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.