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

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 essent ...

s. He taught at the

University of Budapest A university () is an institution of tertiary education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase , which roughly means "community of teachers and scholars". Univ ...

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 leaf primordia and shoot apex of monocot embryo remain enclosed. The coleoptile protects the first leaf as well as the growing ...

of ''Avena'' when cut and placed on gelatin bends towards light as demonstrated earlier by Boysen-Jensen. He however took it further by taking the dark-grown coleoptile and placed it on either side of the base of the cut growing stem and was able to show that some substance in it caused the bending to either side without the need for the light stimulus. This substance was able to pass even through a layer of gelatin. This was later retested by Fritz Went who came up with the word auxin in 1928 for the plant growth hormone. He established the Hungarian plant physiology institute and was a member of the board of the Hungarian Natural History Society. Paál died from coronary atherosclerosis and was survived by his wife Mária Jozefa Solt.

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{{DEFAULTSORT:Paal, Arpad 1889 births 1943 deaths Hungarian botanists