Fig. 3: Correlations between stomatal conductance to leaf and xylem ABA concentration and xylem sap pH of the two genotypes of tomato grown at different CO2 levels.

Correlations of stomatal conductance (gs) to leaf ABA concentration ([ABA]leaf) (a) and xylem sap ABA concentration ([ABA]xylem) (b), and xylem pH (c) of wild-type tomato “Ailsa Craig” (WT) and its respective ABA-deficient mutant (flacca) grown under ambient (400 ppm, a[CO2]) and elevated (800 ppm, e[CO2]) CO2 environments. Triple asterisks (***) indicates that the regression line is statistically significant (P < 0.001) and ns denotes no significance