Figure 4.

Carotenoid-to-chlorophyll ratios of wild-type (○) and sodB⁻ (•) strains. Chlorophyll and carotenoids were extracted into 100% acetone. The resulting values are the ratios of blue peak absorbance (A_blue) to red peak absorbance (A_red) over 48-h treatment periods for control (A), 0.5 μm MV-treated (B), and 5 μm NF-treated (C) groups (see Methods). Each point is the mean of five or six samples. Error bars are sds. For comparison, purified chlorophyll a from spinach yielded a blue:red ratio of 4.53. Symbols are as in Figure 3.