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Wilhelm Johannsen
Wilhelm Johannsen (3 February 1857 – 11 November 1927) was a Danish pharmacist, botanist, plant physiologist, and geneticist. He is best known for coining the terms gene, phenotype and genotype, and for his 1903 "pure line" experiments in genetics. Biography Johannsen was born in Copenhagen. While very young, he was apprenticed to a pharmacist and worked in Denmark and Germany beginning in 1872 until passing his pharmacist's exam in 1879. In 1881, he became assistant in the chemistry department at the Carlsberg Laboratory under the chemist Johan Kjeldahl. Johannsen studied the metabolism of dormancy and germination in seeds, tubers and buds. He showed that dormancy could be broken by various anesthetic compounds, such as diethyl ether and chloroform. In 1892, he was appointed lecturer at Royal Veterinary and Agricultural University and later became professor of botany and plant physiology. He taught plant physiology. His best-known research concerned so-called ''pure lines' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johan Kjeldahl
Johan Gustav Christoffer Thorsager Kjeldahl ( 16 August 1849 – 18 July 1900), was a Danish chemist who developed a method for determining the amount of nitrogen in certain organic compounds using a laboratory technique which was named the Kjeldahl method after him. Professional life Kjeldahl worked in Copenhagen at the Carlsberg Laboratory, associated with Carlsberg Brewery, where he was head of the ''Chemistry department'' from 1876 to 1900. He was given the job to determine the amount of protein in the grain used in the malt industry. Less protein meant more beer. Kjeldahl found the answer was in developing a technique to determine nitrogen with accuracy but existing methods in analytical chemistry related to proteins and biochemistry at the time were far from accurate. Kjeldahl method In order to solve the problem of determining accurate nitrogen content in a sample, Kjeldahl developed a method which involves a two-step reaction: a distillation and a back titration. He fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Bean
''Phaseolus vulgaris'', the common bean, is a herbaceous annual plant grown worldwide for its edible dry seeds or green bean, green, unripe pods. Its leaf is also occasionally used as a Leaf vegetable, vegetable and the straw as fodder. Its Plant taxonomy, botanical classification, along with other ''Phaseolus'' species, is as a member of the legume Family (biology), family Fabaceae. Like most members of this family, common beans acquire the nitrogen they require through an association with rhizobia, which are Nitrogen fixation, nitrogen-fixing bacteria. The common bean has a long history of cultivation. All wild members of the species have a climbing habit, but many cultivars are classified either as ''bush beans'' or ''climbing beans'', depending on their style of growth. Best-known cultivar groups include the kidney bean, the navy bean, the pinto bean, and the #Green beans and wax beans, wax bean. The other major types of commercially grown beans are the runner bean (''Phaseo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugenius Warming
Eugenius (died 6 September 394) was a usurper in the Western Roman Empire (392–394) against Emperor Theodosius I. While Christian himself, Eugenius capitalized on the discontent in the West caused by Theodosius' religious policies targeting pagans. He renovated the pagan Temple of Venus and Roma and restored the Altar of Victory, after continued petitions from the Roman Senate. Eugenius replaced Theodosius' administrators with men loyal to him, including pagans. This revived the pagan cause. His army fought the army of Theodosius at the Battle of the Frigidus, where Eugenius was captured and executed. Life A Christian and former teacher of grammar and rhetoric, as well as ''magister scriniorum'', Eugenius was an acquaintance of Arbogast, the ''magister militum''. Arbogast was of Frankish origin and ''de facto'' ruler of the western portion of the Empire. Rise to power Following the death of Valentinian II, Eugenius was elevated to ''augustus'' on 22 August 392 at Lyons, by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Physiology
Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, genetics, biophysics and molecular biology. Fundamental processes such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed germination, dormancy and stomata function and transpiration, both parts of plant water relations, are studied by plant physiologists. Aims The field of plant physiology includes the study of all the internal activities of plants—those chemical and physical processes associated with life as they occur in plants. This includes study at many levels of scale of size and time. At the smallest scale are molecular interactions of photosynthesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botany
Botany, also called , plant biology or phytology, 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'') meaning " pasture", " herbs" "grass", or " fodder"; is in turn derived from (), "to feed" or "to graze". Traditionally, botany has also included 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 of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Veterinary And Agricultural University
The Royal Veterinary and Agricultural University ( da, Kongelige Veterinær- og Landbohøjskole, abbr. KVL) was a veterinary and agricultural science university in Denmark. It was founded in 1856 and operated until 2007, when it became a part of the University of Copenhagen. It had its headquarters in Frederiksberg, Copenhagen. History The university was founded in 1856. Its main building was inaugurated in 1858. The Royal Veterinarian School moved from Sankt Annæ Gade into the main building after its inauguration. On January 1, 2007, the Royal Veterinary and Agricultural University was merged into the University of Copenhagen and was renamed as the Faculty of Life Sciences. This was later split up, with the veterinary part merging into the Faculty of Health and Medical Sciences and the rest merging into the Faculty of Science. Locations Main campus The original three-winged main building (with the pergola) on Bülowsvej 17 was built between 1856 and 1858 and was designed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure The molecule adopts a tetrahedral molecular geometry with C3v symmetry group, symmetry. Natural occurrence The total global flux of chloroform through the environment is approximately tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear. Chloroform volatilizes readily from soil and surface water and undergoes degradation in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane. It has been used as a recreational drug to cause intoxication. Production Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anesthetic
An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia — in other words, to result in a temporary loss of sensation or awareness. They may be divided into two broad classes: general anesthetics, which result in a reversible loss of consciousness, and local anesthetics, which cause a reversible loss of sensation for a limited region of the body without necessarily affecting consciousness. A wide variety of drugs are used in modern anesthetic practice. Many are rarely used outside anesthesiology, but others are used commonly in various fields of healthcare. Combinations of anesthetics are sometimes used for their synergistic and additive therapeutic effects. Adverse effects, however, may also be increased. Anesthetics are distinct from analgesics, which block only sensation of painful stimuli. Local anesthetics Local anesthetic agents prevent the transmission of nerve impulses without causi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuber
Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing season, and as a means of asexual reproduction. ''Stem tubers'' form thickened rhizomes (underground stems) or stolons (horizontal connections between organisms); well known species with stem tubers include the potato and yam. Some writers also treat modified lateral roots (''root tubers'') under the definition; these are found in sweet potatoes, cassava, and dahlias. Terminology The term originates from the Latin , meaning "lump, bump, swelling". Some writers define the term "tuber" to mean only structures derived from stems; others use the term for structures derived from stems or roots., p. 124 Stem tubers A stem tuber forms from thickened rhizomes or stolons. The top sides of the tuber produce shoots that grow into typical stems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote, and grows within the mother plant to a certain size before growth is halted. The seed coat arises from the integuments of the ovule. Seeds have been an important development in the reproduction and success of vegetable gymnosperm and angiosperm plants, relative to more primitive plants such as ferns, mosses and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates. The term "seed" also has a general me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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