Foliar nutrition and growth in Red Pine: distribution of photoassimilated carbon in seedlings during bud expansion

14CO2 was supplied to shoots of 4-year-old seedlings of red pine, and segments analyzed after 8 h, 3 days, and 7 days. The distribution of 14C after 7 days was similar to that observed earlier in a seedling 6 days after feeding. This pattern of spatial distribution developed within 3 days, after which it was stable.Most of the 14C was found initially in sugars, but redistribution among metabolites continued for 7 days. Transfer to insoluble compounds reached 55–60% in the seedlings, more in the expanding bud and the leaves. Glucose and fructose were initially equally labeled, but the ratio of 14C fructose to 14C glucose increased with time as labeled glucose disappeared more rapidly.Transfer of 14C to quinic and shikimic acids began immediately in the expanding bud and after 3 days these acids contained more of the activity in the bud than sugars. Young leaves also acquired substantial label in quinic and shikimic acids, but the major increase occurred later.