Figure 4.

Influence of scion genotypes and lighting on the apex on the levels of RBOH1 transcripts and H₂O₂ accumulation in the systemic leaves. A, Influence of different photoreceptor mutants as scions on the levels of RBOH1 transcripts in the systemic leaves of grafted plants. B, Influence of different photoreceptor mutants as scions on the accumulation of H₂O₂ in the systemic leaves of grafted plants. C, RBOH1 transcripts in the systemic leaves in plants with dgt as scion or rootstock. D, Accumulation of H₂O₂ in the systemic leaves in grafted plants with dgt as scion or rootstock. E, Cytochemical localization of H₂O₂ accumulation in mesophyll cells of systemic leaves with CeCl₃ staining in grafted plants with dgt as scion or rootstock. The apex was exposed to WL (L) at 300 μmol m⁻² s⁻¹ for 30 min or not (dark [D]), then the fourth leaves (systemic leaf) of the grafted plants were harvested for the analysis and cytochemical detection of H₂O₂. During the illumination treatments, the other parts of the plant were kept in darkness. Values in A to D are means of four plants ± sd, with different letters indicating significant differences at P < 0.05 according to Tukey’s test. Arrows in E indicate that H₂O₂-induced CeCl₃ precipitates in the apoplast of systemic leaves. FW, Fresh weight.