Árpád Paál
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Árpád Paál
Árpád Paál (15 April 1889 – 9 April 1943) was a Hungarian botanist and plant physiologist who was among the first to experimentally demonstrate the existence of auxins. He taught at the University of Budapest where he established a plant physiology institute. Paál was born in Budapest to Árpád and Anna Dávid. He received a doctorate in the humanities from the University of Budapest (1911) and then travelled through Europe. From 1915 he worked at the botany and pathology station under the ministry of agriculture. In 1918 he became a private lecturer at Budapest University. He became an assistant professor in 1922 and headed the botany department from 1929. He studied plant growth and the response to stimuli. He conducted experiments on the bending of the growing apex of plants towards light. In 1919 he conducted experiments to show that the coleoptile Coleoptile is the pointed protective sheath covering the emerging shoot in monocotyledons such as grasses in which few lea ...
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Auxin
Auxins (plural of auxin ) are a class of plant hormones (or plant-growth regulators) with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essential for plant body development. The Dutch biologist Frits Warmolt Went first described auxins and their role in plant growth in the 1920s. Kenneth V. Thimann became the first to isolate one of these phytohormones and to determine its chemical structure as indole-3-acetic acid (IAA). Went and Thimann co-authored a book on plant hormones, ''Phytohormones'', in 1937. Overview Auxins were the first of the major plant hormones to be discovered. They derive their name from the Greek word ( – 'to grow/increase'). Auxin is present in all parts of a plant, although in very different concentrations. The concentration in each position is crucial developmental information, so it is subject to tight regulation through both metabolism and transp ...
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Eötvös Loránd University
Eötvös Loránd University (, ELTE, also known as ''University of Budapest'') is a Hungarian public research university based in Budapest. Founded in 1635, ELTE is one of the largest and most prestigious public higher education institutions in Hungary. The 28,000 students at ELTE are organized into nine faculties, and into research institutes located throughout Budapest and on the scenic banks of the Danube. ELTE is affiliated with 5 Nobel laureates, as well as winners of the Wolf Prize, Fulkerson Prize and Abel Prize, the latest of which was Abel Prize winner László Lovász in 2021. The predecessor of Eötvös Loránd University was founded in 1635 by Cardinal Péter Pázmány in Nagyszombat, Kingdom of Hungary (today Trnava, Slovakia) as a Catholic university for teaching theology and philosophy. In 1770, the university was transferred to Buda. It was named Royal University of Pest until 1873, then University of Budapest until 1921, when it was renamed Royal Hungarian Pá ...
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Coleoptile
Coleoptile is the pointed protective sheath covering the emerging shoot in monocotyledons such as grasses in which few leaf primordia and shoot apex of monocot embryo remain enclosed. The coleoptile protects the first leaf as well as the growing stem in seedlings and eventually, allows the first leaf to emerge. Coleoptiles have two vascular bundles, one on either side. Unlike the flag leaves rolled up within, the pre-emergent coleoptile does not accumulate significant protochlorophyll or carotenoids, and so it is generally very pale. Some preemergent coleoptiles do, however, accumulate purple anthocyanin pigments. Coleoptiles consist of very similar cells that are all specialised to fast stretch growth. They do not divide, but increase in size as they accumulate more water. Coleoptiles also have water vessels (frequently two) along the axis to provide a water supply. When a coleoptile reaches the surface, it stops growing and the flag leaves penetrate its top, continuing to grow ...
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Peter Boysen Jensen
Peter Boysen Jensen (18 January 1883 – 21 November 1959) was a Danish plant physiologist. His research was fundamental to further work on the auxin theory of tropisms. Early life and education Peter was born in Hjerting, near Esbjerg in southern Jutland. Being raised on a farm, he discovered early his affinity to nature. He studied botany during his first premed year, and decided to focus on plant physiology after being influenced by ecologist Eugenius Warming. (1840–1905) and Wilhelm Johannsen (1857–1927) were Boysen Jensen's plant physiology teachers and advisors. While he was a college student in Copenhagen however, neither of these was actively involved in experimental plant physiology. In 1908, Boysen Jensen earned the degree of ''magister scientiarum''. He spent three months of the following year in Wilhelm Pfeffer's Leipzig lab and another four with the biochemist Ernst Schulze in Zürich. Boysen Jensen completed his doctoral studies in 1910, with the thesis ''Th ...
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Frits Went
Friedrich August Ferdinand Christian Went (June 18, 1863 – July 24, 1935) was a Dutch botanist. Went was born in Amsterdam. He was professor of botany and director of the Botanical Garden at the University of Utrecht. His eldest son was the Dutch botanist Frits Warmolt Went, who in 1927 as a graduate student worked on plant hormones, specifically the role of auxin in phototropism. He became member of the Royal Netherlands Academy of Arts and Sciences in 1898. Went died, aged 72, in Wassenaar. References

1863 births 1935 deaths 19th-century Dutch botanists 20th-century Dutch botanists Foreign members of the Royal Society Members of the Royal Netherlands Academy of Arts and Sciences Scientists from Amsterdam University of Amsterdam alumni Academic staff of Utrecht University {{Netherlands-botanist-stub ...
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1889 Births
Events January * January 1 ** The total solar eclipse of January 1, 1889 is seen over parts of California and Nevada. ** Paiute spiritual leader Wovoka experiences a vision, leading to the start of the Ghost Dance movement in the Dakotas. * January 4 – An Act to Regulate Appointments in the Marine Hospital Service of the United States is signed by President Grover Cleveland. It establishes a Commissioned Corps of officers, as a predecessor to the modern-day U.S. Public Health Service Commissioned Corps. * January 8 – Herman Hollerith receives a patent for his electric tabulating machine in the United States. * January 15 – The Coca-Cola Company is originally incorporated as the Pemberton Medicine Company in Atlanta, Georgia. * January 22 – Columbia Phonograph is formed in Washington, D.C. * January 30 – Mayerling incident: Rudolf, Crown Prince of Austria, and his mistress Baroness Mary Vetsera commit a double suicide (or a murder-suicide) at the Mayerling hun ...
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1943 Deaths
Events Below, the events of World War II have the "WWII" prefix. January * January 1 – WWII: The Soviet Union announces that 22 German divisions have been encircled at Stalingrad, with 175,000 killed and 137,650 captured. * January 4 – WWII: Greek-Polish athlete and saboteur Jerzy Iwanow-Szajnowicz is executed by the Germans at Kaisariani. * January 10 – WWII: Guadalcanal campaign, Guadalcanal Campaign: American forces of the 2nd Marine Division and the 25th Infantry Division (United States), 25th Infantry Division begin their assaults on the Battle of Mount Austen, the Galloping Horse, and the Sea Horse#Galloping Horse, Galloping Horse and Sea Horse on Guadalcanal. Meanwhile, the Japanese Seventeenth Army (Japan), 17th Army makes plans to abandon the island and after fierce resistance withdraws to the west coast of Guadalcanal. * January 11 ** The United States and United Kingdom revise previously unequal treaty relationships with the Republic of China (1912–194 ...
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