Figure 2.

Effect of cold treatment on pollen tube growth. Flowers were excised from cold-treated plants and submerged in Tris-EDTA solution (10 mm Tris and 1 mm EDTA, pH 8.0), shaken twice for 15 min, and filtered through a Nitex filter. The pollen in the filtrate was incubated in 20% (w/v) Suc medium containing 2 mm calcium chloride and 1.65 mm boric acid. Total numbers of germinated pollen after 4 h were counted and plotted relative to the control. Approximately 500 pollen grains were used in each experiment, and all experiments were repeated four times. In each bin, the value of the sd is presented as an error bar.