Canadian Forest Service Publications
Nitrogenous substances associated with differential cone production responses of Douglas-fir to ammonium and nitrate fertilization. 1970. Ebell, L.F.; McMullan, E.E. Canadian Journal of Botany 48(12): 2169-2177.
Issued by: Pacific Forestry Centre
Catalog ID: 28183
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Nitrogenous substances were analyzed from 6-week-old foliage of 13-year-old Douglas fir, treated at vegetative bud break with 200 to 1600 lb/ac of ammonium or nitrate nitrogen. Increasing rates of nitrate nitrogen elevated seed cone production the next year by 2 to 7 times, whereas ammonium nitrogen produced no responses. Total nitrogen increases and shoot growth were similar from the two forms of nitrogen. Increases in total free amino acids with increasing rates of nitrate treatment were double those from ammonium, but size of the free amino acid pool appeared unrelated to seed cone production. Amino acid patterns, and traces of several guanidino compounds, from ammonium treatments did not vary appreciably from those of the untreated control. Most of the increase in total nitrogen from ammonium treatment was incorporated as protein, but electrophoretic patterns did not vary qualitatively with the form of nitrogen supplied. Large accumulations of basic amino acids, notably arginine, and guanidino substances resulted from nitrate treatment. This arginine-type metabolism appeared quantitatively associated with seed cone production.