Investigating short-term nitrogen pollution on the physiology and biogenic volatile organic compound (BVOC) emissions from Pinus sylvestris in Scotland

Biogenic volatile organic compound (BVOC), produced by plant, such as isoprenes and monoterpene, can influence regional and global atmosphere chemistry. Although some factor controlled the emission rates of BVOCs from plants are reasonable well understand, the influence of pollutants, such as ammonia (NH3) deposition, is yet unclear. Monoterpene emission rates were measured from Pinus sylvestris (Scots pine) trees (7 years old) originating from four distinct locations in Scotland, and grown under ambient conditions at Centre for Ecology and Hydrology (CEH), Edinburgh. Nine monoterpene compounds were emitted from Pinus sylvestris, with α-pinene and δ3-carene being the most abundant emitted compounds. The mean total monoterpene emission rate was 1.39±1.92 μg g-1 h-1 (based on a dry weight of needles). Monoterpene emissions of Pinus sylvestris were found to be independent of genetic factors, photosynthetic rates, and a narrow range of instantaneous temperature changes. A tendency of increasing in emission rates, over time, was associated with new needle growth, and with historical accumulated temperature and PAR. However, the significance of these relationships needs further investigation. NH3 treatments were applied to selected pine shoots using a PET bag-enclosure method. The effects of short-term dry NH3 deposition (up to 168.5 μg m-3) tended to decrease monoterpene emission rates of young Pinus sylvestris, particularly α-pinene and δ3-carene. Although no statistical evidence was found for the effects of NH3 treatment on emission rates, these results nonetheless provide a first valuable, comparative feasibility study that can be used as a grounds for investigating the effects of N-treatment on BVOC emissions.