Figure 2

Absorption spectra of intact Synechococcus cells. Nitrate-replete cells (at 16 hours with 0.24 g NaNO₃ L^-1; dashed line) and nitrate-limited cells (at 48 hours with 0.24 g NaNO₃ L^-1; solid line). The spectra were recorded in dilute cell suspensions (OD₇₃₀ = 0.3 to 0.4) and normalized to an OD₇₃₀ of 0.5. The peak at 637 nm is due to phycobilisomes and the peak at 683 nm is due to chlorophyll a. OD₇₃₀, optical density at 730 nm.