Figure 5.

Microautoradiographs of leaf areas which were exposed to ¹⁴CO₂. (A) In the unstimulated leaf, label is concentrated in bundle sheath cells (B). (B) In leaves which were cold-shocked at their tips label concentrated at the cell walls between mesophyll (M) and bundle sheath cells (arrows). (C) In tip-wounded leaves label was more or less distributed equally in all living cells. There was a slight accumulation, however, at the mesophyll/bundle sheath cell wall. P, phloem; PX, protoxylem; V, vessel.