CARBON ALLOCATION PATTERNS IN 2 CLOSELY-RELATED STOLONIFEROUS VACCINIUM SPECIES

Carbon translocation was studied in two populations of two closely rel ated, stoloniferous Vaccinium species; the sub-arctic V. microcarpum a nd the boreo-memoral V. oxycoccos, both growing in nutrient-poor bogs. The youngest tip of the stolen was labelled using pattern studied aft er four weeks of growth. The sub-arctic plants showed more acropetal t ranslocation than the boreal plants, indicating that the stolen apex a cts as a strong sink. This may reflect the larger need for this specie s to invest in lateral growth to be able to complete its life-cycle in the short growing season. The cutting-off of the apical region did no t affect carbon translocation. The reason for this might be that the r apidly developing leaves just behind the apex, and nor the apex itself , are the strongest carbon sinks. Alternatively, the high respiration rate of the apex might mask the carbon transported there. The sub-arct ic plants translocated relatively more carbon to leaves than to stolon s than did the boreal plants. This might reflect the stronger need for the subarctic species to save carbon in a more readily available form to efficiently utilize the more restricted periods of growth in its c limatically harsher environment.