RELATIONSHIPS AMONG FOLIAR CHEMISTRY, FOLIAR POLYAMINES, AND SOIL CHEMISTRY IN RED SPRUCE TREES GROWING ACROSS THE NORTHEASTERN UNITED-STATES

Forest trees are constantly exposed to various types of natural and an thropogenic stressors. A major long-term goal of our research is to de velop a set of early physiological and biochemical markers of stress i n trees before the appearance of visual symptoms. Six red spruce (Pice a rubens Sarg.) stands from the northeastern United States were select ed for collection of soil and foliage samples. All of the chosen sites had soil solution pH values below 4.0 in the Oa horizon but varied in their geochemistry. Some of these sites were apparently under some fo rm of environmental stress as indicated by a large number of dead and dying red spruce trees. Samples of soil and needles (from apparently h ealthy red spruce trees) were collected from these sites four times du ring a two-year period. The needles were analyzed for perchloric acid- soluble polyamines and exchangeable inorganic ions. Soil and soil solu tion samples from the Oa and B horizons were analyzed for their exchan ge chemistry. The data showed a strong positive correlation between Ca and Mg concentrations in the needles and in the Oa horizon of the soi l. However, needles from trees growing on relatively Ca-rich soils wit h a low exchangeable Al concentration and a low Al:Ca soil solution ra tio had significantly lower concentrations of putrescine and spermidin e than those growing on Ca-poor soils with a high exchangeable ill con centration and a high AI:Ca soil solution in the Oa horizon. The magni tude of this change was several fold higher for putrescine concentrati ons than for spermidine concentrations. Neither putrescine nor spermid ine were correlated with soil solution Ca, Mg, and Al concentrations i n the B horizon. The putrescine concentrations of the needles always c orrelated significantly with exchangeable Al (r(2)=0.73, p less than o r equal to 0.05) and soil solution Al:Ca ratios (r(2)=0.91, p less tha n or equal to 0.01) of the Oa horizon. This suggests that in conjuncti on with soil chemistry, putrescine and/or spermidine may be used as a potential early indicator of Al stress before the appearance of visual symptoms in red spruce trees.