© 2000 Heron Publishing—Victoria, Canada
Influence of temperature and leaf-to-air vapor pressure deficit on net photosynthesis and stomatal conductance in red spruce
(Picea rubens)
Michael E. Day (1)
1. Department of Forest Ecosystem Science, University of Maine, 5755 Nutting Hall, University of Maine, Orono, ME 04469-5755,
USA (Day@apollo.umenfa.maine.edu) / Received March 3, 1999
Summary
The roles of temperature (T) and leaf-to-air vapor pressure deficit (VPD) in regulating net photosynthesis (Anet) and stomatal conductance (Gs) of red spruce (Picea rubens Sarg.) were investigated in a field study and in a controlled environment experiment. Both Anet and Gs exhibited a relatively flat response to temperatures between 16 and 32 °C. Temperatures between 32 and 36 °C markedly decreased
both Anet and Gs. Vapor pressure deficits above 2 kPa had significant effects on both Anet and Gs. The influence of VPD on Anet and Gs fit a linear response model and did not interact significantly with T effects.
Keywords:
carbon gain, climate warming, drought, gas exchange, respiration, tree decline.
