© 2000 Heron Publishing—Victoria, Canada
Acid mist and soil Ca and Al alter the mineral nutrition and physiology of red spruce
P. G. Schaberg (1), D. H. Dehayes (2), G. J. Hawley (2), G. R. Strimbeck (2), J. R. Cumming (3), P. F. Murakami (1) and C. H. Borer (2)
1. Northeastern Research Station, P.O. Box 968, Burlington, VT 05402, USA / 2. School of Natural Resources, The University of Vermont, Burlington, VT 05405, USA / 3. Department of Biology, West Virginia University, Morgantown, WV 26506, USA / Received February 24, 1999
Summary
We examined the effects and potential interactions of acid mist and soil solution Ca and Al treatments on foliar cation concentrations,
membrane-associated Ca (mCa), ion leaching, growth, carbon exchange, and cold tolerance of red spruce (Picea rubens Sarg.) saplings. Soil solution Ca additions increased foliar Ca and Zn concentrations, and increased rates of respiration
early in the growing season (July). Soil Al treatment had a broad impact, reducing foliar concentrations of Ca, Mg, Mn, P
and Zn, and resulting in smaller stem diameters, sapling heights and shoot lengths compared with soil treatments with no added
Al. Aluminum treatment also reduced respiration when shoots were elongating in July and decreased net photosynthesis at the
end of the growing season (September). Three lines of evidence suggest that Al-induced alterations in growth and physiology
were independent of foliar Ca status: (1) Ca concentrations in foliage of Al-treated saplings were within the range of sufficiency
established for red spruce; (2) mCa concentrations were unaffected by Al treatment; and (3) no Al × Ca interactions were detected.
Acid mist treatment increased foliar Fe and K concentrations and increased leaching of Ca, Mg, Mn, Zn, Fe, and Al from foliage.
Leaching losses of Ca were more than twice those of the element with the next highest amount of leaching (Zn), and probably
led to the reductions in mCa concentration and membrane stability of acid-treated saplings. Acidic mist resulted in enhanced
shoot growth, and consistent reductions in foliar cold tolerance in the fall and winter. Of the few significant interactions
among treatments, most involved the influence of mist pH and Al treatment on foliar nutrition. In general, reductions in cation
concentration associated with Al addition were greater for pH 5.0-treated saplings than for pH 3.0-treated saplings. We propose
that H+-induced leaching of mCa from mesophyll cells is the mechanism underlying acid-induced reductions in foliar cold tolerance
of red spruce.
Keywords:
acid precipitation, aluminum, calcium, cations, cold tolerance, foliage, growth, leaching, membrane-associated calcium, photosynthesis,
Picea rubens, respiration.
