Fig. 1 Identification of phytoene in norflurazon-treated wild-type leaves. Chromatograms at 285 nm from a
C18 HPLC analysis of carotenoids in Arabidopsis wild-type leaves, generated with or without norflurazon
supplementation (+/À NFZ). UV/VIS spectra of α-tocopheryl acetate as internal standard (I), 15-cis-phytoene
(II) and all-trans-phytoene (III) are given as insets in Fig. 2. Only in the presence of norflurazon, phytoene is
detected in wild-type Arabidopsis leaves and its amount upon norflurazon treatment represents carotenogenic
pathway flux
Fig. 2 Identification of phytoene in norflurazon-treated seed-derived calli. Chromatograms at 285 nm from a
C18 HPLC analysis of carotenoids in seed-derived calli of Arabidopsis wild-type and one line constitutively
overexpressing AtPSY (At12), generated with or without norflurazon supplementation (+/À NFZ). UV/VIS
spectra of α-tocopheryl acetat as internal standard (I), 15-cis-phytoene (II) and all-trans-phytoene (III) are
given as insets. AtPSY overexpression in At12 as well as norflurazon treatment leads to accumulation of
phytoene. Phytoene amounts upon norflurazon treatment represent carotenogenic pathway flux
Quantification of Carotenoid Pathway Flux
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