Interactive effects of elevated CO2, warming, reduced rainfall, and nitrogen on leaf gas exchange in five perennial grassland species

Melissa A. Pastore, Tali D. Lee, Sarah E. Hobbie, Peter B. Reich

Research output: Contribution to journalArticle

Abstract

Global changes can interact to affect photosynthesis and thus ecosystem carbon capture, yet few multi-factor field studies exist to examine such interactions. Here, we evaluate leaf gas exchange responses of five perennial grassland species from four functional groups to individual and interactive global changes in an open-air experiment in Minnesota, USA, including elevated CO2 (eCO2), warming, reduced rainfall and increased soil nitrogen supply. All four factors influenced leaf net photosynthesis and/or stomatal conductance, but almost all effects were context-dependent, i.e. they differed among species, varied with levels of other treatments and/or depended on environmental conditions. Firstly, the response of photosynthesis to eCO2 depended on species and nitrogen, became more positive as vapour pressure deficit increased and, for a C4 grass and a legume, was more positive under reduced rainfall. Secondly, reduced rainfall increased photosynthesis in three functionally distinct species, potentially via acclimation to low soil moisture. Thirdly, warming had positive, neutral or negative effects on photosynthesis depending on species and rainfall. Overall, our results show that interactions among global changes and environmental conditions may complicate predictions based on simple theoretical expectations of main effects, and that the factors and interactions influencing photosynthesis vary among herbaceous species.

Original languageEnglish (US)
Pages (from-to)1862-1878
Number of pages17
JournalPlant Cell and Environment
Volume43
Issue number8
DOIs
StatePublished - Aug 1 2020

Keywords

  • CO
  • climate change
  • drought
  • functional groups
  • global change
  • grassland
  • photosynthesis: carbon reactions
  • stomata

PubMed: MeSH publication types

  • Journal Article

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