Translocation from Soybean Leaves, II.

Abstract

A simple method for the localized feeding of radiocarbon dioxide to leaves is described. C14O2 is generated within a flexible tube above a column of mercury and withdrawn through the serum vial stopper at the end of the tube by means of a hypodermic needle and syringe. It is then injected through a similar serum vial stopper into an L-shaped cylinder whose opposite end is flanged, greased lightly and attached gently to the area of the leaf to be fed the C14O2. In 20 min. experiments with soybean leaflets it is found that the primary causative condition influencing the direction and amount of photosynthate translocation is growth. The presence of a sugar gradient resulting from starvation does not appear to influence translocation. Diffusion from one area of a leaf to another is so slow as to be negligible compared to the rate of translocation through the veins.