Figure 4.

Alleviation of HNE-induced leaf necrosis by the overexpression of At-AER. Fully expanded, mature leaves of a similar size were collected from 11- to 12-week-old plants, three plants for each line. A 5-cm × 5-cm section of a leaf was put in a petri dish. Cut edges were covered with moist cotton wool to prevent drying. In each section, 12 punctures spaced by at least 5 mm apart were made using a hypodermic syringe needle. To the 12 punctures in a section, three of the same HNE solution (20 μL each) × four concentrations (0, 1, 5, and 10 mm) were applied. Leaf sections were kept in a moist atmosphere at 28°C under a 16/8-h photoperiod at 30 μmol m⁻² s⁻¹ with white-fluorescent lamps. Two days after incubation leaf necrosis was evaluated by the bleached area, and the three values for an HNE solution at the same concentration in a leaf were averaged. Represented results are the means and sd of the averages obtained from three plants of each line. Single and double asterisks represent significant differences from the corresponding control data using a two-sided Student's t test; P < 0.05 and 0.01, respectively.