Estimating Leaf CO₂ Assimilation in C₃ Plants Using a Handheld Porometer With Chlorophyll Fluorometer in Field...

Area of Science:

• Plant physiology
• Photosynthesis research
• Environmental science

Background:

• Leaf CO2 assimilation rate (An) is crucial for plant productivity.
• Traditional An measurement methods are cumbersome for field use.
• A need exists for efficient, portable tools for field-based photosynthesis assessment.

Purpose of the Study:

• To develop and validate a convenient handheld method for estimating leaf CO2 assimilation rate (An) in the field.
• To integrate stomatal conductance and chlorophyll fluorescence measurements into a biochemical photosynthesis model.
• To assess the accuracy and applicability of this method across diverse plant species.

Main Methods:

• Utilized a handheld porometer coupled with a chlorophyll fluorometer.
• Integrated stomatal conductance and quantum yield of PSII photochemistry into a biochemical photosynthesis model.
• Calibrated the model parameter incorporating uncertainties for field conditions.

Main Results:

• Successfully estimated An variations in 12 plant species under field conditions.
• Achieved a root mean square error of 2.0 μmol m-2 s-1 with the calibrated method.
• Demonstrated that uncalibrated methods significantly overestimate An, highlighting the importance of calibration.

Conclusions:

• The handheld porometer-fluorometer method offers an accessible, high-throughput, and accurate approach for field-based An estimation.
• This technique addresses a key limitation in plant photosynthesis phenotyping.
• Further research is needed to refine the calibrated parameter and reduce uncertainties for broader application.