Figure 7.

Zx epoxidation. The reconversion of Zx to Vx after pre-illumination at three different actinic light intensities (450, 900, and 1,800 μE of white light) for 5, 30, 90, and 180 min was determined for WT (A–C), pgr1 (D–F), npq4 (G–I), and L17 (J–L) plants. During the whole experiment, detached leaves were placed on water in temperature-controlled cuvette (20°C). At indicated time, leaves were rapidly frozen in liquid N₂ and the pigment composition was determined by HPLC analyses. The Zx content in % of the total VAZ-pool size (= sum of Vx, Ax and Zx) is shown. Data represent mean values of 3–4 independent measurements. For clarity, error bars, which ranged from 1 to 5% in all cases, are not shown.