Figure 4.

Relative transcript levels for LeETR1, LeETR2, LeETR3 (NR), TAPG1 (tomato abscission polygalacturonase 1), and actin in flower abscission zones from second generation (R1) plants. Leaf petiole explants were exposed to 25 μL L⁻¹ ethylene in air at 25°C for 0, 48, and 72 h and RNA extracted from the 2-mm abscission zone tissue at the base of the petiole. Fifteen micrograms of total RNA was loaded per lane. Probe preparation, hybridization and washing conditions, and exposure times were as described in Figure 2. The blot hybridized to the TAPG1 probe was exposed to x-ray film overnight with intensifying screen at −70°C.