© 2007 Heron Publishing—Victoria, Canada
Interspecific variability of stem photosynthesis among tree species
Daniel Berveiller (1, 2), Daniel Kierzkowski (3) and Claire Damesin (1)
1. Laboratoire Écologie, Systématique et Évolution (ESE), CNRS & Université Paris Sud, Bât 362, 91405 Orsay Cedex, France / 2. Corresponding author (daniel.berveiller@ese.u-psud.fr) / 3. Laboratory of General Botany, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland / Received November 25, 2005; accepted March 19, 2006; published online October 2, 2006
Summary
The photosynthetic characteristics of current-year stems of six deciduous tree species, two evergreen tree species and ginkgo
(Ginkgo biloba L.) were compared. Gas exchange, chlorophyll concentration, nitrogen concentration and maximum quantum yield of PSII were
measured in stems in summer and winter. A light-induced decrease in stem CO2 efflux was observed in all species. The apparent gross photosynthetic rate in saturating light ranged from 0.72 µmol m–2 s–1 (ginkgo, in winter) to 3.73 µmol m–2 s–1 (Alnus glutinosa (L.) Gaertn., in summer). Despite this variability, a unique correlation (slope = 0.75), based on our results and those reported
in the literature, was found between gross photosynthetic rate and dark respiration rate. Mass-based gross photosynthetic
rate decreased with stem mass per area and correlated to chlorophyll concentration and nitrogen concentration, both in summer
and winter. The radial distribution of stem chlorophyll differed among species, but all species except ginkgo had chlorophyll
as deep as the pith. In summer, the maximum quantum yield of stem PSII (estimated from the ratio of variable to maximal fluorescence;
Fv/Fm) of all species was near the optimal value found for leaves. By contrast, the values were highly variable in winter, suggesting
large differences in sensitivity to low-temperature photoinhibition. The winter values of Fv/Fm were only 31–60% of summer
values for the deciduous species, whereas the evergreen conifer species maintained high Fv/Fm in winter. The results highlight the interspecific variability of gross photosynthesis in the stem and its correlation with
structural traits like those found for leaves. The structural correlations suggest that the selection of photosynthetic traits
has operated under similar constraints in stems and leaves.
Keywords:
chlorophyll, F
v/F
m, nitrogen, stem gas exchange.
