Pigment content of young leaves of WT Arabidopsis and of the pdx1 mutant. A) Plants aged 4 weeks. B) Chlorophyll and carotenoid content of young leaves. Chl, total chlorophyll; Xanth, xanthophylls; β-car, β-carotene. C) Level of various chlorophyll precursors in young leaves: Pchlide, protochlorophyllide; Chlide, chlorophyllide; GG-, DHGG- and THGG-Chl, geranylgeranyl-chlorophyll, dihydrogeranylgeranyl-chlorophyll and tetrahydrogeranylgeranyl-chlorophyll, respectively. Data are mean values of 4 measurements + SD. *, significantly different from the WT value with P < 0.01 (t test).