Figure 2.

Altered apyrase transcript and activity under the control of the 35S promoter affects tuber development. A, Combined transcript levels of StApy1 and StApy3 in tuber tissue of RNAi lines (two-digit code) and overexpressors (three-digit code) were determined from cDNA by real-time PCR and expressed as percentages of the wild type. B, Apyrase activity was analyzed using an assay containing 1 mm ATP as substrate, and the activities are expressed as percentages of the wild type. C, Lines with decreased apyrase expression grown for 10 weeks in a phytotron produced a higher number of smaller tubers showing a rod-like shape (see D). Results are means ± se, n = 6 to 8 (A and B) and 10 to 13 (C). Significant differences from the wild type according to Student's t test are indicated with asterisks (P < 0.05). D shows typical examples.