carpels.
The n / family includes the genera Spirea, Tavolga, Ryabinnik.
The central genus is the Spireyne genus, widespread in Siberia and the Far East. Spireae are shrubs with simple leaves, without stipules. The flowers are usually white or pink, in paniculate, corymbose or umbellate inflorescences. The fruit is a multileaf.
Genus meadowsweet, species of meadowsweet. It is a large perennial plant up to 2m high, with a short rhizome. The leaves are intermittent-pinnate, dark green above, with thin white tomentose pubescence below. When rubbed, the leaves give off a pungent odor. The flowers are yellowish-white in a dense paniculate inflorescence. The fruits are single-seeded leaflets. The meadowsweet has long been used in folk medicine as an astringent.
* Ca (5) Co 5 A ¥ G 6-10
Subfamily Pink (1.700)
Herbaceous plants are widespread in various phytocenoses from tundra to mountain tropics. Flowers are collected in corymbose or racemose dichasia, rarely single flowers.
dog rose - * Ca (5) Co 5 A ¥ G ¥
Gynoecium is apocarpous, polymeric, but in the ovary there is always one, rarely two ovules.
The fruits are varied, but more often it is a composite drupe and many-nuts. Many species of this family have juicy complex fruits, in the formation of which hypanthium is involved.
Many plants of this family are characterized by reproduction using rhizomes, stolons or mustaches.
Substances of the secondary metabolism of rosacea are used as medicines.
1. common raspberry - its fruits contain a significant amount of salicylic acid, which determines their diaphoretic and antipyretic effect in case of colds.
2. medicinal burnet - the flower does not have a corolla, the calyx is purple 4-divisible. A decoction of the rhizome is used as a hemostatic agent for uterine and hemorrhoidal bleeding.
3. Erect cinquefoil (narrow, galangal). It differs in a 4-membered perianth and a sub-calyx. Galangal tincture (25 g of rhizomes per 500 ml of vodka) is used for intestinal catarrh and dysentery.
4. marsh cinquefoil (popular name - decop) - a decoction of rhizomes is used for joint diseases and jaundice. Also used as an astringent, hemostatic and diaphoretic.
5. cinnamon rose hips - contains a large amount of vitamin "C", as well as vitamins "B2", "K", carotene and citric acid. Condensed aqueous rosehip extract with sugar (holosas) is used as a choleretic drug.
3. Apple subfamily. Subfamily plum.