sunflowers {photosynthesisLRC}R Documentation

Light Response Curves from a Common Garden Experiment in Helianthus

Description

This dataset contains photosynthetic light response curves for 28 sunflower species in the genus Helianthus. The data was gathered in a common garden to evaluate phylogenetic change to photosynthetic response across as a function-valued trait (Davis et al. 2024).

Usage

sunflowers

Format

A data frame with 666 rows and 22 variables:

SampleID

A unique identifier for each sample, a combination of Species_Replicate_Date (character).

Species

The species name of the sunflower (character).

Replicate

The number assigned to indicate repeated individuals of the same species (numeric).

Date

The day at which the measurement was taken (character, DD:MM:YY format).

Time

The time at which the measurement was taken (character, HH:MM format).

CO2r

The TARGAS-1 reference CO2 (µmol CO2 mol^-1, numeric).

CO2a

The TARGAS-1 ambient CO2 reading (µmol CO2 mol^-1, numeric).

H2Or

Humidity reading measured by the TARGAS-1 reference during the time of measurement (mb, numeric).

H2Oa

Humidity reading measured in the air by the TARGAS-1 during the time of measurement (mb, numeric).

atm

Atmospheric pressured at the measurement (mb, numeric).

Flow.Supply

Air flow moving through the TARGAS-1 (cc/min, numeric).

Flow.sample

Air flow passing back into the TARGAS-1 from the PLC (cc/min, numeric).

PARe

Photosynthetically Active Radiation levels in the environment, measured at the PLC (µmol m^-2 s^-1, numeric).

PARi

Photosynthetically Active Radiation levels on the leaf (µmol m^-2 s^-1, numeric).

Tleaf

Leaf temperature in the PLC during the measurement (degrees Celsius, numeric).

Trans

Transpiration rate (mmol H2O m^-2 s^-1, numeric).

VPD

Vapor pressure deficit during the measurement (mb, numeric).

gs

Stomatal conductance (mmol H2O m^-2 s^-1, numeric).

A

Photosynthetic rate (µmol CO2 m^-2 s^-1, numeric).

Ci

Concentration of leaf internal CO2 (µmol CO2 mol^-1, numeric).

Area

The area of the leaf measured (cm^2, numeric).

Details

All plants were grown in fertilized 1 gallon pots during August- December 2019 at the University of Central Florida's Transgenic Greenhouse. Measurements were taken for two hours before and after solar noon with the Portable Photosynthetic Systems (PPS) TARGAS-1 on the most recently expanded full leaf during the juvenile stage just before flowering (V4-6) (NDSU Stages of Sunflower Development). The TARGAS-1 portable leaf cuvette (PLC) was clamped on the leaf perpendicular to the leaf margin, and photosynthetic measurements were taken at approximately 420 ppm CO2, ambient humidity, and 500 ppm flow. Photosynthetic responses were recorded at 9 levels with an acclimation of 2-5 minutes at PARi 0, PARi 50, PARi 100, PARi 250, PARi 500, PARi 1000, PARi 2000, PARi 2500 (µmol s/m2). The data was manually curated such that duplicate instantaneous assimilation points were removed and only one single representative sample from each replicate was used in analysis. The data set includes the Sample name, the species name, the replicate number, and 19 other variables obtained from the TARGAS-1 measurement.

Author(s)

Rebekah Davis, University of Central Florida

Source

Data collected by Rebekah Davis at the University of Central Florida.

References

Davis, R.E., C. M. Mason, E. W. Goolsby 2024 Comparative evolution of
photosynthetic light response curve: approaches and pitfalls in
phylogenetic modeling of a function-valued trait. IJPS, in review

Kandel, H., A. A. Schneiter, J. F. Miller, D. R. Berglund 2019 Stages of
Sunflower Development. North Dakota State University Extension
(https://www.ndsu.edu/agriculture/extension/publications/stages-
sunflower-development)

Examples

# Load the dataset
data(sunflowers)

# View the first few rows
head(sunflowers)

# Summary statistics for photosynthetic rate (A)
summary(sunflowers$A)

# Plot the photosynthetic rate vs. PARi
plot(sunflowers$PARi, sunflowers$A,
     xlab = "PAR (µmol m^-2 s^-1)",
     ylab = "Photosynthetic rate (µmol CO2 m^-2 s^-1)")


[Package photosynthesisLRC version 1.0.6 Index]