Photosynthetic quantum yield
nounPronunciation: /ˌfoʊtoʊsɪnˈθɛtɪk ˈkwɑntəm ˈjiːld/
The efficiency of photosystem II at converting absorbed photons into separated electron-hole pairs, expressed as the ratio of electrons transferred to photons absorbed. This parameter is highly sensitive to abiotic stress and indicates the functional integrity of photosynthetic machinery.
Plain English
A measure of how efficiently plants convert light energy into chemical energy, which decreases under stress.
Etymology & History
Usage
"Photosynthetic quantum yield declined significantly in heat-stressed leaves, indicating photoinhibition of photosystem II."
Style guide notes: Specify measurement conditions (light intensity, temperature, dark adaptation time) when reporting quantum yield values.
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Frequently Asked Questions
How is quantum yield measured in stressed plants?
Using chlorophyll fluorescence methods; Fv/Fm ratio estimates maximum quantum yield of PSII.
What quantum yield value indicates severe stress?
Values below 0.7 (compared to ~0.83 normal) suggest significant photosystem damage or photoinhibition.
Why Test Candidates on This?
Essential non-invasive indicator for rapid stress tolerance screening and photosynthetic performance under abiotic constraints.
Required skill level: Mid