FIGURE 4.

ech2 mutations impair hypocotyl elongation and mobilization of TAG. (A) Seeds of the WT and all the mutant lines indicated above were surface sterilized and sown on MS media plates without sucrose. After cold treatment for 3 days at 4°C, the plates were transferred to a growth room (6 h light at 22°C) to induce seed germination. Then, the plates were double covered with aluminum foil and etiolated seedlings were harvested every 24 h (starting from germination) to measure their length. Data were collected from ≥ 17 seedlings at each time. Data are mean ± SD (n = 3 independent experiments). Asterisk indicates significant difference at P < 0.05 compared to WT. (B) Etiolated seedlings were obtained as described in (A). TAG contents were quantified as described in Section “Materials and Methods”; 20 dry seeds or 20 etiolated seedlings were used for each measurement. Data are mean ± SD (n ≥ 5 independent experiments). Asterisk indicates significant difference at P < 0.05 compared to the WT. TAG, triacylglycerol.