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The Scientific World Journal
Volume 2012, Article ID 525827, 10 pages
http://dx.doi.org/10.1100/2012/525827
Research Article

The Impact of Root Temperature on Photosynthesis and Isoprene Emission in Three Different Plant Species

1Institute of Agro-Environmental & Forest Biology (IBAF), National Research Council (CNR), Via Salaria km 29,300, 00015 Monterotondo Scalo, Rome, Italy
2Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), University of Tuscia, Via S. Camillo De Lellis snc, 01100 Viterbo, Italy
3Department of Agronomy, Food, Natural Resources, Animals, Environment (DAFNAE), University of Padova, Agripolis, Viale dell'Università 16, 35020 Legnaro, Italy
4Institute of Plant Protection (IPP), National Research Council (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence, Italy

Received 13 March 2012; Accepted 1 April 2012

Academic Editors: A. Bosabalidis and J. S. Carrion

Copyright © 2012 Mauro Medori et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Most of the perennial plant species, particularly trees, emit volatile organic compounds (BVOCs) such as isoprene and monoterpenes, which in several cases have been demonstrated to protect against thermal shock and more generally against oxidative stress. In this paper, we show the response of three strong isoprene emitter species, namely, Phragmites australis, Populus x euramericana, and Salix phylicifolia exposed to artificial or natural warming of the root system in different conditions. This aspect has not been investigated so far while it is well known that warming the air around a plant stimulates considerably isoprene emission, as also shown in this paper. In the green house experiments where the warming corresponded with high stress conditions, as confirmed by higher activities of the main antioxidant enzymes, we found that isoprene uncoupled from photosynthesis at a certain stage of the warming treatment and that even when photosynthesis approached to zero isoprene emission was still ongoing. In the field experiment, in a typical cold-limited environment, warming did not affect isoprene emission whereas it increased significantly CO2 assimilation. Our findings suggest that the increase of isoprene could be a good marker of heat stress, whereas the decrease of isoprene a good marker of accelerated foliar senescence, two hypotheses that should be better investigated in the future.