Net carbon dioxide exchange rate of wild blueberries is influenced by carbon dioxide concentration, light intensity and air temperature

The main and interactive effects of carbon dioxide concentration (100 to 1,000 ppm CO2), light intensity (0 to 2,000 mu mol m(-2) s(-1) PPF) and air temperature (12 to 35 degrees C) were examined on upright stems in field studies conducted in 2013. Light intensity was the most important factor accounting for 52% of the net carbon dioxide exchange rate (NCER) model variation followed by carbon dioxide concentration (31%) and temperature (2.1%). Net photosynthesis required light intensities greater than 600 mu mol m(-2) s(-1) for saturation to occur, greatly increased under CO2 enrichment and was optimum under CO2 concentrations at 24 degrees C. In a related field study examining seasonal changes in whole plant NCER, inclusion of the root and rhizomes were observed to greatly reduce NCER. Quantifying the response of the wild blueberry to these environmental variables and understanding the whole plant NCER dynamics is critical with respect to optimizing plant growth and development and also provides insight into the potential effects of climate change.