Composition of root pressure exudate from conifers.

Abstract

Root pressure exudates collected from detopped seedlings of Douglas-fir, grand fir, noble fir, Pacific silver fir, ponderosa pine, lodgepole pine, and Engelmann spruce were analyzed for sugars, amino acids, organic acids, nitrogen, potassium, calcium, and magnesium. Sugar concentrations ranged from 0.10 percent to 5 percent, and included glucose, sucrose, fructose, and two unknowns, possibly rhamnose, and ribose. Amino acid concentrations ranged from 0.02 to 0.10 percent, and organic acids from 0.01 to 0.06 percent. Aspartic acid, glutamic acid and glutamine were the main amino acids in the exudates of all species with lesser amounts of glycine, serine, asparagine, arginine, leucine, and alanine. Nitrogen concentrations ranged from 0.005 to 0.012 percent, potassium from 0.006 to 0.018 percent, and calcium from 0.001 to 0.005 percent. Magnesium concentration was 0.001 percent in all species. The pH of the exudates ranged from 5.3 to 5.7. Except for the relatively high concentrations of sugar in the exudates from grand fir and noble fir, there were no species-related differences in amounts of the various constituents.

Citation

Ketchie, D.O.; Lopushinsky, W. 1981. Composition of root pressure exudate from conifers. Res. Note PNW-RN-395. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 6 p