Red algae. Department of red algae - rhodophyta Place in food chains, impact on nature

The biological meaning of the appearance 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 visible among the greenery of leaves, single flowers did not live. Many drooping inflorescences sway easily under the influence of air movement, thereby contributing to the dispersion of pollen.

Inflorescences are characteristic of the vast majority of plant flowers. Usually inflorescences are grouped near the top of the plant at the ends of branches, but sometimes, especially in tropical trees, they appear on trunks and thick branches. This phenomenon is known as caulifloria. An example is the chocolate tree. It is believed that in rainforest conditions, caulifloria makes flowers more accessible to pollinating insects. Another example of caulifloria is found in the leguminous carob plant, widely cultivated in the Crimea and the Caucasus.

The inflorescence has a main axis, or inflorescence axis, and lateral axes, which may be branched to varying degrees or unbranched. Their final branches - pedicels - bear flowers.

At simple inflorescences, the 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 in apical flowers, as a result of which their growth is limited. Such inflorescences are called closed ( sympodial), or defined. In closed inflorescences, the apical flowers usually open before the underlying lateral ones, and therefore they are called primroses.

In open inflorescences, the growth of the main axis is unlimited (i.e., open), and the flowers are located on the side of the morphological top of the flowering shoot. The same can apply to the side axles. Such inflorescences are called open ( monopodial), or undefined. In open inflorescences, flowers bloom sequentially from the bottom up, so they are called lateral flowers.

2. Monopodial, or bothriod inflorescences.

Monopodial (open, or side-flowered) inflorescences have a main axis that continues to grow all the time, and lateral axes carry flowers. In such an inflorescence, the lower flowers bloom first, and later the upper ones sequentially. There are simple and complex botryoid inflorescences

Simple botryoid inflorescences

K and st - 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);

Earring - the main axis of the inflorescence, unlike the brush, hangs down (birch);

K about l about s - on the main elongated axis there are sessile flowers (plantain);

For the first time - the main axis of the inflorescence is very fleshy, the arrangement of flowers is like that of an ear (corn);

Shch and current - the flowers are located in the same plane, the lower flowers have longer pedicels than the upper ones (pear, apple, plum);

Umbrella - the pedicels of individual flowers are of the same length and extend from the upper part of the axis, like the spokes of an umbrella (onion, cherry);

Basket - numerous sessile flowers are located on a shortened and saucer-shaped thickened axis. Outside is a wrapper of bracts (sunflower, chamomile);

Head - on a shortened and expanded main axis, closely spaced 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 side axes there are simple brushes (lilac, grapes).

2. Complex spike - simple spikelets (wheat, rye, barley) are located on the main axis.

3. Complex umbrella - on the side axes there are simple umbrellas. Simple umbrellas usually have their own bracts (private wraps), and bracts at the base of the umbrella form a common wrap (dill, carrot, anise).

4. Complicated shield (corymbose panicle) - on the lateral axes there are small inflorescences-shields (rowan).

In some cases, mixed inflorescences are observed. For example, oats have a panicle inflorescence, but instead of flowers there are small spikelets, so two inflorescences are mixed: a panicle and an ear.

3. Sympodial or cymoid inflorescences. Fruit morphology.

Sympodial (cymoid) inflorescences are those 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 to grow in the same way. Cymoid inflorescences include the following:

1. Fork, or dichasium. The main axis ends with a flower, the growth of the peduncle continues with opposite lateral lower buds that form flowers, and so on (carnation, cockle, soapwort).

2. Pleiochasium, or false umbrella, - the growth of the peduncle ends with a flower and continues with whorled lower lateral buds that form flowers (euphorbia).

3. Curl - the growth of the peduncle ends with a flower and continues with a lateral bud that forms a flower, and so on repeatedly, with all flowers directed in one direction (potato, forget-me-not, comfrey).

Fruit morphology.

After fertilization, the walls of the ovary of the pistil develop into a pericarp (pericarp). The pericarp is the wall of the fruit that surrounds the seeds, which are formed simultaneously with the pericarp. The pericarp usually consists of three layers:

1) outdoor ( exocarp), sometimes covered with various outgrowths (lionfish in a maple, trailers in a burdock);

2) medium ( mesocarp), which makes up pulp in juicy fruits, containing a lot of sugar (plum, cherry) or oil (olive);

3) internal ( endocarp), which in juicy fruits often turns into a layer

stony cells (pit of plum, cherry) or into juicy pulp (lemon).

All three zones are well distinguished. For example, in a cherry fruit, the thin leathery outer layer is the exocarp, the edible juicy pulp of the fruit is the mesocarp, a hard stone made of stony tissue surrounding the single seed is the endocarp.

Unripe fruits are usually green in color, exocarp and mesocarp cells contain chlorophyll and photosynthesize. As the fruit ripens, it loses its green color and often acquires a bright color due either to anthocyanin in the cell sap (in cherries, grapes, blueberries) or 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 fruits. For example, a berry-like false strawberry fruit is an overgrown juicy colored receptacle, on which there are small dry real fruitlets (achens) formed from the ovaries of pistils. From the overgrown receptacle, rose hips, apple trees, and pears are formed.

In some plant species, the fruit is formed from several pistils. Such a fruit is called prefabricated, or complex (prefabricated fruit of raspberries, blackberries, buttercups).

4. Classification of fruits. All varieties of fruits are divided into the following types.

Non-opening dry fruits

1. A nut, or nutlet, has a woody pericarp, in which there is one loose seed. For example, hazel, oak, beech, hemp.

2. The achene has a leathery pericarp, in which there is one loose seed. For example, in sunflower, dandelion, chamomile and other species from the Compositae 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 cereal family.

4. The lionfish has a nut-shaped or achene-shaped pericarp, which has grown 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, dandelion.

Opening dry fruits

1. Leaflet - a box-shaped single-celled, multi-seeded fruit, formed by one carpel, opening along the ventral suture from top to bottom.

For example, in the milkweed, species of the ranunculus family and the Rosaceae family. A peony produces many leaflets from the pistils of one flower.

2. Bean - a box-shaped single-celled, often multi-seeded fruit, formed by one carpel, opening along the ventral and dorsal sutures from the top to the base. For example, in peas and other species of the legume family. In some species, when the bean valves open, they, spiraling, 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. Pod and pod - a box-shaped two-celled multi-seeded fruit formed by two carpels. In the middle of the fruit, from top to bottom, there is a membranous partition, to the edges of which seeds are attached. The fruit opens with two flaps along two seams from the base to the top. The valves fall off, but the partition with the seeds remains. A pod is a long and narrow fruit - the length is 4 times or more than the width (for example, in mustard), and a pod is short and wide (for example, in a shepherd's bag).

4. A boll is a multi-celled (rarely single-celled) multi-seeded fruit formed by several carpels. The boxes open differently, either with flaps (for example, in cotton, dope, fiber flax, tea, lily, castor bean), then with cloves on top of the box (for example, in many species of the clove family), then with holes (for example, in some types of poppy and bell), then with a lid on the top of the box (for example, for henbane), then with side slits (for example, for okra).

In some species, dry multi-seeded fruits (pods, beans) break up transversely into single-seeded segments when ripe (for example, in wild radish). Such fruits are called segmented.

In other species, dry multi-seeded fruits, when ripe, split longitudinally into separate one-seeded segments, for example, in maple and other species of the maple family, as well as in the families of Umbelliferae, Lamiaceae, Malvaceae, and some others. Such fruits are called fractional.

Juicy fruits

1. Berry - a juicy, usually colored, multi-seeded 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, tomatoes, cucumbers, watermelons, melons, pumpkins, lemons, tangerines, oranges (cucumber, pumpkin, watermelon, melon are false berries, since the outer part of the fleshy fruit they formed from the receptacle).

2. A drupe is usually a juicy and colored, one-celled, one-seeded or multi-seeded fruit formed by one or more carpels. The endocarp of the drupe has the appearance of a bone. For example, plums, cherries, apricots, dogwoods, olives. Multi-stoned drupes - in elderberry, buckthorn laxative. The walnut fruit is a drupe, but its mesocarp is not juicy; the so-called nut itself is the bone of the fruit. In the drupe of the almond, the mesocarp is also not juicy, while in the drupe of the coconut palm it is fibrous.

The fertility of angiosperms is very high. So, one plant of white quinoa produces about 100,000 seeds per year, henbane - ≈ 500,000, gulyavnik ≈ 750,000,

poplar ≈ 27,000,000 seeds.

5. Infructescence. Distribution of fruits and seeds.

In some species, the fruit is formed from the inflorescence. This formation is called infertility. For example, the seed of a beet is a glomerulus, the seed of a mulberry is a “berry”, the seed of a wine berry is a “berry”. The infructescence of mulberries is fused 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 fruit formation without seeds is called parthenocarpy. Parthenocarpy is observed in some varieties of apple, pear ("seedless"), grapes (raisins - dried grapes without seeds), gooseberries, tangerines, oranges, lemons, figs, Japanese persimmons, etc. In some varieties, parthenocarpy can be caused by irritating the stigma with foreign pollen (pollinating a pear with apple pollen, a tomato with potato pollen, an eggplant with tomato pollen), some chemicals, insect bites, cauterization with hot wire, etc. Seedless fruits are usually smaller than fruits with seeds and, therefore, they give smaller yields. However, in consumer practice, seedless fruits are highly valued. Seedless varieties can only reproduce vegetatively.

Distribution of fruits and seeds

Seeds and fruits of angiosperms have many different adaptations for dispersal. Most plant species have adapted to the dispersal of seeds and fruits by wind (anemochory). Seeds of cotton, aspen, poplar, willow, dandelion fruits, etc. have peculiar long hairs and volutes, which contribute to their dispersal by the wind, often over long distances. The fruits of maple, birch, elm, ash, alder, seeds of pine, spruce, etc. have winged outgrowths (which is why the fruits are called lionfish), which contribute to their dispersal by the wind. The cover sheet also contributes to wind dispersal during the linden inflorescence. The seeds of many species from the families of heather, gentian, orchids, etc. are so small and light that they are carried by the wind, like dust, over very long distances. Plants of camel grass, kurai, bedbug, etc., having a spherical shape, after ripening the fruits, are broken off by the wind from the underground part and roll across the steppe for long distances, often forming whole moving shafts, scattering their seeds along the way. These plants have received the common name "tumbleweed".

Seeds and fruits of aquatic plants are spread by water (hydrochory). Rain water (especially after a rainstorm), the water of 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 seed dispersal. Birds (ornithochory) and to a lesser extent other animals (zoochory) eat the juicy fruits. Their seeds, passing through the digestive tract of the animal, are not damaged, do not lose their germination. Together with the excrement of animals, the seeds fall to the ground and germinate.

Thus, the seeds often germinate at a considerable distance from the mother plant. In some species of plants (burdock, carrots, burdock, Velcro), seeds and fruits have various attachments or a sticky surface and cling to the hair of a passing animal or stick to bird feathers and are thus transferred. Small seeds are dispersed by ants, and can also stick with dirt to the hooves of animals and thus be carried.

Some plant species have developed the ability to independently scatter their seeds (autochory). Thus, in the yellow acacia, the valves of ripe beans open and spirally twist with such force and speed that the seeds present in the bean are scattered with force in all directions. This opening of the fruit of the yellow acacia is explained by the fact that when its bean ripens, the outer and inner layers of its valves contract differently and tension arises and grows between them, which causes twisting and shaking of the valves when the bean opens.

In a “mad” cucumber, the ripened fruit of which breaks off from the stalk, the 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, the pressure increases and by the time the fetus ripens, it reaches great tension.

TOPIC 27 : C-in ranunculaceae (Ranunculaceae). C-in poppy (Papaveracea)

1. Ranunculaceae family. 2. Poppy family. WITH. 379 – 383

Ranunculus order.buttercup family (2.000)

About 2000 species. Species of the buttercup family are common in cold temperate and subtropical (mountainous) 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 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, catchment cornflower). The leaf arrangement is alternate.

Many buttercups have modified underground shoots (the rhizome of the anemone and the horse cones of the spring chistyak).

Flowers can be single (genus anemone) and collected in inflorescences (genus buttercup, catchment area, cornflower). Ranunculaceae are extremely diverse in the structure of flowers.

The diversity in the structure of flowers can be expressed by tracing several evolutionary series.

1. Flowers with an indefinite number of members (in the oak anemone, a simple perianth may have 5-8 leaves) → flowers with a certain clearly established number of members (genus wrestler).

2. Simple perianth (genus anemone, genus columbine) → double perianth (genus buttercup)

3. carpels from a large number to one

4. gynoecium from apocarpous to syncarpous

5. flowers from actinomorphic to zygomorphic flowers (wrestler genus, aconite genus

6. the axis of the flower is elongated, so the flower members are arranged in a spiral → the axis of the flower is almost flat, so the flower members are arranged in a circle.

7. unspecialized, entomophilous flowers (often pollinated by flies) → specialized, entomophilous flowers (wrestler genus, larkspur genus).

Many species of ranunculus are characterized staminodes- highly reduced and modified petals (or stamens), which turn into nectaries. Only the basil has no nectaries.

Most species have a lot of pistils, they are free and located on an elongated axis (buttercup, liverwort, marigold genera). 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.

Stamens can be a different number. Most often there are flowers with a large and indefinite number of stamens, some species of stamens can have from 3 to 1.

marsh marigold - * P 5 A ¥ G ¥

Depending on the type of fruit in Ranunculaceae, two subfamilies are distinguished:

winterers (genus bathing suit, wrestler, larkspur), having a leaflet fruit

Ranunculaceae (genus buttercup, anemone, cornflower), having a nut fruit

Alkaloids are very common in all plants of this family. Ranunculaceae are poisonous, they are not fodder plants, but due to the prevalence of alkaloids, plants are used as medicines. In morphologically non-specialized species (genus cornflower, 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 cardiology practice. Alkaloids of all types of ranunculaceae are poisonous, the most poisonous belong to the aconite species.

Spring adonis, reticulate larkspur, wrestler (or aconite) are important medicinal plants.

Spring adonis alkaloids produce a curare-like effect and are used to relax muscles.

Larkspur alkaloids are used in the nervous clinic for diseases associated with impaired motor functions.

Tincture from the herb of Dzungarian aconite, which is part of the preparation "Akofit", is recommended for radiculitis.

Rare and protected species: European bathing suit, spiked raven, northern wrestler.

Poppy order.Poppy family (250)

Plants of this family are distributed mainly in tropical and subtropical regions. They are rare in the temperate zone. On the territory of the Smolensk region, there are 2 species - large celandine and poppy self-seed.

Poppy - herbaceous perennial, sometimes annual plants. The presence of annuals is considered an evolutionarily young feature. The leaf arrangement is alternate, the leaves are simple, without stipules, they can be either whole or dissected.

Poppy flowers are very often large, actinomorphic:

* Ca 2 Co 2 +2 A ¥ G ( ¥ )

As a rule, the sepals fall off during the opening of the flower. The gynoecium consists of several carpels that grow together to form a paracarpous gynoecium. The fruit is a dry capsule, which is covered with teeth. There are many ovules, the fruits are small, contain fats as a reserve material.

A striking anatomical and biochemical feature of poppies is the presence of lactifers, in which milky juice of a complex structure is synthesized. It contains various isoquinoline alkaloids. Milky juice and poppy alkaloids are widely used in medicine.

Of particular importance was the genus poppy, the soporific poppy species - the main raw material for the production of 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 pill poppy is not grown. A certain amount of narcotic alkaloids is also found in oilseed and ornamental varieties of poppy.

Large celandine

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. Celandine grass is used as a choleretic and antibacterial agent for diseases of the liver and gallbladder. Greater celandine is a poisonous plant.

From the herb of celandine, the preparation "Sangviritrin" is made for rinsing the mouth and throat with inflammation, as well as for washing purulent wounds.

For medicinal purposes, a yellow cup is used, from which not narcotic antitussive drug glaucine hydrochloride. Also, for medicinal purposes, small-fruited and heart-shaped makleya are used.

ACTIVITY 28: Rosaceae family (Rosaceae).

1. Rosaceae family, general characteristics.

2. Subfamily Spirea. Subfamily pink.

3. Subfamily apple. Plum subfamily.

1. Rosaceae family (3500)

Representatives of this family are distributed outside the tropical regions of the Northern Hemisphere and are found in different phytocenoses. 56 species of Rosaceae grow in the Smolensk region. Life form: trees, shrubs, herbs (annual and perennial).

The leaves are both simple (solid or dissected) and compound (paired and unpaired, trifoliate), very often there are stipules. The leaf arrangement is alternate, rarely opposite. In some species, spikes (metamorphoses of the epidermis) occur.

Biochemical features of Rosaceae:

There is no unspecialized 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 Rosa)

The structure of rosaceous flowers is not highly specialized for insect pollination. Flowers solitary 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 which case the first circle of sepals forms subchalice. There are many stamens, 2-4 times more than petals. The number of carpels is either indefinite or strictly fixed.

A characteristic feature of a flower is the presence hypanthia- a special formation formed from an overgrown receptacle and the bases of sepals, petals and stamens fused with it. The shape of the hypanthium can be convex, saucer-shaped, concave. The 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 wild rose, apple, pear, plum is an overgrown hypanthium. In addition, the hypanthium provides communication with animals that distribute 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, false fruits are formed in rosaceae (an apple in an apple tree and an apple in a mountain ash) and complex fruits (a multi-nutlet in a strawberry and a multi-drupe in a raspberry).

The Rosaceae family includes four subfamilies: spirea, rose, apple, plum.

2. Subfamily Spirea. Subfamily pink.

Subfamily Spirea (180)

This is the most primitive subfamily, represented by shrubs, rarely trees, and very rarely perennial rhizomatous herbs. The flowers are small, collected either in panicles, or in racemose inflorescences, or in corymbs. Corolla petals are white, rarely 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 apocarpous, usually with 2-5 carpels.

The p / family includes the genera Spirea, Meadowsweet, Fieldfare.

The central genus is the Spireaceae genus, distributed in Siberia and the Far East. Spireas are shrubs with simple leaves, without stipules. The flowers are usually white or pink, in paniculate, corymbose or umbellate inflorescences. The fruit is a multi-leaf.

Genus meadowsweet, species meadowsweet. This is a large perennial plant up to 2 m high, with a short rhizome. The leaves are intermittently pinnate, dark green above, with thin white-tomentose pubescence below. When rubbed, the leaves emit a pungent odor. The flowers are yellowish-white collected in a dense paniculate inflorescence. The fruits are single-seeded leaflets. Meadowsweet has long been used in folk medicine as an astringent.

* Ca (5) Co 5 A ¥ G 6-10

Subfamily Roses (1.700)

Herbaceous plants are widespread in various phytocenoses from the tundra to the mountain tropics. Flowers are collected in corymbose or racemose dichasia, rarely single flowers.

dog rosehip - * Ca (5) Co 5 A ¥ G ¥

The gynoecium is apocarpous, polymeric, but there is always one, rarely two ovules in the ovary.

The fruits are varied, but more often it is a combined 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 whiskers.

Substances of the secondary metabolism of roses are used as medicines.

1. common raspberry - its fruits contain a significant amount of salicylic acid, which causes their diaphoretic and antipyretic effect in colds.

2. officinalis burnet - the flower does not have a corolla, the calyx is purple 4-parted. A decoction of the rhizome is used as a hemostatic agent for uterine and hemorrhoidal bleeding.

3. erect cinquefoil (uzik, galangal). differs by a 4-membered perianth and a calyx with a subcalyx. Galangal tincture (25 g of rhizome per 500 ml of vodka) is used for catarrh of the intestines and dysentery.

4. marsh cinquefoil (popular name - dekop) - a decoction of the rhizome is used for joint diseases and jaundice. It is also used as an astringent, hemostatic and diaphoretic.

5. Cinnamon rosehip - contains a large amount of vitamin "C", as well as vitamins "B 2", "K", carotene and citric acid. Condensed water extract of wild rose with sugar (cholosas) is used as a choleretic drug.

3. Subfamily apple. Plum subfamily.

DIVISION RED ALGAE almost exclusively seaweed. life cycle - the complete absence of flagellar stages is a special form of the oogamous sexual process. 2

Pigments chlorophyll "a" and "b", carotenoids (carotene, zeaxanthin, antheraxanthin, cryptoxanthin, lutein, neoxanthin) phycobilins: phycoerythrins (red) phycocyanins and allophycocyanin (blue) thallus color from raspberry-red to bluish-steel (with an excess of phycocyanin ) 3

Chloroplasts are a sheath of two membranes solitary thylakoids, on the surface of phycobilisomes. The reserve product is the "crimson starch" polysaccharide, which acquires a brown-red color from iodine. Grains of purple starch are always deposited in the cytoplasm without 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 with the help of rhizoids. pseudoparenchymal thalli, interlacing of lateral branches Lamellar thalli of parenchymal structure (porphyry). 5

The cell is dressed in a shell of pectin - hemicellulose components swell in the walls, lime is deposited. Cells uninuclear and multinucleated Chromatophores parietal, numerous, in the form of grains or plates. 6

Asexual reproduction by means of immobile monospore cells - one in sporangium Tetraspores - four Tetraspores - on diploid asexual plants - sporophytes. In sporangia, meiosis occurs before the formation of tetraspores. 7

Sexual process Oogamous The female organ - karpogon in the majority - from the expanded basal part - the abdomen - the egg, and the process - the trichogyne. Karpogon develops on a special short carpogonial branch. eight

Antheridia - small colorless cells contain flagellate-free spermatozoa. The spermatozoa are passively carried by water currents and adhere to the trichogyne. At the point of contact, the spermatium and trichogynes dissolve in their walls; the sperm nucleus moves along the trichogyne in the abdominal part of the carpogon merges with

formation of carpospores After fertilization, the basal part of the carpogon is separated by a septum from the trichogyne - it dies off Development - the formation of carpospores the contents of the zygote (fertilized carpogon) 1. directly divides with the formation of motionless bare spores - carpospore, 10

formation of carpospores 2. branching filaments grow from the fertilized carpogon - 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 axillary cells. can be removed from the carpogon or located on the thallus in close proximity when the auxillary cells are removed from the carpogon, from its abdomen after fertilization, connective cells or oblasts grow uh, threads. 12

cells of ooblastic filaments contain diploid nuclei. The oblastemic filaments grow to the auxilary cells, at the point of contact the membranes dissolve and a message is established between the oblastemic filament cell and the auxilary cell. This fusion of cells is not accompanied by the fusion of their nuclei (the diploid nucleus of the cell of the oblastem filament and the haploid nucleus of the auxilary). fusion with the auxilary cell stimulates the division of the diploid cell nucleus of the oblastemic filament and the development of gonimoblasts contain diploid nuclei and produce diploid carpospores Gonimoblasts - a special generation - 13

In the most highly organized red algae, auxilary cells develop only after carpogon fertilization and in its immediate vicinity. The combination of the auxillary cell (or cells) with carpogon bears the special name of procarp. There is no need for the formation of long oblastemic filaments connecting carp and auxilary cells, the auxilary cell simply merges with the belly of the fertilized carpogon, after which gonimoblasts with carpospores develop from it. . fourteen

CLASS BANGIAN Cells often with stellate chromatophore and pyrenoid. Pores between cells are usually absent. Carpogon without trichogyne, after fertilization, the content of the carpogon directly divides with the formation of carpospores. Asexual reproduction - monospores 17

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 cell of the thallus and have a granular content from an abundance of purple starch, which turns into one motionless naked monospore 20

CLASS FLORIDEIA Cells mostly with parietal chromatophores without pyrenoids There are pores between the cells. Karpogon with trichogina. After fertilization, gonimoblasts develop either directly from the belly of the fertilized carpogon, or from auxilary cells after their fusion with ooblastic filaments. Most asexual reproduction is by tetraspores. Gonimoblasts bearing carposporangia are considered as a special generation - carposporophyte. Details of carposporophyte development (from a fertilized carpogon or from auxilary cells), as well as the time of differentiation of auxillary cells (before or after fertilization), their position on the thallus, etc. form the basis for the division of florides into six orders of magnitude 23

The order is non-malionic. Representatives are characterized by the absence of auxillary cells; gonimoblasts develop directly from the fertilized carpogon 24

The genus Lemanea is found in fast-flowing cold-water rivers. Thallus, having the form of a non-branching bristle 10-15 cm long and 1 mm thick, dark purple or olive-brown in color with nodular swellings. It is attached to the substrate with the help of a sole made of creeping threads. One thread of elongated colorless cells passes along the axis of the thallus. From the upper part of each cell of the central axis, a whorl departs for the most part from four branches diverging along the radii. The basal cells of each such branch are large, elongated. Branches of the second order depart from their distal (morphologically upper) end, which, in turn, branch many times. Terminal branches grow together to form a multilayered bark. Its outer cells are small and filled with chromatophores, 28

The kryptonemia order has auxilary cells that develop before fertilization of the carpogon and are scattered throughout the thallus at a certain distance from the carpogon. After fertilization, more or less long multicellular connecting, or ooblastic, threads grow from the carpogon to the auxillary cells. After the fusion of the auxilary cell with the cell of the oblastem filament and the transition of the diploid nucleus of the filament cell into the auxilar cell, gonimoblasts arise. Developing on gonimoblasts (carposporophyte), carpospores contain a diploid nucleus and germinate into diploid plants - tetrasporophytes, producing only organs of asexual reproduction - tetrasporangia. With the formation of tetraspores, meiosis occurs and haploid tetraspores germinate into haploid plants - gametophytes, bearing genitals. Gametophyte and tetrasporophyte externally (morphologically) do not differ. isomorphic change of generations complicated by diploid carposporophyte. 29

genus Durenea common in the southern seas. The thallus looks like branched pink bushes. thirty

The ceramic order is highly organized; many types of auxillary cells differentiate only after fertilization of the carpogon has occurred. Long oblastic filaments are not formed: the abdomen of the carpogon either directly merges with the adjacent auxilary cell (s), or through short outgrowths, forming cystocarps 36

evolution within the department of Banguiaceae is more primitive. carpogon has not yet developed a typical form, differs little from ordinary vegetative cells. After fertilization, the contents of the carpogon are directly divided into carpospores. Floridians are a more evolved group of Karpogon with Trichogyne. Of the floridia class, the simplest order is the nemaliones, which do not have auxillary cells, and the gonimoblasts, on which carposporangia develop, are formed directly from the ventral part of the fertilized carpogon. Kryptonemias are the next step in progressive evolution: they have auxillary cells that contribute to an increase in the production of carpospores, since not one cystocarp is formed, but many - according to the number of auxillary cells. With auxilary cells scattered randomly over the thallus, more or less long oblastemic filaments are needed. The highest stage of evolution was reached by ceramids, which have procarp and auxilary cells differentiate only after fertilization has occurred. The immediate proximity of the carpogon and the auxillary cell(s) in the procarp facilitates the formation of cpstocarps. This order is the richest in species. 39

The oldest fossil identified as red algae is also the oldest eukaryotic fossil belonging to a particular modern taxon. Bangiomorpha pubescens, a multicellular fossil found in Arctic Canada, is only slightly different from the modern red algae of the Bangia genus, despite being deposited in layers 1.2 billion years ago. 41

DIVISION BROWN ALGAE PHAEORNUTA marine, especially abundant in the cold waters of the northern and southern hemispheres. According to the morphological and anatomical differentiation of the thallus - 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 thread are known. the simplest are heterotrichous thalli, large, false or true tissue structure.

strongly mucilaginous cell walls one nucleus, one or many vacuoles, usually parietal 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 crossed by parallel three-thylakoid lamellae The thylakoid-free pyrenoid protrudes from the chloroplast in the form of a kidney

Chromatophore pigments are colored brown chlorophylls "a" and "c" (chlorophyll "b" is absent) β-carotene Many brown xanthophylls, especially fucoxanthin. 44

Spare polysaccharide - laminarin alcohol mannitol fat is deposited outside the chloroplast in the cytoplasm. Monad cells (zoospores and gametes) have an eye and flagella. Eye - part of the plastid, associated with the flagellar apparatus. Flagella are heteromorphic. 45

Reproduction is vegetative, asexual and sexual. Vegetative reproduction - sections of the thallus. In some, specialized branches (brood buds) break off into new thalli. Asexual reproduction - zoospores formed in single-celled or single-chamber sporangia on diploid plants (sporophytes) before the formation of zoospores, the nucleus is reduced by reduction. Haploid zoospores - into haploid sexual plants - gametophytes, on which genital organs are formed. In protozoa, the sexual process is isogamous, gametes develop in multi-celled or multi-chambered sporangia. In the most highly organized brown algae, the sexual process is oogamous. In oogonia and antheridia, as a rule, one gamete is formed (an egg and a sperm cell, respectively). The egg is always fertilized outside the oogonium. The zygote without a dormant period germinates into a diploid plant.

CLASS ISOGENERATE Order Ectocarpous genus Ectocarpus - the most primitive brown algae. Distributed in all seas, especially cold ones, and grow on underwater objects and other larger algae. fifty

Cutleria order The order includes only two genera: cutleria and zanardinia Cutleria is distributed along the entire coast of Europe, zanardinia - mainly in the Mediterranean Sea, as well as in the Black Sea. Both genera show alternation of generations: in cutleria, the change of generations is heteromorphic, in zanardinia it is isomorphic 55

CLASS HETEROGENERATE Order kelp Gametophytes differ little among themselves and are represented by microscopic, often reduced to a few cells, filamentous outgrowths that bear the reproductive organs. On male gametophytes, antheridia are formed in the form of small cells that develop one spermatozoon each, on female gametophytes - oogonia, in which one egg is formed. Sporophytes of different genera differ sharply and represent the largest lower plants, reaching a length of 60-100 m, with significant morphological dissection and a complex anatomical structure. In most cases, kelp sporophytes are dissected into a leaf-shaped plate, a “trunk” and rhizoids, with the help of which the entire plant is attached to pitfalls and rocks. At the place of transition of the leaf blade into the stem, there is an intercalary meristem, due to the activity of which both the leaf blade and the stem grow. a genus of kelp, the species of which are widespread in the northern seas. 63

CLASS CYCLOSPOROUS The Fucus order is characterized by - - the apical growth of the thallus. The absence of asexual reproduction by the oogamous sexual process. The genital organs are located in the depressions of the thallus - conceptacles, or scaphidia.

genus Sargassum complex morphological division of the thallus is widespread in the southern hemisphere, especially in warm seas. The stem, attached to the substrate with the sole, branches, bears flattened leaf-shaped formations, spherical air bubbles on special stems, branched fruiting twigs 71

Brown algae are a natural group that differs well in its morphology from other divisions of algae. However, as already mentioned, according to a number of features (the presence of chlorophylls "a" and "c", the absence of chlorophyll "b", the location of thylakoids in chloroplasts - three-thylakoid lamellae, according to similar stock products - kelp, chrysolaminarin, according to the structure of monad cells with heterocont and heteromorphic flagella) brown algae show similarities with golden, yellow-green, diatoms and pyrophytes. On this basis, some authors reduce the brown and other enumerated groups of algae to the rank of classes within one large department of Chloroshore. bu1 a. The existence of monad cells in the life cycle of brown algae makes it possible to derive them, as well as the other groups listed, 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, multi-flagellated, diatoms, pyrophytes, and green algae similar to them in a number of characters, since there are no direct transitional forms here. Among brown algae, there is no consistent development of the types of organization of the thallus from monadic to filamentous and lamellar, as is easily observed in green, yellow-green, golden and pyrophyte algae. As already noted, among brown algae, only the highest stages of morphological differentiation of the thallus are represented - heterotrichous and lamellar. Perhaps the simpler forms (monadic, coccoid, simple filamentous) have been completely lost during the long evolution that brown algae have done - an ancient group already known; from Silurian and Devonian deposits. There is no single view regarding the family relationships of orders within the department of brown algae and their location in the system. According to one of the schemes of the phylogenesis 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) sphacelaria, dictyota and fucus, the other - ectocarp, cutleria, kelp. Both 219" 75

groups of orders also differ in the way of growth of thalli: the first is characterized by apical growth, the second is intercalary. Keelin (N. Kull), whose system is the most widespread at the present time, derives three evolutionary lines from the common ancestor of brown algae, which he presents as isogenerate, heterogenerate, and cyclosporic 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 coastal countries, seaweed emissions, rich in potassium and nitrogen, are used as fertilizer, and also used for livestock feed. Some, such as kelp ("seaweed"), are edible. 76

At great depths, up to 250 meters, grow red algae, otherwise known as scarlet. In combination with corals and colorful fishes, variously colored crimsons create the unique beauty of the underwater world. These are predominantly large algae, but, for example, microscopic red algae also belong to the Bangiaceae class.

Why can red algae grow at such considerable depths? This question was asked in the exam in biology. The red pigment allows algae to grow at great depths. 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.

Red algae are characterized by spore asexual reproduction, as well as sexual reproduction (oogamy), sometimes vegetative reproduction by parts of the thallus is also found.

Red algae include phyllophora, porphyra, gracilaria, ptilote, chondrus, in total there are about five thousand species.

Purple- a flat and thin oval plate up to half a meter in diameter. It is characterized only by sexual reproduction. Male germ cells do not have flagella (sperms). 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 the 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 life such as whales. Interestingly, Thor Heyerdahl, on his Kon-Tiki raft expedition, tasted plankton "soup" and found it quite tasty and nutritious.

3. Bottom algae provide shelter and food for fish and various marine animals. Laminaria, for example, is eaten with pleasure by a sea urchin.

4. Algae oxygenates the oceans and atmosphere.

5. However, with the mass reproduction of algae (for example, chlamydomonas) at the time of the so-called "blooming" of water, the oxygen content in it drops and the water is saturated with toxins. River dwellers die from lack of oxygen.

Significance for a person

1. Algae have been eaten for thousands of years in many regions. Such brown and red algae as kelp, undaria, porphyry, hijiki (and Sargasso in general) are especially popular.

2. Red algae are a source of iodine, especially some species rich in iodine.

3. Also, red algae are a source of agar-agar - a gel-forming substance that is used in the confectionery industry, in the cultivation of bacteria, etc.

4. With the help of algae, wastewater is cleaned from fluorine, nitrogen, etc., as well as air from carbon dioxide (chlamydomonas, chlorella, euglena succeeded in this).

5. Algae are food additives: spirulina, kelp, fucus, ulva, chlorella and others.

The name of the department comes from the Greek word rhodon("radon") - pink. The color of red algae is due to a different combination 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 lit areas are colored yellow, brown or black due to the presence of a large amount of photoprotective carotenoids in the cells. It unites 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 diverse: filamentous, bushy, crusty, lamellar, vesicle-shaped, sac-shaped, 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 its own membranes: the nucleus, mitochondria, plastids, the Golgi apparatus and others. From one to many plastids are found in red algae cells. 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 nuclei of red algae 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 number of chromosomes in cells. Mitochondria with flattened cristae.

Chloroplasts of red algae are of various shapes, they are usually located along the cell walls, or parietal. These plastids are mostly disc-shaped and ribbon-like. The shape of chloroplasts can change depending on the age of the algae. Each chloroplast is surrounded by its own two-membrane membrane; there is no chloroplast endoplasmic reticulum. Thylakoids in chloroplasts are solitary, not collected in groups and lie 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 present in the form of small nucleoids scattered throughout the stroma of the chloroplast. Each nucleoid contains several circular molecules of chloroplast DNA.

Of the chlorophylls in the plastids of red algae, only chlorophyll is present. a, 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 - hemispherical and semi-disc-shaped phycobilisomes.

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 in red algae form an irregular network. The most important substances of the polysaccharide amorphous matrix are agar, agaroids, carrageenan. These substances are synthesized in the tanks of the Golgi apparatus, then transported to the cell surface and embedded in the wall. They account for up to 70% of the dry weight of the cell wall. In a number of red algae, a cuticle consisting mainly of protein can be located on top of the cell wall. Among the crimson, there are species with calcified shells: calcite or aragonite is deposited in them. Part of the thallus or the entire 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 purple starch, which is deposited in the cytoplasm, and not in the chloroplast, as in green algae. Crimson 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 medium. 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 body shape of the crimson is very

Rice. 17 Appearance of red algae: A - unicellular alga Porphyridium; B - multicellular alga Delesseria

varied. It can be: filiform (hairlike or rough), lamellar, solid or complexly dissected with outgrowths along the edge, cylindrical, corky (crusts, films pressed to the substrate), coral-like. The variety of external forms of red algae is reduced to several types of thallus differentiation: coccoid, filamentous, multifilamentous, false tissue and tissue. Rhodophyte thalli are attached by rhizoids or soles.

The thalli of Floridean algae are the most complex. Their thalli show signs of tissue differentiation with cell specialization. In their thallus, one can distinguish: a bark consisting of several layers of intensely stained cells; core, consisting of colorless cells, often collected in filaments. The core performs not only a transport function, but also a mechanical one, since it contains threads with thick longitudinal walls. Between the bark and the core of many red algae, there may be an intermediate layer of large colorless cells. The growth of the thallus is most often intercalary (intercalary) and apical (apical), less often basal.

Reproduction.

In red algae, there are three methods of reproduction: vegetative, asexual and sexual.

asexual reproduction carried out with the help of various disputes. Spores can be located in sporangia one, two and four; they are called monospores, bispores, and tetraspores, respectively. Tetraspores can be located in tetrasporangia in different ways: one above the other - linearly, or zonally, crosswise and at the corners of the tetrahedron (Fig. 18).

Rice. 18. Types of arrangement of tetraspores in tetrasporangia (according to: S. Noek van den et al., 1995): A- cruciform; B- cruciform with a turn; AT– 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 spermatozoa, devoid of flagella and passively with a current of water are transferred to the female genital organs - karpogons. Karpogon red algae has the form of a flask and consists of an expanded lower part (abdomen) and an elongated upper - trichogynes which serves to trap the spermatozoa. In most red algae, the carpogon forms at the end of a short branch called the carpogon branch. The cell that gives rise to the carpogon branch is called supporting.

Spermations are formed one at a time in spermatangia, which in turn are formed on mother cells. Mature spermatozoa are mononuclear and lack a rigid cell wall, surrounded by mucus, and may contain chloroplasts. Spermation is passively carried by currents of water, contacts with trichogyne, which is located above the surface of the female gametophyte. The walls of the spermatozoa and trichogynes dissolve at the point of contact, the male nucleus passes through the central channel in the trichogyne and merges with the haploid nucleus of the carpogon. Further development in species of different orders has its own characteristics.

Life cycle.

In the majority of Rhodophyta, after fertilization of female gametes - carpogons by male gametes - spermatozoa from the zygote, after multiple cell fusions, a multicellular filamentous-parenchymal formation appears - carposporophyte (Fig. 19). He imagines

Rice. 19. Life cycle Batrachospermum(by: R. E. Lee, 1999)

yourself gonimoblast, in which diploid cells develop - spores of sexual reproduction, or carpospores, germinating into a new diploid plant - sporophyte. gonimoblast, or cystocarp - this is a complex of the placenta, from which gonimoblast filaments depart with carposporangia at the ends and gonimoblast covers - wrappers. In gonimoblasts, all cells have a diploid set of chromosomes.

In a number of Florideans, the gonimoblast is surrounded by a sheath. In this case, this structure is called a cystocarp (Fig. 20). In carposporangia

Rice. 20. Life cycle polysiphonies(by: R. E. Lee, 1999)

carpospores are formed, which germinate into a diploid tetrasporophyte. On a tetrasporophyte in tetrasporangia, a reduction division occurs. Haploid tetraspores germinate 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 renewed - either the gametophyte or the sporophyte. Such a cycle is called heteromorphic with an irregular change in the forms of development. It is celebrated by the Mastokarpovs. There are isomorphic cycles with a regular change in the forms of development, when the sexual and asexual forms are outwardly represented by the same independent free-living generations. This cycle of development is typical for Gracilaria, Chondrusa, Mazella.

Systematics

The Rhodophyta division is traditionally divided into two classes: Bangiaceae - Bangiophyceae and Floridian - Florideophyceae. The last class includes most of the genera and species of purple.