A large class of seed plants, ovule born in sub-room, where seeds wrapped in fruit. Ovule accept flowers or flower stamens of pollen and different fertilization. According to the number of cotyledons is divided into monocots and dicots (as distinguished from 'gymnosperms').
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bèi zi zhí wù
A large class of seed plants, is the most perfect on earth, there was the latest of the plant. Ovule born in sub-room, seeds wrapped in fruit, and did not appear. Common green flowering plants belong to this category
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Angiosperms (angiosperm)
被子植物(angiosperm)
Angiosperms, or flowering plants is the evolution of plant species last seen. They first recorded in the early Cretaceous, late Cretaceous plant kingdom occupying most of the world. Angiosperm seeds hidden in the nutrient-rich fruits, providing a good environment for the development of life. Fertilization by the wind when the mass media, most of it is conducted by insects or other animals, making the flowering plants can be widely distributed. (A) with real flowers Typical angiosperm flower from the flower respect, corolla, androecium, gynoecium Group 4 parts, each part is called floral. In the number of ministries of flowers, the morphological changes are extremely diverse, these changes are in the process of evolution, adapted to the insect, wind-pollinated, bird coal, or water pollination conditions, is natural _select_ion, be preserved, and continue to strengthen due. (B) has the pistil Formed by the carpel pistil, including the ovary, style and stigma 3. Ovules in the ovary harboring get the protection of the ovary, to avoid the biting insects and water loss. Ovary after fertilization develop into fruit. Fruit has a different color, smell, taste, variety of cracking in; peel usually have a variety of hooks, spines, wings, hair. All these characteristics of fruit, for the protection of seed maturity, to help play an important role in seed dispersal, and their evolutionary significance is self-evident. (C) with the phenomenon of double fertilization The phenomenon of double fertilization in which two sperm cells into the embryo sac after the egg to form a zygote and the other one with two polar nuclei combine to form a 3n chromosomes develop into the endosperm, embryo to 3n endosperm chromosome nutrition, contradictions of the new plants increased, so have a stronger life force. All angiosperms have the phenomenon of double fertilization, which is that they have evidence of a common ancestor. (D) highly developed sporophyte Sporophytes of angiosperms, in the shape, structure, life forms, etc., better than the other types of plants, diversification, there is the world's tallest tree, such as almonds by (eucalyptus amygdalina labill.), Up to 156 meters; If there are fine sand and the grass roots of the absence of Ping [wolffia arrhiza (l.) wimm.], per square meter of surface can accommodate three million individuals have weighed 25 kg fruit contains only one seed, such as the King Brown ( King Coconut) [roystonea regia (hbk) ofcook]; also as light as dust, 50,000 seeds weighing only 0.1 grams of plants such as tropical rain forests of some epiphytic orchids; have up to 6 years of plant life, such as Dracaena (dracaena draco l.); also completed within 3 weeks of life cycle of flowering seed plants (as some cruciferous plants growing in the desert); are aquatic, sand students, students stone plant hygiene and saline; the autotrophic Plants, saprophytic, parasitic plants. In anatomy, the secondary xylem of angiosperms have catheters, phloem companion cell; and gymnosperms tracheids are generally (only buy ephedra and Ma rattan exceptions), phloem cells unaccompanied, make perfect conducting tissue transport substances in the body smooth, adaptability to be strengthened. (E) the further degradation of gametophyte (simplified) The features of angiosperms, it has to survive the competition in, superior to the internal conditions of other types of plants. The production of angiosperms, it the first time in the Earth colorful, different types, flowers and fruits lush scene, with the development of forms of flowers, fruits and seeds stored in the high-energy products, directly or indirectly dependent on making plants born animals (especially insects, birds and mammals), to obtain the corresponding development of lush up quickly. Angiosperms are divided into two classes ---- Dicotyledon (Mulan Gang) and monocotyledons Programme (Lily Gang). Angiosperms Latin name angiospermae, comes from the Greek compound. angio-coated and-sperma seed, the two joints, the first frame with a plural Serve angiospermae, the English called angiosperm. Evolution of angiosperms is the plant kingdom's most advanced, most species, the most widely distributed, the most adaptable groups. In different systems, there are 300 to 400 angiosperm multidisciplinary, l ,20-25 is more than million. More than half of the total species in the plant kingdom. They spread out in all climatic zones. Because of high temperatures, rain and more reason, tropical and subtropical most. South American Amazon River area about 4 million. 2-3 million other tropical areas. Temperate regions due to lower temperatures, less rainfall, species decreasing. Situation in China, Yunnan Province, good weather conditions, plant up to thousands more, is located in Hebei Province, north latitude 26-43 degrees. The relative reduction of many species, about 2,500 species. Arctic is significantly reduced, in many places almost no angiosperms, only a few places a few hardy species to survive. Such as the Arctic willow (salix lanata), Arctic poppy (papaver radicatum), the distribution of latitude of 80 degrees. Antarctica in the Southern Hemisphere Jenny Moore Collegiate Bay near the island, thick leaves of plants with pink pink Corot (colobanthus crassifolius) survival. In addition, from the altitude of view, the higher the terrain, the lower the temperature at approximately 100 meters up, the temperature decreased 0.5 ℃, plant species composition has changed; in the Everest region, climate, only a few hardy species only survive. 5,000-5,500 meters in area can find pink V Stellaria (stellaria decumbens). Snow Lotus (saussurea involucrata) in Xinjiang Tianshan height of species. There are extreme desert of the natural environment. Such as the desert of Xinjiang region, Populus (populus diversifolia) and Haloxylon (haloxylon ammodendron) survive, to adapt to arid climate. North Africa, very little rain in the Sahara desert, no rain in some places more than a decade. There is a plant called dwarf teeth squarrosa (odontospermum pygmaeum), the formation of only a few dozen extreme drought YORK short life cycle, called the short-lived plants. It is a little rain water, can grow to flowering and seed germination to complete the generation task. Usually slightly moist, flowers to open, once dried, flowers that close, very sensitive. Americas Mexico desert, there is a special kind of plants to adapt to drought is more pulp plants, known as the cactus. Spiny body, degradation of leaf and stem water content and more to drought. Some of them shaped like a giant species, such as the use knifed open, you can directly drink the water. In saline soil, there are strong salt of angiosperms to Like the most famous. Such as Salicornia (salicornia herbacea) is an annual herb, fleshy, leaves minimal. Internode-like, you can carry out photosynthesis. In its cross-section of the stem has striking features: such as the skin thin and smooth, there are two layers of palisade tissue, the internal cells were large, water and more vascular tissue in the center. More water is due to sodium (na) ions formed under the influence. Salicornia living thing for more than 92% of the weight of water. Salicornia dry the ash left after burning more than most, accounting for more than 45% dry weight. The stem structure, water and ash more and more, are all characteristics typical of halophytes. Born in Salicornia salt marshes, it is the place where most salt, may be its standard representation. Like the evolution of the salt plant is carried out under conditions of salt speech.
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Characteristics of Angiosperms
被子植物的特征
Evolution of angiosperms is the plant kingdom's most advanced, most species, the most widely distributed groups. L now know more than angiosperm genera, more than 20 million, accounting for half of the vegetable kingdom. China has more than 2,700 genera and about 30,000 kinds, is the largest group of medicinal plants. Angiosperm species to have so many, there is such a broad adaptability, it and its structure complicated and inseparable from perfect, especially the reproductive organs of the structure and characteristics of the reproductive process, to give it to adapt to and resist all kinds inherent adverse environmental conditions, making it the competition for survival, the struggle between natural _select_ion process of continuous generation of new variations, new species, and dominated the planet. And gymnosperms, compared with the real flowers of angiosperms, it is also known as flowering plants; ovule concealed in the sub-room, well protected, the formation of the ovary in the fruit after fertilization, both the seeds of all sorts of ways to help protect the seeds spread; with the phenomenon of double fertilization and the triploid endosperm, the endosperm is not simply that such female gametophyte, and with the characteristics of both parents, so that the new plant has a stronger life force; highly developed sporophyte and further differentiation, in addition to trees and shrubs, more herbaceous; in the anatomical structure, the xylem in ducts, phloem sieve tubes, companion cells, the conduit structure and physiological function of a more complete, while the chemical composition, and with the evolution of the angiosperms evolving and complex, containing all angiosperms the various types of natural compounds, with a variety of physiological activity.
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Classification of angiosperms
Angiosperms are divided into two classes, namely, dicotyledons and monocotyledons Gang Gang, and their basic differences are as follows: Dicotyledon monocotyledons Gang Fibrous root root root straight Cambodia into a ring of vascular stem and arranged into a scattered arrangement of vascular cambium, no cambium Leaf-shaped with stockwork veins with a flat or curved vein Spent parts of 4 or 5 base of the base is 3 parts Pollen grains with three apertures with a single pollen grain apertures Embryo with 2 cotyledons cotyledons with a Difference between the above points are not absolute, actually staggered phenomena, such as Dicotyledon the Ranunculaceae, the car record, Compositae and other plants have fibrous root; Piperaceae, water lily, Ranunculaceae, Caryophyllaceae, which are scattered vascular bundles Arrange plants; Lauraceae, Magnoliaceae, Berberidaceae, Ranunculaceae flower base 3; water lily, Ranunculaceae, small continued Branch, poppy, Umbelliferae, which are l cotyledons phenomenon. Programme in monocots, Araceae, Liliaceae, Dioscoreaceae, which are stockwork; Potamogeton Branch, Liliaceae, one hundred subjects such as the base of the flower 4
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Dicotyledon
(A) of the flower petals from the subclass choripetalae Flower petals, also known from the Paleozoic perianth subclass subclass (archichlamydeae). Including without being spent, one by calyx and corolla flowers or distinction, and the petals are usually the type of separation. Stamens and the corolla from the students. Generally have a layer of special embryonic integument. Flower petals from the Division directory subclass Engler system (B) gamopetalous subclass sympetalae This subclass is also called epigenetic perianth subclass (metachlamydeae), the main feature is the number of petals with synthetic Geban Corolla. Corolla form a variety of shapes, such as the funnel-shaped, bell-shaped, lip, tubular, tongue, etc., developed by the radial symmetry to bilateral symmetry. Corolla variety of Link, an increase of the adaptation of insect pollination and the protection of stamens and pistils. Therefore, gamopetalous groups took over from the valve group evolution. Flowers tend to reduce the number of rounds, from 5 (l round of the calyx, petal l round, stamens 2, l round carpel pistil, such as Ericaceae, Persimmon Branch, etc.) was reduced to four (sepals, petals, stamens , carpel are l rounds, such as the Oleaceae, Caprifoliaceae, etc.), but also gradually reduce the number of rounds, such as the number of stamens and the corolla lobes from the same number, such as from 5 (Convolvulaceae, Solanaceae, Primulaceae) Less for the 4-2 (Lamiaceae, Cucurbitaceae), carpel number from 5 (Ericaceae) reduced to 2 (four-wheel flower carpels are mostly 2). Usually without stipules, ovule embryo is only one layer.
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Gamopetalous Division subclass Engler system directory
被子植物 合瓣花亚纲恩格勒系统分科目录
被子植物 合瓣花亚纲恩格勒系统分科目录
Monocotyledons Gang Classification of angiosperms Since the 19th century, many plant workers classified as a "natural" classification system has made great efforts. Development of their systems according to their theory, the classification system has dozens. However, as the origin of angiosperms, the evolution of knowledge, especially lack of fossil evidence, until now there is not a relatively perfect system of classification. The world is still more widely used Engler system and the Hutchinson system. Classification system at all levels, arrangements, systems and tah Cronquist system is considered among his more reasonable. First, the Engler system This is a German taxonomist Si Gele (a.engler) and Brandt (k.pranti) in 1897 in its "natural plants Division records," the system used in the masterpiece, which is the taxonomic history of a relatively complete system, it will plant kingdom sub 13, No. 13 seed plants for the door, and then divided into two sub-door gymnosperms and angiosperms, angiosperm Amon including monocots and dicots two classes, and Dicotyledon divided into the subclass from the flower petals (perianth Palaeozoic subclass) and gamopetalous subclass (subclass of epigenetic perianth). Engler system will be placed monocots dicots before the merge will gamopetalous a class of plants that evolved group of plants, the catkins dicotyledonous plants as the most primitive group of plants, and the Magnoliales , buttercup projects, etc. that is a more evolved groups, many of these ideas for modern taxonomists have disagreed. Si Gele system after several amendments, published in 1964, "Plant Division Notes to" the twelfth edition, has dicots monocots on before. Total of 62 orders, 344 families, of which 48 projects dicotyledons, 290 families, monocots 14 orders and 54 families. Medicinal use of botanical material part of the revised classification of angiosperms Si Gele system, but some content changes. Second, the Hutchinson system This is a British botanist Hutchinson (j.hutchinson) in 1926 and 1934 in its "flowering plant families chi" i, ii in the established system. Revised third edition in 1973, a total of 111 orders, 411 families, of which 82 dicotyledon orders, 342 families, monocots, 29 orders, 69 families. Hutchinson system considers suspicious skin Magnoliales, buttercup head is the original group of angiosperms, but too much emphasis on the two sources of woody and herbaceous, woody plants that evolved by the Magnoliales, herbs by buttercup project evolved, the result that some of the subjects was close to the position in the system are far apart, such as herbaceous and woody Umbelliferae Cornaceae, Araliaceae; woody herb of the mint family and the whip growing woody and so on, this view has been opposed by most modern taxonomists. Third, he asked the system tah This is the former Soviet Union, he was among botanists tah (a.takhtajan) in 1954 in its "origin of angiosperms," a book published in the system, he first broke into the traditional to dicotyledon subclass from flower petals Hop the classification of flower petals subclass; in the classification level on the addition of a "super head" a classification unit. He formerly separate Ranunculaceae of Paeonia Paeoniaceae, etc., and today's plant anatomy, palynology, taxonomy and chemistry of plant cell development is consistent taxonomy, at the international consensus. After several rounds of inter-system in Cartagena, he revised revision in 1980, a total of 28 super-orders, 92 orders, 416 families, of which two to the leaves of plants (magnolia Gang) 20 super-head, 71 head, 333 families, monocots ( Lily Gang) 8 super-orders, 21 orders, 77 families, appear more cumbersome. Fourth, Cronquist system This is the American botanist Cronquist (a.cronquist) in 1968 in its "flowering plant taxonomy and evolution," a book published in the system. Revised edition in 1981, a total of 83 orders, 388 families, of which 64 projects dicotyledons, 318 families, 19 orders of plant leaves alone, 65 families. Cronquist system is close to tah between his system, the angiosperm (called Mulan plant gate) into Magnolia and Lily Gang Gang, but the elimination of the "super-eye," a classification unit, the division of families is also less than tah He intergovernmental system. Some textbooks are now using this system in China. Evolution of the two schools on the morphological characteristics of the oldest problems of angiosperms, the original group and the evolution of the morphological characteristics of groups with their respective problems, research has long been a center of plant taxonomists, the focus of debate, especially in angiosperms " Flower, "the sources, the biggest differences of opinion, the formation of two schools, the so-called" artificial flowers school "and" School of real flowers, "or the" Satin School "and" buttercup school. " German botanist Engler, the former represented the latter to the United States botanist Park facilities and Harrier, the British botanist Hutchinson represented. First, the artificial flower school
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The origin of angiosperms
被子植物的起源
1. Origin time At present the majority of scholars believe that the origin of angiosperms in the Cretaceous or Late Jurassic. According to Scott (scott), Malang (ba-rghoon) and Leopold (leopold) (1960) account had previously conducted a comprehensive discussion of the fossil was found has not been saved before the Cretaceous angiosperm with concrete evidence fossils. Besides the evidence from pollen, also reflected in the Cretaceous strata of the previous, failed to find the angiosperm pollen. Doyle (doyle 1969) and Muller (muller 1970) under the Early Cretaceous and Late Cretaceous pollen between research and support the initial differentiation of angiosperms occurred in the Early Cretaceous, probably in the Jurassic era development for this group is ready condition, this view has also been Orff (wolf 1972) from the United States afraid of Virginia Tucker Center to get the Early Cretaceous strata of the fossil evidence to support the leaf. At the same time, they also concluded that: in the Cretaceous, before the development of Mulan purpose other groups of angiosperms. Pan Guangxue of scholars, who nearly 10 years in the North China region Jurassic Yanliao found and confirmed the existence of primitive angiosperms, also found that time monocot and dicot classes and soft --- Mulan Yi have well-developed inflorescence class. Therefore, the origin of angiosperms should be earlier than the Cretaceous. This view in 1999 the 16th International Botanical Congress raised concerns. 2. Cradle Time on the origin of angiosperms, pollen and leaf fossils the best evidence that angiosperms appeared 135 million years ago in the 1.2 to the early Cretaceous period. In the more ancient Cretaceous sediments, the number of the fossil record of angiosperms and gymnosperms, and ferns is also less than the fossil until 8000 ~ 9000 million years ago the late Cretaceous, angiosperms only in the large earth part of the region accounts for a dominant position. As for the location of the origin of angiosperms, is widely accepted that the origin of angiosperms and early Cretaceous differentiation is likely to or near the equator with some areas of the equatorial belt, which is based on existing and fossil magnolia class in Asia and South East dominate the southern Pacific Ocean, in the Cretaceous low-latitude tropical regions found in the three oldest angiosperm pollen ditch. Chinese plant taxonomists Professor Wu Zhengyi, from the flora of the Chinese point of view, put forward early in the angiosperm flora of the Tertiary before it in the ancient unity of the continent's tropical region, and that of southern China, south-west and Indochina, at latitude 20 ° ~ 40 ° between the vast region, the most unique ancient rich family, genus, these ancient Tertiary flora of tropical origin, that is the modern East Asian temperate and subtropical flora in the beginning This region is the birthplace of angiosperms. On the location of the origin of angiosperms, is still in speculation stage, although most scholars agree with the low-latitude origin, but the exact answer to the origin of angiosperms, there are difficult places, to be more in-depth research. On the ancestors of angiosperms, suggesting that many, there is no conclusion. Including algae, ferns, Gt head, buy hemp vine projects, the projects within the cycads, seed ferns and fern tongue, and so on, most scholars believe, should go to the ancient extinct gymnosperms to find the ancestors of angiosperms. Within the more popular are the seeds of cycads and ferns the two hypotheses. 3. Possible ancestors Angiosperm species are numerous and significant morphological changes, are very widespread, rough look, really difficult to use all the features of a unified go into a class of angiosperms. Therefore, the ancestors of angiosperms, there are different hypotheses, there are two kinds of pluralism and the origin of said unit. Pluralism that does not phase from many angiosperm groups close to classes, is developed in parallel to each other. Hussein patellar, Mise (meeuse), Engler (engler) and Lamb (lam), who is the representative of pluralism. Hussein patellar our taxonomists published in 1950, the origin of a diverse system of angiosperms, but also of scholars have published the only system of angiosperms. Unit is the majority of botanists claim that the origin of angiosperms. Based primarily on angiosperms, there are many unique and highly specialized Of the trait, such as the stamen has four spores (pollen) and the specific medicines capsule interior layer; large fertile leaves (carpels) and the presence of stigma; pistil and stamen position in the flower arrangement of fixed axis; the phenomenon of double fertilization and triploid endosperm; and the presence of sieve tube and companion cells. Therefore, people think only of angiosperms originated in a common ancestor. Hutchinson (hutchinson), Cartagena de Indias, he asked (takhtajan), Cronquist (cronquist) and judd is a unit of the main representatives. If indeed the origin of angiosperms unit, then it actually happened in what kind of plants? Guess is that many, has not yet been decided. People speculated that are: algae, ferns, Gt head, buy hemp vine eyes, the head within the cycads, seed ferns and so on. Currently popular is the purpose and within the cycad seed fern these two hypotheses. Tah and Cronquist between his study of modern angiosperms from the original type, or a living fossil, the proposed group might be the ancestors of angiosperms, a group of ancient gymnosperms. And advocate for the modern Magnoliales primitive angiosperms. This view has been supported by most scholars. So, where a group of the original Mulan class is the origin of angiosperms it? Raimi Castle (lemesle) claim originated within the cycad, Cycas spores that leaves the ball in regular gender, thin single-sex, and magnolia, tulip tree flowers similar; Seed without endosperm, only two fleshy cotyledons and also similar to the structure of secondary xylem, etc., to make the cycads in the origin of angiosperms. However, such claims decreased in recent years. Tah he asked that the spores within the cycad leaf magnolia flower ball and the similarity of the surface, because Mulan class stamens (small fertile leaves), like other primitive angiosperms, as is the separation of small fertile leaves, spirally arranged , and the small spores within the cycad-like leaves arranged round, and in the last base connate, co-generated aggregation of small sporangium capsule; Secondly, the purpose of the cycad megasporophyll degenerate into a small shaft, a straight apical ovule . So to imagine such a simplified megasporophyll into carpel of angiosperms is very difficult. In addition, the cycads in the micropylar tube to accept the small spores, while the angiosperm stigma pollination by, all of which indicate that the origin of angiosperms within the cycads in the less likely. Tah he asked that within the angiosperms with the cycads have a common ancestor, it is possible from the most primitive group of seed fern origin. At present, most scientists accept the phylogeny of angiosperms as a possible seed fern ancestors, but because the fossil record is incomplete, this hypothesis remains to be confirmed by more comprehensive and in-depth study. 4. Angiosperm phylogenetic reconstruction Human studies of plant classification, evolution and phylogenetic purpose is to reveal the plant world, their development and extinction of history, from the extant angiosperms and the fossil record, through macro and micro characteristics of the angiosperm phylogenetic reconstruction, the establishment of a fully natural systems.
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Economic use
Angiosperms is widely used. Most human foods are derived from angiosperms, such as cereals, beans, potatoes, fruits and vegetables. Angiosperms also for construction, paper, textiles, plastics, oil, fiber, sugar, spices, medicines, resin, tannic acid, narcotic drugs, drinks, etc. to provide raw materials. Green plants can regulate the air and the importance of cleaning up the environment, according to reports, the green plants on Earth one hundred million tons per year to provide hundreds of valuable oxygen, removed from the air while hundreds of tons of carbon dioxide, so the greens are humans and All the material basis of animal survival. Wood can also provide energy mankind, the Chinese garden plants rich in natural resources, known as the mother of the world's nickname garden, planting flowers, landscaping has become the city people, regulate the importance of environmental air and clean fashion. Angiosperms and human lives.
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Angiosperms (Angiosperm)
Angiosperms (bèizǐzhíwù) is a kind of seed plants. Angiosperms, or flowering plants is the evolution of plant species last seen. They first appeared in the early Cretaceous, late Cretaceous plant kingdom occupying most of the world. Angiosperm seeds hidden in the nutrient-rich fruits, providing a good environment for the development of life. Fertilization by the wind when the mass media, most of it is conducted by insects or other animals, making the flowering plants can be widely distributed. Also known as angiosperms, flowering plants. The largest group of modern plants, the number of species (about 250,000 or more) and the number of individuals are dominant, the advantages that make up today the Earth's surface vegetation. Position of the classification is inconclusive, the early classification is studied under the angiosperm seed plants as a key link, then upgraded to angiosperm, recently listed as Magnolia Door (Magnoliophyta). Angiosperms provide humanity with food, shelter, clothing, medicines and flowers, is the most important food sources, such as cereals (especially rice, wheat and corn), sugar cane, potatoes, vegetables, tubers and fruit. Angiosperms habits, shape and size vary widely, from tiny to huge floating grass green eucalyptus trees. Most upright growth, but there are winding, creeping or by other mechanical support plant growth. Multi-containing chlorophyll, manufacture their own nutrients, but there are saprophytic and parasitic. There are several families of plants are carnivorous, such as the sundew genus (Drosera) plants to insects and other small animals for food. Many are woody (trees and shrubs), but mostly herbs, herbal woody angiosperms have a more evolved than the features. More cross-pollination, a small number of self-pollination. After germination of pollen grains reach the stigma and produce pollen tubes, down through the style into the ovary cavity. Tube front end with the tube nucleus and reproductive cells. As the pollen tube growth, reproductive cell divides into two male gametes. Normal pollen tube into the ovule through the micropyle. Pollen tube enters the female gametophyte, the top of the rupture, the two male gametes released into the cytoplasm of the female gametophyte. One of the male gamete penetrating the egg, the fertilization fusion with them. Often arise after fertilization develop into the embryo nuclear. Another male gamete with the female gametophyte of the other two nuclei (polar nuclei) combined (or fused with the polar core of a nuclear pre-combination) to form endosperm, the endosperm nucleus produce the endosperm, for the storage of nutrients. Two male gametes are to participate in the process of integration, which is called double fertilization, as unique to angiosperms. Two classes of angiosperms, their seeds the same as the early stages of embryo development, but further development is in a different way ︰ dicotyledonous plants, both sides of the lateral stems cotyledon primordia are developed, but only in monocots cotyledons have developed a native to the top of the movement. Embryo development process clearly shows that the early angiosperms are dicotyledonous embryo stage. Dicotyledon embryo differentiated into four main parts ︰ radicle, hypocotyl, cotyledon and germ. Structural features of angiosperms angiosperm flowers and other organs like the vascular plants, divided into vegetative organs and reproductive organs. A specialized catheter xylem, phloem sieve tube at the end of phase formation of sieve tubes, companion cells in sieve tube side of the phase. Leaf size, shape and structure is inconsistent, there are alternate phyllotaxis, opposite or whorled. Alternate is the original type, wheel of life, and life is derived in the formation of the evolutionary process. Entire, simple leaves with pinnate veins are more original. In the winter or dry season the leaves fall off by the "evergreen" leaves evolved. Leaf epidermis specialized pores. Flowers are highly variable and specialized reproductive branches. Sporophylls (stamens and carpels) hidden in the receptacle, usually by the perianth (sepals and petals) around. Torus is a shortened section of the stem, the original flower child care longer. Sepals usually green, leaf, or bract-like, is a specialized leaves. Petals and sepals are usually alternate, its texture, color (except green outside) and the size is different from the sepals. Stamens (small fertile leaves) general androecium, stamens usually handle each filament and with spore-like part (anther) component. Carpels (megasporophyll) total group called the pistil, carpel surrounded the ovule from the ovary, style and stigma composition. To accept the stigma pollen grains, was born in the top style. (A) with real flowers Typical angiosperm flowers from the calyx, corolla, androecium, gynoecium Group 4 parts, each part is called floral. Outer part of the calyx, composed of the sepals, usually green, has a protective effect of flowers; inner corolla, the petals, bright color, are attractive to the birds, the role of insect pollination; androecium, pollen from the stamens of Health composition; ovary or pistil containing ovules by a group of carpels, the pollen can accept In the number of ministries of flowers, the morphological changes are extremely diverse, these changes are in the process of evolution, adapted to the insect, wind-pollinated, bird coal, or water pollination conditions, is natural _select_ion, be preserved, and continue to strengthen due. (B) has the pistil Formed by the carpel pistil, including the ovary, style and stigma 3. Ovules in the ovary harboring get the protection of the ovary, to avoid the biting insects and water loss. Ovary after fertilization develop into fruit. Fruit has a different color, smell, taste, variety of cracking in; peel usually have a variety of hooks, spines, wings, hair. All these characteristics of fruit, for the protection of seed maturity, to help play an important role in seed dispersal, and their evolutionary significance is self-evident. (C) with the phenomenon of double fertilization The phenomenon of double fertilization in which two sperm cells into the embryo sac after the egg to form a zygote and the other one with two polar nuclei combine to form a 3n chromosomes develop into the endosperm, embryo to 3n endosperm chromosome nutrition, contradictions of the new plants increased, so have a stronger life force. All are angiosperms angiosperm: cell types and tissues. With the phenomenon of double fertilization, which is that they have evidence of a common ancestor. (D) highly developed sporophyte Sporophytes of angiosperms, in the shape, structure, life forms, etc., better than the other types of plants, diversification, there is the world's tallest tree, such as almonds, according to (Eucalyptus amygdalina Labill.), Up to 156 meters; If there are fine sand and the grass roots of the absence of Ping [Wolffia arrhiza (L.) Wimm.], per square meter of surface can accommodate 3 million individuals. Have weighed 25 kg fruit contains only one seed, such as the King Brown (King Coconut) [Roystonea regia (HBK) OFCook]; also as light as dust, 50,000 seeds weighing only 0.1 grams of plant, such as some of the tropical rainforest epiphytic orchid; have up to 6 years of plant life, such as the dragon tree (Dracaena draco L.); also completed within 3 weeks of life cycle of flowering seed plants (as some cruciferous plants growing in the desert); raw water, sand raw, rocky and saline students plant; a self-raised plants are saprophytic, parasitic plants. In anatomy, the secondary xylem of angiosperms have catheters, phloem companion cell; and gymnosperms tracheids are generally (only buy ephedra and Ma rattan exceptions), phloem cells unaccompanied, make perfect conducting tissue transport substances in the body smooth, adaptability to be strengthened. (E) the further degradation of gametophyte (simplified) (F) archegonium disappeared, the rest is the egg apparatus. The features of angiosperms, it has to survive the competition in, superior to the internal conditions of other types of plants. The production of angiosperms, it the first time in the Earth colorful, different types, flowers and fruits lush scene, with the development of forms of flowers, fruits and seeds stored in the high-energy products, directly or indirectly dependent on making plants born animals (especially insects, birds and mammals), to obtain the corresponding development of lush up quickly. Angiosperms are divided into two classes - Dicotyledon (Mulan Gang) and monocotyledons Programme (Lily Gang). Latin name angiosperm Angiospermae, comes from the Greek compound. Angio-coated and-sperma seed, the two joints, the first frame with a plural Serve Angiospermae, the English called Angiosperm. Evolution of angiosperms is the plant kingdom's most advanced, most species, the most widely distributed, the most adaptable groups. In different systems, to more than 300 angiosperms more than 400 families, over 10,000 are 20 to-25 million. More than half of the total species in the plant kingdom. They spread out in all climatic zones. Because of high temperatures, rain and more reason, tropical and subtropical most. South American Amazon River area about 4 million. 2-3 million other tropical areas. Temperate regions due to lower temperatures, less rainfall, species decreasing. Situation in China, Yunnan Province, good weather conditions, plant up to thousands more, is located in Hebei Province, north latitude 26-43 degrees. The relative reduction of many species, about 2,500 species. Arctic is significantly reduced, in many places almost no angiosperms, only a few places a few hardy species to survive. Such as the Arctic willow (Salix lanata), Arctic poppy (Papaver radicatum), the distribution of latitude of 80 degrees. Antarctica in the Southern Hemisphere Jenny Moore Collegiate Bay near the island, thick leaves of plants with pink pink Corot (Colobanthus crassifolius) survival. In addition, from the altitude of view, the higher the terrain, the lower the temperature at approximately 100 meters up, the temperature decreased 0.5 ℃, plant species composition has changed; in the Everest region, climate, only a few hardy species only survive. 5,000-5,500 meters in area can find pink V Stellaria (Stellaria decumbens). Snow lotus (Saussurea involucrata) in Xinjiang Tianshan height of species. There are extreme desert of the natural environment. Such as the desert of Xinjiang region, Populus (Populus diversifolia) and Haloxylon (Haloxylon ammodendron) survive, to adapt to arid climate. North Africa, very little rain in the Sahara desert, no rain in some places more than a decade. There is a plant called dwarf teeth squarrosa (Odontospermum pygmaeum), the formation of only a few dozen extreme drought YORK short life cycle, called the short-lived plants. It is a little rain water, can grow to flowering and seed germination to complete the generation task. Usually slightly moist, flowers to open, once dried, flowers that close, very sensitive. Americas Mexico desert, there is a special kind of plants to adapt to drought is more pulp plants, known as the cactus. Spiny body, degradation of leaf and stem water content and more to drought. Some of them shaped like a giant species, such as the use knifed open, you can directly drink the water. In saline soil, there are strong salt of angiosperms to Like the most famous. Such as Salicornia (Salicornia herbacea) is an annual herb, fleshy, leaves minimal. Internode-like, you can carry out photosynthesis. In its cross-section of the stem has striking features: such as the skin thin and smooth, there are two layers of palisade tissue, the internal cells were large, water and more vascular tissue in the center. More water is due to sodium (Na) ions formed under the influence. Salicornia living thing for more than 92% of the weight of water. Salicornia dry the ash left after burning more than most, accounting for more than 45% dry weight. The stem structure, water and ash more and more, are all characteristics typical of halophytes. Born in Salicornia salt marshes, it is the place where most salt, may be its standard representation. Like the evolution of the salt plant is carried out under conditions of salt speech.
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Angiosperms (fossil)
beizi zhiwu (huashi) Angiosperms (fossil) Cretaceous strata in the past, been found practical and reliable angiosperm fossils, to the late Early Cretaceous, only their footprints. Dating back about 1.12 ~ 1.18 billion years Balie Mu period (Barremian), the United Kingdom and the United States found that a single column bar ditch powder, mesh powder and single-channel single-channel pink star pattern, that California has Aonie fruit (Onoena california .) Just over 106 ~ 112 million years Yap ladder of (Aptian), the United States east of the Potomac (Potomac) fossil group found a number of leaves, a Rutgers leaves, the protea leaves, fig leaves and acacia leaves. 1 ~ 106 million years ago, the Albian (Albian), North America and British Columbia have Myrtaceae myrtle leaves. Single-channel powder stick close column Chloranthaceae (Chloranthaceac). To Tertiary Paleocene (about 0.54 to 0.7 billion years old) found a small tiller Branch, Gentianaceae, freesia, duckweed Branch, Musaceae, Potamogeton Branch, Rubiaceae, Styracaceae, Queensland □ Tree Branch, Cattail Branch, Compositae, Umbelliferae and so on. To 0.38 ~ 0.54 billion years ago in the Eocene, but there Rhizophoraceae, Solanaceae, maple octagonal Gramineae, Caryophyllaceae and Chenopodiaceae and so on. The Labiatae, and broom Deng Cao Ling Branch Division to appear before the Oligocene. According to the characteristics of plant fossils that appeared in the Cretaceous and Paleogene fossils of angiosperms, there are many types of tree species to the Oligocene, the herbs gradually increased, to the late Tertiary and Quaternary, herb even more fossil plants, especially pollen fossils. Balie Mu in the early Cretaceous period, found only in angiosperm fossils to latitude 45 ° south latitude 45 ° between the areas. Jaap ladder to the period, the angiosperm fossils appeared in the south of latitude 45 ° south and latitude 20 ° north of the Strip. To the Late Cretaceous Cenomanian angiosperm fossils only appeared in high-latitude 70 ° ~ 80 ° of the area. This phenomenon indicates that the origin of angiosperms are tropical. (Xu)
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