Transcript Kick-off Meeting

Group Matyssek
Introduction to the Kranzberg site,
Hypotheses and Methods,
Interactions and Timetable
Ecophysiology of Plants
Working Team: Markus Löw (PhD Student), Häberle and Matyssek
Kranzberg site
Experimental Design
10 adult beech trees
1x O3 (ambient )
(control)
2x O3
(<150 ppb)
Sun
branches
Shade
branches
some facts on Kranzberg Forest
beech/spruce mixed stand
age: 50-60 y. height: 25 m
precipitation: 730 -790 mm
mean temp.: 7.0 -7.5 °C
ozone conc.: daily mean: 40 ppb
max. 100 ppb
Scaling within CASIROZ
Tree
My work:
Branch
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Stem increment
Stem respiration
Xylem Sap Flow
Growth pattern
Gas exchange of twigs
Leaf
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patterns •
species
Root
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Cell
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metabolism
antioxidants
Gene expression
Chlorophyll fluorescence
Photosynthetic performance
Stomatal conductance and transpiration
Seasonal phenology
Main Hypotheses of Group Matyssek
• whole-tree response patterns to chronic O3 stress
relates to the O3 uptake rater than AOT concept
Gas exchange  conductivities  validation
Uptake (flux) vs. AOT concept
Micro-deposition samplers (Fabian)
Carbon sink (C gain, Biomass production, Sugars
[Rennenberg, Oßwald])
Xylem sap flow (whole-tree C & N cycling
(Rennenberg)
Isotope ratios 13C/12C, WUE, 18O/16O (Rennenberg),
PEPC / RUBISCO (Oßwald)
• Porometry and continuous gas exchange measurements
• structural & functional branch assessments:
first flush, lammas shoot, phenology  C sink
Main Hypotheses II
• O3 exposure in shade crowns cannot be neglected with
respect to whole-tree sensitivity
• O3 exposure during dusk and at night is significant.
Therefore the risk of O3 injury is as high as under dayconditions (stomata closed and no light dependent supply
of antioxidants)
• Antioxidant status and damage amplifying reactions
determine the degree of symptom development
Methods: Night time measurements in cooperation
with antioxidant-measurements (Tausz)
Main Hypotheses III
• chronic Ozone impact constrains carbon sink strength in
adult trees to an extent which is relevant in relation to
expected stimulation under increasing CO2 conditions
Assessments: structural & functional branch
assessments, stem increment (Dendrometer),
respiration, senescence
Main Hypotheses IV
• Response mechanisms to ozone in adult trees are not
consistent with findings in young trees
Comparison within CASIROZ between adult and
young trees
Comparison to published data
Interactions
Examples of immediate cooperations:
Rennenberg (Isotopes, C & N cycling)
Wieser (Gas exchange young trees, branch autarchy?)
Oßwald (RUBISCO, PEPC, sugars, starch)
Tausz (antioxidants, night assessments)
Hanke (leaves: cytokinins, ABA)
Ceulemans (modeling)
Fabian (climatic data, O3-regimes)
Timetable