Figure 6.

Modulation of the apparent K_i for l-malate, PEPc kinase activity, and translatable kinase mRNA by an increase in temperature at night. Control leaves (●) were exposed to ambient air. Half-N₂ leaves (○) were enclosed in an atmosphere of N₂ for the first half of the dark period to prevent malate accumulation. All leaves were subjected to an 8°C rise in temperature from 2:30 to 3 am. The half-N₂ leaves were subsequently exposed to ambient air at 27°C for the duration of the dark period. Samples for PEPc and PEPc kinase assays and RNA isolation were taken simultaneously from the same leaves at intervals over the dark period. Kinase activity and translatable mRNA values are expressed as percentages of the maximum reached in leaves during a normal dark period at 19°C. The results are from duplicate experiments.