This readme.txt file was generated on 2021/09/20 by Natalie McMann, Alexander Peichel, and Jessica Savage

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GENERAL INFORMATION
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1. Title of Dataset 

Floral and leaf gas exchange and stem hydraulic conductance data observed from 2017 to 2018 on woody plants growing in Minnesota

2. Author Information

  Principal Investigator Contact Information
        Name: Jessica A. Savage	
           Institution: University of Minnesota
           Address: 1035 Kirby Drive, 207 Swenson Science Building, Duluth, MN 55812
           Email: jsavage@d.umn.edu
	   ORCID: 0000-0002-7756-7166

  First Author Contact Information
	Name: Natalie McMann
	   Institution: University of Minnesota
           Address: 1035 Kirby Drive, 207 Swenson Science Building, Duluth, MN 55812
           Email: mcman110@d.umn.edu
	   ORCID: 0000-0001-5275-7775 

  Second Author Contact Information
	Name: Alexander Peichel
	   Institution: University of Minnesota
           Address: 1035 Kirby Drive, 207 Swenson Science Building, Duluth, MN 55812
           Email: peich022@d.umn.edu

3. Date of data collection (single date, range, approximate date) <suggested format YYYYMMDD>

2017/06/12-2018/08/17

4. Geographic location of data collection (where was data collected?): 

Bagley Nature Area, Duluth, MN —(46.8241° N, 92.0868° W)
University of Minnesota Duluth Campus, Duluth, MN —(46° 49' 10.25" N, 92° 04' 54.12" W)
University of Minnesota Twin Cities Campus, St. Paul, MN —(44° 58' 59.3409”N, 93° 11' 11.1236”W)
Wolf Ridge Environmental Learning Center, Finland, MN —(47° 22′ 55.06″ N, 91° 11′ 45.86″ W)

5. Information about funding sources that supported the collection of the data:

National Science Foundation (IOS:1656318), the University of Minnesota – Duluth, the Garden Club of America (Corliss Knapp Engle Scholarship) and the Integrated Biosciences Graduate Program

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SHARING/ACCESS INFORMATION
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1. Licenses/restrictions placed on the data:

Manuscript copyright held by Wiley Online Library

2. Links to publications that cite or use the data:

McMann, N., Peichel A., & Savage, J. 2022. Early spring flowers rely on xylem hydration but are not limited by stem xylem conductivity. New Phytologist, 233(2), 838-850.  

3. Links to other publicly accessible locations of the data:

None

4. Links/relationships to ancillary data sets:

None

5. Was data derived from another source?
           If yes, list source(s):

No

6. Recommended citation for the data:

McMann, N., Peichel A., & Savage, J. 2022. Early spring flowers rely on xylem hydration but are not limited by stem xylem conductivity. New Phytologist, 233(2), 838-850.  

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DATA & FILE OVERVIEW
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1. File List
   A. Filename: Floral_gas_exchange 
      Short description: This file contains data on the diffusive conductance, transpiration, and net photosynthesis of inflorescences during anthesis.

   B. Filename: Leaf_gas_exchange      
      Short description: This file contains data on the diffusive conductance and transpiration of mature leaves during the growing season.

   C. Filename: Stem_xylem
	 Short description: This file contains data on the stem xylem hydraulic conductance and stem anatomy of branches during anthesis and during the growing season.

2. Relationship between files: All of these files are data collected during a project investigating the relationship between flowering and plant vasculature.     

3. Additional related data collected that was not included in the current data package:

McMann, N., Peichel A., and Savage, J. (2021). Plant phenology and floral anatomy data observed from 2017 to 2020 on woody plants growing in Minnesota
McMann, N., Peichel A., and Savage, J. (2021). Floral gas exchange data observed from cut and intact inflorescences and during a heating experiment in 2018 on woody plants growing in Duluth, MN

4. Are there multiple versions of the dataset? yes/no

Yes, data from the following data package was used to calculate values in this dataset: 

McMann, N., Peichel A., and Savage, J. (2021). Plant phenology and floral anatomy data observed from 2017 to 2020 on woody plants growing in Minnesota

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METHODOLOGICAL INFORMATION
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1. Description of methods used for collection/generation of data: 

See descriptions under “Variable Lists” below and publication for details. 

	A. Floral_gas_exchange and Leaf_gas_exchange
	Inflorescence and leaf gas exchange data was collected using a portable gas exchange analyzer (6400, LI-COR, Lincoln, NE) for five species in 2017 or 2018. Inflorescence gas exchange measurements were taken during anthesis on at least six inflorescences per species using an opaque LI-COR conifer chamber with an RGB light source attached (6400-22 and 6400-18/A). Leaf gas exchanged measurements occurred in July and early August of 2018 on one to three mature leaves of at least six individuals using the same light level and flow rate as the inflorescences with the standard broadleaf LI-COR chamber (6400-02B). In spring of 2020, inflorescences surface area was estimated from eight to ten individuals per species. The length and diameter of catkins was measured with calipers and then used to calculate cylindrical surface area. Petals or tepals were scanned and measured with ImageJ (version 1.48) to determine the corolla area of flowers, with the resulting area multiplied by two to account for both sides of the surface. Leaf surface area was obtained through scanning and image processing with ImageJ (version 1.48). 

	B. Stem_xylem
	Branches for stem xylem conductivity measurements for each species were collected early in the morning the day after inflorescence or leaf gas exchange measurements. Branches were cut underwater at least two maximum vessel lengths away from segments that would be used for measurements, then covered in black plastic bags and placed in a bucket of water for several hours in a cold room to relax the water potential. 
	To prepare samples for measurement, straight, unbranching stem segments were excised from the branches underwater. Segments were at least the minimum sample length for that species as determined by cutting back segments until resistivity decreased (Melcher et al., 2012) and contained 2-5 years of xylem growth. Flow rate of the stem segment was measured by gravimetrically perfusing partially degassed, filtered (0.22 µm) 10 mM KCl solution at a standard temperature of 20°C through the stem under a driving pressure of 1–1.5 kPa (Sperry et al., 1988b). The flow rate was recorded with a liquid flow sensor (SLI-0430, Sensirion, Switzerland) upstream of the stem segment (Wason et al., 2018). All stem segments were measured within 24 hours of branch collection.
	After flow measurements, the middle of segment was cut out with a razor blade and imaged with a stereoscope to determine the years of growth of the xylem. 

2. Methods for processing the data: 
NA

3. Instrument- or software-specific information needed to interpret the data:

NA

4. Standards and calibration information, if appropriate:

NA

5. Environmental/experimental conditions:

Measurements in the file “Floral_gas_exchange” were made between 10am and 3pm during anthesis for each species.
The following conditions were maintained: light level = 1200 µmol m-2 s-1 and flow rate = 400 μmol s-1. All other conditions were ambient and are reported in the file. 

Measurements in the file “Leaf_gas_exchange” were made between 8am and 11am on sunny days. 
The following conditions were maintained: light level = 1200 µmol m-2 s-1, flow rate = 400 μmol s-1, and CO2 = 400 ppm. All other conditions were ambient and are reported in the file. 

6. Describe any quality-assurance procedures performed on the data:

All data entry was triple checked.

7. People involved with sample collection, processing, analysis and/or submission:

Natalie McMann, Jessica Savage, Alexander Peichel, Erin O’Connell, Kennedy Mosher, and Thomas Kiecker

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DATA-SPECIFIC INFORMATION FOR: Floral_gas_exchange
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1. Number of variables: 13

2. Number of cases/rows: 36

3. Missing data codes:
     NA

4. Variable List

    A. Name: species
       Description: Scientific name of the species

    B. Name: plant_id
       Description: This is the individual code referenced in other data sets and in archived samples.

    C. Name: date
       Description: This is date on which the measurements were taken [MM/DD/YY].
 
    D. Name: temp
       Description: This is the temperature (°C) in the LI-COR chamber during collection. 

    E. Name: rh
       Description: This is the relative humidity (%) in the LI-COR chamber during collection. 

    F. Name: vpd
       Description: This is the vapor pressure deficit (kPa) in the LI-COR chamber during collection. 

    G. Name: cndsa
       Description: This is inflorescence diffusive conductance standardized by inflorescence surface area [mol m^-2 s^-1].

	H. Name: cndg
       Description: This is inflorescence diffusive conductance standardized by inflorescence dry mass [mol g^-1 s^-1].

	I. Name: cndinflo
       Description: This is inflorescence diffusive conductance standardized by number of inflorescences in the LI-COR chamber [mol inflorescence^-1 s^-1].

    J. Name: trmmolsa
       Description: This is inflorescence transpiration standardized by inflorescence surface area [mmol m^-2 s-1].

    K. Name: trmmolg
       Description: This is inflorescence transpiration standardized by inflorescence dry mass [mmol g^-1 s^-1].

    L. Name: photo
       Description: This is net photosynthesis [µmol CO2 m^-2 s^-1] of the inflorescence standardized by surface area.

    M. Name: total_inflo_SA
       Description: This is the total inflorescence surface area [m^2] downstream of the stem segment measured for stem xylem hydraulic conductivity. Total inflorescence surface area was estimated by multiplying the number of inflorescences downstream of the stem segment by the average surface area of an inflorescence. 

    N. Name: branch_cndtotal
	  Description: This is the total diffusive conductance [mol branch^-1 s^-1] of the inflorescences downstream of the stem segment measured for stem xylem conductance. 

    N. Name: branch_trmmoltotal
	  Description: This is the total transpiration [mmol branch^-1 s^-1] of the inflorescences downstream of the stem segment measured for stem xylem conductance. 

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DATA-SPECIFIC INFORMATION FOR: Leaf_gas_exchange
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1. Number of variables: 13

2. Number of cases/rows: 34

3. Missing data codes:
     NA

4. Variable List

    A. Name: species
       Description: Scientific name of the species

    B. Name: plant_id
       Description: This is the individual code referenced in other data sets and in archived samples.

    C. Name: date
       Description: This is the date on which the measurement were taken [MM/DD/YY]. 

    D. Name: temp
       Description: This is the temperature (°C) in the LI-COR chamber during collection. 

    E. Name: rh
       Description: This is the relative humidity (%) in the LI-COR chamber during collection. 

    F. Name: vpd
       Description: This is the vapor pressure deficit (kPa) in the LI-COR chamber during collection.

    G. Name: cnd
       Description: This is leaf diffusive conductance standardized by the surface area in the chamber [mol m^-2 s^-1].

    H. Name: trmmol
       Description: This is leaf transpiration standardized by the surface area in the chamber [mmol m^-2 s^-1].

    I. Name: total_leaf_SA
       Description: This is the total leaf surface area [m^2] downstream of the stem segment measured for stem xylem hydraulic conductivity. Total leaf surface area was measured with ImageJ.

    J. Name: branch_cndtotal
	  Description: This is the total diffusive conductance [mol branch^-1 s^-1] of the leaves downstream of the stem segment measured for stem xylem conductance. 

    K. Name: branch_trmmoltotal
	  Description: This is the total transpiration [mmol branch^-1 s^-1] of the leaves downstream of the stem segment measured for stem xylem conductance. 

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DATA-SPECIFIC INFORMATION FOR: Stem_xylem
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1. Number of variables: 8

2. Number of cases/rows: 69

3. Missing data codes:
     NA

4. Variable List

    A. Name: species
       Description: Scientific name of the species

    B. Name: plant_id
       Description: This is the individual code referenced in other data sets and in archived samples.

    C. Name: collection date
       Description: This is the day that the samples was collected and measured [MM/DD/YY]. 

    D. Name: pressure
       Description: Driving pressure (MaP) throughout the flow measurement. Pressure was generated gravimetrically through a height differentially between the source of the liquid perfusing through the stem and the reservoir. 

    E. Name: sample_length
       Description: This is the length [m] of the stem segment used for the conductance/conductivity measurement

    F. Name: conductance
       Description: Conductance [g MPa^-1 s^-1], defined as flow rate divided by the driving pressure, of the sample segment. 

    G. Name: conductivity
       Description: Conductivity [g m MPa^-1 s^-1], defined as the flow rate multiple by segment length divided by the driving pressure, of the sample segment. 

    H. Name: sample_age
	  Description: Years of xylem growth present in the sample, as determined from a cross-section of the middle of the stem segment.