Lam 2026, Nat. Commun.

The Lam 2026 model — "Dissecting the contributions to non-photochemical quenching in a land plant under fluctuating light" — is a fluorescence-lifetime-based kinetic model of non-photochemical quenching (NPQ) built to separate the individual photoprotective mechanisms that operate in a vascular land plant. It was parameterised against whole-leaf chlorophyll fluorescence-lifetime and xanthophyll-concentration measurements made on wild-type Nicotiana benthamiana and a panel of NPQ mutants, which let the authors assign a per-molecule quenching effectiveness to each xanthophyll and tease apart the distinct quenching components. Accordingly, the model tracks the xanthophyll-cycle pigments — violaxanthin (V), antheraxanthin (A) and zeaxanthin (Z) — together with their association with the PsbS- and antenna-bound quenching states (the PV/PA/PZ and QV/QA/QZ/QL/PL species), the violaxanthin-deepoxidase activation that drives the cycle, and a PSII photodamage term.

Because it is calibrated on time-resolved fluorescence lifetimes rather than steady-state amplitudes, the model can quantitatively predict both wild-type and mutant NPQ behaviour across light–dark regimes and fluctuating light, and it is used to explore how the relative amounts of the regulatory enzymes (the VDE : ZEP : PsbS ratio) shape the trade-off between photoprotection and light-harvesting efficiency — with implications for improving crop yield. It is included in GreenSloth as a recent, data-driven model that resolves the kinetics of the xanthophyll cycle and the multiple distinct contributions to NPQ in unusual detail.

Scheme

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Model definition