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Basic Technical IVT Commonly tested

Photosynthetic Light-Use Efficiency

noun

Pronunciation: /ˌfoʊtəʊsɪnˈθɛtɪk laɪt juːs ɪˈfɪʃənsi/

The ratio of photosynthetic carbon fixation to absorbed photon flux density, indicating how effectively plants convert light energy into chemical energy under stress conditions. Under abiotic stress, this efficiency typically declines due to impaired electron transport, reduced ribulose-1,5-bisphosphate regeneration, and increased photoprotective dissipation.

Plain English

The measure of how well plants convert light into chemical energy for growth when stressed.

Etymology & History

Origin languageGreek, Latin
Rootphotosynthesis (Greek photos, light + synthesis) + efficentia (Latin, effectiveness)
First recorded use1970s
Usage frequencyVery common

Usage

"Photosynthetic light-use efficiency declined significantly in drought-exposed wheat genotypes compared to irrigated controls."

Style guide notes: Specify measurement method and light intensity range when reporting efficiency values for comparability.

Also known as

quantum yield of photosynthesis apparent quantum efficiency

Contrasted with

photosynthetic inefficiency

Related Terms

Frequently Asked Questions

How is photosynthetic light-use efficiency measured?

It is calculated as the slope of the light response curve at limiting light intensities using fluorescence or gas exchange techniques.

Why does this efficiency decrease under drought stress?

Stomatal closure reduces CO2 availability and electron transport slows, while energy is diverted to photoprotective mechanisms.

Why Test Candidates on This?

Key performance indicator for assessing photosynthetic stress response in crop and model species evaluations.

Required skill level: Senior

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