As global temperatures rise, understanding the effects of increased temperature on daily carbon dioxide fluxes is necessary to predict changes to the global carbon cycle. Using tunable diode laser spectroscopy, I measured CO2 fluxes and changes in isotopic composition of root respiration, leaf respiration and photosynthesis over a 12-hour night to day transition. I found that after a 10°C increase in growth temperature for four weeks, root CO2 fluxes acclimated to the higher temperature (i.e. they were not significantly different from controls). In contrast, both photosynthesis and respiration of leaves were higher at the elevated growth temperature. Though the root fluxes were not significantly different between growth temperatures, two patterns may become significant with greater replication: (1) the difference in rates of mid-day/mid-night root respiration in plants grown at 22°C may be greater than those grown at 32°C and (2) variability in the isotopic composition of root respired CO2 is greater during the mid-night period compared to mid-day period. These data show that leaves and roots respond differently to grow temperature and suggest that root respiration during the day may respond to temperature differently from root respiration at night.
respiration, temperature, Q10, Populus, photosynthesis, isotope, root
Level of Degree
UNM Biology Department
First Committee Member (Chair)
Second Committee Member
Zulick, Rachel. "The effect of increased growth temperature on mid-day and mid-night CO2 fluxes in Populus deltoides." (2012). https://digitalrepository.unm.edu/biol_etds/117