144-426: Arabis thaliana Arabidopsis thaliana , the thale cress , mouse-ear cress or arabidopsis , is a small plant from the mustard family ( Brassicaceae ), native to Eurasia and Africa. Commonly found along the shoulders of roads and in disturbed land, it is generally considered a weed. A winter annual with a relatively short lifecycle, A. thaliana is a popular model organism in plant biology and genetics. For
288-755: A Mathiola species, to seventeen (n=17). About 35% of the species in which chromosomes have been counted have eight sets (n=8). Due to polyploidy , some species may have up to 256 individual chromosomes, with some very high counts in the North American species of Cardamine , such as C. diphylla . Hybridisation is not unusual in Brassicaceae, especially in Arabis , Rorippa , Cardamine and Boechera . Hybridisation between species originating in Africa and California, and subsequent polyploidisation
432-733: A blade and a claw or not, and consistently lack basal appendages. The blade is entire or has an indent at the tip, and may sometimes be much smaller than the claws. The mostly six stamens are set in two whorls: usually the two lateral, outer ones are shorter than the four inner stamens, but very rarely the stamens can all have the same length, and very rarely species have different numbers of stamens such as sixteen to twenty four in Megacarpaea , four in Cardamine hirsuta , and two in Coronopus . The filaments are slender and not fused, while
576-490: A corymb ; their structure is that of the typical Brassicaceae . The fruit is a siliqua 5–20 mm long, containing 20–30 seeds . Roots are simple in structure, with a single primary root that grows vertically downward, later producing smaller lateral roots. These roots form interactions with rhizosphere bacteria such as Bacillus megaterium . A. thaliana can complete its entire lifecycle in six weeks. The central stem that produces flowers grows after about 3 weeks, and
720-399: A homeodomain and Blazquez et al 2001 that fve produces a WD40 repeat . The UVR8 protein detects UV-B light and mediates the response to this DNA-damaging wavelength. A. thaliana was used extensively in the study of the genetic basis of phototropism , chloroplast alignment, and stomal aperture and other blue light-influenced processes. These traits respond to blue light, which
864-473: A salicylic acid (SA) analog, has been used historically as an antifungal compound in crop plants. BTH, as well as SA, has been shown to induce SAR in plants. The initiation of the SAR pathway was first demonstrated in A. thaliana in which increased SA levels are recognized by nonexpresser of PR genes 1 ( NPR1 ) due to redox change in the cytosol, resulting in the reduction of NPR1. NPR1 , which usually exists in
1008-490: A botanically and pharmacologically important herbal Historia Plantarum in 1544 and a pharmacopoeia of lasting importance, the Dispensatorium in 1546. Naturalist Conrad von Gesner (1516–1565) and herbalist John Gerard (1545– c. 1611 ) published herbals covering the supposed medicinal uses of plants. Naturalist Ulisse Aldrovandi (1522–1605) was considered the father of natural history , which included
1152-430: A complex multicellular eukaryote , A. thaliana has a relatively small genome of around 135 megabase pairs . It was the first plant to have its genome sequenced, and is an important tool for understanding the molecular biology of many plant traits, including flower development and light sensing . Arabidopsis thaliana is an annual (rarely biennial ) plant, usually growing to 20–25 cm tall. The leaves form
1296-414: A considerable problem in agriculture, and the biology and control of plant pathogens in agriculture and natural ecosystems . Ethnobotany is the study of the relationships between plants and people. When applied to the investigation of historical plant–people relationships ethnobotany may be referred to as archaeobotany or palaeoethnobotany . Some of the earliest plant-people relationships arose between
1440-452: A continuum between the major morphological categories of root, stem (caulome), leaf (phyllome) and trichome . Furthermore, it emphasises structural dynamics. Modern systematics aims to reflect and discover phylogenetic relationships between plants. Modern Molecular phylogenetics largely ignores morphological characters, relying on DNA sequences as data. Molecular analysis of DNA sequences from most families of flowering plants enabled
1584-661: A cut-flower Matthiola (stock) and the model organism Arabidopsis thaliana (thale cress). Pieris rapae and other butterflies of the family Pieridae are some of the best-known pests of Brassicaceae species planted as commercial crops. Trichoplusia ni ( cabbage looper ) moth is also becoming increasingly problematic for crucifers due to its resistance to commonly used pest control methods. Some rarer Pieris butterflies, such as P. virginiensis , depend upon native mustards for their survival in their native habitats. Some non-native mustards such as Alliaria petiolata (garlic mustard), an extremely invasive species in
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#17327802260391728-495: A display of phenotypic plasticity . On January 2, 2019, China's Chang'e-4 lander brought A. thaliana to the moon. A small microcosm 'tin' in the lander contained A. thaliana , seeds of potatoes, and silkworm eggs. As plants would support the silkworms with oxygen, and the silkworms would in turn provide the plants with necessary carbon dioxide and nutrients through their waste, researchers will evaluate whether plants successfully perform photosynthesis , and grow and bloom in
1872-518: A guardee protein in a hypothesis known as the guard hypothesis . The first R-gene cloned in A. thaliana was RPS2 (resistance to Pseudomonas syringae 2), which is responsible for recognition of the effector avrRpt2. The bacterial effector avrRpt2 is delivered into A. thaliana via the Type III secretion system of P. syringae pv. tomato strain DC3000 . Recognition of avrRpt2 by RPS2 occurs via
2016-400: A hierarchical classification of plant species that remains the reference point for modern botanical nomenclature . This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus. For the purposes of identification, Linnaeus's Systema Sexuale classified plants into 24 groups according to
2160-836: A leafstalk. The leaf blade is usually simple, entire or dissected , rarely trifoliolate or pinnately compound . A leaf rosette at the base may be present or absent. The leaves along the stem are almost always alternately arranged , rarely apparently opposite. The stomata are of the anisocytic type. The genome size of Brassicaceae compared to that of other Angiosperm families is very small to small (less than 3.425 million base pairs per cell), varying from 150 Mbp in Arabidopsis thaliana and Sphaerocardamum spp., to 2375 Mbp Bunias orientalis . The number of homologous chromosome sets varies from four (n=4) in some Physaria and Stenopetalum species, five (n=5) in other Physaria and Stenopetalum species, Arabidopsis thaliana and
2304-401: A model for flower development. The developing flower has four basic organs - sepals , petals , stamens , and carpels (which go on to form pistils ). These organs are arranged in a series of whorls, four sepals on the outer whorl, followed by four petals inside this, six stamens, and a central carpel region. Homeotic mutations in A. thaliana result in the change of one organ to another—in
2448-412: A multiplex (oligomeric) state, becomes monomeric (a single unit) upon reduction. When NPR1 becomes monomeric, it translocates to the nucleus, where it interacts with many TGA transcription factors , and is able to induce pathogen-related genes such as PR1 . Another example of SAR would be the research done with transgenic tobacco plants, which express bacterial salicylate hydroxylase, nahG gene, requires
2592-409: A notch at the tip. The seed does not contain endosperm . Brassicaceae have a bisymmetrical corolla (left is mirrored by right, stem-side by out-side, but each quarter is not symmetrical), a septum dividing the fruit, lack stipules and have simple (although sometimes deeply incised) leaves. The sister family Cleomaceae has bilateral symmetrical corollas (left is mirrored by right, but stem-side
2736-404: A plant sucks water through them under water stress. Lignin is also used in other cell types like sclerenchyma fibres that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in
2880-552: A polymer of fructose is used for the same purpose in the sunflower family Asteraceae . Some of the glucose is converted to sucrose (common table sugar) for export to the rest of the plant. Unlike in animals (which lack chloroplasts), plants and their eukaryote relatives have delegated many biochemical roles to their chloroplasts , including synthesising all their fatty acids , and most amino acids . The fatty acids that chloroplasts make are used for many things, such as providing material to build cell membranes out of and making
3024-444: A powerful tool for the study of the subdiscipline of plant pathology , that is, the interaction between plants and disease-causing pathogens . The use of A. thaliana has led to many breakthroughs in the advancement of knowledge of how plants manifest plant disease resistance . The reason most plants are resistant to most pathogens is through nonhost resistance - not all pathogens will infect all plants. An example where A. thaliana
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#17327802260393168-464: A process that generates molecular oxygen (O 2 ) as a by-product. The light energy captured by chlorophyll a is initially in the form of electrons (and later a proton gradient ) that's used to make molecules of ATP and NADPH which temporarily store and transport energy. Their energy is used in the light-independent reactions of the Calvin cycle by the enzyme rubisco to produce molecules of
3312-505: A pure form of carbon made by pyrolysis of wood, has a long history as a metal- smelting fuel, as a filter material and adsorbent and as an artist's material and is one of the three ingredients of gunpowder . Cellulose , the world's most abundant organic polymer, can be converted into energy, fuels, materials and chemical feedstock. Products made from cellulose include rayon and cellophane , wallpaper paste , biobutanol and gun cotton . Sugarcane , rapeseed and soy are some of
3456-950: A reliable phylogeny . Although a substantial effort was made through molecular phylogenetic studies , the relationships within the Brassicaceae have not always been well resolved yet. It has long been clear that the Aethionema are sister of the remainder of the family. One analysis from 2014 represented the relation between 39 tribes with the following tree. Aethionemae Megacarpaeae Heliophileae Coluteocarpeae Conringieae Buniadeae Kernereae Schizopetaleae Thlaspideae Isatideae Sisymbrieae Brassiceae Thelypodieae Eutremeae Calepineae Biscutelleae Arabideae Cochlearieae Anchonieae Hesperideae Anastaticeae Dontostemoneae Chorisporeae Euclidieae Iberideae Erysimeae Lepidieae Smelowskieae Yinshanieae Plant sciences Botany , also called plant science (or plant sciences ), plant biology or phytology ,
3600-425: A rosette at the base of the plant, with a few leaves also on the flowering stem . The basal leaves are green to slightly purplish in color, 1.5–5 cm long, and 2–10 mm broad, with an entire to coarsely serrated margin; the stem leaves are smaller and unstalked, usually with an entire margin. Leaves are covered with small, unicellular hairs called trichomes . The flowers are 3 mm in diameter, arranged in
3744-536: A student of Aristotle who invented and described many of its principles and is widely regarded in the scientific community as the "Father of Botany". His major works, Enquiry into Plants and On the Causes of Plants , constitute the most important contributions to botanical science until the Middle Ages , almost seventeen centuries later. Another work from Ancient Greece that made an early impact on botany
3888-616: A thin wall (or septum). The family contains 372 genera and 4,060 accepted species . The largest genera are Draba (440 species), Erysimum (261 species), Lepidium (234 species), Cardamine (233 species), and Alyssum (207 species). The family contains the cruciferous vegetables , including species such as Brassica oleracea (cultivated as cabbage , kale , cauliflower , broccoli and collards ), Brassica rapa ( turnip , Chinese cabbage , etc.), Brassica napus ( rapeseed , etc.), Raphanus sativus (common radish ), Armoracia rusticana ( horseradish ), but also
4032-413: A thin wall grows that divides the cavity, both placentas and separates the two valves (a so-called false septum). Rarely, there is only one cavity without a septum. The 2–600 ovules are usually along the side margin of the carpels, or rarely at the top. Fruits are capsules that open with two valves, usually towards the top. These are called silique if at least three times longer than wide, or silicle if
4176-460: A useful proxy for temperature in historical climatology , and the biological impact of climate change and global warming . Palynology , the analysis of fossil pollen deposits in sediments from thousands or millions of years ago allows the reconstruction of past climates. Estimates of atmospheric CO 2 concentrations since the Palaeozoic have been obtained from stomatal densities and
4320-1010: A variety of spatial scales in groups, populations and communities that collectively constitute vegetation. Regions with characteristic vegetation types and dominant plants as well as similar abiotic and biotic factors, climate , and geography make up biomes like tundra or tropical rainforest . Herbivores eat plants, but plants can defend themselves and some species are parasitic or even carnivorous . Other organisms form mutually beneficial relationships with plants. For example, mycorrhizal fungi and rhizobia provide plants with nutrients in exchange for food, ants are recruited by ant plants to provide protection, honey bees , bats and other animals pollinate flowers and humans and other animals act as dispersal vectors to spread spores and seeds . Plant responses to climate and other environmental changes can inform our understanding of how these changes affect ecosystem function and productivity. For example, plant phenology can be
4464-628: A way of drug discovery . Plants can synthesise coloured dyes and pigments such as the anthocyanins responsible for the red colour of red wine , yellow weld and blue woad used together to produce Lincoln green , indoxyl , source of the blue dye indigo traditionally used to dye denim and the artist's pigments gamboge and rose madder . Sugar, starch , cotton, linen , hemp , some types of rope , wood and particle boards , papyrus and paper, vegetable oils , wax , and natural rubber are examples of commercially important materials made from plant tissues or their secondary products. Charcoal ,
Arabidopsis thaliana - Misplaced Pages Continue
4608-456: A wider range of shared characters and were widely followed. The Candollean system reflected his ideas of the progression of morphological complexity and the later Bentham & Hooker system , which was influential until the mid-19th century, was influenced by Candolle's approach. Darwin 's publication of the Origin of Species in 1859 and his concept of common descent required modifications to
4752-406: Is De materia medica , a five-volume encyclopedia about preliminary herbal medicine written in the middle of the first century by Greek physician and pharmacologist Pedanius Dioscorides . De materia medica was widely read for more than 1,500 years. Important contributions from the medieval Muslim world include Ibn Wahshiyya 's Nabatean Agriculture , Abū Ḥanīfa Dīnawarī 's (828–896)
4896-405: Is peppermint , Mentha × piperita , a sterile hybrid between Mentha aquatica and spearmint, Mentha spicata . The many cultivated varieties of wheat are the result of multiple inter- and intra- specific crosses between wild species and their hybrids. Angiosperms with monoecious flowers often have self-incompatibility mechanisms that operate between the pollen and stigma so that
5040-460: Is 367,808 base pairs long and contains 57 genes. There are many repeated regions in the Arabidopsis mitochondrial genome. The largest repeats recombine regularly and isomerize the genome. Like most plant mitochondrial genomes, the Arabidopsis mitochondrial genome exists as a complex arrangement of overlapping branched and linear molecules in vivo . Genetic transformation of A. thaliana
5184-476: Is a broad, multidisciplinary subject with contributions and insights from most other areas of science and technology. Research topics include the study of plant structure , growth and differentiation, reproduction , biochemistry and primary metabolism , chemical products, development , diseases , evolutionary relationships , systematics , and plant taxonomy . Dominant themes in 21st-century plant science are molecular genetics and epigenetics , which study
5328-421: Is able to combat pathogens in a nonspecific manner. A stronger and more specific response in plants is that of effector-triggered immunity (ETI), which is dependent upon the recognition of pathogen effectors, proteins secreted by the pathogen that alter functions in the host, by plant resistance genes (R-genes) , often described as a gene-for-gene relationship . This recognition may occur directly or indirectly via
5472-602: Is different from out-side), stipules and mostly palmately divided leaves, and mostly no septum. Capparaceae generally have a gynophore , sometimes an androgynophore , and a variable number of stamens. Almost all Brassicaceae have C3 carbon fixation . The only exceptions are a few Moricandia species, which have a hybrid system between C3 and C4 carbon fixation , C4 fixation being more efficient in drought, high temperature and low nitrate availability. Brassicaceae contain different cocktails of dozens of glucosinolates . They also contain enzymes called myrosinases , that convert
5616-415: Is edible by humans in a salad or cooked, but it does not enjoy widespread use as a spring vegetable. Botanists and biologists began to research A. thaliana in the early 1900s, and the first systematic description of mutants was done around 1945. A. thaliana is now widely used for studying plant sciences , including genetics , evolution , population genetics, and plant development. Although A. thaliana
5760-762: Is gathered by ethnobotanists. This information can relay a great deal of information on how the land once was thousands of years ago and how it has changed over that time. The goals of plant ecology are to understand the causes of their distribution patterns, productivity, environmental impact, evolution, and responses to environmental change. Plants depend on certain edaphic (soil) and climatic factors in their environment but can modify these factors too. For example, they can change their environment's albedo , increase runoff interception, stabilise mineral soils and develop their organic content, and affect local temperature. Plants compete with other organisms in their ecosystem for resources. They interact with their neighbours at
5904-550: Is generally applicable to other flowering plants. Studies of A. thaliana have provided considerable insights with regards to the genetics of leaf morphogenesis, particularly in dicotyledon-type plants. Much of the understanding has come from analyzing mutants in leaf development, some of which were identified in the 1960s, but were not analysed with genetic and molecular techniques until the mid-1990s. A. thaliana leaves are well suited to studies of leaf development because they are relatively simple and stable. Using A. thaliana ,
Arabidopsis thaliana - Misplaced Pages Continue
6048-795: Is likely only poorly understood and only known in general terms (e.g. as "DNA-binding protein without known specificity"). Uniprot lists more than 3,000 proteins as "uncharacterized" as part of the reference proteome. The plastome of A. thaliana is a 154,478 base-pair-long DNA molecule, a size typically encountered in most flowering plants (see the list of sequenced plastomes ). It comprises 136 genes coding for small subunit ribosomal proteins ( rps , in yellow: see figure), large subunit ribosomal proteins ( rpl , orange), hypothetical chloroplast open reading frame proteins ( ycf , lemon), proteins involved in photosynthetic reactions (green) or in other functions (red), ribosomal RNAs ( rrn , blue), and transfer RNAs ( trn , black). The mitochondrial genome of A. thaliana
6192-513: Is perceived by the phototropin light receptors. Arabidopsis has also been important in understanding the functions of another blue light receptor, cryptochrome , which is especially important for light entrainment to control the plants' circadian rhythms . When the onset of darkness is unusually early, A. thaliana reduces its metabolism of starch by an amount that effectively requires division . Light responses were even found in roots, previously thought to be largely insensitive to light. While
6336-604: Is probably essential to Golgi - vacuole trafficking. This is still a wide open field and plant SNAREs' role in trafficking remains understudied. The DNA of plants is vulnerable to ultraviolet light, and DNA repair mechanisms have evolved to avoid or repair genome damage caused by UV. Kaiser et al. showed that in A. thaliana cyclobutane pyrimidine dimers (CPDs) induced by UV light can be repaired by expression of CPD photolyase . On May 12, 2022, NASA announced that specimens of Arabidopsis thaliana had been successfully germinated and grown in samples of lunar regolith . While
6480-429: Is routine, using Agrobacterium tumefaciens to transfer DNA into the plant genome. The current protocol, termed "floral dip", involves simply dipping flowers into a solution containing Agrobacterium carrying a plasmid of interest and a detergent. This method avoids the need for tissue culture or plant regeneration. The A. thaliana gene knockout collections are a unique resource for plant biology made possible by
6624-451: Is still a major foundation of modern botany. Her books Plant Anatomy and Anatomy of Seed Plants have been key plant structural biology texts for more than half a century. The discipline of plant ecology was pioneered in the late 19th century by botanists such as Eugenius Warming , who produced the hypothesis that plants form communities , and his mentor and successor Christen C. Raunkiær whose system for describing plant life forms
6768-400: Is still given to these groups by botanists, and fungi (including lichens) and photosynthetic protists are usually covered in introductory botany courses. Palaeobotanists study ancient plants in the fossil record to provide information about the evolutionary history of plants . Cyanobacteria , the first oxygen-releasing photosynthetic organisms on Earth, are thought to have given rise to
6912-444: Is still in use today. The concept that the composition of plant communities such as temperate broadleaf forest changes by a process of ecological succession was developed by Henry Chandler Cowles , Arthur Tansley and Frederic Clements . Clements is credited with the idea of climax vegetation as the most complex vegetation that an environment can support and Tansley introduced the concept of ecosystems to biology. Building on
7056-535: Is surmised for Lepidium species native to Australia and New Zealand. Flowers may be arranged in racemes , panicles , or corymbs , with pedicels sometimes in the axil of a bract, and few species have flowers that sit individually on flower stems that spring from the axils of rosette leaves. The orientation of the pedicels when fruits are ripe varies dependent on the species. The flowers are bisexual , star symmetrical (zygomorphic in Iberis and Teesdalia ) and
7200-502: Is the science of plant life and a branch of biology . A botanist , plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word botanē ( βοτάνη ) meaning " pasture ", " herbs " " grass ", or " fodder "; Botanē is in turn derived from boskein ( Greek : βόσκειν ), "to feed" or "to graze ". Traditionally, botany has also included
7344-498: Is the study of ferns and allied plants. A number of other taxa of ranks varying from family to subgenus have terms for their study, including agrostology (or graminology) for the study of grasses, synantherology for the study of composites, and batology for the study of brambles. Study can also be divided by guild rather than clade or grade . Dendrology is the study of woody plants. Many divisions of biology have botanical subfields. These are commonly denoted by prefixing
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#17327802260397488-553: The A. thaliana genome is maintained by the Arabidopsis Information Resource. The genome encodes ~27,600 protein -coding genes and about 6,500 non-coding genes. However, the Uniprot database lists 39,342 proteins in their Arabidopsis reference proteome. Among the 27,600 protein-coding genes 25,402 (91.8%) are now annotated with "meaningful" product names, although a large fraction of these proteins
7632-530: The A. thaliana research community dates to a newsletter called Arabidopsis Information Service, established in 1964. The first International Arabidopsis Conference was held in 1965, in Göttingen , Germany. In the 1980s, A. thaliana started to become widely used in plant research laboratories around the world. It was one of several candidates that included maize, petunia , and tobacco. The latter two were attractive, since they were easily transformable with
7776-564: The Angiosperm Phylogeny Group to publish in 1998 a phylogeny of flowering plants, answering many of the questions about relationships among angiosperm families and species. The theoretical possibility of a practical method for identification of plant species and commercial varieties by DNA barcoding is the subject of active current research. Botany is divided along several axes. Some subfields of botany relate to particular groups of organisms. Divisions related to
7920-499: The Book of Plants , and Ibn Bassal 's The Classification of Soils . In the early 13th century, Abu al-Abbas al-Nabati , and Ibn al-Baitar (d. 1248) wrote on botany in a systematic and scientific manner. In the mid-16th century, botanical gardens were founded in a number of Italian universities. The Padua botanical garden in 1545 is usually considered to be the first which is still in its original location. These gardens continued
8064-417: The C 4 carbon fixation pathway for photosynthesis which avoid the losses resulting from photorespiration in the more common C 3 carbon fixation pathway. These biochemical strategies are unique to land plants. Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism . Some of these compounds are toxins such as
8208-504: The alkaloid coniine from hemlock . Others, such as the essential oils peppermint oil and lemon oil are useful for their aroma, as flavourings and spices (e.g., capsaicin ), and in medicine as pharmaceuticals as in opium from opium poppies . Many medicinal and recreational drugs , such as tetrahydrocannabinol (active ingredient in cannabis ), caffeine , morphine and nicotine come directly from plants. Others are simple derivatives of botanical natural products. For example,
8352-565: The auxin plant hormones by Kenneth V. Thimann in 1948 enabled regulation of plant growth by externally applied chemicals. Frederick Campion Steward pioneered techniques of micropropagation and plant tissue culture controlled by plant hormones . The synthetic auxin 2,4-dichlorophenoxyacetic acid or 2,4-D was one of the first commercial synthetic herbicides . 20th century developments in plant biochemistry have been driven by modern techniques of organic chemical analysis , such as spectroscopy , chromatography and electrophoresis . With
8496-626: The cell theory with Theodor Schwann and Rudolf Virchow and was among the first to grasp the significance of the cell nucleus that had been described by Robert Brown in 1831. In 1855, Adolf Fick formulated Fick's laws that enabled the calculation of the rates of molecular diffusion in biological systems. Building upon the gene-chromosome theory of heredity that originated with Gregor Mendel (1822–1884), August Weismann (1834–1914) proved that inheritance only takes place through gametes . No other cells can pass on inherited characters. The work of Katherine Esau (1898–1997) on plant anatomy
8640-444: The cellulose and lignin used to build their bodies, and secondary products like resins and aroma compounds . Plants and various other groups of photosynthetic eukaryotes collectively known as " algae " have unique organelles known as chloroplasts . Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Chloroplasts and cyanobacteria contain
8784-432: The gravitropic response of A. thaliana root organs is their predominant tropic response, specimens treated with mutagens and selected for the absence of gravitropic action showed negative phototropic response to blue or white light, and positive response to red light, indicating that the roots also show positive phototropism. In 2000, Dr. Janet Braam of Rice University genetically engineered A. thaliana to glow in
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#17327802260398928-427: The indigenous people of Canada in identifying edible plants from inedible plants. This relationship the indigenous people had with plants was recorded by ethnobotanists. Plant biochemistry is the study of the chemical processes used by plants. Some of these processes are used in their primary metabolism like the photosynthetic Calvin cycle and crassulacean acid metabolism . Others make specialised materials like
9072-466: The ovary positioned above the other floral parts . Each flower has four free or seldom merged sepals , the lateral two sometimes with a shallow spur, which are mostly shed after flowering, rarely persistent, may be reflexed, spreading, ascending, or erect, together forming a tube-, bell- or urn-shaped calyx. Each flower has four petals , set alternating with the sepals, although in some species these are rudimentary or absent. They may be differentiated into
9216-426: The pines , and flowering plants ) and the free-sporing cryptogams including ferns , clubmosses , liverworts , hornworts and mosses . Embryophytes are multicellular eukaryotes descended from an ancestor that obtained its energy from sunlight by photosynthesis . They have life cycles with alternating haploid and diploid phases. The sexual haploid phase of embryophytes, known as the gametophyte , nurtures
9360-411: The 17th century. A. thaliana readily grows and often pioneers rocky, sandy, and calcareous soils. It is generally considered a weed, due to its widespread distribution in agricultural fields, roadsides, railway lines, waste ground, and other disturbed habitats, but due to its limited competitive ability and small size, it is not categorized as a noxious weed. Like most Brassicaceae species, A. thaliana
9504-408: The 3-carbon sugar glyceraldehyde 3-phosphate (G3P). Glyceraldehyde 3-phosphate is the first product of photosynthesis and the raw material from which glucose and almost all other organic molecules of biological origin are synthesised. Some of the glucose is converted to starch which is stored in the chloroplast. Starch is the characteristic energy store of most land plants and algae, while inulin ,
9648-655: The Brassicaceae or recognizing them in the segregate family Cleomaceae . The APG III system has recently adopted this last solution, but this may change as a consensus arises on this point. Current insights in the relationships of the Brassicaceae, based on a 2012 DNA-analysis, are summarized in the following tree. family Resedaceae family Gyrostemonaceae family Pentadiplandraceae family Tovariaceae family Capparaceae family Cleomaceae family Brassicaceae family Emblingiaceae Early classifications depended on morphological comparison only, but because of extensive convergent evolution , these do not provide
9792-517: The Candollean system to reflect evolutionary relationships as distinct from mere morphological similarity. Botany was greatly stimulated by the appearance of the first "modern" textbook, Matthias Schleiden 's Grundzüge der Wissenschaftlichen Botanik , published in English in 1849 as Principles of Scientific Botany . Schleiden was a microscopist and an early plant anatomist who co-founded
9936-778: The L er collection of mutants is derived from this initial line, L er -0 does not correspond to the Landsberg accessions, which designated La-0, La-1, etc. Trichome formation is initiated by the GLABROUS1 protein. Knockouts of the corresponding gene lead to glabrous plants. This phenotype has already been used in gene editing experiments and might be of interest as visual marker for plant research to improve gene editing methods such as CRISPR/Cas9. In 2005, scientists at Purdue University proposed that A. thaliana possessed an alternative to previously known mechanisms of DNA repair , producing an unusual pattern of inheritance , but
10080-699: The United States , can be toxic to their larvae . Species belonging to the Brassicaceae are mostly annual , biennial , or perennial herbaceous plants , some are dwarf shrubs or shrubs , and very few vines . Although generally terrestrial, a few species such as water awlwort live submerged in fresh water. They may have a taproot or a sometimes woody caudex that may have few or many branches, some have thin or tuberous rhizomes , or rarely develop runners . Few species have multi-cellular glands. Hairs consist of one cell and occur in many forms: from simple to forked, star-, tree- or T-shaped, rarely taking
10224-482: The Vegetable Kingdom at the start of chapter XII noted "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented." An important adaptive benefit of outcrossing is that it allows the masking of deleterious mutations in
10368-412: The above pair of categories gives rise to fields such as bryogeography (the study of the distribution of mosses). Different parts of plants also give rise to their own subfields, including xylology , carpology (or fructology) and palynology , these been the study of wood, fruit and pollen/spores respectively. Botany also overlaps on the one hand with agriculture, horticulture and silviculture, and on
10512-816: The accumulation of SA for its expression Brassicaceae See list of Brassicaceae genera Brassicaceae ( / ˌ b r æ s ɪ ˈ k eɪ s iː ˌ iː , - s i ˌ aɪ / ) or (the older) Cruciferae ( / k r uː ˈ s ɪ f ər i / ) is a medium-sized and economically important family of flowering plants commonly known as the mustards , the crucifers , or the cabbage family . Most are herbaceous plants , while some are shrubs . The leaves are simple (although are sometimes deeply incised), lack stipules , and appear alternately on stems or in rosettes . The inflorescences are terminal and lack bracts . The flowers have four free sepals , four free alternating petals , two shorter free stamens and four longer free stamens. The fruit has seeds in rows, divided by
10656-534: The adaptation of this species to different environments. A. thaliana is native to Europe, Asia, and Africa, and its geographic distribution is rather continuous from the Mediterranean to Scandinavia and Spain to Greece . It also appears to be native in tropical alpine ecosystems in Africa and perhaps South Africa. It has been introduced and naturalized worldwide, including in North America around
10800-439: The ancestor of plants by entering into an endosymbiotic relationship with an early eukaryote, ultimately becoming the chloroplasts in plant cells. The new photosynthetic plants (along with their algal relatives) accelerated the rise in atmospheric oxygen started by the cyanobacteria , changing the ancient oxygen-free, reducing , atmosphere to one in which free oxygen has been abundant for more than 2 billion years. Among
10944-473: The anthers consist of two pollen producing cavities, and open with longitudinal slits. The pollen grains are tricolpate . The receptacle carries a variable number of nectaries , but these are always present opposite the base of the lateral stamens. There is one superior pistil that consists of two carpels that may either sit directly above the base of the stamens or on a stalk . It initially consists of only one cavity but during its further development
11088-602: The availability of high-throughput transformation and funding for genomics resources. The site of T-DNA insertions has been determined for over 300,000 independent transgenic lines, with the information and seeds accessible through online T-DNA databases. Through these collections, insertional mutants are available for most genes in A. thaliana . Characterized accessions and mutant lines of A. thaliana serve as experimental material in laboratory studies. The most commonly used background lines are L er (Landsberg erecta ), and Col, or Columbia. Other background lines less-often cited in
11232-533: The bacterial EF-Tu protein, the prokaryotic elongation factor used in protein synthesis , as well as the laboratory-used ligand elf18. Using Agrobacterium -mediated transformation , a technique that takes advantage of the natural process by which Agrobacterium transfers genes into host plants, the EFR gene was transformed into Nicotiana benthamiana , tobacco plant that does not recognize EF-Tu, thereby permitting recognition of bacterial EF-Tu thereby confirming EFR as
11376-447: The base of most food chains because they use the energy from the sun and nutrients from the soil and atmosphere, converting them into a form that can be used by animals. This is what ecologists call the first trophic level . The modern forms of the major staple foods , such as hemp , teff , maize, rice, wheat and other cereal grasses, pulses , bananas and plantains, as well as hemp , flax and cotton grown for their fibres, are
11520-500: The blue-green pigment chlorophyll a . Chlorophyll a (as well as its plant and green algal-specific cousin chlorophyll b ) absorbs light in the blue-violet and orange/red parts of the spectrum while reflecting and transmitting the green light that we see as the characteristic colour of these organisms. The energy in the red and blue light that these pigments absorb is used by chloroplasts to make energy-rich carbon compounds from carbon dioxide and water by oxygenic photosynthesis ,
11664-446: The broader historical sense of botany include bacteriology , mycology (or fungology) and phycology - the study of bacteria, fungi and algae respectively - with lichenology as a subfield of mycology. The narrower sense of botany in the sense of the study of embryophytes (land plants) is disambiguated as phytology. Bryology is the study of mosses (and in the broader sense also liverworts and hornworts). Pteridology (or filicology)
11808-803: The case of the agamous mutation, for example, stamens become petals and carpels are replaced with a new flower, resulting in a recursively repeated sepal-petal-petal pattern. Observations of homeotic mutations led to the formulation of the ABC model of flower development by E. Coen and E. Meyerowitz . According to this model, floral organ identity genes are divided into three classes - class A genes (which affect sepals and petals), class B genes (which affect petals and stamens), and class C genes (which affect stamens and carpels). These genes code for transcription factors that combine to cause tissue specification in their respective regions during development. Although developed through study of A. thaliana flowers, this model
11952-513: The characters may be artificial in keys designed purely for identification ( diagnostic keys ) or more closely related to the natural or phyletic order of the taxa in synoptic keys. By the 18th century, new plants for study were arriving in Europe in increasing numbers from newly discovered countries and the European colonies worldwide. In 1753, Carl Linnaeus published his Species Plantarum ,
12096-452: The chromosome number in 1907) did not propose A. thaliana as a model organism, though, until 1943. His student, Erna Reinholz, published her thesis on A. thaliana in 1945, describing the first collection of A. thaliana mutants that they generated using X-ray mutagenesis . Laibach continued his important contributions to A. thaliana research by collecting a large number of accessions (often questionably referred to as " ecotypes "). With
12240-583: The class Violales ). Following Bentham and Hooker, John Hutchinson in 1948 and again in 1964 thought the Brassicaceae to stem from near the Papaveraceae . In 1994, a group of scientists including Walter Stephen Judd suggested to include the Capparaceae in the Brassicaceae. Early DNA-analysis showed that the Capparaceae—as defined at that moment—were paraphyletic , and it was suggested to assign
12384-679: The dark when touched. The effect was visible to ultrasensitive cameras. Multiple efforts, including the Glowing Plant project , have sought to use A. thaliana to increase plant luminescence intensity towards commercially viable levels. In 1990, Janet Braam and Ronald W. Davis determined that A. thaliana exhibits thigmomorphogenesis in response to wind, rain and touch. Four or more touch induced genes in A. thaliana were found to be regulated by such stimuli. In 2002, Massimo Pigliucci found that A. thaliana developed different patterns of branching in response to sustained exposure to wind,
12528-461: The developing diploid embryo sporophyte within its tissues for at least part of its life, even in the seed plants, where the gametophyte itself is nurtured by its parent sporophyte. Other groups of organisms that were previously studied by botanists include bacteria (now studied in bacteriology ), fungi ( mycology ) – including lichen -forming fungi ( lichenology ), non- chlorophyte algae ( phycology ), and viruses ( virology ). However, attention
12672-435: The disease process. The PEN genes were later mapped to identify the genes responsible for nonhost resistance to B. graminis . In general, when a plant is exposed to a pathogen, or nonpathogenic microbe, an initial response, known as PAMP-triggered immunity (PTI), occurs because the plant detects conserved motifs known as pathogen-associated molecular patterns (PAMPs). These PAMPs are detected by specialized receptors in
12816-463: The earliest was the Padua botanical garden . These gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomy and led in 1753 to the binomial system of nomenclature of Carl Linnaeus that remains in use to this day for the naming of all biological species. In the 19th and 20th centuries, new techniques were developed for
12960-419: The efforts of early humans to identify – and later cultivate – plants that were edible, poisonous, and possibly medicinal, making it one of the first endeavours of human investigation. Medieval physic gardens , often attached to monasteries , contained plants possibly having medicinal benefit. They were forerunners of the first botanical gardens attached to universities , founded from the 1540s onwards. One of
13104-453: The extensive earlier work of Alphonse de Candolle , Nikolai Vavilov (1887–1943) produced accounts of the biogeography , centres of origin , and evolutionary history of economic plants. Particularly since the mid-1960s there have been advances in understanding of the physics of plant physiological processes such as transpiration (the transport of water within plant tissues), the temperature dependence of rates of water evaporation from
13248-516: The flowers naturally self-pollinate. In the lab, A. thaliana may be grown in Petri plates, pots, or hydroponics, under fluorescent lights or in a greenhouse. The plant was first described in 1577 in the Harz Mountains by Johannes Thal [ de ] (1542–1583), a physician from Nordhausen , Thüringen , Germany, who called it Pilosella siliquosa . In 1753, Carl Linnaeus renamed
13392-485: The form of a shield or scale. They are never topped by a gland. The stems may be upright, rise up towards the tip, or lie flat, are mostly herbaceous but sometimes woody. Stems carry leaves or the stems may be leafless (in Caulanthus ), and some species lack stems altogether. The leaves do not have stipules , but there may be a pair of glands at base of leaf stalks and flower stalks . The leaf may be seated or have
13536-575: The fossil record. It is widely regarded as a marker for the start of land plant evolution during the Ordovician period. The concentration of carbon dioxide in the atmosphere today is much lower than it was when plants emerged onto land during the Ordovician and Silurian periods. Many monocots like maize and the pineapple and some dicots like the Asteraceae have since independently evolved pathways like Crassulacean acid metabolism and
13680-427: The function of these receptors has helped plant biologists understand the signaling cascades that regulate photoperiodism , germination , de-etiolation , and shade avoidance in plants. The genes FCA , fy , fpa , LUMINIDEPENDENS ( ld ), fly , fve and FLOWERING LOCUS C ( FLC ) are involved in photoperiod triggering of flowering and vernalization . Specifically Lee et al 1994 find ld produces
13824-451: The functional relationships between plants and their habitats – the environments where they complete their life cycles . Plant ecologists study the composition of local and regional floras , their biodiversity , genetic diversity and fitness , the adaptation of plants to their environment, and their competitive or mutualistic interactions with other species. Some ecologists even rely on empirical data from indigenous people that
13968-582: The genera closest to the Brassicaceae to the Cleomaceae . The Cleomaceae and Brassicaceae diverged approximately 41 million years ago. All three families have consistently been placed in one order (variably called Capparales or Brassicales ). The APG II system merged Cleomaceae and Brassicaceae. Other classifications have continued to recognize the Capparaceae, but with a more restricted circumscription, either including Cleome and its relatives in
14112-453: The genetics behind leaf shape development have become more clear and have been broken down into three stages: The initiation of the leaf primordium , the establishment of dorsiventrality , and the development of a marginal meristem . Leaf primordia are initiated by the suppression of the genes and proteins of class I KNOX family (such as SHOOT APICAL MERISTEMLESS ). These class I KNOX proteins directly suppress gibberellin biosynthesis in
14256-444: The global carbon and water cycles and plant roots bind and stabilise soils, preventing soil erosion . Plants are crucial to the future of human society as they provide food, oxygen, biochemicals , and products for people, as well as creating and preserving soil. Historically, all living things were classified as either animals or plants and botany covered the study of all organisms not considered animals. Botanists examine both
14400-461: The glucosinolates into isothiocyanates , thiocyanates and nitriles , which are toxic to many organisms, and so help guard against herbivory. Carl Linnaeus in 1753 regarded the Brassicaceae as a natural group, naming them "Klass" Tetradynamia. Alfred Barton Rendle placed the family in the order Rhoeadales , while George Bentham and Joseph Dalton Hooker in their system published from 1862 to 1883, assigned it to their cohort Parietales (now
14544-471: The guardee protein RIN4, which is cleaved. Recognition of a pathogen effector leads to a dramatic immune response known as the hypersensitive response , in which the infected plant cells undergo cell death to prevent the spread of the pathogen. Systemic acquired resistance (SAR) is another example of resistance that is better understood in plants because of research done in A. thaliana . Benzothiadiazol (BTH),
14688-429: The help of Albert Kranz, these were organised into a large collection of 750 natural accessions of A. thaliana from around the world. In the 1950s and 1960s, John Langridge and George Rédei played an important role in establishing A. thaliana as a useful organism for biological laboratory experiments. Rédei wrote several scholarly reviews instrumental in introducing the model to the scientific community. The start of
14832-457: The host known as pattern recognition receptors (PRRs) on the plant cell surface. The best-characterized PRR in A. thaliana is FLS2 (Flagellin-Sensing2), which recognizes bacterial flagellin , a specialized organelle used by microorganisms for the purpose of motility, as well as the ligand flg22, which comprises the 22 amino acids recognized by FLS2. Discovery of FLS2 was facilitated by the identification of an A. thaliana ecotype, Ws-0, that
14976-621: The important botanical questions of the 21st century are the role of plants as primary producers in the global cycling of life's basic ingredients: energy, carbon, oxygen, nitrogen and water, and ways that our plant stewardship can help address the global environmental issues of resource management , conservation , human food security , biologically invasive organisms , carbon sequestration , climate change , and sustainability . Virtually all staple foods come either directly from primary production by plants, or indirectly from animals that eat them. Plants and other photosynthetic organisms are at
15120-478: The internal functions and processes within plant organelles , cells, tissues, whole plants, plant populations and plant communities. At each of these levels, a botanist may be concerned with the classification ( taxonomy ), phylogeny and evolution , structure ( anatomy and morphology ), or function ( physiology ) of plant life. The strictest definition of "plant" includes only the "land plants" or embryophytes , which include seed plants (gymnosperms, including
15264-449: The leaf is different from the ventral (abaxial) surface. A. thaliana is well suited for light microscopy analysis. Young seedlings on the whole, and their roots in particular, are relatively translucent. This, together with their small size, facilitates live cell imaging using both fluorescence and confocal laser scanning microscopy . By wet-mounting seedlings in water or in culture media, plants may be imaged uninvasively, obviating
15408-404: The leaf primordium. Many genetic factors were found to be involved in the suppression of these class I KNOX genes in leaf primordia (such as ASYMMETRIC LEAVES1, BLADE-ON-PETIOLE1 , SAWTOOTH1 , etc.). Thus, with this suppression, the levels of gibberellin increase and leaf primordium initiate growth. The establishment of leaf dorsiventrality is important since the dorsal (adaxial) surface of
15552-403: The leaf shapes and sizes of ancient land plants . Ozone depletion can expose plants to higher levels of ultraviolet radiation-B (UV-B), resulting in lower growth rates. Moreover, information from studies of community ecology , plant systematics , and taxonomy is essential to understanding vegetation change , habitat destruction and species extinction . Inheritance in plants follows
15696-576: The leaf surface and the molecular diffusion of water vapour and carbon dioxide through stomatal apertures. These developments, coupled with new methods for measuring the size of stomatal apertures, and the rate of photosynthesis have enabled precise description of the rates of gas exchange between plants and the atmosphere. Innovations in statistical analysis by Ronald Fisher , Frank Yates and others at Rothamsted Experimental Station facilitated rational experimental design and data analysis in botanical research. The discovery and identification of
15840-401: The length is less than three times the width. The fruit is very variable in its other traits. There may be one persistent style that connects the ovary to the globular or conical stigma , which is undivided or has two spreading or connivent lobes. The variously shaped seeds are usually yellow or brown in color, and arranged in one or two rows in each cavity. The seed leaves are entire or have
15984-567: The lunar environment. Thalianin is an Arabidopsis root triterpene . Potter et al. , 2018 finds synthesis is induced by a combination of at least 2 facts, cell-specific transcription factors (TFs) and the accessibility of the chromatin . Understanding how plants achieve resistance is important to protect the world's food production, and the agriculture industry. Many model systems have been developed to better understand interactions between plants and bacterial , fungal , oomycete , viral , and nematode pathogens. A. thaliana has been
16128-576: The maintenance of biodiversity . Botany originated as herbalism , the study and use of plants for their possible medicinal properties . The early recorded history of botany includes many ancient writings and plant classifications. Examples of early botanical works have been found in ancient texts from India dating back to before 1100 BCE, Ancient Egypt , in archaic Avestan writings, and in works from China purportedly from before 221 BCE. Modern botany traces its roots back to Ancient Greece specifically to Theophrastus ( c. 371 –287 BCE),
16272-493: The major groups of organisms that carry out photosynthesis , a process that uses the energy of sunlight to convert water and carbon dioxide into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells. As a by-product of photosynthesis, plants release oxygen into the atmosphere, a gas that is required by nearly all living things to carry out cellular respiration. In addition, they are influential in
16416-474: The mechanisms and control of gene expression during differentiation of plant cells and tissues . Botanical research has diverse applications in providing staple foods , materials such as timber , oil , rubber, fibre and drugs, in modern horticulture , agriculture and forestry , plant propagation , breeding and genetic modification , in the synthesis of chemicals and raw materials for construction and energy production, in environmental management , and
16560-446: The need for fixation and sectioning and allowing time-lapse measurements. Fluorescent protein constructs can be introduced through transformation . The developmental stage of each cell can be inferred from its location in the plant or by using fluorescent protein markers , allowing detailed developmental analysis . The photoreceptors phytochromes A, B, C, D, and E mediate red light-based phototropic response. Understanding
16704-596: The number of their male sexual organs. The 24th group, Cryptogamia , included all plants with concealed reproductive parts, mosses , liverworts , ferns , algae and fungi . Botany was originally a hobby for upper-class women. These women would collect and paint flowers and plants from around the world with scientific accuracy. The paintings were used to record many species that could not be transported or maintained in other environments. Marianne North illustrated over 900 species in extreme detail with watercolor and oil paintings. Her work and many other women's botany work
16848-447: The other hand with medicine and pharmacology, giving rise to fields such as agronomy , horticultural botany, phytopathology and phytopharmacology . The study of plants is vital because they underpin almost all animal life on Earth by generating a large proportion of the oxygen and food that provide humans and other organisms with aerobic respiration with the chemical energy they need to exist. Plants, algae and cyanobacteria are
16992-404: The outcome of prehistoric selection over thousands of years from among wild ancestral plants with the most desirable characteristics. Botanists study how plants produce food and how to increase yields, for example through plant breeding , making their work important to humanity's ability to feed the world and provide food security for future generations. Botanists also study weeds, which are
17136-791: The pain killer aspirin is the acetyl ester of salicylic acid , originally isolated from the bark of willow trees, and a wide range of opiate painkillers like heroin are obtained by chemical modification of morphine obtained from the opium poppy . Popular stimulants come from plants, such as caffeine from coffee, tea and chocolate, and nicotine from tobacco. Most alcoholic beverages come from fermentation of carbohydrate -rich plant products such as barley (beer), rice ( sake ) and grapes (wine). Native Americans have used various plants as ways of treating illness or disease for thousands of years. This knowledge Native Americans have on plants has been recorded by enthnobotanists and then in turn has been used by pharmaceutical companies as
17280-509: The phenomenon observed (reversion of mutant copies of the HOTHEAD gene to a wild-type state) was later suggested to be an artifact because the mutants show increased outcrossing due to organ fusion. The plant's small size and rapid lifecycle are also advantageous for research. Having specialized as a spring ephemeral , it has been used to found several laboratory strains that take about 6 weeks from germination to mature seed. The small size of
17424-531: The plant Arabis thaliana in honor of Thal. In 1842, German botanist Gustav Heynhold erected the new genus Arabidopsis and placed the plant in that genus. The generic name, Arabidopsis , comes from Greek , meaning "resembling Arabis " (the genus in which Linnaeus had initially placed it). Thousands of natural inbred accessions of A. thaliana have been collected from throughout its natural and introduced range. These accessions exhibit considerable genetic and phenotypic variation, which can be used to study
17568-432: The plant has little direct significance for agriculture, A. thaliana the model organism has revolutionized our understanding of the genetic, cellular, and molecular biology of flowering plants. The first mutant in A. thaliana was documented in 1873 by Alexander Braun , describing a double flower phenotype (the mutated gene was likely Agamous , cloned and characterized in 1990). Friedrich Laibach (who had published
17712-516: The plant is convenient for cultivation in a small space, and it produces many seeds. Further, the selfing nature of this plant assists genetic experiments. Also, as an individual plant can produce several thousand seeds, each of the above criteria leads to A. thaliana being valued as a genetic model organism. Arabidopsis is often the model for study of SNAREs in plants . This has shown SNAREs to be heavily involved in vesicle trafficking . Zheng et al. 1999 found an Arabidopsis SNARE called AtVTI1a
17856-488: The plants successfully germinated and grew into seedlings, they were not as robust as specimens that had been grown in volcanic ash as a control group, although the experiments also found some variation in the plants grown in regolith based on the location the samples were taken from, as A. thaliana grown in regolith gathered during Apollo 12 & Apollo 17 were more robust than those grown in samples taken during Apollo 11 . A. thaliana has been extensively studied as
18000-490: The plants with a highly fermentable sugar or oil content that are used as sources of biofuels , important alternatives to fossil fuels , such as biodiesel . Sweetgrass was used by Native Americans to ward off bugs like mosquitoes . These bug repelling properties of sweetgrass were later found by the American Chemical Society in the molecules phytol and coumarin . Plant ecology is the science of
18144-486: The pollen either fails to reach the stigma or fails to germinate and produce male gametes . This is one of several methods used by plants to promote outcrossing . In many land plants the male and female gametes are produced by separate individuals. These species are said to be dioecious when referring to vascular plant sporophytes and dioicous when referring to bryophyte gametophytes . Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in
18288-442: The polymer cutin which is found in the plant cuticle that protects land plants from drying out. Plants synthesise a number of unique polymers like the polysaccharide molecules cellulose , pectin and xyloglucan from which the land plant cell wall is constructed. Vascular land plants make lignin , a polymer used to strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when
18432-556: The practical value of earlier "physic gardens", often associated with monasteries, in which plants were cultivated for suspected medicinal uses. They supported the growth of botany as an academic subject. Lectures were given about the plants grown in the gardens. Botanical gardens came much later to northern Europe; the first in England was the University of Oxford Botanic Garden in 1621. German physician Leonhart Fuchs (1501–1566)
18576-443: The receptor of EF-Tu. Both FLS2 and EFR use similar signal transduction pathways to initiate PTI. A. thaliana has been instrumental in dissecting these pathways to better understand the regulation of immune responses, the most notable one being the mitogen-activated protein kinase (MAP kinase) cascade. Downstream responses of PTI include callose deposition, the oxidative burst , and transcription of defense-related genes. PTI
18720-461: The rise of the related molecular-scale biological approaches of molecular biology , genomics , proteomics and metabolomics , the relationship between the plant genome and most aspects of the biochemistry, physiology, morphology and behaviour of plants can be subjected to detailed experimental analysis. The concept originally stated by Gottlieb Haberlandt in 1902 that all plant cells are totipotent and can be grown in vitro ultimately enabled
18864-680: The same fundamental principles of genetics as in other multicellular organisms. Gregor Mendel discovered the genetic laws of inheritance by studying inherited traits such as shape in Pisum sativum ( peas ). What Mendel learned from studying plants has had far-reaching benefits outside of botany. Similarly, " jumping genes " were discovered by Barbara McClintock while she was studying maize. Nevertheless, there are some distinctive genetic differences between plants and other organisms. Species boundaries in plants may be weaker than in animals, and cross species hybrids are often possible. A familiar example
19008-680: The scientific literature are Ws, or Wassilewskija, C24, Cvi, or Cape Verde Islands, Nossen, etc. (see for ex.) Sets of closely related accessions named Col-0, Col-1, etc., have been obtained and characterized; in general, mutant lines are available through stock centers, of which best-known are the Nottingham Arabidopsis Stock Center-NASC and the Arabidopsis Biological Resource Center-ABRC in Ohio, USA. The Col-0 accession
19152-525: The smallest genomes among plants. It was long thought to have the smallest genome of all flowering plants, but that title is now considered to belong to plants in the genus Genlisea , order Lamiales , with Genlisea tuberosa , a carnivorous plant, showing a genome size of approximately 61 Mbp. It was the first plant genome to be sequenced, completed in 2000 by the Arabidopsis Genome Initiative. The most up-to-date version of
19296-603: The study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress . Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants , including some 391,000 species of vascular plants (of which approximately 369,000 are flowering plants ) and approximately 20,000 bryophytes . Botany originated in prehistory as herbalism with
19440-450: The study of plants, including methods of optical microscopy and live cell imaging , electron microscopy , analysis of chromosome number , plant chemistry and the structure and function of enzymes and other proteins . In the last two decades of the 20th century, botanists exploited the techniques of molecular genetic analysis , including genomics and proteomics and DNA sequences to classify plants more accurately. Modern botany
19584-471: The study of plants. In 1665, using an early microscope, Polymath Robert Hooke discovered cells (a term he coined) in cork , and a short time later in living plant tissue. During the 18th century, systems of plant identification were developed comparable to dichotomous keys , where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters . The choice and sequence of
19728-487: The then-current technologies, while maize was a well-established genetic model for plant biology. The breakthrough year for A. thaliana as a model plant was 1986, in which T-DNA -mediated transformation and the first cloned A. thaliana gene were described. Due to the small size of its genome , and because it is diploid , Arabidopsis thaliana is useful for genetic mapping and sequencing — with about 157 megabase pairs and five chromosomes , A. thaliana has one of
19872-526: The use of genetic engineering experimentally to knock out a gene or genes responsible for a specific trait, or to add genes such as GFP that report when a gene of interest is being expressed. These technologies enable the biotechnological use of whole plants or plant cell cultures grown in bioreactors to synthesise pesticides , antibiotics or other pharmaceuticals , as well as the practical application of genetically modified crops designed for traits such as improved yield. Modern morphology recognises
20016-485: The word plant (e.g. plant taxonomy, plant ecology, plant anatomy, plant morphology, plant systematics, plant ecology), or prefixing or substituting the prefix phyto- (e.g. phytochemistry , phytogeography ). The study of fossil plants is palaeobotany . Other fields are denoted by adding or substituting the word botany (e.g. systematic botany ). Phytosociology is a subfield of plant ecology that classifies and studies communities of plants. The intersection of fields from
20160-399: Was one of "the three German fathers of botany", along with theologian Otto Brunfels (1489–1534) and physician Hieronymus Bock (1498–1554) (also called Hieronymus Tragus). Fuchs and Brunfels broke away from the tradition of copying earlier works to make original observations of their own. Bock created his own system of plant classification. Physician Valerius Cordus (1515–1544) authored
20304-455: Was selected by Rédei from within a (nonirradiated) population of seeds designated 'Landsberg' which he received from Laibach. Columbia (named for the location of Rédei's former institution, University of Missouri - Columbia ) was the reference accession sequenced in the Arabidopsis Genome Initiative. The Later (Landsberg erecta) line was selected by Rédei (because of its short stature) from a Landsberg population he had mutagenized with X-rays. As
20448-412: Was the beginning of popularizing botany to a wider audience. Increasing knowledge of plant anatomy , morphology and life cycles led to the realisation that there were more natural affinities between plants than the artificial sexual system of Linnaeus. Adanson (1763), de Jussieu (1789), and Candolle (1819) all proposed various alternative natural systems of classification that grouped plants using
20592-477: Was unable to detect flg22, leading to the identification of the gene encoding FLS2. FLS2 shows striking similarity to rice XA21, the first PRR isolated in 1995 . Both flagellin and UV-C act similarly to increase homologous recombination in A. thaliana , as demonstrated by Molinier et al. 2006. Beyond this somatic effect, they found this to extend to subsequent generations of the plant . A second PRR, EF-Tu receptor (EFR), identified in A. thaliana , recognizes
20736-442: Was used to determine the genes responsible for nonhost resistance is Blumeria graminis , the causal agent of powdery mildew of grasses. A. thaliana mutants were developed using the mutagen ethyl methanesulfonate and screened to identify mutants with increased infection by B. graminis . The mutants with higher infection rates are referred to as PEN mutants due to the ability of B. graminis to penetrate A. thaliana to begin
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