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| Titel |
Emission of aromatic compounds from poplar |
| VerfasserIn |
Katja Behnke, Monika Springer, Joerg-Peter Schnitzler, Astrid Kiendler-Scharr, Thomas Mentel, Ralf Tillmann, Stefanie Andres, Einhard Kleist, Juergen Wildt |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048343
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| Zusammenfassung |
| While unstressed grey poplar (Populus x canescens) emits mainly isoprene, plants infested
with Pollaccia radiosa showed strong additional emissions of green leaf volatiles (GLV),
terpenoids (mono-, sesqui- and homoterpenes), and aromatic compounds. To obtain more
information regarding the mechanisms of stress-induced emissions of aromatic compounds
we tried to mimic Pollaccia radiosa infestation by ozone- (O3) or methyl jasmonate- (MeJA)
exposures.
Exposing poplar plants to MeJA resulted in strong emissions of terpenoids. Contrary,
emissions of aromatic compounds and GLV were low if detectable at all. For O3 exposures
the plants’ responses were dependent on O3 flux densities (Φ(O3)). O3 exposures at
Φ(O3) < 50 nmolm-2s-1 for up to 90 to 100 minutes did not induce strong
GLV emissions but induced a strong release of aromatic compounds. The pattern of
aromatic compounds was dominated by methyl salicylate emission and the emission
strengths of reduced carbon reached several percent of the carbon uptake via net CO2
assimilation. Labeling of the emitted volatiles during 13CO2 application proved
the de novo biosynthesis of stress induced emissions of terpenoids and aromatic
compounds.
During experiments at Φ(O3) < 50 nmolm-2s-1 the emission patterns of aromatic
compounds differed markedly from those observed following infection by Pollaccia radiosa.
Enforcing O3 exposures to levels inducing GLV emissions (Φ(O3) up to 200 nmol m-2 s-1)
led to emission patterns of aromatic compounds, similar to those found after fungal
infection. The emission strengths measured for aromatic compounds emitted after such
acute ozone stresses were much lower than those found at lower Φ(O3). From this
observation we presumed that ozone induced membrane-degradation and the resulting
formation of jasmonic acid (JA) suppresses the emissions of aromatic compounds from
poplar.
Indeed, the ozone-induced emission of aromatic compounds from poplar, namely methyl
salicylate, could be suppressed when applying MeJA (< 0.5 ppb) to ozone stressed plants. In
parallel the emission pattern of aromatic compounds shifted from a methyl salicylate
dominated emission to an emission pattern with indole as main aromatic compound. This
switch indicates a strong cross talk between jasmonic acid and shikimate pathway-related
biosynthesis of volatile aromatic compounds.
Here we show that oxidative stress to poplar, below the threshold of membrane oxidation
can induce a strong de novo production of volatile aromatic compounds requiring several
percent of intrinsic net CO2 assimilation. However, the increase of oxidative stress to a level
resulting in membrane degradation and accumulation of jasmonic acid diminished the carbon
costs for volatile aromatic compounds and increased the carbon costs for terpenoids. |
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