Figure 1.

Progression during senescence of the relationship between F_v/F_m and Chl content for mutant (•) and WT (○) plants of each anthocyanin-producing species and B. papyrifera for the low-stress (A–D) and outdoor (E–H) treatments. P values for differences in F_v/F_m between mutant and WT regressions are indicated parenthetically on the graphs at intervals of 100 μmol m^–2 Chl content for the low-stress treatment and 50 μmol m^–2 Chl content for non-senesced anthocyanic leaves for the outdoor treatment. The development of anthocyanins in senescing leaves of WT plants from the outdoor treatment is indicated on the graphs of the anthocyanin-producing species by a three-parameter sigmoid line: [y = a/1 + e ^ – (x – x₀/b)], representing the leaf reflectance index (R₅₅₀)^–1 – (R₇₀₀)^–1 for each data point on the graphs.