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| Titel |
Leaf photosynthesis/respiration relationships of different tree species in the northwestern part of Russia. |
| VerfasserIn |
V. Pridacha, T. Sazonova, A. Olchev |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250065503
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| Zusammenfassung |
| Measurements of leaf photosynthesis, respiration and stomatal conductance of Norway
spruce (Picea abies (L.) Karst), Silver (Betula pendula Roth), White (Betula pubescens) and
Karelian (Betula pendula var. carelica) birches were provided using the portable
photosynthesis system LI-6400 (Li-Cor, USA) on the experimental plots of the Forest
research Institute of Karelian Research Center of RAS in Petrozavodsk, Russia. LI-6400
allows to provide the measurements of photosynthesis and respiration rates of individual
leaves at various PAR, temperatures, humidity and concentration of CO2 in the measuring
chamber. During the field campaigns in 2011 the CO2 and light response curves of
photosynthesis of leaves under different air temperatures as well as the temperature response
functions of dark respiration (Rd) of the leaves of different species were estimated.
The measuring program is include also the measurements of nitrogen content in
leaves.
The method suggested by Sharkey et al (2007) was used to estimate the maximal
velocity of Rubisco for carboxylation (Vcmax), the rate of electron transport at light
saturation (Jmax), photorespiratory compensation point as well as the rate of use of
triose phosphates (TPU) that characterizes the availability of internal inorganic
phosphates (Ci) in leaves for Calvin’s cycle. It was assumed that the initial slope of the
relationship between leaf photosynthesis rate and CO2 concentration in sub-stomatal
air space (Ci < 200 ppm) can be considered as an area of Rubisco limitation of
photosynthesis. The upper part of CO2 response curve from approximately 300 ppm
and higher is influenced by, first of all, the rate of regeneration of RuBP, and after
that by availability of inorganic phosphate in leaves. The temperature dependences
of Vcmax, Jmax and TPU were estimated using the statistical analysis of Vcmax
and Jmax data set using equations suggested by Medlin et al (2002). Temperature
dependence function of TPU was derived using algorithm proposed by Sharkey et al
(2007).
The results of field measurements in summer 2011 show a relatively weak differences
among Vcmax, Jmax and TPU, and also Rd for Silver, White and Karelian birches. The
maximal values of Vcmax (T=25Ë C) are obtained for the Karelian birch (Vcmax (T=25Ë C)
= 117 μmol m-2 s-1), and the minimum values - for the Silver birch (Vcmax (T=25Ë C) =
97 μmol m-2 s-1). The maximum values Jmax (T=25Ë C) are obtained for the
White birch (Jmax (T=25Ë C) = 164 μmol m-2 s-1), and minimum also for the
Silver birch (Jmax (T=25Ë C) = 157 μmol m-2 s-1). Values TPU max are varied
from 11.0 to 12.3 μmol m-2 s-1, and Rd (T=25Ë C) - from 2.0 to 2.4 μmol m-2
s-1.
The results of provided leaf photosynthesis, respiration and stomatal conductance
measurements were used in the process-based Mixfor-SVAT model (Olchev et al 2002, 2008)
to derive the possible response of CO2/H2O budgets of Karelian forest ecosystems to future
climatic changes.
The study was supported by grants (11-04-01622-a and 09-04-00299-a) of the Russian
Foundation of Basic Research (RFBR). |
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