Plants are primarily multicellular, dominated by the photosynthesis eukaryote of the Plantae kingdom. They form the Viridiplantae clade (Latin for "greenery") that includes flowering plants, conifers and other gymnosperms, ferns, clubmosses, horns, moss, moss and green algae, and excluding red and brown algae. Historically, plants are treated as one of two kingdoms including all non-animal living creatures, and all algae and fungi are treated as plants. However, all current Plantae definitions exclude fungi and some algae, as well as prokaryotes (arcaea and bacteria).
Green plants have cell wall containing cellulose and obtain most of their energy from sunlight through photosynthesis by primary chloroplasts originating from endosymbiosis with cyanobacteria. Their chloroplasts contain chlorophyll a and b, which gives them a green color. Some plants are secondary or mycotrophic parasites and may lose the ability to produce normal chlorophyll or photosynthesis. Plants are characterized by sexual reproduction and alternating generations, although asexual reproduction is also common.
There are about 300-315 thousand plant species, most of which, some 260-290 thousand, are seed plants (see table below). Green plants provide most of the world's molecular oxygen and are the foundation of most of the Earth's ecosystems, especially on land. Plants that produce grains, fruits and vegetables form basic human foodstuffs, and have been domesticated for thousands of years. Plants have many cultural uses and others as ornaments, building materials, writing materials and in various kinds, they have become a source of drugs and medicines. Scientific studies of plants are known as botany, the branch of biology.
Video Plant
Definisi
All living things are traditionally placed into one of two groups, plants and animals. This classification may have originated from Aristotle (384 BC - 322 BC), which makes the distinction between plants, generally immobile, and animals, often moving to catch their food. Much later, when Linnaeus (1707-1778) created the basis of modern systems of scientific classification, these two groups became the kingdom of Vegetabilia (later Metaphyta or Plantae) and Animalia (also called Metazoa). Since then, it has become clear that plant kingdoms as originally defined include some unrelated groups, and mushrooms and some algae groups have been transferred to the new kingdom. However, these organisms are still often considered plants, especially in a popular context.
The term "plant" in general implies the ownership of the following features: multicellularity, possession of cell walls containing cellulose and the ability to perform photosynthesis with primary chloroplasts.
Current definition of Plantae
When the name Plantae or plant is applied to a particular group of organisms or taxon, it usually refers to one of the four concepts. From at least to the most inclusive, these four groups are:
Another way to look at the relationship between the different groups that have been called "plants" is through the cladogram, which shows their evolutionary relationship. This has not been fully resolved, but one relationship received between the three groups described above is shown below. Those called "plants" are in bold.
The way in which groups of green algae are combined and named varies between authors.
Alga
Algae consist of several different groups of organisms that produce food with photosynthesis and thus are traditionally incorporated into the plant kingdom. Seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, brown algae, red and green. There is good evidence that brown algae evolved independently of others, from non-photosynthetic ancestors that form endosymbiotic relationships with red algae rather than from cyanobacteria, and they are no longer classified as plants as defined here.
The Viridiplantae, a green plant - green algae and ground plant - form a clade, a group consisting of all the same ancestral descendants. With a few exceptions, greenery has the following characteristics in common; primary chloroplasts are derived from cyanobacteria containing chlorophyll a and b , cell wall containing cellulose, and food store in the form of starch contained in plastids. They undergo closed mitosis without centriolus, and usually have a mitochondrial with flat crystals. Chloroplasts of green plants are surrounded by two membranes, indicating they are derived directly from endosymbiotic cyanobacteria.
Two additional groups, Rhodophyta (red algae) and Glaucophyta (glaucophyte algae), also have primary chloroplasts that appear to originate directly from endosymbiotic cyanobacteria, although they differ from Viridiplantae in pigments used in photosynthesis and are very different in color.. These groups also differ from green plants in that the storage polysaccharide is floridean starch and stored in the cytoplasm rather than in the plastids. They seem to have the same origin with Viridiplantae and all three groups form the Archaeplastida clade, whose name is that their chloroplast is derived from an ancient endosymbiotic event. This is the broadest modern definition of the term 'plant'.
In contrast, most other algae (eg brown algae/diatoms, haptophytes, dinoflagellates, and euglenids) not only have different pigments but also have chloroplasts with three or four surrounding membranes. They are not close relatives of Archaeplastida, may acquire chloroplasts separately from the digested or symbiotic green and red algae. Thus they are not included in the broadest modern definition of the plant kingdom, although they were in the past.
Green plants or Viridiplantae are traditionally divided into green algae (including stoneworts) and ground plants. However, it is now known that terrestrial plants evolved from within a group of green algae, so the green algae themselves are a paraphyletic group, a group that excludes some common ancestral descendants. Paraphyletic groups are generally avoided in the modern classification, so in the latest treatments Viridiplantae has been divided into two clades, Chlorophyta and Streptophyta (including land plants and Charophyta).
Chlorophyta (a name that has also been used for all green algae) is a sister group for Charophytes, from which terrestrial plants evolved. There are about 4,300 species, especially unicellular or multicellular marine organisms such as sea lettuce, Ulva .
Another group in Viridiplantae is Streptophyta, especially freshwater or terrestrial, which consists of land plants along with Charophyta, which consists of several groups of green algae such as desmids and stoneworts. Streptophyte algae are either unicellular or form a multicellular filament, branched or unbranched. The Spirogyra genus is a streptophyte algae filament that is familiar to many people, as it is often used in teaching and is one of the organisms responsible for "foaming" algae in ponds. Freshwater fish are very similar to land plants and are believed to be their closest relatives. Growing immersed in fresh water, they consist of a central rod with a circle of branches.
Mushroom
The original classification of Linnaeus places mushrooms inside the Plantae, as they are undoubtedly not animals or minerals and this is the only other alternative. With the development of the 19th century in microbiology, Ernst Haeckel introduced a new royal Protista beside Plantae and Animalia, but whether mushrooms are best placed in Plantae or should be reclassified because the protists remain controversial. In 1969, Robert Whittaker proposed the creation of the Fungi Kingdom. Molecular evidence has shown that the most recent ancestor (concestor), of Fungi may be more similar to that of Animalia than that of Plantae or other kingdoms.
Whittaker's original classification is based on fundamental differences in nutrition between Fungi and Plantae. Unlike plants, which generally obtain carbon through photosynthesis, and so is called autotroph, fungi have no chloroplasts and generally obtain carbon by decomposing and absorbing the surrounding material, and so-called heterotrophic saprotrof. In addition, the multicellular mushroom substructure differs from the plant, taking the form of many chitinous microscopic strands called hyphae, which may further be divided into cells or may form syncytium containing many eukaryotic nuclei. The fruit body, in which the fungus is the best known example, is the reproductive structure of a fungus, and unlike the structure produced by the plant.
Maps Plant
Diversity
The table below shows some estimates of the number of species from different green plant divisions (Viridiplantae). This suggests there are about 300,000 species of Viridiplantae living, of which 85-90% are flowering plants. (Note: since these come from different sources and different dates, they are not always comparable, and like all species, subject to the degree of uncertainty in some cases.)
The naming of plants is governed by the International Code of Nomenclature for algae, fungi, and plants and the International Code of Nomenclature for Aquaculture Plants (see taxonomy of cultivated crops).
Evolution
The evolution of plants has resulted in increased levels of complexity, from the earliest algae algae, through bryofita, lycopods, ferns to the complex gymnosperms and the current angiosperms. Plants in all these groups continue to grow, especially in the environment in which they evolve.
An algal extraction formed on the ground 1,200 million years ago , but not until the Ordovician Period, about 450 million years ago , that land plants emerged. However, new evidence from the study of carbon isotope ratios in Precambrian rocks has suggested that complex photosynthetic plants developed on Earth over 1000 m.y.a. For more than a century, it was assumed that the ancestors of terrestrial plants evolved in an aquatic environment and then adapted to life on land, an idea usually credited to the botanist Frederick Orpen Bower in his 1908 book "The Origin of a Land Flora". A recent alternative view, supported by genetic evidence, is that they evolved from a single celled terrestrial algae. Primitive soil plants began diversifying in the late Silurian Period, approximately 420 million years ago , and their diversified results featured in great detail in the early Devonian fossil collection of Rhynie chert. It preserves early plants in cellular detail, fossilized in volcanic springs. In the middle of the Devonian Period, most of the known features in plants today are present, including roots, leaves and secondary wood, and by the end of the Devonian era the seeds had evolved. The late Devonian plants thus reach a level of sophistication that allows them to form tall tree forests. Evolutionary innovation continued in the Carboniferous Period and then the geological period and is ongoing today. Most plant groups are relatively untouched by the Permo-Triassic extinction event, although the community structure is changing. It may have set the scene for the evolution of flowering plants in Trias (~ 200 million years ago ), which exploded in Cretaceous and Tertiary. The main group of newly evolved plants is the grass, which became important in the middle of Tertiary, from about 40 million years ago . Grass, as well as many other groups, developed a new mechanism of metabolism to survive with low CO 2 and warm, dry conditions in the tropics during the last 10 million years .
A proposed 1997 phylogenetic tree of Plantae, after Kenrick and Crane, is as follows, with modifications to Pteridophyta from Smith et al. The Prasinophyceae is a paraphyletic collection of ancient green algae deviant lines, but treated as a group outside of Chlorophyta: the authors then did not follow this advice.
The new proposed classification follows Leliaert et al. 2011 and modified with Silar 2016 for green algae and NovÃÆ'kov & amp; Baraba? -Krasni 2015 for land plant clade. Note that Prasinophyceae here is placed inside Chlorophyta.
Embryophytes
The plants that are probably most familiar to us are the multicellular ground plants, called embryophytes. Embryophytes include vascular plants, such as ferns, conifers and flowering plants. They also include bryophytes, where lichens and liverwings are the most common.
All of these plants have eukaryotic cells with cell walls composed of cellulose, and most obtain their energy through photosynthesis, using light, water and carbon dioxide to synthesize food. About three hundred species of plants do not photosynthesize but are parasites in other species of photosynthesis plants. Embryophytes are distinguished from green algae, which are a mode of photosynthetic life similar to modern plant species believed to have evolved from, by having specialized reproductive organs protected by non-reproducing tissues.
Bryophytes first appeared at the beginning of the Paleozoic. They mainly live in habitats where moisture is available for significant periods, although some species, such as Targionia are tolerant of drying. Most bryophyte species remain small throughout their life cycle. This involves a switch between two generations: a haploid stage, called a gametophyte, and a diploid stage, called sporophyte. In bryofita, sporophyte is always unbranched and remains dependent on its parent gametophyte. Embryophytes have the ability to secrete cuticles on the outer surface, a waxy coating that gives the impression of resistance to drought. In mosses and horn lichen, the cuticle is usually only produced in sporophytes. Stomata is absent from liverweed, but occurs in sporangia moss and horn moss, allowing gas exchange.
Vascular plants first appeared during the Silurian period, and by Devonian have diversified and spread to many different terrestrial environments. They developed a number of adaptations that allowed them to spread to more arid places, especially the tissues of the xylem and phloem vessels, which transport water and food to all organisms. The root system capable of obtaining groundwater and nutrients also evolved during Devonian. In modern vascular plants, sporophytes are usually large, branched, nutritious independent and live longer, but there is growing evidence that Paleozoic gametophytes are as complex as sporophyte. Gametophytes from all vascular plant groups evolved into diminished size and excellence in the life cycle.
In seed crops, microgametophytes are reduced from multicellular free living organisms to some cells in pollen grains and miniature megagametophyte remain in the megasporangium, attached and dependent on the parent plant. A megasporangium is enclosed in a protective layer called an integument known as an ovule. After fertilization through sperm produced by pollen, embryonic sporophyte develops within the ovule. Integumentes become seed layers, and ovules develop into seeds. Seed plants survive and reproduce in very dry conditions, because they do not depend on free water for sperm movement, or the development of free living gametophytes.
The first seeded plant, pteridosperms (seed fern), now extinct, appears in Devon and diversifies through Carbon. They are the ancestors of modern gymnosperms, of which four surviving groups are widespread today, especially conifers, whose trees are dominant in some biomes. The name gymnosperm comes from the Greek composite word ???????????? gymnos, "naked" and "sperm", "seed"), as an ovule and the next seed is not covered in a protective structure (carpel or fruit), but is covered naked, usually on a cone scale. Fossil
Plant fossils include roots, wood, leaves, seeds, fruit, pollen, spores, phytoliths, and amber (fossil resins produced by some plants). Land fossil plants are recorded in terrestrial, lacustrine, fluvial and near-shore marine sediments. Pollen, spores and algae (dinoflagellates and acritarchs) are used to determine the order of sedimentary rocks. The remains of fossil plants are not as popular as fossil animals, although fossil plants are locally abundant in many regions around the world.
The earliest fossils that can clearly be transferred to the Plantae Kingdom are the fossilized green algae of the Cambrian. These fossils resemble the calculated multicellular members of Dasycladales. Precambrian fossils were previously known to resemble single cell green algae, but the definitive identity with the algae group is uncertain.
The earliest fossils associated with green algae are from Precambrian (about 1200 mya). The resistant outer wall of the prasinophyte cyst (known as phycomata) is well preserved in the Paleozoic fossil deposits (about 250-540 mya). The filamentous fossils ( Proterocladus ) of the central Neoproterozoic sediments (about 750 mya) have been associated with Cladophorales, while the oldest reliable records of Bryopsidales, Dasycladales) and stoneworts are from Paleozoic.
The oldest embryophytic fossils are known to originate from the Ordovician, though such fossils are fragmentary. By Siluria, the fossils of all the crops are preserved, including the simpler vascular plants of Cookies in mid-Siluria and the much larger and more complex Barycwanathia longifolia lycophyte at the end of the Silurian. From the early rendering of Devonian Rhynie, detailed fossil lycophytes and rhyniophytes have been found that show details of individual cells in plant organs and symbiotic associations of these plants with fungi from the order of Glomales. The Devonian period also saw the evolution of leaves and roots, and the first modern tree, Archaeopteris . This tree with fern-like leaves and stems with heterosporous conifer-like woods produces spores of two different sizes, the first step in the evolution of seeds.
Coal size is the main source of fossil Paleozoic plants, with many plant groups present today. The pile of leftover coal mines is the best place to collect; Coal itself is the remains of petrified plants, although the structural details of plant fossils are rarely seen in coal. In the Fossil Forests of Victoria Park in Glasgow, Scotland, the Lepidodendron tree stump is found in its original growth position.
The fossil remains of conifers and angiospermic roots, stems and branches may be abundant locally in lakes and marine sediments from the Mesozoic and Kenozoic era. Sequoia and its allies, magnolias, oaks, and palms are often found.
Petrified wood is often found in some parts of the world, and is most commonly found in dry areas or deserts that are more easily exposed by erosion. Petrified wood is often highly silicified (organic matter replaced by silicon dioxide), and impregnated tissue is often preserved in fine detail. Such specimens may be cut and polished using a lapidary apparatus. Petrified wood forest fossils have been found on all continents.
Fossils of fern seeds such as Glossopteris are widespread in several continents in the southern hemisphere, a fact that supports the original idea of ​​Alfred Wegener on the theory of continental drift.
Structure, growth and development
Most of the solid material in the plant is taken from the atmosphere. Through the process of photosynthesis, most plants use energy in the sun to convert carbon dioxide from the atmosphere, plus water, into simple sugars. This sugar is then used as a building block and forms the main structural component of the plant. Chlorophyll, a pigment containing green magnesium is essential for this process; usually in plant leaves, and often in other parts of the plant. Parasitic plants, on the other hand, use the resources of their host to provide the materials needed for metabolism and growth.
Plants usually depend on the soil mainly to support and water (in quantitative terms), but they also obtain nitrogen, phosphorus, potassium, magnesium and other nutrients from the soil. Epiphytic and lithophytic plants depend on the air and dirt nearby for nutrients, and carnivorous plants supplement their nutritional needs, especially for nitrogen and phosphorus, with the prey of the insects they catch. In order for most plants to grow successfully they also need oxygen in the atmosphere and around the roots (soil gas) for respiration. Plants use oxygen and glucose (which can be produced from stored starch) to provide energy. Some plants grow as submerged water fish, using dissolved oxygen in the surrounding water, and some special vascular plants, such as mangroves and reeds ( Phragmites australis ), can grow with their roots under anoxic conditions.
Factors affecting growth
Plant genomes control their growth. For example, selected varieties or wheat genotypes grow rapidly, mature within 110 days, while others, under the same environmental conditions, grow more slowly and mature within 155 days.
Growth is also determined by environmental factors, such as temperature, available water, available light, carbon dioxide and nutrients available in the soil. Any changes in the availability of these external conditions will be reflected in plant growth and development time.
Biotic factors also affect plant growth. Plants can be so crowded that no individual produces normal growth, causing etiolation and chlorosis. Optimal plant growth may be inhibited by grazing animals, less optimal soil composition, lack of mycorrhizal fungi, and attacks by insects or plant diseases, including those caused by bacteria, fungi, viruses and nematodes.
Simple plants like algae may have short life spans as individuals, but their population is generally seasonal. Annual plants grow and reproduce in one growing season, biennial plants grow for two growing seasons and typically reproduce in the second year, and perennial plants live for many growing seasons and once mature will often reproduce every year. This designation often depends on climate and other environmental factors. Annual plants in the alpine or temperate zone can be biennial or enduring in warm climates. Among vascular plants, perennials include evergreens that keep their leaves year-round, and fallen plants that lose their leaves for some of its parts. In temperate and boreal climates, they generally lose their leaves during the winter; many tropical plants lose their leaves during the dry season.
The rate of plant growth varies greatly. Some moss grows less than 0.001 millimeters per hour (mm/h), while most of the trees grow 0.025-0.250 mm/hr. Some climbing species, such as kudzu, which do not need to produce thick support networks, can grow up to 12.5 mm/hr.
Plants protect themselves from frozen stress and dehydration with antifreeze proteins, proteins and shock sugar (general sucrose). LEA protein expression (Late Embryogenesis Abundant) is induced by pressure and protects other proteins from aggregation as a result of drying and freezing.
Freezing effect
When water is frozen in plants, the consequences for crops depend largely on whether the freezing occurs in the cell (intracellular) or outside cells in the intercellular space. Intracellular clotting, which usually kills cells irrespective of the toughness of plants and tissues, is rare in nature because the cooling rate is rarely high enough to support it. A cooling rate of several degrees Celsius per minute is usually required to cause intracellular ice formation. At a cooling rate of several degrees Celsius per hour, ice segregation occurs in the intercellular space. This may or may not be lethal, depending on the hardiness of the network. At freezing temperatures, the water in the intercellular space of plant tissue freezes first, although the water may remain unfrozen until the temperature falls below -7 ° C (19 ° F). After the initial formation of intercellular ice, the cells shrink when water is lost to a separate ice, and cells undergo frozen drying. This dehydration is now considered the fundamental cause of a frozen injury.
DNA damage and repair
Plants continue to be exposed to various biotic and abiotic pressures. This pressure often causes DNA damage directly, or indirectly through the formation of reactive oxygen species. Plants are capable of DNA damage response which is an important mechanism for maintaining genome stability. The DNA damage response is very important during seed germination, as the quality of the seeds tends to worsen with age as it relates to the accumulation of DNA damage. During the germination repair process is activated to deal with this accumulated DNA damage. In particular, single and double-strand breaks in DNA can be improved. Checkpoint DNA kinase ATM has a key role in integrating development through germination with an improved response to DNA damage accumulated by old seeds.
Plant cell
Plant cells are usually distinguished by central vacuoles containing large water, chloroplasts, and rigid cell walls consisting of cellulose, hemicellulose, and pectin. Cell division is also characterized by the development of a phragmoplast for the formation of cell plates in the final stages of cytokinesis. Just as in animals, plant cells differentiate and develop into several cell types. Totipotent meristematic cells can differentiate into vascular, storage, protective (eg epidermal layer), or reproductive tissue, with more primitive plants lacking some tissue type.
Physiology
Photosynthesis
Plants are photosynthetic, which means they make their own food molecules using energy derived from light. The main mechanism of plants to capture light energy is chlorophyll pigment. All green plants contain two forms of chlorophyll, chlorophyll a and chlorophyll b . The latter of these pigments are not found in red or brown algae. Simple photosynthetic equations are as follows: -
C 6 O 2 O -> (in the presence of light and chlorophyll) 6 6O 2
Immune system
By means of cells that behave like nerves, plants receive and distribute in their information systems about the intensity and quality of light incidents. Light incidents that stimulate chemical reactions in one leaf, will cause a chain reaction signal to the entire plant through a type of cell called bundle sheath cells . The researchers, from the Warsaw University of Life Sciences in Poland, found that plants have special memory for various light conditions, which prepare their immune systems against seasonal pathogens. Plants use pattern recognition receptors to recognize preserved microbial markings. This introduction triggers an immune response. The first plant receptors of preserved microbial signs were identified in rice (XA21, 1995) and in Arabidopsis thaliana (FLS2, 2000). Plants also carry immune receptors that recognize highly variable pathogenic effects. This includes the NBS-LRR protein group.
Internal distribution
Vascular plants differ from other plants in nutrients transported between their different parts through a special structure, called xylem and phloem. They also have roots to take water and minerals. Xylem moves water and minerals from the roots to the rest of the plant, and the phloem provides roots with sugar and other nutrients produced by the leaves.
Genomics
Plants have some of the largest genomes among all organisms. The largest plant genome (in terms of number of genes) is wheat ( Triticum asestivum ), predicted to encode ~ 94,000 genes and thus almost 5 times more than the human genome. The first sequenced plant genome is from Arabidopsis thaliana that encodes about 25,500 genes. In terms of DNA sequences, the smallest published genome is from a carnivorous bladder ( Utricularia gibba) at 82 Mb (though still encoding 28,500 genes) while the largest, from Norwegian Spruce ( Picea abies ), extending over 19,600 Mb (encoding about 28,300 genes).
Ecology
Photosynthesis conducted by terrestrial plants and algae are the major sources of energy and organic matter in almost all ecosystems. Photosynthesis, originally by cyanobacteria and then by eukaryotes of photosynthesis, radically alters the composition of the Earth's early anoxic atmosphere, which consequently is now 21% oxygen. Animals and most other organisms are aerobic, relying on oxygen; they are not limited to anaerobic environments that are relatively rare. Plants are the major producers in most terrestrial ecosystems and form the basis of food webs in these ecosystems. Many animals rely on plants for shelter as well as oxygen and food.
Land plants are a key component of the water cycle and several other biogeochemical cycles. Some plants have coexisted with nitrogen-fixing bacteria, making the plant an important part of the nitrogen cycle. Plant roots play an important role in soil development and prevention of soil erosion.
Distribution
Plants are distributed almost all over the world. While they inhabit many biomes and ecoregions, only a few can be found outside the tundra in the northernmost area of ​​the continental shelf. At the southern end, plants have adapt persistently to the prevailing conditions. (See Antarctic flora.)
Plants are often the dominant physical and structural components of the habitat in which they occur. Many of the Earth's biomes are named for this type of vegetation because plants are the dominant organisms in the biome, such as grasslands, taiga and tropical rainforests.
Ecological relationship
Many animals have been living with plants. Many animals pollinate flowers in exchange for food in the form of pollen or nectar. Many animals kill seeds, often by eating fruit and throwing seeds in their droppings. Myrmecophytes are plants that have lived together with ants. The factory provides the house, and sometimes the food, to the ants. Instead, the ants keep the plants from herbivores and sometimes compete crops. Ant waste provides organic fertilizer.
The majority of plant species have various types of fungi associated with their root system in a kind of mutualistic symbiosis known as mycorrhiza. Mushrooms help plants get water and mineral nutrients from the soil, while plants provide fungal carbohydrates produced in photosynthesis. Some plants serve as homes for endophytic fungi that protect plants from herbivores by producing toxins. Endophytic fungi, Neotyphodium coenophialum , in high fescue ( Festuca arundinacea ) do tremendous economic damage to the livestock industry in the US.
Various parasitic forms are also quite common among plants, from the semi-parasitic mistletoe which only takes some nutrients from its host, but still has photosynthetic leaves, to the fully parasitic broomrape and toothwort which acquire all their nutrients through connection to other plant roots, and therefore not has chlorophyll. Some plants, known as myco-heterotrophs, mycorrhizal fungal parasites, and hence act as epiparasitic in other plants.
Many plants are epiphytes, which means they grow in other plants, usually trees, without parasites. Epiphytes can indirectly harm their host plants by cutting off the mineral nutrients and light that will be received by the host. The weight of large amounts of epiphytes can damage tree limbs. Hemiepiphytes like fig strangers start as epiphytes but end up organizing their own roots and defeating and killing their hosts. Many orchids, bromeliads, ferns and lichens often grow as epiphytes. Bromeliad epiphytes collect water in the leaves of axils to form phytotelmata that may contain complex aquatic food webs.
About 630 plants are carnivores, such as Venus Flytrap ( Dionaea muscipula ) and the sundew species ( Drosera ). They trap small animals and digest them to get mineral nutrients, especially nitrogen and phosphorus.
Importance
The study of the use of plants by people is called economic botany or ethnobotany. The cultivation of human plants is part of agriculture, which is the basis of human civilization. Plant agriculture is divided into agronomy, horticulture and forestry.
Food
Humans depend on crops for food, either directly or as feed for domestic animals. Agreement on agriculture with the production of food crops, and has played a key role in the history of world civilization. Agriculture includes agronomy for lush crops, horticulture for vegetables and fruits, and forestry for timber. Around 7,000 plant species have been used for food, although most of the food today comes from only 30 species. The main staples include cereals such as rice and wheat, root flour and tubers like cassava and potatoes, and beans like peas and beans. Vegetable oils like olive oil provide lipids, while fruits and vegetables donate vitamins and minerals to the diet.
Drugs
Medicinal plants are a major source of organic compounds, both for their drug and physiological effects, and for the synthesis of various organic chemicals industries. Hundreds of medicines come from plants, both traditional medicines used in herbs and chemicals that are purified from plants or first identified in them, sometimes by ethnobotanical search, and then synthesized for use in modern medicine. Modern herbal medicines include aspirin, taxol, morphine, quinine, reserpine, colchicine, digitalis and vincristine. Plants used in herbalism include ginkgo, echinacea, feverfew, and Saint John's wort. The Pharmacopoeia of Dioscorides, De Materia Medica , describes about 600 medicinal plants, written between 50 and 70 AD and remained in use in Europe and the Middle East until about 1600 AD; it is the forerunner of all modern pharmacopoeies.
Nonfood Products
Plants grown as industrial plants are the source of a wide range of products used in manufacturing, sometimes so intensive that it endangers the environment. Nonfood products include essential oils, natural dyes, pigments, waxes, resins, tannins, alkaloids, amber, and cork. Products derived from plants include soaps, shampoos, perfumes, cosmetics, paints, varnishes, turpentine, rubber, latex, lubricants, linoleum, plastics, inks, and gums. Renewable fuels from plants include firewood, peat and other biofuels. Fossil fuels of coal, petroleum and natural gas come from the remnants of aquatic organisms including phytoplankton in geological time.
Structural and fiber resources from plants are used to build dwellings and to produce clothing. Wood is used not only for buildings, ships, and furniture, but also for smaller items such as musical instruments and sports equipment. Wood blended to make paper and cardboard. Fabrics are often made of cotton, hemp, hemp or synthetic fibers such as rayon and acetate derived from plant cellulose. The threads used for sewing fabrics are also mostly derived from cotton.
Aesthetic uses
Thousands of plant species are cultivated for aesthetic purposes as well as providing shade, modifying temperatures, reducing wind, reducing noise, providing privacy, and preventing soil erosion. Plants are the basis of a multibillion-dollar tourism industry per year, which includes trips to historic parks, national parks, rainforests, colorful autumnal jungles and festivals such as Japanese and American cherry blossoms.
While some gardens are planted with food crops, many are grown for aesthetic, ornamental, or conservation purposes. Arboretum and botanical gardens are a common collection of living plants. In private outdoor gardens, grass lawns, shady trees, ornamental trees, shrubs, vines, herbaceous plants and bedding plants are used. Gardens can grow plants in a natural state, or perhaps statue of their growth, such as topiary or espalier. Gardening is the most popular recreational activity in the US, and working with plants or horticultural therapy is beneficial to rehabilitate people with disabilities.
Plants can also be grown or stored inside the house as an ornamental plant, or in special buildings such as greenhouses designed for the care and cultivation of live plants. The Venus flytrap, sensitive plants and revival plants are examples of plants sold as novelties. There are also art forms that specialize in cut or live cropping arrangements, such as bonsai, ikebana, and arrangement of cut or dried flowers. Ornamental plants sometimes change the course of history, as in tulipomania.
The architectural design resembles a plant appearing in the capital of the Ancient Egyptian column, carved into Egyptian lotus or papyrus. Crop images are often used in painting and photography, as well as on textiles, money, stamps, flags and emblems.
Scientific and cultural use
Basic biological research has often been done with plants. In genetics, plant breeding of nuts allows Gregor Mendel to derive the underlying laws governing inheritance, and chromosome examination in corn allows Barbara McClintock to show their relationship to the inherited trait. The plant Arabidopsis thaliana is used in the laboratory as a model organism to understand how genes control the growth and development of plant structures. NASA predicts that space station or space colony will one day depend on plants to support life.
The ancient trees are respected and many are famous. The tree rings itself is an important method for dating in archeology, and serves as a record of the past climate.
Prominent plant figures in mythology, religion, and literature. They are used as national and state symbols, including country trees and state flowers. Plants are often used as a memorial, a gift and to mark special occasions such as birth, death, weddings and holidays. Flower arrangements can be used to send hidden messages.
Negative effects
Weeds are undesirable plants that grow in managed environments such as agriculture, urban areas, parks, lawns, and parks. People have spread plants beyond their original reach and some of these introduced plants become invasive, destroying existing ecosystems by moving native species, and occasionally into serious weed farming.
Source of the article : Wikipedia
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