Henry Horatio Dixon
|Henry Horatio Dixon|
|Born||May 19, 1869
|Died||December 20, 1953
|Institutions||Trinity College Dublin|
|Known for||cohesion-tension theory|
|Notable awards||Fellow of the Royal Society|
Henry Horatio Dixon FRS (May 19, 1869, Dublin - December 20, 1953, Dublin) was a plant biologist and professor at Trinity College Dublin. Along with John Joly, he put forward the cohesion-tension theory of water and mineral movement in plants. 
He was born in Dublin, the youngest of the seven sons of George Dixon, a soap manufacturer and Rebecca (née Yeates) Dixon. He was educated at Rathmines School and Trinity College, Dublin. After studying in Bonn, Germany he in 1894 he was appointed assistant and later full Professor of Botany at Trinity. In 1906 he became Director of the Botanic gardens and in 1910 of the Herbarium also. He had a close working relationship with physicist John Joly and together they developed the cohesion theory of the ascent of sap.
In 1908 he was elected a Fellow of the Royal Society, his application citation describing him as "[Assistant to the] Professor of Botany in the University of Dublin. Has published various papers on Vegetable Histology, Cytology and Physiology. Joint author with J Joly, of papers, 'On the Ascent of Sap' (Phil Trans, vol 186, B, 1895); 'The Path of the Transpiration-Current' (Annals of Botany, vol ix, 1895); author also of the following papers: - 'Fertilization of 'Pinus silvestris' (ibid, vol viii, 1894); 'On the Vegetative Organs of 'Vanda teres' (Proc Roy Irish Acad, 3rd Ser, vol iii, 1894); 'On the Chromosomes of 'Lilium longiflorum' and 'On the Nuclei of the Endosperm of 'Fritillaria imperials' (ibid, 1896); 'On the Osmotic Pressure in the Cells of Leaves' (ibid, vol iv, 1897); 'On the Physics of the Transpiration-Current' (Notes from the Botanical School, Trinity College, Dublin, 1897); 'Transpiration into a Saturated Atmosphere' (Proc Roy Irish Acad, 3rd Ser, vol iv, 1898); 'On the First Mitosis of the Spore-mother-Cells of Lilium' (ibid, vol vi, 1899); 'The Possible Function of the Nucleolus in Heredity' (Annals of Botany, vol xiii, 1899); 'On the Structure of Coccospheres and the Origin of Coccoliths' (Proc Roy Soc, vol lxvi, 1900); 'On the Germination of Seeds after Exposure to High Temperature' (notes from Botanical School, Trinity College, Dublin, 1902); 'Cohesion Theory of the Ascent of Sap' (Proc Roy Dublin Soc, vol x, 1903); 'Observations on the Temperature of Subterranean Organs of Plants' (Trans Roy Irish Acad, vol xxxii, B, 1903), and other papers on histological and physiology subjects.". He delivered the society's Croonian Lecture in 1937.
- Atkins, William Ringrose Gelston (1954). "Henry Horatio Dixon. 1869-1953". Obituary Notices of Fellows of the Royal Society 9: 78–26. doi:10.1098/rsbm.1954.0007. JSTOR 769200.
- "Henry Horatio Dixon.". Plant Physiology 14 (4): i4–619. Oct 1939. ISSN 0032-0889. PMC 437778. PMID 16653610.
- "Plant Physiology". Plant Physiol. (American Society of Plant Biologists) 14 (4): i4–619. October 1939. PMC 437778. PMID 16653610.
- "Library and Archive Catalogue". Royal Society. Retrieved 5 January 2011.
- "Henry H. Dixon". Royal Dublin Society. Retrieved 2013-02-10.