INFLUENCE OF ALTITUDE, SAMPLING YEAR AND NEEDLE AGE CLASS ON STRESS-PHYSIOLOGICAL REACTIONS OF SPRUCE NEEDLES INVESTIGATED ON AN ALPINE ALTITUDE PROFILE
E. Bermadingerstabentheiner, INFLUENCE OF ALTITUDE, SAMPLING YEAR AND NEEDLE AGE CLASS ON STRESS-PHYSIOLOGICAL REACTIONS OF SPRUCE NEEDLES INVESTIGATED ON AN ALPINE ALTITUDE PROFILE, Journal of plant physiology, 148(3-4), 1996, pp. 339-344
The aim of the presented study was to characterize the physiological s
tate of spruce needles from an alpine profile depending on altitude (9
70-1420 m above sea level) and needle age class (current year needles,
one-year-old needles) during two consecutive years by investigating c
omponents of the antioxidative scavenging system (water extractable th
iols, ascorbic acid, total peroxidase). The chlorophyll content was me
asured as a non-specific indicator of the general plant condition. Wit
h the exception of thiols the one-year-old needles always had higher n
eedle contens of antioxidants and chlorophylls and the means of thiols
and chlorophylls were significantly higher in the second sampling yea
r. A more or less continous increase of antioxidants and a decrease of
chlorophylls with increasing altitude was observed from the middle el
evations (1140-1240 m a.s.l.) up to the highest site near the timberli
ne (1420 m a.s.l.) and was interpreted as a response of the needles to
increased oxidative stress due to the more uncomfortable environmenta
l conditions at these elevations. However, high levels of antioxidants
near the valley bottom (970-1050 m a.s.l.) also indicated an enhancem
ent of the detoxification system and rather low chlorophyll levels (me
ans of one-year-old needles <1100 mu g/g dw) probably reflected high e
nvironmental impact on the trees at these sites.