TABLE 1.

C/N ratios of Synechocystis sp. PCC 6803 strains at various growth stages

Strain	C/N ratioa
	Cultures in nitrate		Cultures in ammonium
	Initial stage	Late stage	Initial stage	Late stage
SFCΩ5	4.065 ± 0.029	4.480 ± 0.039	4.041 ± 0.076	4.605 ± 0.128
SCh11	4.105 ± 0.012b	4.583 ± 0.040b	4.045 ± 0.087	4.574 ± 0.096
SCh12	4.024 ± 0.017b	4.495 ± 0.137	4.055 ± 0.068	4.663 ± 0.156

^aChlorophyll contents were about 1 and 10 μg/ml for initial and late stages of growth, respectively. Values are the averages ± standard deviations of eight determinations. 

^bStatistically different from the wild-type value (SFCΩ5) at α = 0.01.