Dresden 2020 – wissenschaftliches Programm
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UP 4.3: Vortrag
Dienstag, 17. März 2020, 15:40–16:00, HSZ 105
Ozone impact on plant physiology and nitrogen partitioning — •Stefanie Falk1, Ane Victoria Vollsnes2, Frode Stordal1, and Terje Koren Berntsen1 — 1University of Oslo, Department of Geosciences — 2University of Oslo, Department of Biosciences
Ozone is an important trace gas in the Earth’s atmosphere. Stratospheric ozone protects all lifeforms on its surface from harmful UV radiation. In the boundary layer, ozone is regarded as a toxic pollutant and cause to an average global loss of yield in the four major crops of about 3−15 %. Future projections indicate that high ozone concentrations may affect food security in the future especially in Asia.
Ozone alters the plants photosynthesis through, e.g. reduction of CO2 uptake (decrease in stomatal/ mesophyll conductance), processing of CO2 (decrease in enzymes/proteins important for light capture, electron transport, and carboxylation), and enhancement in defense and repair reactions. A key determinant for photosynthesis is the concentration of leaf nitrogen. Each CO2 processing step has a nitrogen cost associated.
In the absence of ozone, such a nitrogen cost model (LUNA in CLM5.0) has been shown to capture 55−65 % of the observed variation in the maximum electron transport rate Jmax and maximum carboxylation rate Vcmax, respectively.
Based on data of deciduous trees from recent peer-reviewed articles, we establish a relationship between accumulative ozone dose (CUO) and the change in nitrogen cost for photosynthesis and show first results.