Root growth and N dynamics in response to multi-year experimental warming, summer drought and elevated CO2 in a mixed heathland-grass ecosystem

M. F. Arndal, I. K. Schmidt, J. Kongstad, Claus Beier, A. Michelsen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Ecosystems exposed to elevated CO2 are often found to sequester more atmospheric carbon due to increased plant growth. We exposed a Danish heath ecosystem to elevated CO2, elevated temperature and extended summer drought alone and in all combinations in order to study whether the expected increased growth would be matched by an increase in root nutrient uptake of NH4+-N and NO3- -N. Root growth was significantly increased by elevated CO2. The roots, however, did not fully compensate for the higher growth with a similar increase in nitrogen uptake per unit of root mass. Hence the nitrogen concentration in roots was decreased in elevated CO2, whereas the biomass N pool was unchanged or even increased. The higher net root production in elevated CO2 might be a strategy for the plants to cope with increased nutrient demand leading to a long-term increase in N uptake on a whole-plant basis. Drought reduced grass root biomass and N uptake, especially when combined with warming, but CO2 was the most pronounced main factor effect. Several significant interactions of the treatments were found, which indicates that the responses were nonadditive and that changes to multiple environmental changes cannot be predicted from single-factor responses alone.
Original languageEnglish
JournalFunctional Plant Biology
Volume41
Issue number1
Pages (from-to)1-10
Number of pages10
ISSN1445-4408
DOIs
Publication statusPublished - 2013

Keywords

  • PLANT
  • ATMOSPHERIC CARBON-DIOXIDE
  • NUTRIENT-UPTAKE
  • TEMPERATE HEATH
  • SOIL-TEMPERATURE
  • CLIMAITE PROJECT
  • FAGUS-SYLVATICA
  • NITROGEN UPTAKE
  • PLANT-TISSUES
  • PICEA-ABIES
  • BIOMASS
  • Calluna vulgaris
  • CLIMAITE
  • Deschampsia flexuosa
  • excised roots
  • ingrowth core
  • N-15-assay
  • Danish heath ecosystem
  • elevated temperature
  • environmental change
  • grass root biomass
  • mixed heathland-grass ecosystem
  • multi-year experimental warming
  • net root production
  • root growth
  • single-factor response
  • soil moisture content
  • summer drought
  • Dicotyledones Angiospermae Spermatophyta Plantae (Angiosperms, Dicots, Plants, Spermatophytes, Vascular Plants) - Ericaceae [26035] Calluna vulgaris species
  • Monocotyledones Angiospermae Spermatophyta Plantae (Angiosperms, Monocots, Plants, Spermatophytes, Vascular Plants) - Gramineae [25305] Deschampsia flexuosa species
  • ammonia-nitrogen
  • carbon 7440-44-0
  • carbon dioxide 124-38-9
  • nitrate-nitrogen
  • nitrogen 7727-37-9 nutrient
  • 07504, Ecology: environmental biology - Bioclimatology and biometeorology
  • 07506, Ecology: environmental biology - Plant
  • 10060, Biochemistry studies - General
  • 12002, Physiology - General
  • 51526, Plant physiology - General and miscellaneous
  • Environmental Sciences
  • temperature treatment applied and field techniques
  • Chemical Coordination and Homeostasis
  • Climatology
  • adaptation
  • bioassay
  • drought stress
  • global warming
  • growth rate
  • nitrogen
  • nutrient dynamics
  • physiological response
  • root
  • terrestrial ecosystem
  • 15N-assay.
  • Excised roots
  • Ingrowth core

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