This repository contains gas exchange measurement data used to generate the figures in the associated manuscript. The data includes both measured (IRGA and porometer) and simulated gas exchange parameters for various plant species under different environmental conditions.

Overview

The dataset comprises leaf-level and canopy-scale gas exchange measurements along with model simulations. Data were collected using infrared gas analyzers (IRGA) and leaf porometers, with complementary simulations performed to validate stomatal conductance models.

File Naming Convention

Files are named according to the figure they correspond to in the manuscript:

• Figure[N]-[Instrument/Method]-[Description].[ext]

Where:

• [N] = Figure number in manuscript
• [Instrument/Method] = Data collection method (IRGA, Porometer, Simulated)
• [Description] = Brief description of the experiment or data type
• [ext] = File extension (.csv, .txt, or .xlsx)

Data Files

Figure 2 - Steady-State vs Non-Steady-State Comparison

• Figure2-Steady-State-IRGA.xlsx: Steady-state IRGA measurements
• Figure2-Nonsteady-State-Porometer.csv: Non-steady-state porometer measurements

Figure 3 - Species Response Curves (Light and VPD)

Light response curves:

• Figure3-Cowpea-Light.csv: Cowpea light response data
• Figure3-Redbud-Light.csv: Eastern redbud light response data
• Figure3-Walnut-Light.csv: Walnut light response data

Vapor pressure deficit (VPD) response curves:

• Figure3-Cowpea-VPD.csv: Cowpea VPD response data
• Figure3-Redbud-VPD.csv: Eastern redbud VPD response data
• Figure3-Walnut-VPD.csv: Walnut VPD response data

Figure 4 - Diurnal Simulation

• Figure4-Simulated-Redbud-Diurnal.txt: Simulated diurnal cycle for eastern redbud canopy

Figure 5 - Subject Leaf Measurements

• Figure5-IRGA-Subject-Leaf.csv: IRGA measurements on the subject leaf

Figure 6 - Steady-State and Non-Steady-State Validation

Measured data:

• Figure6-Steady-State-Measured.csv: Steady-state measured data
• Figure6-Nonsteady-State-Measured.csv: Non-steady-state measured data

Simulated data:

• Figure6-Steady-State-Simulated.txt: Steady-state simulation results
• Figure6-Nonsteady-State-Simulated.txt: Non-steady-state simulation results

Figure 7 - Single Leaf vs Canopy Measurements

• Figure7-IRGA-Single-Leaves.csv: IRGA measurements on individual leaves
• Figure7-Porometer-Canopy.csv: Porometer measurements across the canopy

Figure 8 - Time Constant Simulations

Simulations with different stomatal time constants (τ):

• Figure8-Simulated-900tau.txt: Simulation with τ = 900s
• Figure8-Simulated-3600tau.txt: Simulation with τ = 3600s
• Figure8-Simulated-9000tau.txt: Simulation with τ = 9000s

Figure 9 - Neighboring Leaf Effects

• Figure9-IRGA-Subject-Leaf.csv: IRGA measurements on subject leaf during neighboring leaf experiment
• Figure9-Porometer-Neighboring-Leaves.csv: Porometer measurements on neighboring leaves

Figure 10 - Real vs Simulated Canopy

• Figure10-Real-Canopy.csv: Measured canopy-scale gas exchange
• Figure10-Simulated-Canopy.txt: Simulated canopy-scale gas exchange

Data File Formats

CSV Files (.csv)

Comma-separated values with header row containing variable names and (where applicable) a second row with units.

Common variables include:

• gs, gsw: Stomatal conductance to water vapor (mol m⁻² s⁻¹)
• gbw: Boundary layer conductance to water vapor (mol m⁻² s⁻¹)
• E: Transpiration rate (mmol m⁻² s⁻¹)
• A, An: Net photosynthesis rate (µmol m⁻² s⁻¹)
• Ci: Intercellular CO₂ concentration (µmol mol⁻¹)
• Ca: Ambient CO₂ concentration (µmol mol⁻¹)
• Tleaf: Leaf temperature (°C)
• Tair: Air temperature (°C)
• Q, PPFD: Photosynthetic photon flux density (µmol m⁻² s⁻¹)
• VPD, VPDleaf: Vapor pressure deficit (kPa or mmol mol⁻¹)
• RH, h: Relative humidity (%)
• Patm, Pa, P_atm: Atmospheric pressure (kPa)

Text Files (.txt)

Tab-delimited or space-delimited text files from simulation outputs, with header row containing variable names.

Excel Files (.xlsx)

Microsoft Excel format with data in spreadsheet format, typically with headers in the first row.

Species Information

• Cowpea (Vigna unguiculata)
• Eastern redbud (Cercis canadensis)
• Walnut (Juglans sp.)

Instrumentation

IRGA (Infrared Gas Analyzer)

LICOR LI-6800 steady-state measurements of gas exchange parameters including photosynthesis, transpiration, and stomatal conductance.

Leaf Porometer

LICOR LI-600 non-steady-state measurements of stomatal conductance and transpiration across multiple leaves or spatial locations.

Column Descriptions

Common IRGA Variables

• obs: Observation number
• time: Timestamp of measurement
• species: Plant species measured
• gsw: Stomatal conductance to water vapor
• gbw: Boundary layer conductance to water vapor
• gtw: Total conductance to water vapor
• E_apparent: Apparent transpiration rate
• VPcham, VPref, VPleaf: Vapor pressure in chamber, reference, and at leaf surface
• VPDleaf: Leaf-to-air vapor pressure deficit
• H2O_r, H2O_s, H2O_leaf: Water vapor concentrations
• leaf_area: Leaf area enclosed in chamber
• Tref, Tmeas, Tleaf: Temperature measurements
• P_atm, Patm: Atmospheric pressure
• flow, flow_s: Flow rates
• Qamb: Ambient light intensity

Common Simulated Variables

• leaf: Leaf identifier
• x, y, z: Spatial coordinates
• zenith, azimuth: Solar angles
• area: Leaf area
• PPFD: Photosynthetic photon flux density
• gs: Stomatal conductance
• gbw: Boundary layer conductance
• Tleaf, Tair: Leaf and air temperature
• RHair: Air relative humidity
• VPD: Vapor pressure deficit
• A: Net photosynthesis
• E: Transpiration
• psiL, psiStem: Leaf and stem water potential
• sunlitivity: Degree of sunlit exposure (0-1)

Notes

• Missing or invalid data are typically indicated by specific values (e.g., 999.9, 9999, -9999) or blank fields
• Timestamp formats may vary between instruments; refer to individual file headers for specific formats