FIGURE 5.

(A) Germination is retarded by low TTFA concentrations. Wild type seeds were sown on half-strength MS agar plates without TTFA or with varying concentrations of this complex II inhibitor. Germination was scored at different times and is complete at 4 days. Values are means ± SD of three replicates, each containing 80–200 seeds. (B,C) Post-germinative growth is strongly inhibited by TTFA. Seeds were sown on half-strength MS agar plates, stratified, and grown for 10 days under long-day conditions to evaluate germination (brown symbols), cotyledon expansion (red symbols) and seedling establishment (orange symbols). In a different experiment, they were grown in the dark to measure hypocotyl elongation (black symbols). Values are means ± SD of three replicates each containing around 50 sown seeds. Germinated seeds, seedlings with expanded cotyledons and seedlings with true leaves were counted, and values are given as percentages of sown seeds. Hypocotyl lengths are given as percentages of hypocotyl length in the absence of TTFA. (C) Photographs were taken at the same magnification after 10 days of growth under long-day conditions.