Prof Howard Thomas

Prof Howard Thomas

Emeritus Professor

Contact Details


Investigation and modification of cellular and biochemical mechanisms of plant senescence and death, with special emphasis on pigment and protein metabolism.

Cloning, mapping and exploiting genes determining senescence, late-season and post-harvest deterioration, food, feed and bioprocessing quality and consumer perception in a range of crop and amenity species.

Use of imaging and machine-learning methods for non-destructive analysis of plant development and remote field to landscape-level monitoring of crops and ecosystems.

Cultural significance of scientific research and promotion of links between science and the arts.


Senescence and crop performanceThomas, H. & Ougham, H. 2017 Crop Physiology: Application for Genetic Improvement and Agronomy. Sadras, V. O. & Calderini, D. (eds.). Academic International Press, p. 223-250
On plant growth and formThomas, H. & Ougham, H. 2017 In : New Phytologist.216, 2, p. 337-3382 p.
The Millers' Tales: Sustainability, the Arts and the WatermillArcher, J. E. E., Thomas, H. & Marggraf Turley, R. 2017 Literature and Sustainability : Concept, Text and Culture. Johns-Putra, A., Parham, J. & Squire, L. (eds.). Manchester: Manchester University Press, p. 1332 p. 1
The Autumn King: Remembering the Land in King LearArcher, J. E. E., Thomas, H. & Marggraf Turley, R. 2017 Literary Theory: An Anthology. Rivkin, J. & Ryan, M. (eds.). 3 ed. Oxford: Wiley, p. 1547-1566 (Blackwell Anthologies)
Introduction to a Virtual Issue on plant senescenceThomas, H. & Ougham, H. 2016 In : New Phytologist.212, 3, p. 531-5366 p.
Remembering Darnel, a Forgotten Plant of Literary, Religious, and Evolutionary SignificanceThomas, H., Archer, J. E. E. & Marggraf Turley, R. 2016 In : Journal of Ethnobiology.36, 1, p. 29-44
Senescence and programmed cell deathThomas, H., Ougham, H., Mur, L. & Jansson, S. 2015 Biochemistry and Molecular Biology of Plants. Buchanan, B. B., Gruissem, W. & Jones, R. L. (eds.). Wiley, p. 925-982
Reading shakespeare with the grain: Sustainability and the hunger businessArcher, J. E. E., Thomas, H. & Marggraf Turley, R. 2015 In : Green Letters: Studies in Ecocriticism.19, 1, p. 8-20
Soper at oure aller cost: The Politics of Food Supply in the Canterbury TalesArcher, J. E. E., Marggraf Turley, R. & Thomas, H. 2015 In : The Chaucer Review.50, 1 & 2, p. 1-29
Moving accidents by flood and field: The Arable and Tidal Worlds of George Eliot'sArcher, J. E., Marggraf Turley, R. & Thomas, H. 2015 In : ELH: English Literary History.82, 2, p. 701-72829 p.
Food and the Literary ImaginationArcher, J. E., Marggraf Turley, R. & Thomas, H. 2014 Basingstoke: Springer Nature. 212 p.
Multiscale digital Arabidopsis predicts individual organ and whole-organism growthChew, Y. H., Wenden, B., Flis, A., Mengin, V., Taylor, J., Davey, C. L., Tindal, C., Thomas, H., Ougham, H. J., De Reffye, P., Stitt, M., Williams, M., Muetzelfeldt, R., Halliday, K. J. & Millar, A. J. 2014 In : Proceedings of the National Academy of Sciences of the United States of America.111, 39, p. E4127-E4136
The stay-green traitThomas, H. & Ougham, H. J. 2014 In : Journal of Experimental Botany.65, p. 3889-3900
Reading with the Grain: Sustainability and the Literary ImaginationArcher, J. E., Marggraf Turley, R. J. & Thomas, H. 2013 2013 INSPIRE Lecture on Literature and Sustainability. Lampeter: Prifysgol Cymru Y Drindod Dewi Sant, 15 p.
The Autumn King: Remembering the Land in King LearArcher, J. E., Turley, R. M. & Thomas, H. 2012 In : Shakespeare Quarterly.63, 4, p. 518-543
Evolution, Physiology and Phytochemistry of the Psychotoxic Arable Mimic Weed Darnel (Lolium temulentum L.)Thomas, H., Archer, J. E. & Marggraf Turley, R. 2011 Progress in Botany. Lüttge, U. E., Beyschlag, W., Büdel, B. & Francis, D. (eds.). Springer Nature, Vol. 72, p. 73-10432 p.
A flexible quantitative methodology for the analysis of gene-flow between conventionally bred maize populations using microsatellite markersRobson, P. R. H., Kelly, R., Jensen, E. F., Giddings, G. D., Leitch, M., Davey, C., Gay, A. P., Jenkins, G., Thomas, H. & Donnison, I. S. 2011 In : Theoretical and Applied Genetics.122, 4, p. 819-82911 p.
GrassesRaven, J. & Thomas, H. 2010 In : Current Biology.20, 19, p. R837-R839
Accumulation of chlorophyll catabolites photosensitizes the hypersensitive response elicited by Pseudomonas syringae in ArabidopsisMur, L. A. J., Aubry, S., Mondhe, M., Kingston-smith, A., Gallagher, J., Timms-taravella, E., James, C., Papp, I., Hörtensteiner, S., Thomas, H. & Ougham, H. 2010 In : New Phytologist.188, 1, p. 161-17414 p.
Evolution of plant senescenceThomas, H., Huang, L., Young, M. & Ougham, H. J. 2009 In : BMC Evolutionary Biology.9, 163, 163
PlasMo: Making existing plant and crop mathematical models available to plant systems biologistDavey, C., Ougham, H. J., Millar, A., Thomas, H., Tindal, C. & Muetzelfeldt, R. 2009 Aspects 93: Integrated Agricultural Systems.p. S225-S226
PlaSMo: Making existing plant and crop mathematical models available to plant systems biologistsOugham, H. J., Millar, A., Muetzelfeldt, R., Tindal, C., Thomas, H. & Davey, C. 2009 In : Comparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology.p. 225-
Response to Sinkkonen: Ultraviolet reflectance in autumn leaves and the un-naming of coloursArchetti, M., Doring, T. F., Hagen, S. B., Hughes, N. M., Leather, S. R., Lee, D. W., Lev-Yadun, S., Manetas, Y., Ougham, H. J., Schaberg, P. G. & Thomas, H. 2009 In : Trends in Ecology and Evolution.24, 5, p. 237-2382 p.
Faecal Markers - Markers developed to optimise visualisation of faecal contamination on animal carcasses in the abattoirLee, M., Theodorou, M., Ougham, H. & Thomas, H. 2009
Unravelling the evolution of autumn colours: an interdisciplinary approachDoring, T. F., Lev-Yadun, S., Ougham, H. J., Leather, S. R., Schaberg, P. G., Archetti, M., Manetas, Y., Thomas, H., Lee, D. W., Hagen, S. B. & Hughes, N. M. 2009 In : Trends in Ecology and Evolution.24, 3, p. 166-1738 p.
Making crop and plant mathematical models easily accessible to the plant science and systems biology communitiesDavey, C., Ougham, H. J., Millar, A., Thomas, H., Tindal, C. & Muetzelfeldt, R. 2009
Genome restructuring in hybrids: marriages of inconvenienceJones, R. N., Thomas, H., Naganowska, B. (ed.), Kachlick, P. I. (ed.) & Krajewski, P. (ed.) 2009 p. pp11-2818 p.
Markers and mapping revisited: finding your geneJones, R. N., Ougham, H. J., Thomas, H. & Pasakinskiene, I. S. 2009 In : New Phytologist.183, 4, p. 935-96632 p.
The control of chlorophyll catabolism and the status of yellowing as a biomarker of leaf senescenceOugham, H. J., Hortensteiner, S., Armstead, I. P., Donnison, I. S., King, I. P., Thomas, H. & Mur, L. A. J. 2008 In : Plant Biology.10, S1, p. 4-1411 p.
Does fructan have a functional role in physiological traits? Investigation by quantative trait locus mappingTurner, L. B., Cairns, A. J., Armstead, I. P., Thomas, H., Humphreys, M. W. & Humphreys, M. O. 2008 In : New Phytologist.179, 3, p. 765-77511 p.
Senescence: developmental program or timetable?Thomas, H. & Jansson, S. 2008 In : New Phytologist.179, 3, p. 575-5795 p.
Systems biology and the biology of systems: how, if at all, are they related?Thomas, H. 2008 In : New Phytologist.177, 1, p. 11-155 p.
Nondestructive analysis of senescence in mesophyll cells by spectral resolution of protein synthesis-dependent pigment metabolismGay, A. P., Thomas, H., Roca, M., James, C. L., Taylor, J., Rowland, J. J. & Ougham, H. J. 2008 In : New Phytologist.179, 3, p. 663-67412 p.
The adaptive value of leaf colourThomas, H., Ougham, H. J. & Archetti, M. 2008 In : New Phytologist.179, p. 9-135 p.
Rice pseudomolecule-anchored cross-species DNA sequence alignments indicate regional genomic variation in expressed sequence conservationArmstead, I. P., Huang, L. S., King, J., Ougham, H. J., Thomas, H. & King, I. P. 2007 In : BMC Genomics.8, 283, 16
Throwing new light on the hypersensitive responseMur, L., Mondhe, M., Papp, I., Holton, N., Hoertensteiner, S., Kingston-Smith, A., Thomas, H. & Ougham, H. 2007 In : Comparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology.146, 4, C2.9
The genetic control of senescence revealed by mapping quantitative trait lociDonnison, I. S., Thomas, H., Armstead, I. P., Ougham, H. J., Howarth, C. J. & Galyuon, I. K. A. 2007 Annual Plant Reviews: Senescence Processes in Plants. Gan, S. (ed.). Wiley, Vol. 26, p. 171-20131 p.
Modification of nitrogen remobilisation, grain fill and leaf senescence in maize (Zea mays L.) by transposon insertional mutagenensis in a protease geneDonnison, I., Gay, A., Thomas, H., Edwards, K. J., Edwards, D., Evans, C., Thomas, A. & Ougham, H. 2007 In : New Phytologist.173, 3, p. 481-49414 p.
Cross-species identification of Mendel's/locusArmstead, I. P., Donnison, I. S., Aubry, S., Harper, J. A., Hörtensteiner, S., James, C. L., Mani, J., Moffet, M., Ougham, H. J., Roberts, L. A., Thomas, A. M., Weeden, N., Thomas, S. & King, I. P. 2007 In : Science.315, 5808, p. 73
From crop to model to crop: identifying the genetic basis of the staygreen mutation in the Lolium/Festuca forage and amenity grassesArmstead, I. P., Donnison, I. S., Aubry, S., Harper, J. A., Hortensteiner, S., James, C. L., Mani, J., Moffet, M., Ougham, H. J., Roberts, L. A., Thomas, A. M., Weeden, N., Thomas, S. & King, I. P. 2006 In : New Phytologist.172, 4, p. 592-5976 p.
Molecular tagging of a senescence gene by introgression mapping of a stay-green mutation from Festuca pratensisThomas, A. M., Thomas, H., Armstead, I. P., King, I. P., Harper, J. A., Moore, B. J., Huang, L. S., Fentem, P. A., Ougham, H. J., Jones, R. N., Jones, T. A. H., Roberts, L. A., King, J. & Donnison, I. S. 2005 In : New Phytologist.165, 3, p. 801-8066 p.
Bringing medicinal plants into cultivation: opportunities and challenges for biotechnologyErnst, E., Thomas, H. & Canter, P. H. 2005 In : Trends in Biotechnology.23, 4, p. 180-1856 p.
The colour of autumn leaves as symptoms of cellular recycling and defences against environmental stressesOugham, H. J., Thomas, H., Morris, P. & Schatten, G. P. (ed.) 2005 In : Current Topics in Developmental Biology.66, p. 135-16026 p.
Construction of a Festuca pratensis BAC library for map-based cloning in IFestulolium substitution linesDonnison, I. S., O'Sullivan, D. M., Thomas, A., Canter, P., Moore, B., Armstead, I., Thomas, H., Edwards, K. J. & King, I. P. 2005 In : Theoretical and Applied Genetics.110, 5, p. 846-8516 p.
Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animalsMerry, R. J., Leemans, D. K., Kingston-Smith, A. H., Theodorou, M. K. & Thomas, H. 2005 In : British Journal of Nutrition.p. 73-797 p.
Introgression mapping in the grassesKing, I. P., King, J., Armstead, I. P., Harper, J. A., Roberts, L. A., Thomas, H., Ougham, H. J., Jones, R. N., Thomas, A. M., Moore, B. J. & Humphreys, M. O. (ed.) 2005 p. 31-4111 p.
Discriminating stay-green grasses using hyperspectral imaging and chemometricsTaylor, J., Moore, B. J., Rowland, J. J., Thomas, H. & Ougham, H. J. 2005 Molecular breeding for the genetic improvement of forage crops and turf. Humphreys, M. O. (ed.). Wageningen Academic Publishers, p. 120
Modification of senescence in ryegrass transformed with IPT under the control of a monocot senescence-enhanced promoterLi, Q., Robson, P. R. H., Bettany, A. J. E., Donnison, I. S., Thomas, H. & Scott, I. M. 2004 In : Plant Cell Reports.22, 11, p. 816-8216 p.
Analysis of the chlorophyll catabolism pathway in leaves of an introgression senescence mutant of Lolium temulentumRoca, M., James, C. L., Pruzinská, A., Hörtensteiner, S., Thomas, H. & Ougham, H. J. 2004 In : Phytochemistry.65, 9, p. 1231-12388 p.
Leaf senescence is delayed in maize expressing the Agrobacterium IPT gene under the control of a novel maize senescence-enhanced promoterRobson, P. R. H., Donnison, I. S., Wang, K., Frame, B., Pegg, S. E., Thomas, A. M. & Thomas, H. 2004 In : Plant Biotechnology Journal.2, 2, p. 101-11212 p.
Chlorophylls and their breakdown in green plant tissues: genetic and environmental controlOugham, H. J., Hortensteiner, S., Roca, M., Thomas, H., James, C. L. & Dufossel, L. (ed.) 2004 p. 8-103 p.
Identification of molecular markers for crown rust (Puccinia coronata) resistance in a Lolium/Festuca introgression population using syntenic relationships with riceArmstead, I., Roderick, H. W., Harper, J. A., Thomas, H. M., King, I. P. & Humphreys, M. O. 2004
Photoinhibition and resistance to winter damage in stay-green amenity grassesGay, A., Smith, E. L., Kingston-Smith, A., Thorogood, D., Roca, M., Ougham, H., Thomas, H., Evans, C., Davies, T. & Moss, L. 2004 Comparative Biochemistry and Physiology, Part A.Vol. 137, S170
Defining senescence and death.Wagstaff, C., Thomas, H., Ougham, H. J. & Stead, A. J. 2003 In : Journal of Experimental Botany.54, 385, p. 1127-11326 p.
Do green plants age and, if so, how?Thomas, H. 2003 Topics in Current Genetics.Springer Nature, p. 145-17127 p.
Hyperspectral imaging and machine learning as a no-invasive screening tool to determine crop maturity, nutritional status and stressOugham, H., Gay, A., Donnison, I., Thomas, H., Evans, C. & Rowlands, J. 2003 p. AR09
Hyperspectral imaging and machine learning as a non-invasive screening tool to determine crop maturity, nutritional status and stressOugham, H., Gay, A., Donnison, I., Thomas, H., Evans, C. & Rowlands, J. 2003
Effects of a stay-green mutation on plant nitrogen relations in Lolium perenne during N starvation and after defoliationMacduff, J. H., Thomas, H. & Humphreys, M. O. 2002 In : Annals of Botany.p. 11-2111 p.
Ageing in plantsThomas, H. 2002 In : Mechanisms of Ageing and Development.123, 7, p. 747–753
What stay-green mutants tell us about nitrogen remobilization in leaf senescenceOugham, H. J., Canter, P. H., Donnison, I. S., Thomas, H., Lea, P. J. (ed.), Morot-Gaudry, J. F. (ed.) & Hirel, B. (ed.) 2002 In : Journal of Experimental Botany.p. 801-8088 p.
Developing a chromosome substitution series in Lolium/FestucaHarper, J. A., Armstead, I., King, I. P., Roberts, L., Schledde, T., Wagner, N. & Thomas, H. 2002
Hyperspectral imaging as a non-invasive tool to determine crop maturity, nutritional status and stressGay, A., Donnison, I., Taylor, J., Thomas, H. & Ougham, H. 2002
Introgression mapping - the route to designer breeding in grassesThomas, H., Morgan, W. G., Humphreys, M. W., Harper, J. A., Armstead, I., Moore, B. J., King, J., Roberts, L., James, A. R., Humphreys, J., Hawkins, S. L. & King, I. P. 2001 Proceedings of the XVIth EUCARPIA Congress. Edinburgh, Scotland, p. 139-145
Programmed cell death assays for plantsJones, A. M., Coimbra, S., Fath, A., Sottomayor, M. & Thomas, H. 2001 Apoptosis: Cell Death. Schwartz, L. M. & Ashwell, J. D. (eds.). Elsevier, Vol. 66, p. 437-45115 p. (Methods in Cell Biology)
Recent advances in the cell biology of chlorophyll catabolismThomas, H., Ougham, H. J. & Hortensteiner, S. 2001 In : Advances in Botanical Research.35, p. 1-5252 p.
The capture and gratuitous disposal of resources by plantsSadras, V. O. & Thomas, H. 2001 In : Functional Ecology.p. 3-1210 p.
Introgression mapping reveals a 1:1 correspondence between chiasma frequency and genetic distanceKing, J., Thomas, H. M., Armstead, I., Jones, R. N., Kearsey, M. J., Roberts, L. A., Morgan, W. G. & King, I. P. 2001 p. 1341 p.
Retrotransposon Evolution in Diverse Plant GenomesLangdon, T., Seago, C. M., Mende, M., Leggett, J. M., Thomas, H., Forster, J. W., Thomas, H., Jones, R. N. & Jenkins, G. 2000 In : Genetics.156, 1, p. 313-32512 p.
De Novo Evolution of Satellite DNA on the Rye B ChromosomeLangdon, T., Seago, C. M., Jones, R. N., Ougham, H., Thomas, H., Forster, J. W. & Jenkins, G. 2000 In : Genetics.154, 2, p. 869-88415 p.
Chlorophyll breakdown in Chlorella protothecoides: characterization of degreening and cloning of degreening-related genesHörtensteiner, S., Chinner, J., Matile, P., Thomas, H. & Donnison, I. 2000 In : Plant Molecular Biology.42, 3, p. 439-450
Species relationships, introgression and physical mapping in Lolium perenne x Festuca pratensis hybridsKing, I., Morgan, W. G., Armstead, I., Jones, T. A. H., Jones, R. N., Harper, J., Roberts, L., Taylor, S. & Thomas, H. 2000 Chromosomes Today: Proceedings 13th International Chromosome Conference. Olmo, E. & Redi, C. A. (eds.). Springer Nature, Vol. 13, p. 277-286
Evidence for root contraction in white clover (Trifolium repens L.)Cresswell, A., Sackville Hamilton, N. R., Thomas, H., Charnock, R. B., Cookson, A. R. & Thomas, B. J. 1999 In : Annals of Botany.84, 3, p. 359-36911 p.
Introgression mapping in the grasses. I. Introgression of Festuca pratensis chromosomes and chromosome segments into Lolium perenneKing, I. P., Morgan, W. G., Armstead, I. P., Harper, J. A., Hayward, M. D., Bollard, A., Nash, J. V., Forster, J. W. & Thomas, H. M. 1998 In : Heredity.81, 4, p. 462-467
Physically mapping quantitative traits for stress resistance in the forage grassesHumphreys, M. W., Pasakinskiene, I., James, A. R. & Thomas, H. 1998 In : Journal of Experimental Botany.49, 327, p. 1611-1618
Chlorophyll a fluorescence and antioxidant analyses provide evidence for the operation of alternative electron sinks during leaf senescence in a stay-green mutant of Festuca pratensisKingston-Smith, A. H., Thomas, H. & Foyer, C. H. 1997 In : Plant, Cell and Environment.20, 11, p. 13231337 p.
Leaf senescence in a non-yellowing mutant of Festuca pratensis: implications of the stay-green mutation for photosynthesis, growth and nutrition Hauck, B., Gay, A., Macduff, J., Griffiths, C. M. & Thomas, H. 1997 In : Plant, Cell and Environment.20, 8, p. 1007-1018
Introgression, tagging and expression of a leaf senescence gene in FestuloliumThomas, H., Evans, C., Thomas, H. M., Humphreys, M. W., Morgan, W. G., Hauck, B. & Donnison, I. 1997 In : New Phytologist.137, 1, p. 29-34
Leaf development in Lolium temulentum: photosynthesis in relation to growth and senescenceGay, A. & Thomas, H. 1995 In : New Phytologist.160, 2, p. 159-168
Photosynthesis and light energy dissipation in senescing leaves of grass mutants blocked in chlorophyll degradationSouriau, N., Hauck, B., Gay, A., Foyer, C. H. & Thomas, H. 1995 Photosynthesis: From Light to Biosphere. Mathis, P. (ed.). Springer Nature, p. 953-956
Intergenomic translocations and the genomic composition of Avena maroccana Gdgr. revealed by FISHLeggett, J. M., Thomas, H. M., Meredith, M. R., Humphreys, M. W., Morgan, W. G. & King, I. P. 1994 In : Chromosome Research.2, 2, p. 163-164
Leaf Development in Lolium temulentum: Photosynthesis and Photosynthetic Proteins in Leaves Senescing under Different IrradiancesMae, T., Thomas, H., Gay, A., Makino, A. & Hidema, J. 1993 In : Plant and Cell Physiology.p. 391-399
Effect of light intensity during senescence on photosynthesis and photosynthetic proteins of Lolium temulentumGay, A., Mae, T. & Thomas, H. 1993 Crop Adaptation to Cool, Wet Climates. Wilson, D., Thomas, H. & Pithan, K. (eds.). p. 159-166