abscisic acid signaling threshold
nounPronunciation: /ˌæbˈsɪzɪk ˈæsɪd ˈsɪɡnəlɪŋ ˈθrɛʃhoʊld/
The minimum level of abscisic acid (ABA) concentration required to trigger downstream physiological responses in plant tissues, varying among tissues and stress conditions. Threshold determination involves ABA receptor binding kinetics and signal transduction cascade sensitivity.
Plain English
The amount of stress hormone that plants must produce before their cells recognize the signal and activate protective responses like closing stomata.
Etymology & History
Usage
"Guard cells possess a lower ABA signaling threshold than leaf mesophyll cells, allowing rapid stomatal closure at the first sign of water deficit."
Style guide notes: When reporting ABA threshold values, specify tissue type and measurement methodology to ensure reproducibility and comparability.
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Frequently Asked Questions
Why do different plant tissues have different ABA signaling thresholds?
Tissues vary in ABA receptor abundance and signal amplification efficiency, requiring different hormone concentrations for equivalent physiological responses.
How does ABA signaling threshold relate to drought tolerance?
Plants with lower ABA thresholds activate protective mechanisms earlier during water stress, potentially improving survival under severe drought conditions.
Why Test Candidates on This?
Important assessment topic in plant hormone physiology and drought stress response mechanism courses.
Required skill level: Senior