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Related Concept Videos

Oxidation of Phenols to Quinones01:17

Oxidation of Phenols to Quinones

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Updated: Jun 16, 2026

High-Throughput Analysis of Non-Photochemical Quenching in Crops Using Pulse Amplitude Modulated Chlorophyll Fluorometry
10:08

High-Throughput Analysis of Non-Photochemical Quenching in Crops Using Pulse Amplitude Modulated Chlorophyll Fluorometry

Published on: July 6, 2022

Antioxidants Differentially Regulate Non-Photochemical Quenching.

Aline de Rodrigues de Queiroz1,2, Jeremy H Brown1,2, Nicole R Buan1,3

  • 1Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.

Plant, Cell & Environment
|June 15, 2026
PubMed
Summary
This summary is machine-generated.

Six antioxidants were tested for their effects on non-photochemical quenching (NPQ) in plants. Different antioxidants showed unique impacts on NPQ kinetics, with some suppressing and others enhancing the process, revealing specific mechanisms.

Keywords:
arabidopsisascorbic acidglutathionemelatoninoxidative stressphotosynthesisxanthophylls

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Area of Science:

  • Plant Physiology
  • Photosynthesis Research
  • Biochemistry

Background:

  • Non-photochemical quenching (NPQ) is a crucial photoprotective mechanism in plants, dissipating excess light energy as heat.
  • Exogenous antioxidants are often applied to enhance plant stress tolerance, but their specific effects on NPQ remain unclear and inconsistent.
  • Understanding antioxidant impacts on NPQ is vital for interpreting plant responses to environmental stress.

Purpose of the Study:

  • To systematically investigate and compare the effects of six different antioxidants on NPQ kinetics in Arabidopsis thaliana.
  • To elucidate the specific mechanisms by which antioxidants modulate NPQ, focusing on their interaction with the xanthophyll cycle.
  • To determine if antioxidant-induced NPQ changes depend on canonical NPQ components.

Main Methods:

  • Arabidopsis thaliana seedlings were treated with individual concentration gradients of six antioxidants: ascorbate, chitosan, coenzyme M, reduced glutathione, melatonin, and N-acetyl cysteine.
  • Standardized pH and illumination regimes were employed to ensure consistent experimental conditions.
  • NPQ kinetics were measured, and experiments utilizing psbs, vde, and zep null mutants were conducted to assess the involvement of canonical NPQ components and the xanthophyll cycle.

Main Results:

  • Antioxidants induced divergent and context-dependent shifts in NPQ kinetics. Coenzyme M significantly suppressed NPQ induction, maximum, and relaxation rates.
  • Melatonin and N-acetyl cysteine generally enhanced NPQ maximum or relaxation, while ascorbate accelerated NPQ induction.
  • Ascorbate and coenzyme M exhibited opposing effects on the xanthophyll cycle, influencing violaxanthin de-epoxidation and xanthophyll flux, with these effects dependent on canonical NPQ components.

Conclusions:

  • The study demonstrates that different antioxidants exert specific and distinct regulatory effects on NPQ in plants.
  • Two distinct antioxidant-specific mechanisms modulating NPQ via the xanthophyll cycle were identified: ascorbate enhances de-epoxidation, while coenzyme M suppresses it.
  • These findings provide crucial mechanistic insights into how exogenous antioxidants interact with photoprotective pathways in plants, clarifying previous inconsistencies in the literature.