Temporal patterns of inorganic nitrogen uptake by mature sugar maple (<i>Acer saccharum</i>Marsh.) and red spruce (<i>Picea rubens</i>Sarg.) trees using two common approaches

Socci, Anne M.; Templer, Pamela H.

doi:10.1080/17550874.2011.624557

Cited by 31 publications

(26 citation statements)

References 48 publications

(87 reference statements)

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“…In this study, there were instances of net efflux of both NH 4 + and NO 3 − by roots in all of the plots. Net efflux of NH 4 + and NO 3 − has been observed in previous studies using the in situ depletion method (Lucash et al ., , ; Socci & Templer, ) and could be attributed to several factors. Even though the concentrations of NH 4 + and NO 3 − provided in this study were similar to concentrations that occur under natural field conditions, it is possible that concentrations of NH 4 + and NO 3 − in the solution induced efflux by altering the osmotic potential of roots (Rygiewicz & Bledsoe, ).…”

Section: Discussionmentioning

confidence: 99%

“…Two commonly used methods to measure N uptake by trees include the ex situ excised root method (Epstein et al, 1963) and the in situ N depletion method (BassiriRad et al, 1999). Although both methods are useful in comparative studies, we used the N depletion method in this study because the roots remain connected to the plant, thus potentially yielding a more accurate measurement of root N uptake than roots that have been excised and measured in the laboratory (Bloom & Caldwell, 1988;Socci & Templer, 2011).…”

Section: Plant Nitrogen Uptakementioning

confidence: 99%

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Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest

Campbell

Socci

Templer

2014

Global Change Biology

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The depth and duration of snow pack is declining in the northeastern United States as a result of warming air temperatures. Since snow insulates soil, a decreased snow pack can increase the frequency of soil freezing, which has been shown to have important biogeochemical implications. One of the most notable effects of soil freezing is increased inorganic nitrogen losses from soil during the following growing season. Decreased nitrogen retention is thought to be due to reduced root uptake, but has not yet been measured directly. We conducted a 2-year snow-removal experiment at Hubbard Brook Experimental Forest in New Hampshire, USA to determine the effects of soil freezing on root uptake and leaching of inorganic nitrogen simultaneously. Snow removal significantly increased the depth of maximal soil frost by 37.2 and 39.5 cm in the first and second winters, respectively (P < 0.001 in 2008/2009 and 2009/2010). As a consequence of soil freezing, root uptake of ammonium declined significantly during the first and second growing seasons after snow removal (P = 0.023 for 2009 and P = 0.005 for 2010). These observed reductions in root nitrogen uptake coincided with significant increases in soil solution concentrations of ammonium in the Oa horizon (P = 0.001 for 2009 and 2010) and nitrate in the B horizon (P < 0.001 and P = 0.003 for 2009 and 2010, respectively). The excess flux of dissolved inorganic nitrogen from the Oa horizon that was attributable to soil freezing was 7.0 and 2.8 kg N ha(-1) in 2009 and 2010, respectively. The excess flux of dissolved inorganic nitrogen from the B horizon was lower, amounting to 1.7 and 0.7 kg N ha(-1) in 2009 and 2010, respectively. Results of this study provide direct evidence that soil freezing reduces root nitrogen uptake, demonstrating that the effects of winter climate change on root function has significant consequences for nitrogen retention and loss in forest ecosystems.

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Section: Discussionmentioning

confidence: 99%

Section: Plant Nitrogen Uptakementioning

confidence: 99%

Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest

Campbell

Socci

Templer

2014

Global Change Biology

Self Cite

123

104

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“…compared with that of NO 3 -in most treatments, and this result is consistent with previous studies in which conifers have shown a preference for NH 4 ? (Lucash et al 2005;Socci and Templer 2011). The greater capacity for NH 4 ?…”

Section: Following Forest Disturbance Nhmentioning

confidence: 97%

Distinct effect of pH on N uptake and assimilation in two conifer species

Meng

Zhang

Су

et al. 2016

Trees

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Key message Prince Rupprecht's Larch from the Loess Plateau takes up and assimilates a greater proportion of N as NO 3 2 , particularly at neutral pH, whereas Chinese Fir assimilates a greater proportion of N as NH 4 1 , particularly at low pH levels.Abstract The effects of pH on nitrate and ammonium uptake and assimilation in two coniferous species were compared. Prince Rupprecht's Larch (Larix principis-rupprechtii Mayr) grows on the loess plateau in alkaline soils with low available nitrogen (N), whereas Chinese Fir (Cunninghamia lanceolata) grows in acidic soils. In the present study, the net fluxes in ammonium (NH 4 ? ) and nitrate (NO 3 2 ) were measured using a non-invasive microelectrode ion flux measurement system, and the expression of NH 4 ? and NO 3 2 transporters (AMTs and NRTs, respectively) as well as H ? -ATPase was examined to provide insights into the N uptake mechanisms in Prince Rupprecht's Larch and Chinese Fir. The enzyme assays involved in N assimilation were also determined. For Prince Rupprecht's Larch, low pH (pH 4) resulted in a decrease in net ammonium uptake, which remained unchanged in Chinese Fir. Net nitrate uptake in Prince Rupprecht's Larch and Chinese Fir was much lower in soils with pH 4 relative to those with pH 7. Low pH significantly decreased the H ? -ATPase activity and the expression level of NRTs in roots of Prince Rupprecht's Larch. However, the expression level of AMTs in Prince Rupprecht's Larch was significantly higher at pH 7 than at pH 4. The H ? -ATPase activity in roots of Chinese Fir remained unaltered in response to changes in pH, and the transcript abundances of AMTs and NRTs were down-regulated by low pH. Low pH decreased N assimilation in both conifer species with the exception of NH 4 ? assimilation in Chinese Fir, which displayed higher glutamine synthetase (GS) and glutamate synthetase (GOGAT activities) at low pH. Prince Rupprecht's Larch from the Loess Plateau takes up and assimilates a greater proportion of N as NO 3 2 , particularly at neutral pH, whereas Chinese Fir assimilates a greater proportion of N as NH 4 ? , particularly at low pH levels. This study contributes to our understanding of nitrogen metabolism mechanisms in response to pH changes.

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“…Many trees, such as Acer saccharum, P. rubens, Tsuga Canadensis and Quercus rubra, use NH 4 ? as their preferred nitrogen form (Socci and Templer 2011;Templer and Dawson 2004). In this study, the measured net influx of NH 4 ?…”

Section: Nhmentioning

confidence: 99%

Net NH4 + and NO3 − fluxes, and expression of NH4 + and NO3 − transporter genes in roots of Populus simonii after acclimation to moderate salinity

Zhang

Meng

et al. 2014

Trees

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Key message Net NH 4 1 flux was higher in fine roots of P. simonii after NaCl treatment compared to the NO 3 2 flux which was consistent with the expression levels of AMTs and NRTs. Abstract The characteristics of nitrogen uptake under salt stress would provide insights into the mechanisms of salt tolerance in plants. In the present study, net NH 4 ? and NO 3 -fluxes were measured using the non-invasive microtest technique, and transcript abundance of ammonium/ nitrate transporter genes (AMTs/NRTs) were determined by real time PCR in the fine roots of Populus simonii after treatment for 21 days with 75 mM NaCl. The NH 4 ? and NO 3 -fluxes showed heterogeneous spatial patterns along the root tip in nutrient solution. The maximum influx of NH 4? occurred near the root tip, while that of NO 3 -was 15 mm from the root tip. The net NO 3 -flux was inhibited by ca. 25 % with the provision of NH 4? . On average, the newly grown fine roots took up more NH 4 ? after the 75 mM NaCl treatment than did the control. Consistent with the NH 4 ? and NO 3 -influxes, most AMTs were upregulated in the salt-treated roots relative to the control, while most NRTs were down-regulated. Our study provides insights into nitrogen uptake and the AMT/NRT expression levels in the fine roots of P. simonii after acclimation to moderate salinity. This may be valuable for understanding nitrogen uptake mechanisms after adaptation to salinity.

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Temporal patterns of inorganic nitrogen uptake by mature sugar maple (Acer saccharumMarsh.) and red spruce (Picea rubensSarg.) trees using two common approaches

Cited by 31 publications

References 48 publications

Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest

Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest

Distinct effect of pH on N uptake and assimilation in two conifer species

Net NH4 + and NO3 − fluxes, and expression of NH4 + and NO3 − transporter genes in roots of Populus simonii after acclimation to moderate salinity

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