FIGURE 2.

Biological responses of Col-0 WT plants, pepr1, and pepr2 single mutants and pepr1/pepr2 double mutants to AtPep1 (1 μm). Open bars represent untreated controls, filled bars represent AtPep1 treatments. Error bars represent S.E. (n ≥ 6). Asterisks (*) indicate a significant difference based on t test analysis (p < 0.05). All experiments were repeated three times with similar results. A–C, growth response. Growth was quantified by determining the total fresh weight per seedling (A) and length of the longest root per seedling (B) after 10 days of growth in the absence or presence of AtPep1 (1 μm). Representative seedlings were photographed (C). D, ROS production. ROS production was registered continuously with cut and preincubated leaf pieces using the luminol bioassay. The basal level of ROS production before addition of AtPep1 (open bars) is compared with the average ROS production during a 30-min measurement after addition of 1 μm AtPep1 (filled bars). See supplemental Fig. S1 for the full kinetic of ROS production. E, ethylene production: ethylene production by cut and preincubated leaf pieces was measured after 4 h of incubation.