Young spruce (Picea abies [L.] Karst; 2-yr)
and beech trees (Fagus sylvatica L.; current-year and 1-yr-old
seedlings) were grown under field conditions at a rural
site near the city of Basel (Schönenbuch; 400 m above sea
level) and 2-yr-old spruce trees at an elevated montainous site (Wengernalp;
1890 m above sea level). The plants
were exposed in open-top-chambers (OTC) either to charcoal-filtered air
or ambient air with ozone being the
predominant air pollutant at both sites. The exposures lasted up to 1 yr.
the end of the growth period the plants
were harvested and the pool sizes of the major non-structural carbohydrates
determined. Exposure to
ambient air compared with filtered air controls caused an increase of glucose,
fructose, pinitol, starch and, in some
cases, sucrose in needles whereas carbohydrate contents in roots and twigs
of spruce were reduced, in particular
at Wengernalp. In beech saplings at Schönenbuch, a significant
rise of sucrose and, in some cases, of raffinose,
together with a significant reduction of glucose and fructose was observed
in buds, leaves, twigs, and roots in
ambient air compared with filtered air. In phloem exudates of current year
seedlings, a 54–160% higher
content of carbohydrates was found in ambient air than in filtered air.
In roots of the beech saplings, the amount
of soluble carbohydrates increased and starch contents mostly decreased.
general, starch storage in roots and
stems was more abundant in beech trees. Spruce, especially at the mountainous
site, accumulated high amounts
of soluble carbohydrates in needles, in particular glucose.