Xylem sap phosphorus sampling using microdialysis-a non-destructive high sampling frequency method tested under...

Area of Science:

• Plant Physiology
• Plant Nutrition
• Analytical Chemistry

Background:

• Understanding plant nutrient flux is crucial for plant nutrition.
• Current xylem sap sampling methods are destructive and infrequent.
• A non-destructive method is needed for high-frequency nutrient concentration monitoring.

Purpose of the Study:

• To evaluate microdialysis (MD) as a non-destructive method for xylem sap phosphate (PO43-) concentration measurement.
• To assess the feasibility of MD for in situ, high-frequency monitoring of nutrient dynamics in living trees.

Main Methods:

• Microdialysis (MD) probes were tested in vitro and in vivo using beech tree stem segments.
• Relative recovery (RR) was analyzed concerning pumping rate and simulated sap flow velocity.
• MD was applied in a 24-hour field campaign on two beech trees.

Main Results:

• Optimal sampling intervals were determined based on the exponential decline of RR with increasing pumping rates.
• MD showed minimal sensitivity to simulated sap flow velocity and ionic strength differences.
• In situ field application successfully captured diurnal variations in xylem sap PO43- concentration and flux in living trees.

Conclusions:

• Microdialysis (MD) is a viable, non-destructive alternative to traditional methods for xylem sap nutrient analysis.
• MD allows for bi-hourly resolution of phosphate (PO43-) concentration dynamics in xylem sap under field conditions.
• The technique proved effective in assessing nutrient flux variability and diurnal patterns in trees of different ages.