FIG. 3.

F_O fluorescence increases with the phycocyanin content in Synechococcus sp. strain PCC 7942. F_O fluorescence is normalized to the molar chlorophyll concentration to allow for different culture concentrations and plotted against the molar ratio of phycocyanin (PC) to chlorophyll (Chl). Each point is a single determination on an independently grown culture. ○, wild-type cells; ■, mutant strain which lacks phycobilisome rods and contains no phycocyanin. Note that at low phycocyanin contents, F_O in the wild type falls toward the level in the rodless mutant. Modified from reference 23 with permission of the publisher.