Figure 1.

Dependencies of the rates of isoprene emission and net assimilation, and the chloroplastic DMADP pool size, on incident photosynthetic quantum flux density in hybrid aspen (clone 200) leaves. The measurements were carried out at an ambient CO₂ concentration of 390 μmol mol⁻¹, O₂ concentration of 210 mmol mol⁻¹, and leaf temperature of 28°C to 30°C. An in vivo method based on the postillumination isoprene release was used to determine the chloroplastic DMADP pool size concomitant with leaf physiological measurements (Rasulov et al., 2009). Error bars show sd (n = 5). Data were fitted by Equation 1 (r² > 0.98, P < 0.001 for all).