Effects of chronic exposure to ozone on soluble sugar and ascorbic acid contents of pine seedlings

Small seedlings of five pine species (Pinus strobus, echinata, elliottii, serotina, and taeda) were exposed to low levels of ozone for periods from 5 to 22 weeks. Exposure to 5 parts per hundred million ozone resulted in significant increases in total soluble carbohydrates, reducing sugars, and ascorbic acid. In seedlings exposed to 15 pphm ozone, soluble sugars were higher than in the controls but ascorbic acid levels were not.