Figure 5.

Measurement of flux through the TCA cycle and OPP pathway in wild-type and transgenic tubers with decreased PKc by incubation of tuber discs in positionally labeled isotopomers of [¹⁴C]Glc. Tuber discs were cut from freshly harvested 10-week-old tubers and incubated in [¹⁴C]Glc labeled in either the C1, C3,4, or C6 position for 6 h. The evolved CO₂ gas was continuously captured in 10% KOH and the amount of label released as CO₂ was measured. TCA cycle flux was determined as the ratio of label evolved as CO₂ from the C3,4 incubation compared to the C1 incubation, while OPP pathway flux was determined as the ratio of label evolved as CO₂ from the C6 incubation compared to the C1 incubation. Data shows the mean of three replicate incubations per Glc isotopomer per line, and error bars represent ses. *, Significant difference from wild-type levels (P < 0.05); n = six tubers from six different plants.