Fig. 1.

Responses of (A, B) photosynthetic rate (A) and (C, D) observed ¹³C photosynthetic discrimination (${\Delta }_{obs}^{13}$) to variation in the CO₂ partial pressure inside the leaf (C_i) in Setaria viridis (circles) and Zea mays (squares). In Setaria, three leaf temperatures (T_L) were measured: 40, 25, and 10 °C, as indicated in the key. Measurements in Zea were at T_L=25 °C. Values are means ±SE; n=4 in Setaria and n=3 in Zea.