Figure 6. Foliage abscisic acid (ABA) levels (A and B) and leaf water potentials (Ψl) (C and D) as branches of the conifer species Callitris rhomboidea (A and C) and angiosperm speciesUmbellularia californica (B and D) that were rehydrated overnight were subsequently dehydrated on the laboratory bench for 12 h. Bench dehydration started at time = 0. Branches were taken from either unstressed plants (white) or plants that were exposed to a soil drought for 10 d after peak ABA levels were measured (black). Data represent means and standard errors (n=5) in C. rhomboidea and pooled data for 5 branches in U. californica . Generalized additive model (GAM) curves and standard errors are represented by black solid and dashed lines for ABA levels in branches harvested from U. californica plants exposed to drought for 10 d after peak ABA and grey lines for ABA levels in branches harvested from unstressed U. californica plants.