Features of vote coniferous plants. General characteristics of vote plants
All seed plants, in contrast to dispute plants that breed seeds. This gives them certain advantages: the dispute is only one cell; Seed - multicellular formation, contains a germ of the future plant and the supply of nutrients, covered with a skin, which protects the embryo from adverse effects ambient. In seed plants, fertilization precedes pollination, transfer of pollen grains (formations where male sex cells) in seed beginners (formations in which female sex cells contain). Pollination is carried out using winds, animals, etc .. The sexual process does not depend on the presence of water.
The first seed plants arose in the middle of Devon (360 million years ago), their dominance began significantly later, probably with climate change (increasing aridness and cooling) in Mesozoy. Seed plants are very diverse, but have common features of the structure: they have roots, shoots and organs that ensure their reproduction by seeds. In seed plants include two departments higher Plants - vote and flowering.
Goloons have a seed that lies on scales openly and protected only by seed peel. Today, the gone has more than 700 species. The emergence of seeds, a variety of life forms (trees, bushes), the presence of stomps makes it possible to significantly reduce evaporation. Software trunks are usually 40-70 m, but can reach 100 m and more (for example, in a mammoth tree) the thickening of the trunk occurs due to the growth of wood (Cambium activities), the main part of the cells of which is dead. Such a trunk is better with the winds. In the crust on the wood of coniferous many resin strokes (tubules) filled with resin. In case of damage to the barrel on its surface, droplets of thick adhesive resin appear, which delays the wound.
Reproduction of voted. Gamotes are exclusively ricuosporovy plant, sexual individuals live on non-treating and feed on their nutrients. Consider how the reproduction occurs in pine. Seeds it forms for 12-15 years of life. Pollen grains and seed beginners are formed in cones. Bumps are shortened valid shootsin which the leaves turned into scales.
Pine is a monocoa plant, since it has men's (with anthers) and female (with seeds) cones located on one plant. Young women's shishes of reddish color, with scales, fit into each other tightly, are located on the tops of the shoots. Each scales are placed two seed beginnings (and then seeds). Men's cones are formed at the base of young elongated shoots, gray-yellow. Each scales have two anthers in which pollen grains are formed. Pollen grains are covered with two shells, on both sides, the shell is easily adjacent to each other, forming air cavities. Thanks to this, pollen is transferred over long distances. During pollination, pollen grain in the spring enters the nephelters, scales of the bumps are closed, the bump closes, and the pollen grain germinates with a pollen tube. Fertilization occurs only in the next summer. By this time, eggs in the genitals are formed inside the seed primaries, feed fabric appears - endosperm. The pollen tube reaches an egg, two icegutics of sperm move along it, one of which fertilizes the egg, the other - dies. Seed germ turns into seed.
Seed consists of an embryo, endosperm and seed peel, which was formed from the covers of the seed beginnings. The ripening of seeds occurs on the third year after the formation of cones. On the same plant pine can be seen simultaneously cones of different ages. Pine seeds are similar to the seed of floral, only her endosperm of another origin is the primary, formed from the gender maternal individual (the ingrowth). Pine seeds are very hardy about environmental conditions: it germs even on the rocks, withstands frost.
33. Voted: general characteristics of the department, features structure and reproduction of conifers, representatives, meaning in nature, human use.
Goloral - an ancient group mostly evergreen plants. Fossil remnants of the voters belong to the Upper Devona of the Paleozoic Era (about 350 million years ago), but the flourishing of the gone accounted for TRIAS, Yura and the beginning of the chalk period of the Mesozoic era. The Mesozoic Era, probably, in connection with the formative processes, the local glaciation and aridization of the climate appeared cold-resistant types of voted, capable of exist in conditions of temperate and moderately cold areas of the Northern Hemisphere. These cold-resistant views subsequently occupied the dominant position in the addition of vegetation cover. Golorals are presented exclusively
wood forms: trees, shrubs and lianami. The leaves of the gifts are extremely varied in shape, sizes, morphological and anatomical features. In the form of the leaves there are needle, scratched, cochetic, and others. Wood voted well developed, has a large mechanical strength (consists of tracheid with bold pores, underdeveloped parenchyma; Libribform is missing). There are no companion cells in Floem.
Reproduction is carried out using seeds; Most of the species they germinate after the rest period. In the prevailing majority of species, the embryonic root forms a rod root system.
Goloral - Different Source Plants. Microspores are formed in microspores on microstrobils, and megasy - in megastoprangies on megastobials. Micro and megastrobys are attached to the axis, which is a shortened sporing escape (strobal), diverse different species. Dustca, or Microscpore, - Male Gametophyte, the aggregate of dusty is called dusty. Male gametophyte in pollen grain is strongly reduced. Pollen, as a rule, is spread by the wind and falls into the segments, located at the base of the seed scales of megastobil. Inside the meager, a female Gametophyte is developing, which, like male, is strongly reduced. Female Gametophyte is associated with sporophyte (parent plant).
The department unites 6 classes, of which two extinct - seed ferns and benuttitite, four now live - Cycadopsida, ginkgovy (Ginkgopsida), wrapped (chlamydospermatopsida) and conifer (Pinopsida).
Class Seed Ferns (Pteridospermatopsida) The greatest heyday was reached in the coal period and completely extinct in Triassa. They were represented by trees and liaans with large cenche leaves.
Bennettitite class (Bennettitopsida) Also represented the tree shapes carrying large pasta leaves at the top. Osoeple strobes appeared on the flower (Fig. 185).
Cycadopsida class Currently there are about 120 species growing in the tropics and subtropics of the globe. These tree plants with large rigid evergreen leaves are similar to palm trees; Dwoom. The strobes are formed at the ends of the barrel among the leaves. Among the coagovy there are epiphytes. They look very decorative and used for winter gardens, oranges (Fig. 186). The bark and core are edible, contain up to 40% starch.
Harmidospermatopsida class Includes three orders of magnetic, velvichy and ephedron (Fig. 187).
Their origin is unknown, since there are no paleobotanic finds. Gnetic grow in wet rainforests of Asia, South America and West Africa. Most of these are Liana, but there are small trees and shrubs. In the blinks wide one-piece oppositely arranged leaves with mesh housing, like biloving in dysfotic flowering plants. Plants dioarm. In order, the Velvichy family of the same name with the only species - Velvichia is amazing (Welwitschia Mirabilis)growing only in the rocky desert of Namibia and Angola. These plants are long-livers, their age reaches 2000 years. They have a long root, short and thick stem. Upstairs from the stem move two lying on the ground the opposite sheet up to 3 m long. The plant is downtown.
Ginkgov class (Ginkgopsida) Presents the only relic representative - Ginkgo Two (Ginkgo Biloba). His homeland is Japan, China, subtropics. This leaf fall tree reaches 30 m in height and up to 3 m in the diameter of the barrel. Leaves of sweet, dichotomic shape, up to 10 cm long. The plant is dwarm. Microatruts in the form of earrings. Seed outwardly resembles a plum. In the nucleation of the seed - the root, skelters and two seedlies (Fig. 188).
Conifer class (Pinopsida) Includes two subclass: Cordate (Cordaitidae) and conifer (Pinidae). Cordate - completely extinct plants. The widespread distribution of Cordates falls at the end of the carbon - the beginning of Perm. Together with other voted, they participated in the formation of stone coal. These were mainly large trees up to 30 m high and up to 1 m in
the diameter of the trunk. Cordate formed forests in the territories of the Northern and South Hemispheres.
Subclass coniferous most numerous among all gamed plants: includes 7 families, 55 genera and about 600 species; Representatives of the subclasses are found throughout the globe, except for the Arctic and Antarctic. The residues of conifers are found in the mountain rocks of the upper carbon, the heyday was reached in Jurassic and chalome periods.
Modern coniferous - these are trees, shrubs and woody shapes that play a large role in the vegetable cover of the Earth. In the extensive territories of Eurasia and North America, forests grow, which are pure plantings of one species. Thus, the main dominant species of taiga forests of the European part of Russia is erener (Picea Abies).
Among the conifers there are giants of the plant world: sequoia evergreen (Sequoja sempervirens)whose height reaches 100 m, and the diameter of the barrel 10; Mammoth Tree SEQUOJADENDRON GIGANTEUM)from the thickness of the barrel to them lives up to 4000 years; Swamp cypress (TAXODIUM MUCRONATUM) With the diameter of the trunk to 16 m. Recordsman-long-lived - Pine durable (Pinus Longaeva), Its age reaches 5 thousand years.
The subclass includes the order of conifer (PINALES) and the Taxales order (Taxales).
Of the current conifers, the coniferous includes several families: Araucaria (Araucariaceae), taxodium (Taxodiaceae), cypress (Cupressaceae), submarines (Podocarpaceae).
Representatives araukaria family relict; Grow out in South America, Australia, on the islands adjacent to it and in the Philippines (Fig. 189).
TO taxodium family include: giant and long-liver sequoia evergreen (Sequoja sempervirens)growing along the Pacific coast of North America; Sequoia-Dendron, or Mammoth Tree SEQUOJADRONRON GIGANTEA)who bent up the shoots resemble the mammoth tissue; Swamp cypress, or taxodium double (Taxodium Distichum)growing in the floodplain river Mississippi, whose separate copies live up to 6 thousand years, and many other interesting types of plants (Fig. 190).
TO cypress family (Cupressaceae) includes 19 genera and more than 130 species, representatives of the Northern and South Hemispheres (Fig. 191). In the subfamily of the Tuty 15 delivery, among which the most widespread genus (Thuja) with several species growing in North America and East Asia, cypress (Cupressus) et al. (See Fig. 191, L).
Tui - monodomal shrubs or trees with a height of 12-18 m with high-quality wood. Sustainable air pollution, healing essential oils that kill pathogenic microbes are isolated. Strike shrubs made of endemic sort of microbiota (Microbiota)growing on the southern slopes of Si-hot-aline, are widely used in decorative greening parks and the gardens of our country.
Species of kind juniperus (Juniperus) (up to 70 species), found from the Arctic to subtropics. Plants are represented by low shrubs up to 12 m, trees and stabular forms. Widely used in decorative crop production. Juniper - frost-resistant and
4000 m above sea level. Juniper grow very slowly, live up to 1000 years. The most widespread juniper ordinary (/. communis, Fig. 191, B)growing throughout the northern hemisphere. Prefers pinemas. The needy leaves live up to 10 years. A distinctive feature of the juniper is that after fertilization, scales are growing, they become meaty, forming a juicy bump called shishkojig. Wood juniper solid, resinous, fragrant, goes on crafts, manufacture of pencils, etc. The leaves of juniper are isolated into the atmosphere of medicinal phytoncides that kill pathogenic microbes, thereby cleansing the surrounding air, but in conditions of large cities do not live, since unstable smoke.
IN family of submarines (PodoCarpaceae) includes up to 10 genera and up to 140 species growing in wet, shady places are mainly southern hemispheres.
In order, tissue in contemporary systematics include Taxaceae and Pine (Pinaceae) families.
Representatives tissue families Grow mainly in the northern hemisphere. A distinctive feature of the plants is that at the end of the shoots of single-sighs, surrounded by the outstanding cup-shaped meaty seminal peel are located roofing. Representative of the most common kind of tees (Taxus) - tees berry (T. Baccata) - tree height up
15 -20 m. It grows in the undergrowth of the coarse forests of the Mediterranean, in the Crimea, in the Caucasus. Live tears to 2-3 thousand years old. Tis Berry is a very shadowless and slow-growing look: the increase for the year is only 2-3 cm. The berry tees has a very valuable, almost non-flavory wood. In Russia, the tees berries is listed in the Red Book and declared a protected plant (Fig. 192).
Pine Family (Pinaceae) is the most numerous among all voted (10 genera with 250 species). Types of families grow in the northern hemisphere, being the main forest-forming rocks of moderate and moderately cold regions. Rod Pine (Pinus) There are 100 species (Fig. 193), childbirth of fir (Abides) and fir (Piced) - 40-50 species (Fig. 194, A, b), other families of the family are from 4 to 15 species.
Pine - mostly evergreen plants, are represented, as a rule, with trees up to 30 m high, on average they live until 200-400 years. Among pine are giants (Western larch - Larix Decidua., Cedar Himalayan - Cedrus Deodard) Both long-livers, individual copies wait to 3 - 4 thousand years (Fig. 195). Some species grow in the shape of a stabel shrub (cedar stabel - Pinus Pwnila).
The leaves of most pine narrow, needle, called cheese. Winter kidneys are protected by resinous substances. Not-
which species have elongated and shortened shoots. Wood with well-pronounced annual rings and resin strokes. All pine monocarbon plants.
Pine have a large nationality meaning: High-valued wood is on construction work, on the manufacture of musical instruments, wood is used in the pulp and paper industry, due to the release of phytoncides (therapeutic bactericidal substances) representatives of pine plays a huge role in the recovery of the surrounding
media, some species form whole natural zones (fir taiga forests); In addition, pine have a large water protection and anti-erosion value.
According to the presence or absence of shortened shoots, the family is divided into 3 submenses: fir, larch and pine.
Fakee (AbiTinae) elongated shoots and cones ripen in one year (see Fig. 193). Fir includes bodies of fir, spruce, pseudotsuga, Tsuga.
Pihti (Abides) Includes approximately 40 species growing in moderate and cold-tempered zones of the northern hemisphere. Siberian fir is widespread in Russia (A. Sibirica). This is a high tree (up to 50 m) with an acute pyramid crown, with a flat, spirally located on the escape of a mustache, reprehensive cones. Fir - the most frost-resistant, very shadowy look. In Western Siberia, it forms dark-haired hardwater fir forests. Valuable wood fir goes to
cellulose production, resinous boron is used to obtain a balm. Fir - air purity indicator. She does not carry his pollution and therefore in urban landings it is extremely rare.
Rod El (Picea) There are up to 50 species, also common in the northern hemisphere. For the European part of Russia, it is characterized by erener (P. abies,
see fig. 194, B), for Siberia - Spruce Siberian (P. Obovata), Far East - Spruce Ayanskaya (P. ajanesis), Tian-Shan Mountains and Altai - Spirit Schela, Caucasus - Eastern Spruce (P. orientalis). Spruce Egelman (P. Engelmannii) And spruce Canadian (P. canadensis) Grow out in North America, the decorative forms of which are known as "silver" and "blue" ate. These two kinds of firing gas and dust resistant. Ate - high trees with a pyramidal crown, live on average up to 150 years, but it also happens to 900 years old, shadowish, root system surface. With strong winds, ate usually hardened with the root, unlike pines, which break. Four leaves or flat, pointed on top, prickly; Live up to 5-10 years, sometimes - up to 30.
Spruce - valuable construction breed, from weathered wood makes musical instruments; Get high quality cellulose for the best varieties Paper, as well as artificial silk - viscose. Spruce is one of the necessary attributes of New Year holidays.
Representatives of the birth of pseudotsui and Tsugs grow mainly in North America, Japan, China and Himalayas. Plants are high: pseudootsuuga up to 50 m, and tosuga up to 30 m, possess valuable wood and very decorative.
To the subfamily of larch (Laricoideae) include childbirth: larch (LARIX), phelical, or gold larch (Pseudolarix), and cedar CEDRUSSee fig.
In larch two types of shoots with needle leaves. The larch on elongated shoots the leaves grow spirally, and on short-circuited - bunches of 20-40 cups. Larch is a light-loving cold-resistant plant, undemanding to growing conditions. The most widely distributed 3 types: Larch Siberian (L. Sibirica), larch Dauroskaya, or Gmlin (L. Gmelinii), and larch american (L. Laricina). Highly valuable larch wood is used in construction, goes to the manufacture of cellulose. Larch is resistant to the contamination of the atmosphere.
Flusher and larch - deciduous plants.
Cedar ( Cedrus.) - evergreen thermal-loving plant with an expanted umbrella or pyramidal crown. In the Mediterranean, the Cedar Atlas is growing (S. Atlantica), Cedar Lebanese (S. libani), Cedar Cyprus (S. Brevifolia), and in the Himalayas - Cedar Himalayan (S. deodara.See fig. 195). In the height of the cedar reaches 50 m, they live up to 1000 years. Cedar cones ripen on the 2nd - 3rd year, when ripening crumbling. Cedar wood is highly appreciated in construction, cedar nuts have high nutritional and healing properties.
To the subfamily pine belongs one kind of pine. Russia is widespread in Russia (P. Sylvestris)whose cheops are collected in the pair. Features of the structure and reproduction of voters will look at this example.
The pine has two types of shoots, and on elongated shoots there are crying leaves that perform the function of renal scales, in the sinuses of which the kidneys are laid and in the spring of the current year, shortened shoots with multiple chevings are formed. At the top of the elongated shoots from the sneakers in the spring, elongated lateral shoots grow in the form of a mutual. At the base of the elongated shoots, men's cones are formed - microatruts; Women's cones are developing at the top of the elongated escape in the year of its formation. Men's cones are painted in yellow, female - in a brown-red. Each cone consists of an axis with lining crumbling scales, in which seed scales are located in the sinus. On the upper side of the seed scales, 2 sicks are formed. Main fabric of the nephery forms nomecellus. Nicklouse outside almost completely surrounded integul. The remaining hole on the top of the nicklice is called doodle, or micropilee.. Through it, the sprouted pollen falls on the top of the nicklice, at which one larger maternal cell is soon standing out - megaspora. As a result of the reduction division in the maternal cell - megapar is formed four haploid cells. Three of them that the micropilene is dying, and the bottom will grow strongly and begins to share. From this cell, a female quantifier is developing - Gametophyte with nutrient reserves in special fabric - endosperm.
In the upper part of the outflow, two strongly reduced archegononia are formed, in which there is a well-developed egg cell and a small abdominal canaline cell above it. In pollution, pollen falls on the seals, and then through the micropile pollen Camera. After pollination, the pollen tube begins to slowly heat up, and fertilization occurs only in the spring of next year. The exineral of the dusty is bursting, and the vegetative cell surrounded by an intine is converted to the pollen tube, it is embedded in a nicknole fabric and grows towards archeganis. The anteridial cell of the Dusty is divided into spermatogenic Cell I. cell-leg. The spermatogenic cell is divided into two cells, forming two sinter without flagella. The pollen tube is then bursting and its contents flows: one of the sperms merges with the egg and fertilizes it, the other sperm with the residues of vegetative and the leg cells is destroyed. From the resulting zygota begins to develop a germ. Part of the endosperma nutrients is on its development, and part persists in seeds for germination of seedlings.
The shaped germ consists of an embryonic root, an embryonic stalk carrying from 3 to 15 cotyledons.
The seedup after fertilization turns into a seed. Outside the seed is covered with a leather - a modified intended integuter. By this time, the bump increases in size by about twice and becomes green. Seeds ripen in the fall of the second year, and fall out at the end of the third year. The bumps acquire a brown color, crumbling scales open and seeds fall out. The alternation of generations in the life cycle is represented in Fig. 196.
Pine ordinary is widespread in the European part of Russia, Siberia, in the Far East. Pine kidneys are used in medicine. Pine highlights healing phytoncides (volatile substances) that kill pathogenic microbes, especially tuberculous wand. Pine is sensitive to dust and gas pollution of the atmosphere, so in large industrial cities it is impractical to grow it. From pine
coniferous extracts used for therapeutic baths. The pine needles contains vitamin C; Infusions are used for the prevention of avitaminosis C and periodontitis. The pine is obtained by turpentine, rosin, camphor, etc. due to the density and other valuable qualities of wood pine are widely used in housing, shipbuilding, joiner and furniture production and in mines as a fastener material.
Read the information .
Allocate departments:
- ginkgovoid
- gingeroid
- sovietovoids
- coniferous
Let us consider coniferous plants that are the most common among votes.
- the department includes only wood forms of plants (trees and shrubs).
- most are evergreen plants (adaptation that increase the winter hardiness).
- there are no flowers and fruits, seeds are open - in scales or cones (male and female).
- there are no real vessels in the wood (adaptation - needle-shaped leaves, for smaller moisture evaporation).
|
General structure |
Consists of wood. |
|
|
Extracted needle-shaped shapes - needles or scaly leaves. |
||
|
Reproduction |
One-bedroom or dwarm, but the strobes are always same-sex, i.e. Contain either male or women's generative bodies. Microstatus - men's cones. Megastobils are women's cones. Pollination is the transfer of microspores from male cones on women's. |
|
|
Phase life cycle | ||
|
Value |
Used as timber and raw materials for paper production. Environmental - play a big role in creating and cleaning the microclimate of the planet. Resin fossil coniferous trees - amber. |
|
|
Cedar, cypress, fir, juniper, larch, spruce, pine, sequoia, tees, kauri and mn. Dr. |
||
Consider example . Rod Pine
|
Description |
Evergreen, rich in a resin tree of large sizes, less often shrub. |
|
|
General structure |
Consists of wood. Fabrics - Xylem consists of tracheid (no vessels), Floem. Intermediate layer between fabrics - Cambier. |
|
|
On long shoots - brown and scaly. On short-circuit - needle, located beams of 2 - 5 pcs. |
||
|
Rocket-type root system, well developed. |
||
|
It is formed in strobils - "cones" (female). Equipped with wounded growth. |
||
|
Reproduction |
Method of dividing cells - Meiosis. The reproduction bodies are strobal (there are sporesophilles that form sporangies - spore-forming organs). MicroTrobils - Men's bumps in the form of a rose of green, are located at the base of young twigs. On the underside of each flake - 2 pollen bags. In them, after dividing cells, haploid microspores develop. Pollen grains are formed from the microspores (are gamemarketophytes). Megastrobials - Women's cones of red, are located in the top of the tree, at the ends of young shoots. On seed scales formed by 2 sicks. Pollination - pollen is glued to the seed resinous substance. The vegetative cell pollen forms a pollen tube that penetrates into the segments. Fertilization occurs after 12 - 24 months. The ripening of seeds lasts from 4 months to 3 years. |
|
|
Life cycle phases |
Alternation of diploid and haploid phases of development. The prevailing phase is the diploid (sporophyte). |
|
|
Value |
Valuable Wood Breed - used as a building material. Resin - getting rosin and turpentine. Young shoots and cones - getting essential oils. |
|
Consider examples species of the genus Pine from the Pine Family.
|
Habitat (range) |
|
|
Pine ordinary |
All North of Russia and most of Siberia |
|
Siberian cedar | |
|
Korean cedar |
Amur region |
|
Cedar stabel |
Eastern Siberia, from Transbaikalia to Kamchatka, from Kolyma to the Amur region |
|
Pine Crimean |
Mountains Crimea and Caucasus |
|
Italian Peniya |
Mediterranean - from Madeira to the Caucasus |
|
Pine Gorna |
From Pyrenees to the Caucasus |
|
Pine Weimutova |
North America - from Canada to Allegman |
|
Pine Lambert (Pine gray, pine solid) |
Western North America |
|
Pine lady |
Australia and New Zealand. It grows only in artificial plantations. |
Used Books:
1. Kiology: a full guide to prepare for the exam. / I.Lerner. - M.: AST: Astrel; Vladimir; VKT, 2009.
2. Biology: plants, bacteria, mushrooms, lichens: studies. for 6-7 cl. general education. Institutions / T.I. Serbryakova, A.G. Malevsky, M.A. Gulelenkov et al. - 5th ed. - M.: Enlightenment, 1999.
3. Biology for applicants to universities. Intensive course / G.L.Bilich, V.A. Kryzhanovsky. - M.: Publishing House Onix, 2006.
4.Biology: studies. - Ref. Address / A.G. Lebedev. M.: Ast: Astrel. 2009.
5. Biology. Full course of secondary secondary school: a textbook for schoolchildren and applicants / M.A.Vova, N.A.Sokolova, A.A. Kamensky. - M.: Exam, 2002.
Used Internet resources.
Viced call plants that form seeds, but do not form flowers and fruits. Seeds lie openly and only sometimes covered with scales. The gifted came from primary ferns. Currently, this group includes only about 700 species of trees and shrubs. The voted plant department includes departments: coagovic, ginkgy, coniferous, ephedrov. Conifers have the greatest distribution. Almost all of them are trees. Conifers have a well-pronounced trunk, the leaves from most coniferous hard, needle (needles) and do not fall out; Replaced almost throughout life. The structure of the voter has characteristic features. Among the vote a large number of Wood forms having a large, well-pronounced trunk. For conifers, the greatest life expectancy is characteristic. In the cross-cut stem, a thin boron is distinguished, well-developed wood (conductive tissue) and a poorly pronounced core consisting of a loose parenchymal (primary) tissue. In old barrels, the core is barely noticeable. Wood voters is easier than in flower plants, it consists mainly of tracheid - dead spindle-shaped cells with thick shells that perform a conductive and reference function.
Parenhims in the wood are very small or it is completely absent. Many species in the crust and wood are very small or it is completely absent. Many species in the crust and wood have resin channels filled with resin, essential oils and other substances. The evaporation of these substances create a characteristic aroma of coniferous forest.
The leaves in most coniferous hard, needle (needles) and do not fall out in an unfavorable season. They are covered with thick cuticle - a layer of a special substance allocated by coating fabrics.
The dust is immersed in the sheet fabric, which reduces the evaporation of the water: the replacement of the needle occurs gradually throughout the life of the plant.
Reproduction of conifers on the example of pine
This is a scare brassy plant. Two types of cones are formed on young stems - shortened shoots: male and female. Men's cones are located at the base of young shoots, have the axis to which scales are attached. On the lower side of the scales are two pollen bags, microspores (men's disputes) are formed in them with a single haploid set of chromosomes. Men's gametophytes are formed from the microspides - pollen grains carrying germ cells - sperm.
Little reddish female cones are sitting on the tops of young shoots. The scales of female cones are afraid in pairs, and between them develops. Megaspora (women's dispute) is formed there. As a result of its multiple division, a female Gametophytic egg and endosperm is formed, subsequently feeding the embryo. Pollen, brought by the wind, falls on the scales of female cones. Pollen grain germinates, sperm on the pollen tube reaches an egg and merges with it - fertilization occurs. Connecting, sperm and egg cell form a cell with a double (diploid) set of chromosomes - zygota. This is the first sporophyte cell. From the seminal, seed develops with a nutrient reserve, which is dressed with protective shells. For the second year after the formation of a female bump and transferring to her, the microspores of the seeds are hurt and spread with wind.
So-called ship pines, having a long straight trunk, in previous times were used in shipbuilding. The entire sailing fleet was built mainly of pine. Many conifers and now beautiful building material. In addition, the pine is obtained, cardboard, turpentine and many other valuable products for humans. The cigarette cigarette is eaten.
According to some scientists, there were rates from the pavement of the most ancient ferns-like plants.
In the Republic of Belarus, only 4 species from conifers: Pine ordinary, erendian spruce, white fir and juniper ordinary. About 100 species are introduced: banks pines, Weimutova, black; larch; Tui; Juniper Cossack etc.
1. "Naked" summer and seedsthose. they lie open on the surface sporeophilles(so called the leaves on which sporangies are located) or similar structures and are not hidden in the wound. In seeds only endosperm (residue megagametophyte, haploid).
2. Usually form shishki.(strobils) - a collection of spores on an axis, isolated from the vegetative part. They develop sporangies and disputes. Pollination is carried out by the wind ( anemophilia).
3. Andesternia are reduced and men's gametes are formed directly on Gametophyte.
4. Posted exclusively woody forms: trees, shrubs and lianami ( ephedra) With a monopodial type of branching.
5. In the anatomical structure of the stem, the wood is more developed (by 90 - 95% consists of tracheid, few parenchyma or is missing at all). Xylemcontains only tracheida(with the exception of gingerbye - They have trachea).In the floem not cells-satellite (instead of them - albumin cellsthat are similar to the functions performed with satellite cells, but differ from them origin).
Both the bark and the wood of many modern conifer contains a lot smith strokes.
6. The roots are well developed (main and lateral), form with mushrooms Mikariz.
7. The leaves of the gone plants are greatly varied not only in terms of the number and size, but also on morphology and an anatomical structure. Most needle (needles), simple, with one central vest; Some have large, dissected, similar to Wiray Fern. Basically - evergreen ( larch - leaf fall).
The economic value of conifers:source of diets; Of them get resin, turpentine; used in paper production; Fir balsam manufactures (from Siberian fir bark); From the wood of pine, the ordinary is obtained by viscose, silk, cellulose, balms, resins, camphor, alcohol, acetic acid, tanning substances; in medicine - dosage (vitamin C concentrate, essential oil, etc.); Food animals (moose eat chew and young seedlings, squirrels and various birds - seeds) and others.
