Photorespiration rate
noun phrasePronunciation: /ˌfoʊtoʊˈrɛspɪreɪʃən ˈreɪt/
The metabolic pathway in plants where RuBisCO catalyzes oxygenation of ribulose-1,5-bisphosphate instead of carbon dioxide fixation, consuming ATP and reducing photosynthetic efficiency. Photorespiration increases under high light, temperature, and low CO₂ conditions.
Plain English
A wasteful plant process where oxygen instead of carbon dioxide is processed, losing energy.
Etymology & History
Usage
"Under drought stress, elevated photorespiration rate further reduced net photosynthetic gain."
Style guide notes: Distinguish photorespiration from mitochondrial respiration in all technical discussions.
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Contrasted with
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Frequently Asked Questions
Why does photorespiration increase under stress?
High temperature and drought stress increase CO₂/O₂ ratio favoring oxygenase over carboxylase activity.
How does photorespiration affect crop efficiency?
Photorespiration wastes 25-50% of photosynthetic products as CO₂ and ammonia.
Why Test Candidates on This?
Critical for understanding photosynthetic stress responses and efficiency in crop improvement programs.
Required skill level: Senior