Effects of chronic air pollution stress on photosynthesis, carbon allocation, and growth of white pine trees
Comparisons of annual growth, photosynthetic capacity, and fate of photosynthetic products were made to determine the rate and case of declining vigor of oxidant-stressed white pine (Pinus strobus L.) growing near Oak Ridge, Tennessee. Three approximately 25-year-old trees were selected for study from each of three sensitivity classes based on needle color, length, and duration of retention. Growth ring analysis revealed comparable growth trends in intermediate and tolerant trees whereas sensitive trees experienced a steady decline in average ring width (70 percent decrease over 15 years) and a loss in capacity for recovery of growth. The fate of photosynthetically fixed /sup 14/C was followed after supplying /sup 14/CO/sub 2/ to in situ foliage four times (June, July, August, November) during the growing season. Carbon-14 transport patterns emphasized the role of older needles as sources of photosynthate for new needle growth in spring and storage sinks in the fall. Higher retention of /sup 14/C-photosynthate by foliage and branches of sensitive trees indicatd that photosynthante export to boles and roots was reduced. Photosynthetic capacity (CO/sub 2/ uptake/g dwt ) of foliage of sensitive and tolerant trees was similar. The ratio of respiratory to photosynthetic activity was significantly higher for foliage of sensitive trees. Results suggest that declining vigor of sensitive trees in ths area results from reductions in needle longevity, size, increased respiratory activity, and altered translocation patterns which are induced by chronic air pollution stress.
- Research Organization:
- Oak Ridge National Lab., TN
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6777012
- Journal Information:
- For. Sci.; (United States), Vol. 28:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
TRANSLOCATION
OZONE
PINES
SENSITIVITY
CARBON DIOXIDE
CHRONIC EXPOSURE
GENETIC VARIABILITY
PHOTOSYNTHESIS
PLANT GROWTH
TREE RINGS
BIOLOGICAL VARIABILITY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CONIFERS
GROWTH
LABELLED COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
POLLUTION
SYNTHESIS
TREES
560303* - Chemicals Metabolism & Toxicology- Plants- (-1987)
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)