Figure 2.

Characteristic modifications in leaf isoprene and net assimilation rates, stomatal conductance to water vapor, and chlorophyll fluorescence upon application of 20 mm malate solution in hybrid aspen (clone H200). The measurements were conducted at the standard conditions of leaf temperature of 30°C, light intensity of 700 μmol m⁻² s⁻¹, and leaf chamber CO₂ concentration of 400 μmol mol⁻¹. The start of inhibitor application is shown by the black arrow. F_m′ denotes the maximum chlorophyll fluorescence yield and F_0,a the minimum fluorescence yield in a partly relaxed state achieved by illuminating the leaves with far-red light (150 µmol m⁻² s⁻¹). The red arrow indicates the postulated transition to the reverse mode of the malate shuttle.