Auxins and their role in plant growth were first described by the Dutch scientist Frits Warmolt Went. Back to botany topic list. It was first isolated from human urine. They were the first group of plant growth hormones discovered. Two types of auxins. The plant hormone auxin and its role were first discovered by Frits Warmolt Went (Dutch biologist) in 1920. Plant Growth Regulators Short Questions and Answers One mark questions with answers 1. Click here to navigate to parent product. Auxins book. By Shingo Marumo. Auxin was the first hormone to be discovered. DOI link for Auxins. Kogl and Haagen Smit (1931) were the first to isolate a chemical from the human urine and named it auxin-a (auxentriolic acid). Auxin was the first of these groups to be identified, and was chemically isolated in the 1930’s. Auxins serve dual roles in plants depending on where they are produced. The chemical which works as auxin is Indole Acetic Acid (IAA). These growth-promoting substances were first studied in 1931 by Dutch workers who isolated two growth-regulating acids (auxin-a and auxin-b, obtained from human urine and cereal products, respectively). Gibberellins were first discovered from (a) algae (b) fungi (c) angiosperms (d) bacteria Answer: (b) fungi 2. NAA (naphthalene acetic acid) and 2, 4-D (2, 4-dichlorophenoxyacetic) Pages 48. eBook ISBN 9781315139241. This type of hormone contains different types of organic acid. Later on, Kogl, Haagen Smit and Erxleben (1934) isolated a similar substance from corn germ oil (extracted from germinating corn seeds) and named it auxin-b (auxenolinic acid). Auxins . Auxins function primarily in stem elongation by promoting cell growth. Natural (IAA and indole butyric acid (IBA) Synthetic. The term auxin is given to generally IAA and other natural and synthetic compounds having similar structure and growth regulating properties. Auxin was the first plant hormone to be discovered. The term auxin is given to generally IAA and other natural and synthetic compounds having similar structure and growth regulating properties. It is the first naturally occurring auxin, which was isolated by Kogl and Haagen-Smit from human urine. High concentration of synthetic auxins would (a) kill the plants (b) … This auxin is produced naturally inside the plant body, therefore, it is also called as natural auxin. Kenneth V. Thimann isolated auxin and found its chemical structure to be indole-3-acetic acid (IAA). Auxins Auxins were first isolated from human urine. AUXINS. Went and Thimann co-authored a book on plant hormones, Phytohormones, in 1937. The term auxin is from the Greek articulate auxein which means to grow. Book Chemistry of Plant Hormones. They are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. First Published 1986. Imprint Routledge. Edition 1st Edition. Kenneth V. Thimann first isolated the auxin from the plant body and he also demonstrated its chemical structure as indole-3-acetic acid (IAA). Dwarf plants can be made taller by (a) gibberellins (b) auxin (c) cytokinin (d) vernalin Answer: (a) gibberellins 3. Auxins book. The most widespread auxin is indoleacetic acid , or simply IAA. Indole-3-acetic acid (IAA) is the major naturally occurring auxin and one of the major growth factors in plants. Indole - 3 - acetic acid is the most common, naturally occurring plant hormone of the auxin class. Auxin was the first plant hormone to be discovered. They were isolated initially from human urine. Auxins were discovered by Dutch botanist F.W.Went (1928) by experimenting on oat (Avena sativa). It is the best known of the auxins and has been the subject of extensive studies by plant physiologists. Auxins . They were isolated initially from human urine. IAA is an auxin which is very important in the growth and development of plant tissues. 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