Studies on the light and dark interconversions of leaf xanthophylls

Yamamoto, Harry Y.; Nakayama, Tatsuo; Chichester, C. O.

doi:10.1016/0003-9861(62)90060-7

Cited by 318 publications

(146 citation statements)

References 4 publications

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“…Zeaxanthin-dependent quenching represents a latent potential. It requires conversion of violaxanthin to zeaxanthin (34), an activity which is also ApH dependent and relatively slow (11). Furthermore, the amount of zeaxanthin that can be formed depends on socalled violaxanthin availability, the fraction of the total violaxanthin pool that can form zeaxanthin.…”

Section: Xanthophyll Cycle and Photoprotectionmentioning

confidence: 99%

“…Exchange of protons for Mg2+ (16), conversion of PSII from fluorescent to nonfluorescent forms (32), and zeaxanthin formation have been implicated (9). Zeaxanthin is formed from violaxanthin (34) by action of violaxanthin deepoxidase whose activity requires an acidified lumen (11). Depending on treatment, zeaxanthin formation results in increased irreversible or reversible qN (8,9).…”

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confidence: 99%

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Zeaxanthin Formation and Energy-Dependent Fluorescence Quenching in Pea Chloroplasts under Artificially Mediated Linear and Cyclic Electron Transport

Gilmore¹,

Yamamoto²

1991

Plant Physiol.

236

143

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Artificially mediated linear (methylviologen) and cyclic (phenazine methosulfate) electron transport induced zeaxanthin-dependent and independent (constitutive) nonphotochemical quenching in osmotically shocked chloroplasts of pea (Pisum sativum L. cv Oregon). Nonphotochemical (15), which also appears to depend oii the redox state of a membrane component (20). Recently, qE has been related to "down regulation" of photochemistry at PSII (32).The mechanism for qE is unclear. Exchange of protons for Mg2+ (16), conversion of PSII from fluorescent to nonfluorescent forms (32), and zeaxanthin formation have been implicated (9). Zeaxanthin is formed from violaxanthin (34) by action of violaxanthin deepoxidase whose activity requires an acidified lumen (11). Depending on treatment, zeaxanthin formation results in increased irreversible or reversible qN (8, 9). Irreversible or slowly reversible zeaxanthin-dependent nonphotochemical quenching may be related to photoinhibition (8). Rapidly reversible zeaxanthin-dependent qN is concluded to be qE (9, 10). Zeaxanthin-dependent qN appears to have a photoprotective function (3).Whether qE comprises more than one component is controversial. The results of several laboratories support the view that zeaxanthin-dependent qE adds to an underlying zeaxanthin-independent qN (3, 9, 10). Other studies conclude instead that zeaxanthin sensitizes qE to ApH and that, at saturating ApH, zeaxanthin does not increase total qN (18). Both qN (5) and zeaxanthin-dependent qE (3, 9) have been correlated with Fo quenching (qo) which, according to the Butler-Kitajima model (7), suggests quenching occurs in the pigment bed.2 Abbreviations: qN., coefficient for nonphotochemical quenching; q, coefficient for energy-dependent nonphotochemical quenching: Q^, primary electron acceptor of PSII; MV, methylviologen (1,1'-dimethyl-4,4'-bipyridinium dichloride); DBMIB, dibromothymoquinone (2,5-dibromo-3-methyl-6-isopropyl-p-

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Section: Xanthophyll Cycle and Photoprotectionmentioning

confidence: 99%

mentioning

confidence: 99%

Zeaxanthin Formation and Energy-Dependent Fluorescence Quenching in Pea Chloroplasts under Artificially Mediated Linear and Cyclic Electron Transport

Gilmore¹,

Yamamoto²

1991

Plant Physiol.

236

143

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“…However, this term comprises at least three processes: (i) qI, mainly related to photoinhibition, a slowly reversible damage to PSII reaction centers (2,3), although data suggest that a zeaxanthindependent quenching might contribute substantially to this process (4,5), (ii) qT, state transitions, a change in the relative antenna sizes of PSII and PSI, due to the reversible phosphorylation and migration of antenna proteins (LHCII) (6), and (iii) qE, also termed "high-energy state quenching", a form of quenching associated with the development of a low pH in the thylakoid lumen (e.g., ref 7). High-energy state quenching is largely thought to be associated with an increase in thermal dissipation within the light-harvesting apparatus (1,8,9), associated with the generation of a ∆pH (7,10) and with the formation of zeaxanthin via deepoxidation of violaxanthin (11). However, in vitro at least, this term also encompasses acidic pHinduced processes in the PSII reaction center, specifically following the release of a Ca 2+ ion associated with the watersplitting complex (e.g., ref 12).…”

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Nonphotochemical Quenching of Chlorophyll Fluorescence inChlamydomonas reinhardtii

et al. 2006

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Unlike plants, Chlamydomonas reinhardtii shows a restricted ability to develop nonphotochemical quenching upon illumination. Most of this limited quenching is due to state transitions instead of ∆pH-driven high-energy state quenching, qE. The latter could only be observed when the ability of the cells to perform photosynthesis was impaired, either by lowering temperature to ∼0°C or in mutants lacking RubisCO activity. Two main features were identified that account for the low level of qE in Chlamydomonas. On one hand, the electrochemical proton gradient generated upon illumination is apparently not sufficient to promote fluorescence quenching. On the other hand, the capacity to transduce the presence of a ∆pH into a quenching response is also intrinsically decreased in this alga, when compared to plants. The possible mechanism leading to these differences is discussed.The absorption of light in excess of the capacity for photosynthetic electron transport is damaging to photosynthetic organisms (1). That capacity is, however, variable, depending mainly on the efficiency of CO 2 assimilation. For example, decreases in temperature lower the rate with which electrons can be transported within the electron transport chain as well as the capacity of metabolic processes to assimilate the reductant that has been photoproduced. In higher plants, the availability of CO 2 is liable to be limiting under conditions of water stress, due to the closure of stomata. This will again inhibit photosynthetic assimilation. Under such conditions, cells are likely to experience oxidative stress, due to the uncontrolled formation of reactive oxygen species associated with the absorption of light by chlorophyll.Under conditions of excess light, a variety of mechanisms are initiated which protect chloroplasts from damage. In higher plants, a number of processes have been identified, primarily through application of measurements of chlorophyll fluorescence yield. These are all associated with photosystem (PS) 1 II and are collectively referred to as nonphotochemical quenching mechanisms (NPQ; 1). However, this term comprises at least three processes: (i) qI, mainly related to photoinhibition, a slowly reversible damage to PSII reaction centers (2, 3), although data suggest that a zeaxanthindependent quenching might contribute substantially to this process (4, 5), (ii) qT, state transitions, a change in the relative antenna sizes of PSII and PSI, due to the reversible phosphorylation and migration of antenna proteins (LHCII) (6), and (iii) qE, also termed "high-energy state quenching", a form of quenching associated with the development of a low pH in the thylakoid lumen (e.g., ref 7).High-energy state quenching is largely thought to be associated with an increase in thermal dissipation within the light-harvesting apparatus (1,8,9), associated with the generation of a ∆pH (7, 10) and with the formation of zeaxanthin via deepoxidation of violaxanthin (11). However, in vitro at least, this term also encompasses acidic pHinduced proc...

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“…In the study by Othman 20 , lutein and total carotenoids levels in Agria and Desiree minitubers also increased with light. Yamamoto et al 62 demonstrated that the changes were due to the stoichiometric and cyclical conversions among violaxanthin, antheraxanthin and zeaxanthin. Light induces the de-epoxidase reaction, whereas the required acidity for de-epoxidase activity is generated by ATP hydrolysis or supplied by buffer 63 65 .…”

Section: Environmental Stressmentioning

confidence: 99%