Non‐photochemical loss in PSII in high‐ and low‐light‐grown leaves of Vicia faba quantified by several fluorescence parameters including L_NP, , a novel parameter

Abstract

Using the expression of fluorescence originated from the PSII open reaction center in the light by Oxborough and Baker (1997), we obtained a formula that expresses relationships between the quantum efficiency of PSII photochemistry in the dark (Phi(m)= F(v)/F(m)) and in the light Phi'(m)=F'(v)/F'(m):Phi'(m)=Phi(m)+L(NP), where L(NP)(=F(0)/F'(m)) denotes the quantum yield of light induced non-photochemical losses (heat dissipation and fluorescence de-excitation) in PSII. Using L(NP) and other conventional fluorescence parameters, we conducted quenching analyses with leaves of broad bean plants (Vicia faba L.) grown at 700 (high light; HL) and 80 mumol photons m(-2) s(-1) (low light; LL). We also examined whether behavior of q(0) quenching (q(0)=1-F'(0)/F(0)) is related to the reaction center quenching. When the actinic light (AL) was strong, Stern-Volmer quenching [NPQ=(F(m)-F'(m))/F'(m)] and L(NP) increased rapidly and then decreased slowly in HL leaves, while, in LL leaves, they increased slowly. It is probable that rapid formation of a large proton gradient was responsible for sharp rises in both parameters in HL leaves. The steady-state 'excess' parameter [Phi(Ex)= (1 - qP) Phi(m)/(Phi(m)+ L(NP))], fraction of energy migrating to closed PSII centers, increased with the photon flux density of AL in LL leaves. In contrast, in HL leaves, Phi(Ex) did not increase markedly. The examination of the relationship between Phi(Ex) and L(NP) obtained at various AL revealed that in LL leaves the increase in (1 - qP) with the increase in AL prevailed, while, in HL leaves, the increase in L(NP) suppressed the increase in (1 - qP). Using the difference between L(NP) and L(D) (Phi(ND)= L(NP)- L(D), where L(D)= F(0)/F(m)), q(0) and qN (=1-F'(v)/F(v)) were calculated without using measured F'(0). The relationships between q(0) and qN thus obtained for various AL levels were almost identical for both HL and LL leaves, implying no difference in the fluorescence origin between the HL and LL leaves. Usefulness of these equations expressing non-photochemical loss is discussed.

Chlorophyll fluorescence in rice: probing of senescence driven changes of PSII activity on rice varieties differing in grain yield capacity

“…However, in this study, no clear relationship was observed between F v '/F m ' and φ PSII values and those non-photochemical quenching (qNP). In this development stage, decreases in F v '/F m ' and φ PSII were followed by the slight increase (but not significant) in L NP , corroborating the statement made by Lu et al (2002) and Stefanov and Terashima (2008). qNP was higher in BRS Pelota until 6 DAH.…”

“…Therefore, this variation was similar between rice varieties, showing that the two rice varieties present the same efficiency of use the excitation energy during the light-adapted state. According to Stefanov and Terashima (2008), decreases in F v '/F m ' and φ PSII could be associated with an increased non-photochemical loss. However, in this study, no clear relationship was observed between F v '/F m ' and φ PSII values and those non-photochemical quenching (qNP).…”

“…Then, the actinic light was removed and the minimal fluorescence level in the light-adapted state (F o ') was determined through of illuminating the leaf with 1 s of far-red light. Using both light and dark fluorescence parameters, we calculated: a) effective efficiency of PSII photochemistry, when PSII reaction centers were open (F v ' /F m ' ), b) the actual PSII efficiency (φ PSII ), c) photochemical quenching coefficient (qP) (genty et al, 1989), d) the non-photochemical quenching coefficient (qN) (genty et al, 1989), e) the Stern-Volmer quenching (NPQ) (Bilger and Bjorkman, 1990;Demmig-Adams, 1990) (Stefanov and Terashima, 2008).…”

Morphological plasticity, photosynthesis and chlorophyll fluorescence of Athyrium pachyphlebium at different shade levels

“…Light energy absorbed by Chl molecules can undergo three fates: (1) be used to drive photosynthesis, (2) excess energy can be dissipated as heat (nonphotochemical quenching) or, (3) re-emitted as light-Chl fluorescence (Maxwell and Johnson 2000, Stefanov and Terashima 2008, Vredenberg 2008. Thus, photoprotection mechanisms could be different between leaves in full sun and those in shade.…”

“…Chl fluorescence has been increasingly used to examine both the mechanism of photosynthesis and whether the plants are influenced by environmental stress (Van Kooten et al 1990, Lovelock et al 1998, Khan et al 2000. Light energy absorbed by Chl molecules can undergo three fates: (1) be used to drive photosynthesis, (2) excess energy can be dissipated as heat (nonphotochemical quenching) or, (3) re-emitted as light-Chl fluorescence (Maxwell and Johnson 2000, Stefanov and Terashima 2008, Vredenberg 2008.…”