Carotenoid kinetics during prolonged callus development.

<p>WT and <i>ZmPSY1</i>-expressing seeds (Zm) were germinated for 5 days on callus-inducing medium (CIM) under long day, followed by 2 weeks etiolation. Thereafter, calli were transferred on CIM (-) or CIM supplemented with 1 μM NFZ (+) and developed further in the dark. Samples were taken after 0, 5, 10, 15 and 20 days and carotenoids were quantified by HPLC (A) while β-apocarotenals were quantified at 0 days and after 10 and 20 continued etiolation on NFZ by LC-MS (B). Note that carotenoids are given in μg g^-1 DM, while β-apocarotenals are in ng g^-1 DM. All data are mean +/- SD from three biological replicates. Significant difference to preceding time point of same sample type, *<i>P</i><0.05).</p