Table 3.

Flag leaf stomatal conductance (gs, mol m⁻² s⁻¹), internal [CO₂] (Ci, µmol CO₂ mol⁻¹ air), total soluble proteins (TSP, g m⁻²), total Rubisco activity (Vt, µmol CO₂ m⁻² s⁻¹) and Rubisco activation state (Act%, %) before and after foliar application of ABA to the leaves of the wild-type (WT) barley genotype Steptoe and the ABA-deficient mutant Az34

	Leaf gs	Leaf Ci	Leaf TSP	Leaf Rubisco Vt	Leaf Rubisco Act %
WT	0.26 ± 0.01	292 ± 5	7.44 ± 1.56	46.9 ± 12.1	65.9 ± 7.5
WT + ABA	0.14 ± 0.03	245 ± 29	8.10 ± 1.54	43.7 ± 10.4	66.4 ± 3.2
% change after ABA treatment	− 47	− 16	N.s.	N.s.	N.s.
Az34	0.39 ± 0.05	332 ± 9	3.57 ± 0.39	17.0 ± 1.4	76.0 ± 2.9
Az34 + ABA	0.08 ± 0.02	234 ± 14	3.81 ± 0.4	19.8 ± 2.8	56.3 ± 3.8
% change after ABA treatment	− 79	− 30	N.s.	N.s.	− 26
Genotype	0.017	0.081	< 0.001	< 0.001	0.601
ABA treatment	< 0.001	< 0.001	0.839	0.960	< 0.001
Genotype * ABA treatment	< 0.001	0.009	0.200	0.450	< 0.001

The percentage change in response to ABA treatments is calculated when significant. Data are mean ± SE of 4 replicates. Results from two-way ANOVA (P values) are presented for Genotype, ABA treatment and their interaction

N.s. not significant