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

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