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The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

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2 ) Redistribution. The data are provided for use by the Data User. The metadata and this license must accompany all copies made and be available to all users of this Data Set. The Data User will not redistribute the original Data Set beyond this collaboration sphere.
3 ) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly cite the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier. For example:

Shaver, G. 1989. Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska. Arctic LTER, Marine Biological Lab, Woods Hole, Ma 02543. 1989gsttbm http://ecosystems.mbl.edu/arc/terrest/biomass/index.shtml 

4 ) Acknowledgement. The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed significantly to its content. Acknowledgements should identify the supporting party, the party that received the support, and any identifying information such as grant numbers. For example:

Data sets were provided by the Arctic LTER. This material is based upon work supported by the National Science Foundation under Grants #DEB-981022, 9211775, 8702328; #OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529; #BSR 9019055, 8806635, 8507493.

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Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data, Dataset via LTER Data Poral
Dataset ID:2012_GS_ITEX_PF_ShootLightCurve.06
Dataset Title:Light response curves measured from shoots harvested at three levels in the canopy from 19 1m x 1m plots dominated by S. pulchra or B. nana shrubs near LTER Shrub plots at Toolik Field Station, AK the summer of 2012.
Investigator 1: 
First Name:Gaius
Last Name:Shaver
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
Address line 3:
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Investigator 2: 
First Name:Edward
Last Name:Rastetter
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Investigator 3: 
First Name:Mathew
Last Name:Williams
Organization:University of Edinburgh
Address line 2:School of Geosciences
City:Edinburgh
State:
Zip Code:EH9 EJU
Country:United Kingdom
Investigator 4: 
First Name:James
Last Name:Laundre
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
Address line 3:
City:Woods Hole
Zip Code:02543
Country:United States
Investigator 5: 
First Name:Laura
Last Name:van der Pol
Organization:Ecosystems Center at the Marine Biological Laboratory
Address line 2:7 MBL Street
City:Woods Hole
State:MA
Zip Code:02543
Country:United States
Associate Investigators:
Keywords:shoot photosynthesis, shrub canopy, point frame, light response curves, leaf area index
Abstract:This dataset contains light response curves and modeled light curve parameters from shoots clipped from low, mid, and the top parts of tall, shrub canopies dominated either by Salix pulchra or Betula nana. Six shoots were harvested from each 1m x 1m plot, two from each level in the canopy in plots located near the LTER shrub plots at Toolik Field Station, AK the summer of 2012. The species harvested were chosen based on the species present in each plot, thus the species from each segment of the canopy may not be the same. Additional information about each shoot can be found in the "2012_GS_ITEX_PF_ShootA-CiData" and "2012_GS_ITEX_PF_ShootHarvestData" pages, regarding the A-Ci response, area, mass, leaf area index, and leaf nitrogen content of each shoot. The file "2012_GS_ITEX_PercentCover" contains the species cover data for each plot.
For questions about the Metadata and data contact the Investigators.
For information about this web site contact:
Arctic LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7496
Email: arc_im@mbl.edu
Online URL: http://ecosystems.mbl.edu/ARC/
DATA FILE INFORMATION:
Data File URL http://metacat.lternet.edu/das/dataAccessServlet?docid=knb-lter-arc.10157&urlTail=terrest/tracegas/data/2012_GS_ITEX_PF_ShootLightCurve.csv
Data File Name 2012_GS_ITEX_PF_ShootLightCurve
Beginning Date 6/23/2012
End Date 8/7/2012
Number of Data Records 115
Other Files to Reference MANY OTHERS
Availability Status 1
Quality Control Information
Maintenance Description This was a season-long project, though it followed similar methods to ITEX projects performed starting in 2003 that are likely to be replicated in the future for reasearch at the Toolik Field Station, AK.
Log of Changes: Version 2: Missing values changed to #N/A. CH 28Jan2013
Version 3: Metadata updated to newer form (with sites sheet) CH April 2013.
Version 4: Corrected eml excel file name wrong extension. JimL 16May13
Version 5: Correct upper/lower case of missing value. JimL
Version 6: Corrected Distrubution URL. It had xlsfiles in the path. Jim L 19Jun14
 
RESEARCH LOCATION:                  
Location Name LTER Shrub Block 1 LTER Shrub Block 2 Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One Select Site or enter New One  
Geographic Description Upland site; co-located in Block 1 of the Shrub LTER sites; IVO 68 38'18.8" N, 149 34' 07.2" W +/- 50m. Except for plots marked "FERT", plots are outside of the designated LTER treatments, though are exposed to the same environmental conditions. All plots were chosen by the dominant shrub canopy (either Salix pulchraor Betula nana) and preferentially selected to be 90cm+ in height. Outlet site; co-located in Block 2 of the Shrub LTER sites; IVO 68 38'008.1" N, 149 35' 017.1" W +/- 50m. Except for plots marked "FERT", plots are outside of the designated LTER treatments, though are exposed to the same environmental conditions. All plots were chosen by the dominant shrub canopy (either Salix pulchraor Betula nana) and preferentially selected to be 90cm+ in height. Enter Description Enter Description Enter Description Enter Description Enter Description Enter Description  
Location Bounding Box                  
West Bounding Coordinate                  
East Bounding Coordinate                  
North Bounding Coordinate                  
South Bounding Coordinate                  
OR if single point location                  
Latitude 68.6385555555555 68.6355833333333 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Longitude -149.568666666666 -149.588083333333 In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees In Decimal Degrees  
Elevation 747 m 730 m In Meters In Meters In Meters In Meters In Meters In Meters  
Link to Google Map View on Google Map View on Google Map              
                   
 
TAXONOMIC COVERAGE:
Organisms studied Betula nana; Salix pulchra; Salix glauca
 
Methods:HARVEST METHOD:

The methods for setting up each point frame plot are described below in both the section "POINT FRAME PIN-DROP METHODS" The methods here describe how each shoot was harvested from the plots which were used for the point frame method.

Six shoots were harvested from each of 19 1m x 1m point frame plots which were dominated either by Salix pulchra or Betula nana tall, shrub species. The "shoots" described here are branch clippings between eight to ten inches long. Whenever possible they were selected for appearing relatively healthy, intact leaves, and each shoot was taken from a different plant. As these shoots were used for shoot-level and leaf-level measurements, shoots with bi-furcated stems -- or two stems from the same branch/height were cut -- one for leaf-level and the second for shoot-level analyses.

Before being cut, we measured the distance from the point frame to the highest tip on the shoot as well as the distance from the point frame to the shoot five inches from the tip. This way, we could approximate the angle of the shoot relative to the ground. Using the same criteria as for the pin-drop measurements, we measured the distance from the top of the shoot to the soil. In addition, the row number and pin-hole number nearest to the shoot's location with respect to the point frame was also recorded .

We then measured the leaf area index (LAI) of the shoot by holding an LAI-2000 (Li-Cor Inc., Lincoln, Nebraska, USA) in the exact location where the shoot had been and taking the average of three readings (one above, three below). For these measurements we used the one-quarter cut out and took care to always hold the instrument level and with the technician's body casting a uniform shadow over the instrument's eye, with the technician standing between the instrument and the sun. On occasion when it was raining during the shoot harvest, the area near where the shoot had been was marked with flagging tape, and the the LAI measurement was taken at a later date, using the height from frame/distance from ground meausrements as well as the row number and pin hole measurements as a guide.

Once cut, the shoot was placed immediately into water and transported to the lab. Once in the lab, the end of each shoot was clipped under water to ensure that there were no air bubbles in the stem that would inhibit the flow of water. Shoots were then allowed to sit at ambient room conditions (~20-25 degrees Celsius) until the the photosynthetic rates could be measured.

LIGHT RESPONSE CURVE MEASUREMENT:

The light response curve measurements were taken using a Licor 6400 photosynthesis system (Li-Cor Inc., Lincoln, Nebraska, USA) with an opaque conifer chamber with red-blue-green (RGB) light source attachment (model number 6400-22L). The light response curve measurements were taken after each shoot completed an A-Ci curve (see "2012_GS_ITEX_PF_ShootACiData" for details). The methods for setting up the LI-6400 are detailed in the ITEX Manual as updated in 2011.

Each shoot was oriented in the chamber so that the leaves were facing the RGB light source. Care was taken to ensure that no leaves were caught between the foam gaskets. Aditionally, adhesive, mounting tack was used to ensure a seal around the end of the stem that protruded from the chamber and remained in water for the duration of measurements.

The light curve measurements were conducted with the reference CO2 set to a constant 400 umol CO2. Each shoot was allowed to acclimate to the 400 umol CO2 and to the highest light level for the light curve for a few minutes, or until the Ca:Ci ([CO2]amb to [CO2]internal to the cell) ratio was stable around ~0.7 +/- 0.1. The light curve measurements were taken at the following levels in the order listed (units are umol photosynthetically active radiation (PAR) m-2 s-1): 2200, 1800, 1200, 800, 600, 600, 400, 300, 200, 100, 50, 20, 0. The shoot was given a minimum of 60 seconds but not more than 85 seconds to adjust to each new light level before a measurement was taken, and the instrument matched the reference and sample chambers prior to every measurement. The block temperature of the infra-red gas analyzer (IRGA) was adjusted throughout the light curve measurement to maintain a leaf temperature as near as possible to 20 degrees Celsius.

Once the measurment was complete, each shoot was carefully cut from the stem that remained outside the chamber so that only the portion of the shoot inside the chamber remained. This whole shoot was then photographed for later silhouette-area analysis with Image-J software [See "2012_GS_ITEX_PF_ShootHarvestData" for details]. The leaves, stipules, petioles, green and brown stem, and other plant green organs were then clipped from the shoot, lain flat on a hinged, plexiglass folder, and scanned. These images were subsequently processed with the Image-J software to calculate the area of each tissue type; the sum of the area of the leaves, petioles, and stipules were used to correct the default area used when taking the light curve measurements.

Each tissue type was separated, placed in a coin envelope, labeled, and dried at 60 degrees Celsius at least three days before being weighed on a four-point balance with glass enclosure. The mass of each sample can be found in the "2012_GS_ITEX_PF_ShootHarvestData" file.

CHN ANALYSIS:
Grinding: All leaf samples were dried in an oven at 60C before grinding. Samples were small enough to grind the entire sample without subsampling. Leaves were ground using the Retsch MM 200 for 3 minutes or until a talcum powder consistency was achieved.

Weighing: After grinding, samples were stored in glass scintillation vials and dried again at 60C for at least 36 hours. Once samples were removed, vials were tightly re-capped. When not in use, vials were stored in dessicators. 3.5-4.5 mg of each sample was weighed into a 10x12 mm tin capsule. A standard calibration curve was created using increasing amounts of aspartic acid (from about 0.2 mg to 5.0 mg). A chemical standard, acetanilide, and an organic sample, apple leaf, were run after the standard curve. Every ten samples, an aspartic acid check standard and a duplicate of an already-packed sample were run.

CN analysis: CN analysis was run between 10/4/2012 and 11/15/2012 by Rachel Rubin using the ThermoScientific 2000 at the Ecosystems Center, MBL, Woods Hole, MA. Duplicate sample values were averaged (mass, %N and %C) before inclusion into final results. The CHN data is available in the file "PF_CHN_Data".


CURVE MODELS:

Once corrected for the actual leaf area, the light curve for each shoot was modelled with the five photosynthetic models listed below. Although the formulas for each model are different, they were each performed using the Excel Solver function set to minimize the sum of squared difference between the measured photosynthetic rates and the modelled rates. The Solver function was used again to find the light level (umol PAR m-2 s-1) in each model equation that was closest to zero.

The parameters listed in the "PF_ShootLightCurve_Data" are those from the best-fit model (refer to the Best-fit Model (1-5) column).

Model 1: Rectangular Hyperbola (Cosby and Hornberger 1984)




Where:
P = rate of photosynthesis (umol CO2 m-2 ground s-1)
Jmax = light saturated rate of photosynthesis (umol CO2 m-2 ground s-1)
Phi (f) = parameter for quantum yield (Eo) (umol CO2 umol-1 PAR)
I = irradiance (umol PAR m-2 ground s-1)
R = modeled respiration rate (umol CO2 m-2 ground s-1)

Model 2: Incorporating Elevated CO2 - Mechanistic Photosynthesis Model (McMurtie et al. 1992)




Where:
Theta (?) = describes curvature of quantum response
P = rate of photosynthesis (umol CO2 m-2 ground s-1)
R = modeled respiration rate (umol CO2 m-2 ground s-1)
Jmax = light saturated rate of photosynthesis (umol CO2 m-2 ground s-1)
Phi (f) = parameter for quantum yield (Eo) (umol CO2 m-2 ground s-1)
I = irradiance (umol PAR m-2 ground s-1)

Model 3: Leaf Nitrogen Distribution (Chen et al. 1993)




Where:
P = rate of photosynthesis (umol CO2 m-2 ground s-1)
Jmax = light saturated rate of photosynthesis (umol CO2 m-2 ground s-1)
Phi (f) = parameter for quantum yield (Eo) (umol CO2 m-2 ground s-1)
I = irradiance (umol PAR m-2 ground s-1)
R = modeled respiration rate (umol CO2 m-2 ground s-1)
Gamma (?) = describes curvature of quantum response

Model 4: Photoinhibition Model (Platt et al. 1980)



Where:
P = rate of photosynthesis (umol CO2 m-2 ground s-1)
Jmax = light saturated rate of photosynthesis (umol CO2 m-2 ground s-1)
Alpha (a) = parameter for quantum yield (Eo) (umol CO2 m-2 ground s-1)
I = irradiace (umol PAR m-2 ground s-1)
Beta () = photoinhibition parameter
R = modeled respiration rate (umol CO2 m-2 ground s-1)

Model 5: Hyperbolic Tangent Model (Cosby and Hornberger 1984)





Where:
P = rate of photosynthesis (umol CO2 m-2 ground s-1)
Jmax = light saturated rate of photosynthesis (umol CO2 m-2 ground s-1)
Alpha (a) - parameter for quantum yield (Eo) (umol CO2 m-2 ground s-1)
I = irradiance (umol PAR m-2 ground s-1)
R = modeled respiration rate (umol CO2 m-2 ground s-1)


POINT FRAME PIN-DROP METHODS:
We preferentially selected tall shrub canopies dominated either by Betula nana or Salix pulchra, that is canopies that were greater than 75 cm height. Care was taken to select fairly uniform canopies, that is avoiding the edge of a shrub stand or areas where the canopy had a large gaps, suggesting the area may have been disturbed.

We used point frames constructed from a 1.1 m x 1.1 m aluminum square with holes in each corner to accomodate steel rod posts used as the legs of the point frame. In this way, the frame could rest upon the four leg posts that had been hammered into the ground and remain adjustable in each corner. The frame had a level on each side, and great care was taken to ensure that the frame was (a) unable to be pushed deeper into the ground and, (b) level on all four sides prior to taking measurements. These factors were important to the measurement to have accurate data regarding the distance from the frame and the overall height of each point sampled in the canopy.

The aluminum frame had numbered, regularly spaced holes on two opposite sides in order to accomodate a metal bar that could be placed across the frame and locked into place. [These holes on the frame are the row numbers.] The bar that was placed across the frame similarly had numbered, evenly spaced holes in order to accomodate a pin--a long (100-200cm) metal rod with a diameter of ~3.175 mm. [The holes on this bar are the pin hole numbers.] Measurements were only ever taken from odd row numbers, and alternated even/odd pin hole numbers with each row; in this way, for every plot 25 evenly spaced locations were sampled covering an area of one square meter.

The length of the pin was marked every half-centimeter so that the distance could be read easily. Measurements were made by lowering the pin through a pin hole and, once encountering a leaf or stem, recording the following: row#, pin hole#, hit#, and the species hit. If the object hit was not a leaf, the plant tissue was noted; the diameter of each stem hit was estimated in millimeters, and the length of every graminoid blade hit was recorded from the point at which it was hit to the tip. As the primary species of interest for this project were for a select number of species (B. nana, S. pulchra, S. glauca, S. reticulata, V. uliginosum, V. vitis, L. palustre), species that were not the target of interest were classified as functional groups--e.g. graminoid spp., forb, moss.

The last pin-hit recorded for each pin hole was always at the "soil" which was considered to be the transition between the green and brown plant material, often in a mossy layer.

REFERENCES:
Chen J-L., Reynolds J.F., Harley P.C., Tenhunen J.D., 1993. Coordination theory of leaf nitrogen distribution in a canopy. Oecologia. 93: 63-9.

Cosby B.J. and Hornberger, G.M., 1984. Identification of photosynthesis-light models for aquatic systems. I. Theory and simulations. Ecol. Modelling. 23: 1 - 24.

ITEX Manual Updated in 2011

McMurtie R.E., Comins H.N., Kirschbaum M.U.F., and Wang Y-P., 1992. Modifying existing forest growth models to take account of effects of elevated CO2. Aust. J. Bot. 40: 657-77.

Platt, T, CL Gallegos, and WG Harrison. 1980. Photoinhibition of photosynthesis in natural assemblages of marine phytoplankton. J Mar Res. 38:687-701.

Street L. E. Shaver G. R. Williams M. and van Wijk M. T. 2007. What is the relationship between changes in canopy leaf area and changes in
photosynthetic CO2 flux in arctic ecosystems? Journal of Ecology 95: 139-150.

van Wijk M. T. Williams M. and. Shaver G. R. 2005. Tight coupling between leaf area index and foliage N content in arctic plant communities. Oecologia 142: 421427.

Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
YEAR year of measurement datetime   YYYY    
DATE date of measurement datetime   DD-MMM-YY    
SITE Toolik text        
GROUP Measurement location in relation to Toolik Lake LTER Shrub plots; In vicinity of Block1 = Upland, IVO Block 2 = Outlet text        
PLOT Individual plot identifier text        
TREATMENT control or fertilized annually (with N and P) text        
PLOT SIZE 1m x 1m point frame size text        
DOMINANT VEGETATION Dominant canopy vegetation text        
SPP Shoot species sampled text centimeter      
SHOOT ID Identification for each shoot sampled (NOT unique); consists of canopy position (up/mid/low), species abbreviation, and a number text dimensionless      
CANOPY POSN Relative position of shoot in the canopy text dimensionless      
SUM(LEAF, PETIOLE, STIPULE) AREA Area of the shoot leaves, petioles, and stipules used to correct light curve data number centimeterSquared      
AMBIENT CO2 BEFORE MEASUREMENTS Carbon dioxide concentration in the room at the beginning of measurements number micromolePerMole     not recorded=Missing or Not Measured
AMBIENT CO2 AFTER MEASUREMENTS Carbon dioxide concentration in the room after taking measurements number micromolePerMole     not recorded=Missing or Not Measured
AVG LEAF TEMP Average leaf temperature during measurement number celsius     #N/A=Missing or Not Measured
AVG PRESSURE Average pressure during measurement number atmosphere     #N/A=Missing or Not Measured
START-TIME Time at the start of the measurement (24-hr) datetime   HH:MM:SS   #N/A=Missing or Not Measured
PARmax Maximum light level during the light curve (umol PAR m-2 leaf s-1) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
BEST FIT-MODEL (1-5) Number of the best-fit photosynthesis model used to calculate light curve parameters (Pmax, K, etc) number number     #N/A=Missing or Not Measured
SSD Sum of squared difference between the measured values and the best-fit model number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Pmax Modeled light saturated shoot photosynthetic rate (umol CO2 m-2 leaf s-1) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
K Modeled half saturation constant (umol PAR umol-1 CO2) number micromolePerMicromole     #N/A=Missing or Not Measured
RESP_MEAS Rate of CO2 change measured in the dark, and so used to estimate respiration rate number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
RESP_MODEL Respiration rate as modeled from best-fit model (umol CO2 m-2 leaf s-1) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
LCP Modeled light compensation point (umol PAR m-2 leaf s-1) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Eo Modeled quantum yield (umol CO2 umol-1 PAR) number micromolePerMicromole     #N/A=Missing or Not Measured
GPP600 Gross photosynthetic rate at 600 PAR umol m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PNET 600 Net photosynthetic rate at 600 PAR umol m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PNET 300 Net photosynthetic rate at 300 PAR umol m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 0 Actual photosynthetically active radiation (PAR) measured ordered value of 0 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 20 Actual photosynthetically active radiation (PAR) measured ordered value of 20 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 50 Actual photosynthetically active radiation (PAR) measured ordered value of 50 umol PAR m-2 s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 100 Actual photosynthetically active radiation (PAR) measured ordered value of 100 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 200 Actual photosynthetically active radiation (PAR) measured ordered value of 200 umol PAR m-2 s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 300 Actual photosynthetically active radiation (PAR) measured ordered value of 300 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 400 Actual photosynthetically active radiation (PAR) measured ordered value of 400 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 600 (a) First (of two) actual photosynthetically active radiation (PAR) measured ordered value of 600 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 600 (b) Second (of two) actual photosynthetically active radiation (PAR) measured ordered value of 600 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 800 Actual photosynthetically active radiation (PAR) measured ordered value of 800 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 1200 Actual photosynthetically active radiation (PAR) measured ordered value of 1200 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 1800 Actual photosynthetically active radiation (PAR) measured ordered value of 1800 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
PAR 2200 Actual photosynthetically active radiation (PAR) measured ordered value of 2200 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 0 Rate of photosynthesis measured at 0 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 20 Rate of photosynthesis measured at 20 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 50 Rate of photosynthesis measured at 50 umol PAR m-2 leaf s-1 number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 100 Rate of photosynthesis measured at 100 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 200 Rate of photosynthesis measured at 200 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 300 Rate of photosynthesis measured at 300 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 400 Rate of photosynthesis measured at 400 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 600 (a) Rate of photosynthesis measured at 600 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 600 (b) Rate of photosynthesis measured at 600 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 800 Rate of photosynthesis measured at 800 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 1200 Rate of photosynthesis measured at 1200 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 1800 Rate of photosynthesis measured at 1800 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
Photo 2200 Rate of photosynthesis measured at 2200 umol PAR m-2 leaf s-1 (umol CO2 per square meter leaf per second) number micromolePerMeterSquaredPerSecond     #N/A=Missing or Not Measured
COMMENTS Notes or data quality information text        

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