Plant Physiol, September 2000, Vol. 124, pp. 183-190
Long-Term Growth of Ginkgo with CO2 Enrichment
Increases Leaf Ice Nucleation Temperatures and Limits Recovery of the
Photosynthetic System from Freezing1
Andrew C.
Terry,2
W. Paul
Quick, and
David J.
Beerling*
Department of Animal and Plant Sciences, University of Sheffield,
Sheffield S10 2TN, United Kingdom
The importance of subzero temperature interactions with elevated
CO2 on plant carbon metabolism has received rather little attention, despite their likely role in influencing future vegetation productivity and dynamics. Here we focused on the critical issues of
CO2-enrichment effects on leaf-freezing temperatures,
subsequent membrane damage, and recovery of the photosynthetic system.
We show that growth in elevated CO2 (70 Pa) results
in a substantial and significant (P < 0.01)
increase (up to 4°C) in the ice nucleation temperature of leaves of
Maidenhair tree (Ginkgo biloba), which was
observed consistently throughout the 1999 growing season relative to
their ambient CO2 (35 Pa) counterparts. We suggest that
increased sensitivity of leaves to ice damage after growth in elevated
CO2 provides an explanation for increased photoinhibition
observed in the field early and late in the growing season when low
nighttime temperatures are experienced. This new mechanism is proposed
in addition to the earlier postulated explanation for this phenomenon involving a reduction in the rate of triose-P utilization owing to a
decrease in the rate of carbohydrate export from the leaf.
1
D.J.B. gratefully acknowledges funding of this
work through awards from the Natural Environment Research Council of
the United Kingdom (GR8/4223 and GR3/11900) and a Royal Society
University Research Fellowship.
2
Present address: Department of Environmental Science,
University of Bradford, Bradford BD7 1DP, UK.
*
Corresponding author; e-mail d.j.beerling{at}sheffield.ac.uk; fax
44-222-0002.
© 2000 American Society of Plant Physiologists
