MOVEMENT PATTERNS OF CARBON FROM SOURCE TO SINK IN CRANBERRY

The source of photosynthate for developing cranberry (Vaccinium macroc arpon Ait.) fruit can be partitioned spatially among new growth acrope tal to fruit, 1-year-old leaves basipetal to fruit, and adjacent uprig hts along the same runner. Cranberry uprights were labeled with (CO2)- C-14 in an open system with constant activity during flowering or frui t development. When new growth acropetal to fruit was labeled, substan tial activity was found in flowers or fruit. Little activity was found in basipetal tissues, When 1-year-old basipetal leaves were labeled, most of the activity remained in the labeled leaves, with some activit y in flowers or fruit. Almost no labeled C moved into acropetal tissue s. When new growth of adjacent nonfruiting uprights on the same runner were labeled, almost no activity moved into the fruiting upright. The se data confirm that new growth acropetal to developing flowers and fr uit is the primary source of photosynthate for fruit development, Furt hermore, they show that during the short time studied in our experimen t, almost no C moved from one upright to another.