Fig. 1. Mean leaf osmotic potential of well-watered (W) and water-stressed (D) guayule in the summer and winter the day after irrigation. The osmotic potential was measured on 19 plants in each irrigation treatment in summer 2003 (five plants in each of four replications, with one plant missing in one replication), on eight plants in each irrigation treatment in summer 2004 (two plants in each of four replications), on nine plants in each irrigation treatment in winter 2003–2004 (three plants in each of three replications), and on four plants in each irrigation treatment in winter 2004–2005 (one plant in each of four replications). The vertical bar indicates ± standard error.