Table II. Estimated cyclic electron flow under a variety of oxygen, CO₂, and nitrogen availabilities.

Cyclic electron flow is shown as a percentage of LEF required to balance the ATP/NADPH requirements of photosynthesis, photorespiration, and NO₃⁻ assimilation under various oxygen, CO₂, and NO₃⁻ conditions. Determination of LEF was made using Equations 2, 3, and 7 with kinetics from Walker et al. (2013). Calculations were made using H⁺/ATP of both 4 and 4.7. C_c, CO₂ partial pressure within the chloroplast.

Cc	Oxygen	vc	vo	Nitrate	ATP/NADPH Demand	LEF	Cyclic 4.7 H+/ATP	Cyclic 4 H+/ATP
Pa	kPa	μmol m−2 s−1					%
200	1.8	21.9	0.1	0.00	1.50	88	25	21
200	1.8	21.9	0.1	0.17	1.48	90	22	19
20	19.0	6.7	2.5	0.00	1.57	37	33	28
20	19.0	6.7	2.5	0.17	1.51	38	26	22
15	36.8	3.9	3.7	0.00	1.62	30	39	33
15	36.8	3.9	3.7	0.17	1.55	32	30	26