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Plant function and evolutionary biology
RESEARCH ARTICLE

Carbon dioxide fertilisation and supressed respiration induce enhanced spring biomass production in a mixed species temperate meadow exposed to moderate carbon dioxide enrichment

Matthew Haworth A D F , Gerald Moser B , Antonio Raschi A , Claudia Kammann B E , Ludger Grünhage B and Christoph Müller B C
+ Author Affiliations
- Author Affiliations

A Consiglio Nazionale delle Ricerche – Istituto di Biometeorologia, Via Giovanni Caproni 8, 50145 Florence, Italy.

B Department of Plant Ecology, Interdisciplinary Research Centre, University of Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany.

C School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland.

D Present address: CNR – Tree and Timber Institute, Presso Area di Ricerca CNR, Via Madonna del Piano 10, Sesto Fiorentino, 50019 Florence, Italy.

E Present address: Hochschule Geisenheim University, Climate Change Research for Special Crops, Center for Applied Biology, Von-Lade-Str. 1, D-65366 Geisenheim, Germany.

F Corresponding author. Email: matthew.haworth@hotmail.com

Functional Plant Biology 43(1) 26-39 https://doi.org/10.1071/FP15232
Submitted: 15 November 2014  Accepted: 18 October 2015   Published: 30 November 2015

Abstract

The rising concentration of carbon dioxide in the atmosphere ([CO2]) has a direct effect on terrestrial vegetation through shifts in the rates of photosynthetic carbon uptake and transpirational water-loss. Free Air CO2 Enrichment (FACE) experiments aim to predict the likely responses of plants to increased [CO2] under normal climatic conditions. The Giessen FACE system operates a lower [CO2] enrichment regime (480 μmol mol–1) than standard FACE (550–600 μmol mol–1), permitting the analysis of a mixed species temperate meadow under a [CO2] level equivalent to that predicted in 25–30 years. We analysed the physiological and morphological responses of six species to investigate the effect of moderate [CO2] on spring biomass production. Carbon dioxide enrichment stimulated leaf photosynthetic rates and supressed respiration, contributing to enhanced net assimilation and a 23% increase in biomass. The capacity for photosynthetic assimilation was unaffected by [CO2] enrichment, with no downregulation of rates of carboxylation of Rubisco or regeneration of ribulose-1,5-bisphosphate. Foliar N content was also not influenced by increased [CO2]. Enhanced [CO2] reduced stomatal size, but stomatal density and leaf area index remained constant, suggesting that the effect on gas exchange was minimal.

Additional keywords: free air CO2 enrichment, grassland, inhibition of respiration, photosynthetic downregulation, stomatal conductance, stomatal density.


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