Chlorophyll Fluorescence Quenching
noun phrasePronunciation: /ˈklɔːrəfɪl ˌfluːˈresəns ˈkwɛnʃɪŋ/
The non-radiative dissipation of absorbed light energy as heat in chloroplasts, measured as a decrease in chlorophyll fluorescence yield. This process protects photosynthetic machinery during stress but also indicates reduced photosynthetic efficiency.
Plain English
When plants are stressed, they release absorbed light energy as heat instead of using it for photosynthesis.
Etymology & History
Usage
"Increased chlorophyll fluorescence quenching under high temperature stress indicates photoprotective mechanisms are engaged."
Style guide notes: Distinguish between NPQ (non-photochemical quenching) and qP (photochemical quenching) when discussing specific mechanisms.
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Related Terms
Frequently Asked Questions
What is the difference between photochemical and non-photochemical quenching?
Photochemical quenching reflects photosystem II reaction center capacity, while non-photochemical quenching dissipates excess energy as heat.
How is chlorophyll fluorescence quenching measured?
Researchers use pulse amplitude modulation fluorometry to quantify maximum quantum efficiency and quenching coefficients in stressed leaves.
Why Test Candidates on This?
Widely used indicator for rapid assessment of plant stress responses and photosynthetic tolerance mechanisms.
Required skill level: Mid