Photosynthetic-CO2 response curves at different leaf temperatures in tropical montane rainforest tree species from Colombian Andes, 2022

Data collection protocol: in January – March 2022, Aci curves (i.e., CO2 response curves of net photosynthesis) were done at a pre-determined saturating light intensity of 1800 PAR (Qin in the database). Aci curves were done at different leaf temperature targets between 15 and 40 degree Celcius, with 5 degree celcius steps. Before starting any ACi curve, the leaf was allowed to acclimate at each temperature for at least 10 min and the ACi was initiated once both Anet and stomatal conductance were stable for at least 2 min. Throughout each Aci, the stability time at each CO2 reference concentration (410, 50, 100, 150, 250, 410, 800, 1200, 1600, and 2000 in this order) was set to 45 - 180 seconds, the automatic match was programmed before recording any data at each CO2 reference concentration. Measurements were taken with an LI6800 Portable Photosynthesis System under field conditions. LI6800 indicates whether there is a leak, but measurements were always done after ensuring there was no leak in the system, therefore, no subsequent leak correction was necessary. At the beginning of each measurement day, automatic warm-up test was run to detect any problem within the instrument, and only measurements were initiated when all errors have been fixed as suggested by the instrument system. The leaf temperature was derived from the thermocouple of the instrument.