Endogenous CAN1 and CAN2 activity. (A) Changes in endogenous CAN1 and CAN2 activity during stem development. DNase activity of protein extracts from the 4–8 week old stems were analyzed. The abbreviations for the gel tracks refer to the part of stem: (T) – stem tip, (Tm) - upper middle part of stem, (Bm) - lower middle part of stem, (B) - stem base. CAN1 (C1) and CAN2 (C1) nucleases transiently expressed in protoplasts were used as positive controls. (B-C) The endogenous CAN1 and CAN2 nuclease activity of individual leaves of 7 week old (B) and 8 week old (C) rosettes. Consecutive leaf extracts are arranged from the youngest (1) to oldest (10) leaf of rosettes. The CAN1 (C1) and CAN2 (C1) controls as above (Figure 5A).