Author(s): Lamour J; Davidson K; Calderon O; Ely K
Site ID: PA-Gam; PA-PNM
Site Name: Gamboa Area; Parque Natural Metropolitano
Variables: Leaf area index; Leaf gas exchange; Leaf photosynthetic traits (Vcmax and Jmax)
Date Range: Jan. 18, 2022 - April 8, 2022
Description: Photosynthetic CO2 response curves (ACi curves), light response curves (AQ curves), dark adapted dark respiration, conductance curves, and survey measurements for leaves measured in the Parque Natural Metropolitano (PNM) and Gamboa, Panama, from January to April 2022 are presented. Measurements were made on leaves from 46 different tree, shrub and liana species, from sunlit canopy and understory locations. Leaf area index from 8 vertical profiles at PNM are also included. The aim of this measurement campaign was three-fold: (i) to improve our understanding of the vertical variation in leaf-level water use efficiency; (ii) to develop an understanding of the sensitivity of stomata to changes in environmental conditions, especially light, humidity, and temperature; (iii) to improve models which can predict leaf traits from leaf contact spectral measurements. All the gas exchange data and metadata are presented in .csv files and complete instrument output are included in .zip folders. Data and metadata meet the ESS-DIVE leaf-level gas exchange reporting format requirements. The protocol details are provided as pdf documents. In addition to gas exchange data reported here these samples were also used for measurement of leaf optical properties, carbon and nitrogen content, and leaf mass per unit leaf area (LMA). These data can be cross linked using the unique sample ID and are provided in separate data packages.
QA/QC: Full QA-QC
Methods Description: Seven portable photosynthesis systems were used, four LICOR-6400 XT equipped with a 2 × 3 cm2 leaf chamber and red-blue light source (90% red, 10% blue), and 3 LICOR 6800 equipped with a Multiphase Flash Fluorometer leaf chamber (6800-01A). All gas exchange measurements (aside from survey measurements) were conducted on cut branches. Branches were cut in the morning before dawn, quickly immersed into water in a bucket inside the gondola of the crane and recut several times to avoid xylem embolism. All branches were placed into a shaded area where the gas exchange measurements were performed. Leaves without abnormal appearance (shape, disease) were chosen on each branch. Response curve measurements included stomatal response to changes in irradiance, leaf temperature, and relative humidity, in addition to a separate set of measurements to characterize the response of stomata to humidity and temperature in the dark. In addition, we also conducted ACi and AQ curves on a subset of species. Survey measurements were collected using the LI-6800, in situ on fully sunlit canopy leaves. Before each measurement, the conditions within the leaf chamber were set to match ambient air temperature, CO2 concentration, and irradiance. The relative humidity of the air was maintained at 70% for all measurements, a level which allowed for VPDair to be close to mean daytime conditions, while minimizing the risk of condensation forming in the instrument.
Access Level: Public
Originating Institution(s): Brookhaven National Laboratory, Smithsonian Tropical Research Institute
Sponsor Organization(s): U.S. Department of Energy Office of Science Office of Biological and Environmental Research
Contact: Rogers, Alistair - Brookhaven National Laboratory (arogers@bnl.gov)
Version: 1.0
Dataset Citation: Lamour J; Davidson K; Calderon O; Ely K (2023): Leaf gas exchange and fitted parameters, two sites in Panama, 2022. 1.0. NGEE Tropics Data Collection. (dataset). https://doi.org/10.15486/ngt/1896884
Acknowledgement: This research was supported as part of NGEE-Tropics, funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research under contract no. DE-SC0012704.
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