What is photochemical quenching in plants?
What is photochemical quenching in plants?
For example, the high quantum efficiency of photochemistry in limiting light results in a decrease, or quenching, of fluorescence that is termed photochemical quenching (qP). Non-photochemical processes that dissipate excitation energy also quench Chl fluorescence and are collectively called NPQ (or qN).
What is quenching in photosynthesis?
NPQ occurs in almost all photosynthetic eukaryotes (algae and plants), and helps to regulate and protect photosynthesis in environments where light energy absorption exceeds the capacity for light utilization in photosynthesis. …
Which of the following pigment is involved in non-photochemical quenching?
Though carotenoids may be involved in a three-stage photoprotection of photosynthetic systems, the initial stage, so-called non-photochemical quenching, is limited to plants, algae and cyanobacteria.
What is NPQ in photosynthesis?
Nonphotochemical chlorophyll fluorescence quenching (NPQ) is a process in which excess absorbed light energy is dissipated into heat. This process takes place in the photosynthetic membranes of plants, algae, and cyanobacteria (Demmig-Adams et al., 2014).
What is energy dependent quenching?
Energy-dependent quenching (qE) in photosystem II (PSII) is a pH-dependent response that enables plants to regulate light harvesting in response to rapid fluctuations in light intensity.
What is the xanthophyll cycle?
The xanthophyll cycle involves the enzymatic removal of epoxy groups from xanthophylls (e.g. violaxanthin, antheraxanthin, diadinoxanthin) to create so-called de-epoxidised xanthophylls (e.g. diatoxanthin, zeaxanthin).
What is sustained quenching?
Photoinhibitory quenching, qI, is sustained NPQ that continuously depresses the commonly used fluorescence parameter “quantum yield of photosystem II (PSII)”, or Fv/Fm, and is often viewed as a result of PSII core inactivation due to D1 damage.
How does Dcmu affect photosynthesis?
DCMU is a very specific and sensitive inhibitor of photosynthesis. This interrupts the photosynthetic electron transport chain in photosynthesis and thus reduces the ability of the plant to turn light energy into chemical energy (ATP and reductant potential).
What are called photosynthetic pigments?
In land plants, there are two classes of these photosynthetic pigments, the chlorophylls and the carotenoids. The ability of chlorophyll and carotenoid molecules to absorb the energy of light and use it effectively is related to their molecular structure and to their organization within the cell.
Does xanthophyll absorb light?
Xanthophylls are yellow-brown pigments that absorb blue light. One in particular, zeaxanthin, has long been considered as a potential candidate for the chromophore of an additional blue light photoreceptor.
Is PSBs the site of non photochemical quenching in?
Along with a low thylakoid lumen pH and the presence of de-epoxidized xanthophylls, PsbS is necessary for photoprotective thermal dissipation (qE) of excess absorbed light energy in plants, measured as non-photochemical quenching of chlorophyll fluorescence.
What happens to photosynthesis when light intensity increases?
With increasing light intensity, photosynthetic utilization of absorbed light energy reaches saturation, while light absorption continues to increase. This can result in a mismatch between excitation of photosynthetic pigments and a plant’s ability to use the excitation energy for photosynthesis.
Which is the feedback regulation of photosynthesis ( QE )?
Diagram depicting feedback regulation of photosynthetic light harvesting (qE) by one of the products of the light reactions of photosynthesis (ΔpH).
What is the function of PSBs in photosystem II?
E-mail: [email protected] The PsbS protein of photosystem II functions in the regulation of photosynthetic light harvesting.