Fig. 3.

¹O₂-mediated growth inhibition of mature ex1/flu, ex2/flu, ex1/ex2/flu, flu, and wild-type (wt) plants. Plants were grown for 21 days under continuous light until they were ready to bolt. Plants were then either shifted to a 16 h light/8 h dark program (A) or kept under continuous light (B), and the elongation of the inflorescence was followed over the next 30 days. Long-day conditions were used instead of short-day conditions to avoid the overaccumulation of excess amounts of Pchlide during an extended dark period. Under these light conditions, toxic effects of ¹O₂ could be minimized. In contrast to Ler plants used previously (9, 12), the onset of bolting of Col-0 varied greatly between different plants. Growth curves of individual plants were corrected for these differences. Each value represents the average growth measurements of 10 different plants. (C) The accumulation of Pchlide in 21-day-old plants grown under continuous light and transferred to the dark for 8 h. Total Pchlide was extracted from aerial parts of single plants and analyzed by HPLC. For each genotype, seven independent Pchlide measurements are shown.