Figure 2.

H₂O₂ Induces Death of Epidermal Cells above Adventitious Roots.

(A) Rice cv PG56 stem sections were treated with H₂O₂ for 24 h at concentrations between 0.1% (v/v) and 30% (v/v). Controls were not treated with H₂O₂. Treatment with up to 5% (v/v) H₂O₂ resulted in browning of the tissue, whereas higher concentrations caused tissue bleaching.

(B) Node showing Evans Blue staining of epidermal cells above adventitious roots from rice cv PG56 stem sections that were incubated with 5% (v/v) H₂O₂ for 24 h. Cell death was observed only in epidermal cells.

(C) Dose–response curve of epidermal cell death induced by H₂O₂ after 24 h in stem sections of rice cv PG56. Dead epidermal cells were visualized with Evans Blue. Results are averages (±se) from 5 to 28 stem sections analyzed per treatment. Cell death rates induced with 1% (v/v) and higher concentrations of H₂O₂ are significantly different from the control at P < 0.05 (Tukey test).