Table 3.

Average growth rate (μ) of Anabaena variabilis calculated from the cell density over 14-d incubation under different nitrate and ammonium treatments. N-free treatment was set as the control. The experiments were carried out in triplicates and the average of all the values was obtained for each treatment.

Treatment	N Source	Concentration (g L−1)	Growth Rate (μ)
N-free	Absent	0	0.103 ± 0.024
Nitrate	NaNO3	1.5	0.121 ± 0.023
		1.5 × 10−2	0.063 ± 0.023
		1.5 × 10−5	0.127 ± 0.006
Ammonium	Fe-NH4-citrate	0.006	0.156 ± 0.013
		0.006 ×10−2	0.126 ± 0.001
		0.006 ×10−5	0.125 ± 0.012