Fluxes of nitrogen oxides and the biophysical controls for their deposition in soybean (Glycine max Merr.) leaves
The objective of this study was to investigate the fluxes of nitrogen oxides and the biophysical controls for their deposition to soybean (' Glycine max' ('Merr')) leaves. Laboratory data obtained using a glass whole leaf chamber under controlled temperature conditions, demonstrated that water, CO2, and nitrogen dioxide fluxes were increased with increasing light levels. Results exhibited more NO2 deposition in the leaves with higher photosynthesis and transpiration rates. Simulated dewdrops were conveniently placed on a leaf by separating the domes, wetting the leaf, and quickly reclosing the chamber. NO2 deposition onto wet leaves increased after water spraying. Data of the resistance offered to the NO2 deposition to dry and wet soybean leaves demonstrated stomatal control. The resistances increased with decreasing light levels. Maximum resistances were found for dark treatments. During full light treatments leaf stomata were fully opened providing lower resistance to NO2 deposition. The results showed absence of an internal resistance to NO 2 deposition, pointing to a pathway similar to the water flux pathway.