Effects of Sulphur Dioxide on Sugar and Free Amino Acid Content of Pine Seedlings

Treatment of jack pine ( Pinus banksiana Lamb.) seedlings with gaseous SO 2 resulted in a shift between the reducing and non‐reducing sugars. Increasing concentrations of gaseous SO 2 caused an increase in reducing sugars and a decline in the non‐reducing sugars, suggesting a conversion from the latter to the former at high SO 2 concentrations. The total amino acid content of the intact tissues also increased with increasing concentrations of gaseous SO 2 . Gas‐liquid chromatographic analyses of the amino acids indicated that SO 2 (1. 34 mg · m ‐3 for 96 h) resulted in an increase in the content of alanine, valine, glycine, isoleucine, leucine, threonine, aspartic acid tyrosine, lysine, and arginine, and a decrease in the content of serine and glutamic acid. The enzymatic and other implications of such changes are discussed.