Figure 3.

Modulation of Internal ROS Levels Alters Epidermal Cell Death Rates.

(A) Stem sections of rice cv PG56 were preincubated for 3 h with 1 μM DPI, an inhibitor of NADPH oxidase and subsequently treated with or without 150 μM ethephon for 15 h. Dead cells were stained with Evans Blue, and cell death rates were calculated as the percentage of epidermal patches that showed blue staining. Results are means (±se) from six stem sections per treatment. a, b, and c indicate statistically different values. Cell death rates induced with ethephon (E) in the presence of DPI were significantly lower than ethephon-induced cell death at P < 0.001 (Tukey test).

(B) Stem sections of rice cv PG56 were treated with the catalase inhibitor AT to prevent metabolization of H₂O₂ or with 150 μM ethephon for 8 h. Cell death rates were determined using Evans Blue staining. Results are means (±se) from 14 to 37 stem sections analyzed per treatment. a and b indicate statistically different values. Cell death rates induced with 100 mM AT and 150 μM ethephon are significantly different from the control at P < 0.05 (Tukey test).