Decrease in the photosynthetic rate of leaves of Ilex rotunda seedlings exposed to urban atmospheric condition

Abstract

In order to quantify the sole effect of urban atmospheric condition on revegetation trees, we exposed potted I. rotunda seedlings in the central district of Fukuoka City, where air pollutant concentration was high and heat island effect was observed, and in a suburban nursery as control. The seedlings of both sites were subjected to identical sunlight and soil conditions. After 10-week exposure, we observed a significant reduction of the photosynthetic rate of leaves, but not of growth. The reduction of photosynthetic rate would be caused by highly concentrated air pollutant as well as heat island effect. The reduction was due to the reduced carboxylation efficiency and was moderated by the soil of higher nitrogen content.