Photosynthesis and isoprene emission from trees along an urban–rural gradient in Texas

Isoprene emission is an important mechanism for improving the thermotolerance of plant photosystems as temperatures increase. In this study, we measured photosynthesis and isoprene emission in trees along an urban–rural gradient that serves as a proxy for climate change, to understand daily and seasonal responses to changes in temperature and other environmental variables. Leaf‐level gas exchange and basal isoprene emission of post oak (Quercus stellata ) and sweet gum ( Liquidambar styraciflua ) were recorded at regular intervals over an entire growing season at urban, suburban, and rural sites in eastern Texas. In addition, the temperature and atmospheric carbon dioxide concentration experienced by leaves were experimentally manipulated in spring, early summer, and late summer. We found that trees experienced lower stomatal conductance and photosynthesis and higher isoprene emission, at the urban and suburban sites compared to the rural site. Path analysis indicated a daily positive effect of isoprene emission on photosynthesis, but unexpectedly, higher isoprene emission from urban trees was not associated with improved photosynthesis as temperatures increased during the growing season. Furthermore, urban trees experienced relatively higher isoprene emission at high CO 2 concentrations, while isoprene emission was suppressed at the other sites. These results suggest that isoprene emission may be less beneficial in urban, and potentially future, environmental conditions, particularly if higher temperatures override the suppressive effects of high CO 2 on isoprene emission. These are important considerations for modeling future biosphere–atmosphere interactions and for understanding tree physiological responses to climate change..

Medienart:

Artikel

Erscheinungsjahr:

2015

Erschienen:

2015

Enthalten in:

Zur Gesamtaufnahme - volume:21

Enthalten in:

Global change biology - 21(2015), 11, Seite 4221-4236

Sprache:

Englisch

Beteiligte Personen:

Lahr, Eleanor C [VerfasserIn]
Schade, Gunnar W [Sonstige Person]
Crossett, Caitlin C [Sonstige Person]
Watson, Matthew R [Sonstige Person]

Links:

Volltext
onlinelibrary.wiley.com
www.ncbi.nlm.nih.gov
search.proquest.com

Themen:

Biosphere–atmosphere interactions
Carbon dioxide
Climate change
Greenhouse gases
Liquidambar styraciflua
Photosynthesis
Post oak
Quercus stellata
Sweet gum
Temperature
Trees
Urban areas
VOC
Volatile organic compound

doi:

10.1111/gcb.13010

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

OLC1960031325