科研之友
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摘要
The possibility of NOx (NO + NO2) emissions from plants and the underlying mechanisms are still under discussion. Excess NO created possibly as a result of nitrite accumulation in plant leaves has been suggested to result in emissions. Such emission has been observed in laboratory conditions due to nitrate fertilization. In this study, we tested whether nitrate fertilization of Scots pine seedlings growing outdoors leads to accumulation of NO3- or NO2- in the needles and subsequent NOx emission. The experiment was done at the SMEAR II station in Southern Finland. The seedlings received nitrate or ammonium fertilizer or neither. Shoot NOx emissions were measured with dynamic chambers. Total dissolved nitrogen, inorganic nitrogen, NO3-, NO2- and NH4+ concentrations in the soil and needles were determined. NOx fluxes from the shoots were, on average, deposition. There was no indication of fertilization-induced NO or NOx emissions. The highest NO fluxes were observed at night and were humidity-related. It seems unlikely that additional nitrate in the soil could cause significant NOx emission from boreal Scots pine forests in field conditions, possibly because of soil chemistry.
- 出版日期2015-3
