Low-Cost Custom-Built Flow Meters for Plant Hydraulic Conductance: Validation of Accuracy, Precision, and...

Area of Science:

• Plant Physiology
• Biophysics
• Environmental Science

Background:

• Xylem hydraulic conductance is crucial for understanding plant responses to environmental stressors like drought.
• Accurate measurement of xylem traits is essential for plant physiology and ecological studies.
• Existing methods for measuring hydraulic conductance can be expensive and complex.

Purpose of the Study:

• To evaluate the performance, accuracy, and reliability of custom-built, low-cost pressure drop flow meters.
• To assess the suitability of these flow meters for measuring xylem hydraulic conductance across various conditions.
• To promote accessibility of plant hydraulics research through affordable, open-source instrumentation.

Main Methods:

• Nearly 1200 measurements were conducted using custom-built pressure drop flow meters.
• Experiments varied devices, laboratories, reservoir heights (10-45 cm), and tubing resistances.
• Accuracy was validated against reference values obtained by water displacement.

Main Results:

• Flow meters demonstrated high interchangeability, with mean differences generally below 3.5% and never exceeding 5%.
• Precision reached a 1%-7% coefficient of variation under recommended conditions (25-45 cm pressure head).
• Accuracy was strong, with over 78% of measurements deviating by less than 5% from reference values at ≥25 cm.

Conclusions:

• The validated flow meters are portable, affordable (≈2500 CAD), and reliable for measuring xylem hydraulic conductance.
• Their low cost and open-source design make them accessible to resource-limited laboratories.
• These instruments facilitate reproducible multi-laboratory studies and foster international collaborations in plant hydraulics research.