Effects of NO2 on Inflorescence Length, Pollen/Seed Amount and Phenolic Metabolites of Common Ragweed (Ambrosia artemisiifolia L.)
Ambrosia artemisiifolia (common ragweed) is native to North
America; it is a monoecious and wind-pollinated herbaceous annual plant that
belongs to the Asteraceae family and has expanded its distribution out of its
native range to Europe, Australia, Asia, South Africa and South America. And its
pollen is known to be highly allergenic.
Environmental
changes may increase the severity of pollen as stimulated atopic disease by
influencing the large-scale distribution and local incidence of allergenic
species, the flowering time, the pollen production and the allergenicity of
individual pollen grains. It has been shown that elevated CO2
concentrations result in an increase of A.
artemisiifolia growth and pollen production.
In this study, the
authors altered the gaseous air pollution by linking the pollen and seed production
of A. artemisiifolia with elevated NO2
levels and emphasized that this environmental change affected the pollen
amount, as well as phenolic metabolites, which is relevant to human health.
A. artemisiifolia seeds were collected from a single plant
at an outdoor stand (Bad Waldsee, Baden-Württemberg, Germany) to prevent
epigenetic-caused effects. Seeds were sown in standard soil (Floradur®,
Bayerische Gärtnerei Genossenschaft, München, Germany) in small multiflor
palettes (6 × 6 cm) and transferred into four Plexiglas sub-chambers (1.1 m ×
0.9 m × 0.8 m) that were placed in Phytotron walk-in chambers. All physical
parameters, including the wind velocity were identical in the sub-chambers.
The results
indicated that regarding morphological parameters, increased NO2 had
no effect on the inflorescence length, whereas elevated CO2 resulted
in an increased length of the main inflorescence; regarding allergenicity, the
pollen amount clearly increased in both years of the study by approximately 70%
to 80%.
In conclusion, the
data on A. artemisiifolia fumigated
with elevated NO2 support the hypothesis that the overall
allergenicity might be increased by an increased pollen amount. However,
differences in the estimation of allergen exposure between pollen amount and
ELISA data must be considered. As the overall seed production decreased under elevated
NO2, the dispersal of A.
artemisiifolia should not be affected by this air pollutant.
Article by Feng
Zhao, et al, from Germany and Switzerland.
Read more @ http://mrw.so/4pTKTF
Image by BJ Stacey, from Flickr-cc.
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