Aufnahme und Einbau 15N-markierter Stickoxide durch krautige und holzige Pflanzen
Eickriede, A. (Corresponding author)
Publikationen vor 2000; PRE-2000; Retrocat
Jülich Forschungszentrum Jülich, Zentralbibliothek, Verlag 1998
XII, 127 p.
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Berichte des Forschungszentrums Jülich 3568
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Please use the identifier: http://hdl.handle.net/2128/22614 in citations.


At the Research Centre Jülich a special system was developped to expose plants under defined climatic conditions to a nitrogen oxide enriched atmosphere (LATUS, 1989; SEGSCHNEIDER, 1994). In completition and extension to former studies sunflowers ($\textit{Helianthus annuus}$ L.), mays ($\textit{Zea mays}$ L.) and poplar ($\textit{Populus tremula}$ x P. alba) were exposed to nitrogen oxides. By using $^{15}$N enriched nitrogen oxides ($^{15}$NO$_{2}$ and $^{15}$NO, summarised as $^{15}$NO$_{X}$) the uptake and incorporation of $^{15}$NO$_{X}$ in dependance of the exposition concentration (30 to 100 ppb $^{15}$NO, 20 ppb $^{15}$NO$_{2}$), nitrogen nutrition (nitrate or ammonium), and harvesting time were examined. Moreover, the influence of nitrogen oxide exposition on the distribution pattern of $^{15}$NO$_{X}$ nitrogen within the plants and on the amino acid content of plant leaves was investigated. The resultes could be summarised es follows: 1. Leaves are the main sites of uptake of nitrogen oxides. After 7 h exposure to $^{15}$NO in sunflowers as well as in maize 75 to 85 % of the $^{15}$NO nitrogen were located in the leaves independent from exposure concentration and nitrogen nutrition. 80 % of the $^{15}$NO$_{2}$ nitrogen were located in the leaves of sunflower that were exposed to $^{15}$NO$_{2}$, and nearly 90 % in the leaves of popular exposed to the same concentrations of $^{15}$NO$_{2}$. These results show, that leaves are not onfy the main sites of uptake but they are also the main storage sites for nitrogen Laken up as nitrogen oxides from the atmosphere. Only the remaining $^{15}$N tracer was found in the seems and roots. During an exposure of 7 h the translocation of the $^{15}$N tracer between the plant parts seems to be small. 2. After 7 h exposure to $^{15}$NO at a range of 30 to 100 ppb a linear relationship between $^{15}$NO concentrations and the $^{15}$N enrichment in the leaves was found. This indicates thatthe availability of the enzymes involved in the assimilation of $^{15}$NO nitrogen is not a limiting factor at the concentrations applied in this work. An influence of a compartimentation of the different nitrogen fractions on the $^{15}$N enrichment was not the aim of this study. 3. After 7 h exposure of sunflower and maize to $^{15}$NO-Exposition the uptake of nitric oxide was 8 to 10 times smaller compared to the exposure to $^{15}$NO$_{2}$. In the concentration range of 30 to 100 ppb $^{15}$NO the average nitric oxide uptake according to the leaf area were 0,3 to 1,4 nmol m$^{-2}$ s$^{-1}$ by sunflower, and 0,4 to 0,8 nmol m$^{-2}$ s$^{-1}$ by maize. In this study the NO uptake does not depend an the nitrogen nutrition. [...]