High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability

Kahmen, Ansgar; Livesley, Stephen J.; Arndt, Stefan K.

doi:10.1007/s11104-009-9960-x

Cited by 30 publications

(17 citation statements)

References 54 publications

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“…Bloom et al 1992;BassiriRad et al 1999). Similarly, rates of NH 4 + and NO 3 − uptake that we measured using the ex situ 15 N tracer method with excised roots (median range 0-0.23 and 0-0.018 μmol N gdw -1 h −1 , respectively) were within the range of rates observed in other studies as well (Kahmen et al 2009). …”

Section: Nh 4 + Vs No 3 − Uptakesupporting

confidence: 87%

“…We also observed greater NH 4 + uptake by intact compared with excised roots using the in situ depletion method in those roots where there was net uptake. Root excision causes carbohydrate supply to decrease over time, thus interrupting the active flow of nutrients into the root (Bloom and Caldwell 1988;Aslam et al 1996b;Kahmen et al 2009). Our results comparing uptake by intact vs. excised roots could be attributed to the interacting effects of excision and the duration of time between excision in the field and measurement of N uptake (immediately using the in situ depletion method and up to 24 h using the ex situ 15 N tracer method).…”

Section: Root N Uptake Methodsmentioning

confidence: 99%

“…Tree roots have been shown to take up amino acids (Finzi and Berthrong 2005;GalletBudynek et al 2009;Kahmen et al 2009); however, it is thought that temperate forest trees meet most of their N demand through uptake of inorganic N as ammonium (NH 4 + ) and nitrate (NO 3 − ) (Haynes and Goh 1978;Glass 1988;Marschner 1995). Rates of uptake of each N form vary by plant species (Gessler et al 1998a;Kronzucker et al 2003;Templer and Dawson 2004).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Socci

Templer

2011

Plant Ecology & Diversity

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Background: Plant uptake of nitrogen influences many ecosystem processes, yet uptake by trees in northern forests of the United States has not been quantified throughout the growing season. Aims: To measure NH 4 + and NO 3 − uptake by mature sugar maple (Acer saccharum) and red spruce (Picea rubens) trees during the early, mid and late growing season. Methods: At Hubbard Brook Experimental Forest, New Hampshire, we used two approaches to measure nitrogen uptake capacity by mature trees: an in situ depletion method using intact roots and an ex situ 15 N tracer method using excised roots. Results: NH 4 + uptake was greater than NO 3 − for both methods and tree species (P < 0.05). NH 4 + uptake was lowest during the early growing season, while NO 3 − uptake was lowest during the late growing season. Measured rates of NH 4 + uptake were 2-3 orders of magnitude greater using the in situ depletion method compared with the ex situ 15 N tracer method. Conclusions: These results demonstrate seasonal differences in nitrogen uptake by two dominant tree species in a northern forest and show that the method employed can significantly impact measured rates of uptake, which could have implications for understanding the magnitude of plant nitrogen uptake and for cross-study comparisons of this process.

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Section: Nh 4 + Vs No 3 − Uptakesupporting

confidence: 87%

Section: Root N Uptake Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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

Socci

Templer

2011

Plant Ecology & Diversity

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“…Firstly, our results confirmed that the inorganic N forms were still the dominant N sources and were considered to be the preferred N forms taken up by higher plants compared with N-derived from glycine when supplied with equal concentrations (Harrison et al 2007;Kahmen et al 2009;Gioseffi et al 2011).…”

Section: Discussionsupporting

confidence: 75%

Nitrogen acquisition strategies used by Leymus chinensis and Stipa grandis in temperate steppes

Tian

Ouyang

et al. 2016

Biol Fertil Soils

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Leymus chinensis and Stipa grandis are two important plant species of temperate steppes in Inner Mongolia of North China. They differ in their life forms, e.g., L. chinensis is a type of rhizomatous clonal grass, whereas S. grandis is a type of tussock grass. Here we hypothesize that both plant species possess distinct nitrogen (N) acquisition strategies for their growth and survival. To test this hypothesis, we conducted a four-factor experimental field study using a short-term (three hours) 15 N labeling technique in two plant communities mono-dominated by L. chinensis and S. grandis of the temperate steppes over two months (July and August) and at two soil depths. In both of communities, L. chinensis and S. grandis directly absorbed all three of the common forms of N, including substantial portions of N-derived from glycine (organic and inorganic forms) ranged from 2.7 to 17.8 %, although they absorbed more inorganic N. Nitrogen uptake rates showed significant effects of communities, months, soil depths, and N forms. The uptake rate was higher in August than in July and at 0-5 cm than at 5-15 cm soil depths. L. chinensis and S. grandis showed different preference on N form across months. L. chinensis shifted its uptake pattern from more nitrate (NO 3 − ) in July to more ammonium (NH 4 + ) in August, whereas S. grandis took up comparable NH 4 + and NO 3 − in both months. In general, L. chinensis showed a more flexible N acquisition strategy and S. grandis performed a more concentrated and relatively more stable N acquisition strategy. The distinct N acquisition strategies used by L. chinensis and S. grandis varied greatly across different months and soil depths. These findings are more helpful in further understanding the plasticity of nutrient utilization issues of different plant species in response to N-limited conditions of grassland ecosystems.

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“…Although many plant species are capable of absorbing low molecular weight organic molecules such as amino acids (Nasholm et al 1998), these labile molecules constitute a small proportion (*1%) of what is actually comprised in the DON pool (Hannam and Prescott 2003). Furthermore, it is likely that heterotrophic microorganisms are better competitors than plant roots for free amino acids in soil solution (Kahmen et al 2009). Thus, it is unlikely that root uptake could alleviate leaching losses of DON to the same extent as NO 3 -or NH 4 ?…”

Section: Discussionmentioning

confidence: 99%

Reduced soil nutrient leaching following the establishment of tree-based intercropping systems in eastern Canada

et al. 2011

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Tree-based intercropping (TBI) systems, combining agricultural alley crops with rows of hardwood trees, are largely absent in Canada. We tested the hypothesis that the roots of 5-8 years old hybrid poplars, growing in two TBI systems in southern Québec, would play a ''safety-net'' role of capturing nutrients leaching below the rooting zone of alley crops. TBI research plots at each site were trenched to a depth of 1 m on each side of an alley. Control plots were left with tree roots intact. In each treatment at each site, leachate at 70 cm soil depth was repeatedly sampled over two growing seasons using porous cup tension lysimeters, and analyzed for nutrient concentrations. Daily water percolation rates were estimated with the forest hydrology model ForHyM. Average nutrient concentrations for all days between consecutive sampling dates were multiplied by water percolation rates, yielding daily nutrient leaching loss estimates for each sampling step. We estimated that tree roots in the TBI system established on clay loam soil decreased subsoil NO 3 -leaching by 227 kg N ha -1 and 30 kg N ha -1 over two consecutive years, and decreased dissolved organic N (DON) leaching by 156 kg N ha -1 year -1 in the second year of the study. NH 4 ? leaching losses at the same site were higher when roots were present, but were 1-2 orders of magnitude lower than NO 3 -or DON leaching. At the sandy textured site, the safety net role of poplar roots with respect to N leaching was not as effective, perhaps because N leaching rates exceeded root N uptake by a wider margin than at the clay loam site. At the sandy textured site, significant and substantial reductions of sodium leaching were observed where tree roots were present. At both sites, tree roots reduced DON concentrations and the ratio of DON to inorganic N, perhaps by promoting microbial acquisition of DON through rhizodeposition. This study demonstrated a potential safety-net role by poplar roots in 5-8 yearold TBI systems in cold temperate regions.

show abstract

High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability

Cited by 30 publications

References 54 publications

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

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

Nitrogen acquisition strategies used by Leymus chinensis and Stipa grandis in temperate steppes

Reduced soil nutrient leaching following the establishment of tree-based intercropping systems in eastern Canada

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