Figure 2.

Dependencies of net photosynthesis (Pn) and isoprene emission rates from mango leaves on leaf temperature under constant illumination (PAR of 1,000 µmol m^–2 s^–1). A, Average leaf isoprene emissions (GC-MS) and net photosynthesis rates as a function of leaf temperature from four mango leaves. Shaded areas represent ± 1 sd. Also shown are representative PTR-MS time series plots showing the influence of increasing leaf temperature on the dynamics of absolute emissions of [¹²C]isoprene and [¹³C_1–5]isoprene (B) and relative isoprene isotopologue emissions rates (percentage of total; C) from a single mango leaf during photosynthesis under ¹³CO₂. Arrows indicate periods of rapid ¹³C-depletion of isoprenoid intermediates followed by reenrichment. Vertical dashed lines represent optimum temperature ranges for net photosynthesis (Pn_max) and isoprene emissions (I_max).