Short-term effects of warming treatment and precipitation manipulation on the ecophysiological responses of Pinus densiflora seedlings

Abstract

The aim of this study was to investigate the short-term effects of warming treatment and precipitation manipulation on the growth, photosynthetic rate, and chlorophyll content of Pinus densiflora seedlings based on a climate change scenario in Korea. Two-year-old P. densiflora seedlings were planted in a nursery in April 2013. The air temperature of warmed plots (W) was set to increase by 3 degrees C compared to control plots (C) using an infrared heater in May 2013. The three precipitation manipulations consisted of decreased precipitation using transparent panels (-30%; P-), increased precipitation using pumps and drip irrigation (+30%; P+), and a control (0%; P-0). Root collar diameter and seedling height of P. densiflora were measured in April and October 2013. Net photosynthetic rate and total chlorophyll contents were measured from June to October 2013. Warming treatment increased the growth of root collar diameter, and the interaction effect of the warming treatment and precipitation manipulation on it was also significant. In contrast, no significant effects were found for the growth of seedling height. These results demonstrate that warming treatment might affect the growth of root collar diameter and seedling height differently. It was also found that WP-treatment decreased net photosynthetic rates. This pattern might be due to the soil moisture availability, as soil moisture content was lowest in the WP-treatment and net photosynthetic rate was elevated with increasing soil moisture content. Meanwhile, warming treatment increased the total chlorophyll content. The results suggest that chlorophyll synthesis was promoted by a temperature increase in the leaves. The current study, which simulated a climate change environment in an open field, provides important information for the prediction of the ecophysiological effects of changes in temperature and precipitation on P. densiflora seedlings in Korea.