Effects of elevated CO2 concentration and increased temperature on leaf related-physiological responses of phytolacca insularis (native species) and phytolacca americana (invasive species)

Abstract

In the study, the effects of elevated CO2 and temperature on the photosynthetic characteristics, chlorophyll content, nitrogen content, carbon content, and C/N ratio of Phytolacca insularis and Phytolacca americana were examined under control (ambient CO2+ ambient temperature) and treatment (elevated CO2+ elevated temperature) for 2 years (2008 and 2009). The photosynthetic rate, transpiration rate and water use effciency of two plant species were higher under the treatment than the under the control. The stomatal conductance of P. insularis was higher under the control, but that of P. americana was not signifcantly affected by CO2 and temperature under the treatment. The chlorophyll contents of two species were decreased about 72.5% and 20%, respectively, by elevated CO2 and temperature. The nitrogen contents of two species were not signifcantly altered by increase in CO2 and temperature. The carbon contents of the two species were higher under the treatment than under the control. The C/N ratio of P. insularis was higher under the treatment but that of P. americana was not signifcantly affected by CO2 and temperature. These results demonstrated that the physiological responses of P. insularis native plants might be more sensitively infuenced by a CO2-mediated global warming situation than those of the P. americana invasive plants. © The Ecological Society of Korea.