Paper Reviewed
Je, S.-M., Woo, S.Y., Lee, S.H., Kwak, M.J., Lee, T.Y. and Kim, S.H. 2018. Combined effect of elevated CO2 concentration and drought on the photosynthetic apparatus and leaf morphology traits in seedlings of yellow poplar. Ecological Research 33: 403-412.

Yellow poplar (Liriodendron tulipifera) is an important timber species that is widely grown in Korea. However, few researchers have examined the potential impact of future climate change on this species, particularly with respect to changes in atmospheric CO2 concentration and soil water status. As the first group of scientists to do so, Je et al. (2018) recently investigated the physiological and morphological responses of yellow poplar to elevated CO2 and drought, publishing their findings in the journal Ecological Research.

In setting up their experiment, the six Korean researchers grew 3-year-old L. tulipifera seedlings in pots in a greenhouse phytotron at the University of Seoul over a period of four months, subjecting the seedlings to one of two atmospheric CO2 concentrations (ambient or elevated, corresponding to 430 or 640 ppm, respectively) and one of two soil water status regimes (field capacity for well-watered conditions and 50% field capacity to simulate drought).

Results of the analysis revealed, as expected, a reduction in photosynthetic rates under drought conditions and an enhancement under elevated CO2. In the combined elevated CO2 and drought treatment, Je et al. report that the benefits of elevated CO2 mitigated the negative impacts of drought such that they "observed an increase in photosynthetic rate with increased photopigment content, photochemistry efficiency, and light harvesting ability." Furthermore, they note that elevated CO2 decreased leaf specific area and increased wax coverage, suggesting that "elevated CO2 contributed to protect chloroplasts and reduce water loss." Consequently, the scientists conclude that "positive effects of elevated CO2 on functional improvements of the photosynthetic apparatus with changes in morphological traits ameliorate the adverse effect of water shortage on L. tulipifera."