Fig. 2
From: Changes of secondary metabolites in Pinus sylvestris L. needles under increasing soil water deficit
Relationships between predawn shoot water potential (Ψpd) and average (± SE) contents of proline (a), shikimic acid and total polyphenols (b), and abscisic acid (ABA) (c) in needles of five water-deficient Scots pines. Ψ pd,1 , Ψ pd,2 , and dotted lines indicate the limits of the three physiological phases considered (I, Ψpd > −0.6 MPa; II, −0.6 > Ψpd > −1.8 MPa; and III, −1.8 > Ψpd > −2.4 MPa)