Laboratory measurements of stomatal NO 2 deposition to native California trees and the role of forests in the NO x cycle

Delaria, Erin R.; Place, Bryan K.; Liu, Amy X.; Cohen, Ronald C.

Both canopy-level field measurements and laboratory studies suggest that uptake of inline-formulaNO2 through the leaf stomata of vegetation is a significant sink of atmospheric inline-formulaNOx. However, the mechanisms of this foliar inline-formulaNO2 uptake and their impact on inline-formulaNOx lifetimes remain incompletely understood. To understand the leaf-level processes affecting ecosystem-scale atmosphere–biosphere inline-formulaNOx exchange, we have conducted laboratory experiments of branch-level inline-formulaNO2 deposition fluxes to six coniferous and four broadleaf native California trees using a branch enclosure system with direct laser-induced fluorescence (LIF) detection of inline-formulaNO2. We report inline-formulaNO2 foliar deposition that demonstrates a large degree of inter-species variability, with maximum observed deposition velocities ranging from 0.15 to 0.51 inline-formulacm s−1 during the daytime, as well as significant stomatal opening during the night. We also find that the contribution of mesophyllic processing to the overall deposition rate of inline-formulaNO2 varies by tree species but has an ultimately inconsequential impact on inline-formulaNOx budgets and lifetimes. Additionally, we find no evidence of any emission of inline-formulaNO2 from leaves, suggesting an effective unidirectional exchange of inline-formulaNOx between the atmosphere and vegetation.



Delaria, Erin R. / Place, Bryan K. / Liu, Amy X. / et al: Laboratory measurements of stomatal NO2 deposition to native California trees and the role of forests in the NOx cycle. 2020. Copernicus Publications.


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Rechteinhaber: Erin R. Delaria et al.

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