Fig. 1

Net CO₂ assimilation rate (A) of two Acacia species (A. aneura and A. melanoxylon) under well-watered (open circle) and drought-stressed (closed circle) treatments. The vertical line indicates the start of a period where water was withheld completely. The shaded areas indicate the time of heatwaves when air temperatures exceeded 30 °C. Values are means (±SE) of n = 5. Effects of sampling day, species and treatment as well as their interaction were statistically significant (p < 0.01), and asterisks indicate significant differences between water treatments at each sample time (*p < 0.05; **p < 0.01; ***p < 0.001). Letters indicate significant differences between the species under drought-stressed (capital letters) and well-watered treatment (small letters)