Original PTR-MS recording of transients in isoprene emission following rapid changes in temperature. The leaf was always stabilized at 33°C, and temperature was changed step-wise down and up from this reference value. After the exposure to 44°C, the recovery at 33°C required an additional 30 min. In the figure, during the periods with zero isoprene emission, the system was changed to the reference stream. Four replicate experiments were conducted, and in each case reproducible kinetics were observed.