Foliar nutrition and wood growth in red pine: effects of darkening and defoliation on the distribution of14C-photosynthate in young trees

摘要

Young red pine trees were supplied with14CO2through a branch in the third whorl. Darkening or removal of all other needles caused a major diversion of14C to the expanding terminal shoot. Defoliation had a much greater effect than darkening. The diversion can be only partially explained on the basis of removal of competing sources of carbohydrate. Use as well as distribution of labeled photosynthate was affected by the treatments.