UV-induced N2O emission from plants

作者：Bruhn Dan^*; Albert Kristian R; Mikkelsen Teis N; Ambus Per

来源：Atmospheric Environment, 2014, 99: 206-214.

DOI：10.1016/j.atmosenv.2014.09.077

• Epicuticular wax
• Greenhouse gas
• Nitrous oxide
• Plant
• Ultra violet radiation
• Vegetation

Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. %26lt;br%26gt;We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. %26lt;br%26gt;Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m(-2) h(-1), mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth%26apos;s surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

• 出版日期2014-12