Hydraulic safety margin
noun phrasePronunciation: /haɪˈdrɔːlɪk ˈseɪfti ˈmɑːrdʒɪn/
The difference between the water potential at which plants operate during normal conditions and the water potential threshold at which catastrophic xylem dysfunction occurs through cavitation. This margin determines the drought severity a plant can tolerate before experiencing critical hydraulic failure and growth cessation.
Plain English
The safety gap between how dry a plant normally gets and when its water transport system completely fails.
Etymology & History
Usage
"Species with larger hydraulic safety margins showed greater resilience to prolonged drought compared to those with minimal margins."
Style guide notes: Always specify whether margin refers to leaf or stem hydraulic measurements, as these may differ substantially.
Also known as
Contrasted with
Related Terms
Frequently Asked Questions
How is hydraulic safety margin calculated?
It equals the operating water potential minus the water potential causing 50% loss of hydraulic conductivity (P50).
Why do species differ in hydraulic safety margins?
Differences result from variations in xylem anatomy, vessel diameter, pit structure, and inherent cavitation resistance thresholds.
Why Test Candidates on This?
Essential topic in plant water relations and comparative ecology courses examining drought adaptation mechanisms.
Required skill level: Senior