Figure 1.

Seasonal variations (a) and effects of branch age (b) on net assimilation (A) and isoprene emission rates (Is) from a shrub of M. communis. Measurements were performed at leaf temperature of 26°C and light intensity of 1,000 μmol m⁻² s⁻¹. The seasonal variations were measured at intercellular CO₂ concentration (c_i) values between 450 and 500 μL L⁻¹, and the effect of branch age was measured at ambient CO₂ concentrations (approximately 350 μL L⁻¹).