Figure 5.

Application of NO donor SNP rescues senescence-associated phenotypes in dnd1 plants. A, Endogenous H₂O₂ levels in leaves of wild-type (WT; left panels) and dnd1 (right panels) plants were detected using 3,3′-diaminobenzidine staining. Leaves from plants treated with water or with SNP are shown in top and bottom panels, respectively. B, Necrosis, monitored using Trypan Blue staining, in leaf tissue of wild-type and dnd1 plants treated with water (−SNP) or 100 μm SNP (+SNP). Dead cells become blue after staining. This experiment was repeated three times. C, Lipid peroxidation (MDA level) in leaf tissue of wild-type and dnd1 plants treated with water (−SNP; dark bars) or 100 μm SNP (+SNP; light bars). Results are presented as means (n = 3) ± se. ANOVA evaluation of means separation between –SNP and +SNP treatments indicated a significant difference for dnd1 leaves (P 0.05; indicated with a * above bar representing the +SNP treatment) and no significant difference for wild-type leaves. FW, Fresh weight. D, Effect of (50 μm) SNP on SAG transcript accumulation in dnd1 leaves was analyzed by semiquantitative RT-PCR. This experiment was repeated three times.