Research

Plant nitrogen (N) nutrition is a topic that challenges the researcher with a number of problems not encountered in other areas of plant mineral nutrition research. The diversity of N forms present in the soil, their interconversions, their different chemical and physical characteristics and not the least the multitude of adaptations and acclimatisations that plants display to optimize acquisition of various N forms all contribute to the complexity of plant N nutrition.
Thus, plants can use a wide array of chemical N forms, ranging from the simple inorganic N compounds such as NH4+ and NO3- as well as polymeric N forms such as proteins. My research deals with plant N physiology, particularly N acquisition and metabolism of forest plants. This research spans from detailed studies of uptake processes to forest fertilization and environmental effects of N.

We have studied uptake of various N forms and demonstrated how field-grown plants acquire different organic N compounds. These studies have stimulated us to characterize the molecular mechanisms underpinning plant organic N nutrition, specifically the specific transporters mediating uptake of various amino acids as well as metabolism of absorbed organic compounds.
We have discovered that plants have a well-developed capacity for using the common L-enantiomers of amino acids but a very restricted capacity to metabolise their D-counterparts. We have also shown how transgenic plants expressing genes encoding D-amino acid metabolising enzymes can detoxify and grow on D-amino acids. This finding has formed the basis for the development of a new selectable marker in plant biotechnology, now commercialized under the tradename SELDA. Basic L-amino acids, and in particular L-arginine, are absorbed at high rates by many plants and we have shown that such N forms have specific advantages for cultivation of woody plants such as conifer seedlings.
This finding forms the basis for the development of a new fertilizer – arGrow®, which is now commercialized by the company SweTree Technologies.
Read more about Torgny Näsholm's research here
Key Publications
- Näsholm, T., Kielland, K. & Ganeteg, U. (2009). Uptake of organic nitrogen by plants. Tansley Review New Phytologist, 182: 31- 48.
- Svennerstam, H., Ganeteg, U., Bellini, C. & Näsholm, T. (2007). Comprehensive screening of Arabidopsis mutants suggests the Lysine Histidine Tranporter 1 to be involved in root uptake of amino acids. Plant Physiology 143: 1-8
- Erikson, O., Hertzberg, M. & Näsholm, T. (2004). A conditional marker gene allowing both positive and negative selection in plants. Nature Biotechnology, 22: 455-458.
- Lipson, D. and Näsholm, T. (2001). The unexpected versatility of plants: Organic Nitrogen Use and Availability in Terrestrial Ecosystems. Commissioned review. Oecologia 128: 305-316
- Näsholm, T., Ekblad, A., Nordin, A., Giesler, R., Högberg, M. and Högberg, P. (1998). Boreal forest plants take up organic nitrogen. Nature 392, 914-916, 1998.
Contact

Torgny Näsholm
Professor at the Department of Forest Ecology and Management
Swedish University of Agricultural Sciences
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
More information: https://www.slu.se/en/ew-cv/torgny-nasholm/
CV T. Näsholm
- 2007: Professor in Tree Ecophysiology, Swedish University of Agricultural Sciences
- 1998: Senior researcher; Plant Physiology (Formas) 2000: Professor in Plant Physiology, Swedish University of Agricultural Sciences
- 1995: Docent in Plant Physiology, Swedish University of Agricultural Sciences
- 1991: PhD, Swedish University of Agricultural Sciences 1992: Assistant Professor in Plant Physiology, Swedish University of Agricultural Sciences
- 1985: BSc, Umeå University
Publications
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Why does nitrogen addition to forest soils inhibit decomposition?
SOIL BIOLOGY & BIOCHEMISTRY 2019, 137 -
Combining microdialysis with metabolomics to characterize the in situ composition of dissolved organic compounds in boreal forest soil
SOIL BIOLOGY & BIOCHEMISTRY 2019, 136 -
Microbial community response to growing season and plant nutrient optimisation in a boreal Norway spruce forest
SOIL BIOLOGY & BIOCHEMISTRY 2018, 125:197-209 -
Interplay between N-form and N-dose influences ecosystem effects of N addition to boreal forest
PLANT AND SOIL 2018, 423 (1-2):385-395 -
Improving in situ recovery of soil nitrogen using the microdialysis technique
SOIL BIOLOGY & BIOCHEMISTRY 2017, 114:93-103 -
Incorporating mass flow strongly promotes N flux rates in boreal forest soils
SOIL BIOLOGY & BIOCHEMISTRY 2017, 114:263-269 -
Amino acid transporter mutants of Arabidopsis provides evidence that a non-mycorrhizal plant acquires organic nitrogen from agricultural soil
Plant Cell Environ. 2017, 40(3):413-423
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Direct acquisition of organic N by white clover even in the presence of inorganic N
PLANT AND SOIL 2016, 407 (1-2):91-107 -
Informing climate models with rapid chamber measurements of forest carbon uptake
Glob Chang Biol. 2017, 23(5):2130-2139 -
The carbon bonus of organic nitrogen enhances nitrogen use efficiency of plants
Plant Cell Environ. 2017, 40(1):25-35
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Greater carbon allocation to mycorrhizal fungi reduces tree nitrogen uptake in a boreal forest
ECOLOGY, 97 (4):1012-1022 -
Soil diffusive fluxes constitute the bottleneck to tree nitrogen nutrition in a Scots pine forest
PLANT AND SOIL, 2016, 399 (1-2):109-120
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Nitrogen dynamics in managed boreal forests: Recent advances and future research directions
Ambio. 2016;45 Suppl 2:175-87 -
Stem compression reversibly reduces phloem transport in Pinus sylvestris trees
TREE PHYSIOLOGY, 2015, 35(10):1075-1085 -
Nitrogen fluxes at the root-soil interface show a mismatch of nitrogen fertilizer supply and sugarcane root uptake capacity
Sci. Rep. 2015, 5;15727
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Genomics in a changing arctic: critical questions await the molecular ecologist
MOLECULAR ECOLOGY, 2015, 24(10):2301-2309 -
How eco-evolutionary principles can guide tree breeding and tree biotechnology for enhanced productivity.
Tree Physiol. 2014 Nov;34(11):1149-66 -
Genetics of superior growth traits in trees are being mapped but will the faster-growing risk-takers make it in the wild?
Tree Physiol. 2014, 34(11):1141-1148
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Early season dynamics of soil nitrogen fluxes in fertilized and unfertilized boreal forests
SOIL BIOLOGY & BIOCHEMISTRY, 2014; 74 167-176 -
Direct estimation of mass flow and diffusion of nitrogen compounds in solution and soil
New Phytol. 2014; 201(3):1056-64 -
Plant nitrogen status and co-occurrence of organic and inorganic nitrogen sources influence root uptake by Scots pine seedlings
TREE PHYSIOLOGY 2014; 34(2):205-213 -
Exploring the nitrogen ingestion of aphids - a new method using electrical penetration graph and (15)n labelling
PLoS One. 2013 Dec 23;8(12):e83085 -
Organic nitrogen uptake of Scots pine seedlings is independent of current carbohydrate supply
TREE PHYSIOLOGY 2013; 33(6):590-600
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Are ectomycorrhizal fungi alleviating or aggravating nitrogen limitation of tree growth in boreal forests?
New Phytol. 2013 Jan 29
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Inselsbacher E, Näsholm T
The below-ground perspective of forest plants: soil provides mainly organic nitrogen for plants and mycorrhizal fungi
New Phytol. 2012 May 4 [Epub ahead of print] -
Keel SG, Campbell CD, Högberg MN, Richter A, Wild B, Zhou X, Hurry V, Linder S, Näsholm T, Högberg P.
Allocation of carbon to fine root compounds and their residence times in a boreal forest depend on root size class and season
New Phytol: 2012 194(4): 972-981
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Svennerstam H, Jämtgård S, Ahmad I, Huss-Danell K, Näsholm T, Ganeteg U
Transporters in Arabidopsis roots mediating uptake of amino acids at naturally occurring concentrations
New Phytologist: 2011, 191:459-467
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Högberg MN, Briones MJI, Keel SG, Metcalfe DB, Campbell C, Midwood AJ, Thornton B, Hurry V, Linder S, Näsholm T, Högberg P
Quantification of effects of season and nitrogen supply on tree below-ground carbon transfer to ectomycorrhizal fungi and other soil organisms in a boreal pine forest
New Phytologist: 2010 187:485-493
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Näsholm T, Kielland K, Ganeteg U
Uptake of organic nitrogen by plants
New Phytologist: 2009 182:31-48
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Näsholm T, Kielland K, Ganeteg U
Uptake of organic nitrogen by plants
New Phytologist: 2009, published on line
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Forsum O, Svennerstam H, Ganeteg U, Näsholm T
Capacities and constraints of amino acid utilization in Arabidopsis
New Phytologist: 2008 179:1058-1069
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Forsum O, Svennerstam H, Ganeteg U, Näsholm T
Capacities and constraints of amino acid utilization in Arabidopsis
New Phytologist: 2008 179:1058-1069
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Jämtgård S, Näsholm T, Huss-Danell K
Characteristics of amino acid uptake in barley
Plant and Soil: 2008 302:221-231
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Jämtgård S, Näsholm T, Huss-Danell K
Characteristics of amino acid uptake in barley
Plant and Soil: 2008 302:221-231
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Boberg J, Finlay RD, Stenlid J, Näsholm T, Lindahl BD
Glucose and ammonium additions affect needle decomposition and carbon allocation by the litter degrading fungus Mycena epipterygia.
Soil Biology and Biochemistry: 2008 40:995-999
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Boberg J, Finlay RD, Stenlid J, Näsholm T, Lindahl BD
Glucose and ammonium additions affect needle decomposition and carbon allocation by the litter degrading fungus Mycena epipterygia.
Soil Biology and Biochemistry: 2008 40:995-999
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Högberg P, Högberg MN, Göttlicher SG, Betson NR, Keel SG, Metcalfe DB, Campbell C, Schindbacher A, Hurry V, Lundmark T, Linder S, Näsholm T
High temporal resolution tracing of photosynthate carbon from the tree canopy to forest soil microorganisms
New Phytologist: 2008 177:220-228
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Högberg P, Högberg MN, Göttlicher SG, Betson NR, Keel SG, Metcalfe DB, Campbell C, Schindbacher A, Hurry V, Lundmark T, Linder S, Näsholm T
High temporal resolution tracing of photosynthate carbon from the tree canopy to forest soil microorganisms
New Phytologist: 2008 177:220-228
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Svennerstam H, Ganeteg U, Bellini C, Näsholm T
Comprehensive screening of Arabidopsis mutants suggests the lysine histidine transporter 1 to be involved in plant uptake of amino acids
Plant Physiology: 2007 145:1853-1860
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Svennerstam H, Ganeteg U, Bellini C, Näsholm T
Comprehensive screening of Arabidopsis mutants suggests the lysine histidine transporter 1 to be involved in plant uptake of amino acids
Plant Physiology: 2007 145:1853-1860
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Forsum A, Dahlman L, Nasholm T, Nordin A
Nitrogen utilization by Hylocomium splendens in a boreal forest fertilization experiment
Functional Ecology: 2006 20:421-426 -
Persson J, Gardestrom P, Nasholm T
Uptake, metabolism and distribution of organic and inorganic nitrogen sources by Pinus sylvestris
Journal of Experimental Botany: 2006 57:2651-2659 -
Nordin A, Strengbom J, Witzell J, Nasholm T, Ericson L
Nitrogen deposition and the biodiversity of boreal forests: Implications for the nitrogen critical load
Ambio: 2005 34:20-24 -
Erikson O, Hertzberg M, Nasholm T
The dsdA gene from Escherichia coli provides a novel selectable marker for plant transformation
Plant Mol Biol: 2005 57:425-433 -
Strengbom J, Nasholm T, Ericson L
Light, not nitrogen, limits growth of the grass Deschampsia flexuosa in boreal forests
Canadian Journal of Botany-Revue Canadienne De Botanique: 2004 82:430-435 -
Erikson O, Hertzberg M, Nasholm T
A conditional marker gene allowing both positive and negative selection in plants
Nature Biotechnology: 2004 22:455-458 -
Lundquist PO, Nasholm T, Huss-Danell K
Nitrogenase activity and root nodule metabolism in response to O-2 and short-term N-2 deprivation in dark-treated Frankia-Alnus incana plants (vol 119, pg 244, 2003)
Physiologia Plantarum: 2004 120:171-171 -
Dahlman L, Persson J, Palmqvist K, Nasholm T
Organic and inorganic nitrogen uptake in lichens
Planta: 2004 219:459-467 -
Ohlund J, Nasholm T
Regulation of organic and inorganic nitrogen uptake in Scots pine (Pinus sylvestris) seedlings
Tree Physiology: 2004 24:1397-1402 -
Strengbom J, Walheim M, Nasholm T, Ericson L
Regional differences in the occurrence of understorey species reflect nitrogen deposition in Swedish forests
Ambio: 2003 32:91-97 -
Witzell J, Gref R, Nasholm T
Plant-part specific and temporal variation in phenolic compounds of boreal bilberry (Vaccinium myrtillus) plants
Biochemical Systematics and Ecology: 2003 31:115-127 -
Persson J, Hogberg P, Ekblad A, Hogberg MN, Nordgren A, Nasholm T
Nitrogen acquisition from inorganic and organic sources by boreal forest plants in the field
Oecologia: 2003 137:252-257 -
Dahlman L, Persson J, Nasholm T, Palmqvist K
Carbon and nitrogen distribution in the green algal lichens Hypogymnia physodes and Platismatia glauca in relation to nutrient supply
Planta: 2003 217:41-48 -
Persson J, Nasholm T
Regulation of amino acid uptake by carbon and nitrogen in Pinus sylvestris
Planta: 2003 217:309-315 -
Ohlund J, Nasholm T
Low nitrogen losses with a new source of nitrogen for cultivation of conifer seedlings
Environmental Science & Technology: 2002 36:4854-4859 -
Strengbom J, Nordin A, Nasholm T, Ericson L
Parasitic fungus mediates change in nitrogen-exposed boreal forest vegetation
Journal of Ecology: 2002 90:61-67 -
Dahlman L, Nasholm T, Palmqvist K
Growth, nitrogen uptake, and resource allocation in the two tripartite lichens Nephroma arcticum and Peltigera aphthosa during nitrogen stress
New Phytologist: 2002 153:307-315 -
Persson J, Nasholm T
Regulation of amino acid uptake in conifers by exogenous and endogenous nitrogen
Planta: 2002 215:639-644 -
Persson J, Nasholm T
Amino acid uptake: a widespread ability among boreal forest plants
Ecology Letters: 2001 4:434-438 -
Strengbom J, Nordin A, Nasholm T, Ericson L
Slow recovery of boreal forest ecosystem following decreased nitrogen input
Functional Ecology: 2001 15:451-457 -
Nasholm T, Huss-Danell K, Hogberg P
Uptake of glycine by field grown wheat
New Phytologist: 2001 150:59-63 -
Lipson D, Nasholm T
The unexpected versatility of plants: organic nitrogen use and availability in terrestrial ecosystems
Oecologia: 2001 128:305-316 -
Nordin A, Hogberg P, Nasholm T
Soil nitrogen form and plant nitrogen uptake along a boreal forest productivity gradient
Oecologia: 2001 129:125-132 -
Persson J, Nasholm T
A GC-MS method for determination of amino acid uptake by plants
Physiol Plant: 2001 113:352-358 -
Nasholm T, Persson J
Plant acquisition of organic nitrogen in boreal forests
Physiologia Plantarum: 2001 111:419-426 -
Sundberg B, Nasholm T, Palmqvist K
The effect of nitrogen on growth and key thallus components in the two tripartite lichens, Nephroma arcticum and Peltigera aphthosa
Plant Cell and Environment: 2001 24:517-527 -
Nordin A, Uggla C, Nasholm T
Nitrogen forms in bark, wood and foliage of nitrogen-fertilized Pinus sylvestris
Tree Physiology: 2001 21:59-64 -
Ohlund J, Nasholm T
Growth of conifer seedlings on organic and inorganic nitrogen sources
Tree Physiology: 2001 21:1319-1326 -
Nasholm T, Huss-Danell K, Hogberg P
Uptake of organic nitrogen in the field by four agriculturally important plant species
Ecology: 2000 81:1155-1161 -
Sundberg B, Ekblad A, Nasholm T, Palmqvist K
Lichen respiration in relation to active time, temperature, nitrogen and ergosterol concentrations
Functional Ecology: 1999 13:119-125 -
Quist ME, Nasholm T, Lindeberg J, Johannisson C, Hogbom L, Hogberg P
Responses of a nitrogen-saturated forest to a sharp decrease in nitrogen input
Journal of Environmental Quality: 1999 28:1970-1977 -
Hogberg P, Hogberg MN, Quist ME, Ekblad A, Nasholm T
Nitrogen isotope fractionation during nitrogen uptake by ectomycorrhizal and non-mycorrhizal Pinus sylvestris
New Phytologist: 1999 142:569-576 -
Nordin A, Nasholm T, Ericson L
Effects of simulated N deposition on understorey vegetation of a boreal coniferous forest
Functional Ecology: 1998 12:691-699 -
Nasholm T, Ekblad A, Nordin A, Giesler R, Hogberg M, Hogberg P
Boreal forest plants take up organic nitrogen
Nature: 1998 392:914-916 -
Ekblad A, Wallander H, Nasholm T
Chitin and ergosterol combined to measure total and living fungal biomass in ectomycorrhizas
New Phytologist: 1998 138:143-149 -
Nasholm T
Qualitative and quantitative changes in plant nitrogen acquisition induced by anthropogenic nitrogen deposition
New Phytologist: 1998 139:87-90 -
Nasholm T, Nordin A, Edfast AB, Hogberg P
Identification of coniferous forests with incipient nitrogen saturation through analysis of arginine and nitrogen-15 abundance of trees
Journal of Environmental Quality: 1997 26:302-309 -
Taylor AFS, Hogbom L, Hogberg M, Lyon AJE, Nasholm T, Hogberg P
Natural N-15 abundance in fruit bodies of ectomycorrhizal fungi from boreal forests
New Phytologist: 1997 136:713-720 -
Nordin A, Nasholm T
Nitrogen storage forms in nine boreal understorey plant species
Oecologia: 1997 110:487-492 -
Nohrstedt HO, Sikstrom U, Ring E, Nasholm T, Hogberg P, Persson T
Nitrate in soil water in three Norway spruce stands in southwest Sweden as related to N-deposition and soil, stand, and foliage properties
Canadian Journal of Forest Research-Revue Canadienne De Recherche Forestiere: 1996 26:836-848 -
Edfast AB, Nasholm T, Aronsson A, Ericsson A
Applications of mineral nutrients to heavily N-fertilized Scots pine trees: Effects on arginine and mineral nutrient concentrations
Plant and Soil: 1996 184:57-65 -
Ekblad A, Nasholm T
Determination of chitin in fungi and mycorrhizal roots by an improved HPLC analysis of glucosamine
Plant and Soil: 1996 178:29-35 -
Ohlson M, Nordin A, Nasholm T
Accumulation of Amino-Acids in Forest Plants in Relation to Ecological Amplitude and Nitrogen Supply
Functional Ecology: 1995 9:596-605 -
Hogberg P, Jensen P, Nasholm T, Ohlsson H
Uptake of Mg-24 by Excised Pine Roots - a Preliminary-Study
Plant and Soil: 1995 172:323-326 -
Hogberg P, Johannisson C, Hog M, Nasholm T, Hallgren JE
Measurements of Abundances of N-15 and C-13 as Tools in Retrospective Studies of N Balances and Water-Stress in Forests - a Discussion of Preliminary-Results
Plant and Soil: 1995 169:125-133 -
Hogberg P, Nasholm T, Hogbom L, Stahl L
Use of N-15 Labeling and N-15 Natural-Abundance to Quantify the Role of Mycorrhizas in N-Uptake by Plants - Importance of Seed-N and of Changes in the N-15 Labeling of Available-N
New Phytologist: 1994 127:515-519 -
Nasholm T, Edfast AB, Ericsson A, Norden LG
Accumulation of Amino-Acids in Some Boreal Forest Plants in Response to Increased Nitrogen Availability
New Phytologist: 1994 126:137-143 -
Nasholm T
Removal of Nitrogen During Needle Senescence in Scots Pine (Pinus-Sylvestris L)
Oecologia: 1994 99:290-296 -
Gezelius K, Nasholm T
Free Amino-Acids and Protein in Scots Pine-Seedlings Cultivated at Different Nutrient Availabilities
Tree Physiology: 1993 13:71-86 -
Sundberg B, Ericsson A, Little CHA, Nasholm T, Gref R
The Relationship between Crown Size and Ring Width in Pinus- Sylvestris L Stems - Dependence on Indole- 3- Acetic- Acid, Carbohydrates and Nitrogen in the Cambial Region
Tree Physiology: 1993 12:347-362 -
Ericsson A, Norden LG, Nasholm T, Walheim M
Mineral Nutrient Imbalances and Arginine Concentrations in Needles of Picea-Abies (L) Karst from 2 Areas with Different Levels of Airborne Deposition
Trees-Structure and Function: 1993 8:67-74 -
Nasholm T, Hogberg P, Edfast AB
Uptake of Nox by Mycorrhizal and Nonmycorrhizal Scots Pine-Seedlings - Quantities and Effects on Amino-Acid and Protein Concentrations
New Phytologist: 1991 119:83-92 -
Edfast AB, Nasholm T, Ericsson A
Free Amino-Acid-Concentrations in Needles of Norway Spruce and Scots Pine Trees on Different Sites in Areas with 2 Levels of Nitrogen Deposition
Canadian Journal of Forest Research-Revue Canadienne De Recherche Forestiere: 1990 20:1132-1136 -
Nasholm T, McDonald AJS
Dependence of Amino-Acid-Composition Upon Nitrogen Availability in Birch (Betula-Pendula)
Physiologia Plantarum: 1990 80:507-514 -
Nasholm T, Ericsson A
Seasonal changes in amino acids, protein and total nitrogen in needles of fertilized Scots pine trees
Tree Physiol: 1990 6:267-281 -
Nasholm T, Ericsson A
Seasonal-Changes in Amino-Acids, Protein and Total Nitrogen in Needles of Fertilized Scots Pine Trees
Tree Physiology: 1990 6:267-281 -
Nasholm T, Sandberg G, Ericsson A
Quantitative-Analysis of Amino-Acids in Conifer Tissues by High-Performance Liquid-Chromatography and Fluorescence Detection of Their 9-Fluorenylmethyl Chloroformate Derivatives
Journal of Chromatography: 1987 396:225-236 -
Wingsle G, Nasholm T, Lundmark T, Ericsson A
Induction of Nitrate Reductase in Needles of Scots Pine-Seedlings by Nox and No3
Physiologia Plantarum: 1987 70:399-403 -
Hogberg P, Granstrom A, Johansson T, Lundmarkthelin A, Nasholm T
Plant Nitrate Reductase-Activity as an Indicator of Availability of Nitrate in Forest Soils
Canadian Journal of Forest Research-Revue Canadienne De Recherche Forestiere: 1986 16:1165-1169
Svenska

Min forskning rör växters kvävefysiologi. I många ekosystem förekommer kväve i marken företrädesvis i form av olika organiska kväveformer och jag studerar växters förmåga att ta upp och växa på sådana kväveföreningar. Vår forskning har visat att växter har en mycket god förmåga att nyttja basiska aminosyror och denna upptäckt har lett fram till utvecklandet av ett nytt gödselmedel – arGrow.
Vi har också visat att vissa sorters aminosyror – D-enantiomererna – inte kan användas av växter. Genom att flytta en gen från en jästsvamp till en växt har vi framställt en transgen växt med den unika förmågan att kunna växa på D-aminosyror. Denna upptäckt har visats vara mycket värdefull inom växtbiotekniken.