Three types of complementary quantum yields of energy conversion in PSI were calculated according to the methods described
by Erhard et al. [22]: Y(I), Y(ND), and Y(NA). Effective photochemical quantum yield [Y(I)] = (Pm −P)/Pm. Y(ND) (donor side limitation)
represents the fraction of the overall P700 that becomes oxidized in a given state, which is enhanced by a trans-thylakoid proton gradient
(photosynthetic control at the cytb/f complex as well as the downregulation of PSII) and photodamage to PSII. Y(ND) is calculated
using the formula Y(ND) = (P−Po)/Pm.