Fig. 3.

Relationships between daily integrals of respiration per unit of mass (A) and per unit of area (B), and mean night-time temperature on different measurement dates, for soybeans leaves grown and measured at ambient and ambient +350 μmol mol⁻¹ [CO₂]. For respiration rates per unit of mass, linear regressions had r² values of 0·57 and 0·69 for ambient and elevated [CO₂], respectively, and exponential relationships had r² values of 0·59 and 0·68 for ambient and elevated [CO₂], respectively. For respiration rates per unit of area, linear regressions had r² values of 0·27 and 0·50 for ambient and elevated [CO₂], respectively, and exponential relationships had r² values of 0·27 and 0·51, respectively.