Foliar Nitrogen Uptake from Wet Deposition and the Relation with Leaf Wettability and Water Storage Capacity

Abstract

This study assessed the foliar uptake of 15 N-labelled nitrogen (N) originating from wet deposition along with leaf surface conditions, measured by wettability and water storage capacity. Foliar 15 N uptake was measured on saplings of silver birch, European beech, pedunculate oak and Scots pine and the effect of nitrogen form (NH 4 + or NO 3 − ), NH 4 + to NO 3 − ratio and leaf phenology on this N uptake was assessed. Next to this, leaf wettability and water storage capacity were determined for each tree species and phenological stage, and the relationship with 15 NH 4 + and 15 NO 3 − uptake was examined. Uptake rates were on average five times higher (p<0.05) for NH 4 + than for NO 3 − and four times higher for deciduous species than for Scots pine. Developing leaves showed lower uptake than fully developed and senescent leaves, but this effect was tree species dependent. The applied NH 4 + to NO 3 − ratio did only affect the amount of N uptake by senescent leaves. The negative correlation between measured leaf Water Air Soil Pollut (2011) 219:43-57 contact angles and foliar N uptake demonstrates that the observed effects of tree species and phenological stage are related to differences in leaf wettability and not to water storage capacity.

fate of 15N-labeled ammonium and nitrate applied on trees canopy in a mature balsam-fir stand, Quebec /

“…The tendency to higher recovery by older needles found in the present study is contrary to the majority of results found in the literature (Adriaenssens et al 2011;Bowden et al 1989;Boyce et al 1996;Dail et al 2009;Eilers et al 1992). Wilson and Tiley's (1998) study is the only one where recovery was higher or equal in older needles.…”

“…Redistribution pattern of this N is still unknown. Senescent and dead needles and branches also have the capacity to retain some N even if they are non-active (Adriaenssens et al 2011). The treated trees will be destructively sampled at the end of the experiment, which will allow a thorough assessment of the 15 N repartition.…”

“…Secondly,when 15 N tracers were applied to the aboveground vegetation, either in a plantation (Adriaenssens et al 2011;Bowden et al 1989;Chavez-Aguilar et al 2006;Eilers et al 1992;Wilson and Tiley 1998), in a greenhouse (Lumme 1994;Lumme and Smolander 1996;Macklon et al 1996), or directly in the field (Boyce et al 1996;Garten et al 1998;Nave and Curtis 2011;Vose and Swank 1990), it was done only partly on branches of mature trees (Boyce et al 1996;Vose and Swank 1990) or on seedlings or saplings, which may not allow inferences to be made on processes by which the whole mature tree acquires N. Young versus mature trees are known to have important distinctive morphological, structural and physiological features that affect the chemistry and flux of throughfall and stemflow or directly influence N demand (see reviews in Olson et al 1981;Wilson and Tiley 1998). In addition, most studies adding N either directly on the soil or below the aboveground vegetation have been conducted in areas receiving medium-to-high N deposition rates, which are known to alter the natural N cycling and demand in ecosystems (Galloway et al 2003).…”

“…Other factors like duration of exposure and irrigation intensity (Eilers et al 1992;Reiners and Olson 1984) or timing of N application during the year (Adriaenssens et al 2011 ;Amponsah et al 2004) may also affect N uptake by plants.…”

Seasonal variations of throughfall chemistry in pure and mixed stands of Oriental beech (Fagus orientalis Lipsky) in Hyrcanian forests (Iran)

“…The lower NO 3 − and NH 4 + concentrations and fluxes observed under canopy compared to bulk precipitation, including in the dormant season, show that these two forms of inorganic N were absorbed by foliage, also in the senescent stage, and by branches. Adriaenssens et al (2011) likewise found a significant uptake of nitrogen, mostly of NH 4 + but also of NO 3 − , by the senescent leaves of European beech. Nitrogen uptake at leaf senescence was assumed by these authors to be linked to N retranslocation by trees (see also Houle et al 1999).…”