Fig. 3. Mean midday C exchange rate of well-watered (W) and water-stressed (D) guayule in December 2003 and January and February 2004, an average of 3 to 4 d after irrigation of the water-stressed plants. Carbon exchange measurements were recorded within 1 h of solar noon. Measurements were taken on 12 plants in each irrigation treatment (three plants in each of four replications). The vertical bar indicates ± standard error.