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Kerstin Huss-danell - One of the best experts on this subject based on the ideXlab platform.
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Local and systemic effects of phosphorus and nitrogen on nodulation and nodule function in Alnus incana
Journal of experimental botany, 2003Co-Authors: Francesco G. Gentili, Kerstin Huss-danellAbstract:Phosphorus (P) and nitrogen (N) effects on nodulation, nitrogenase activity and plant growth were studied in the root-hair-infected actinorhizal plant Alnus incana (L.) Moench. A split-root experiment, as well as a short-term experiment with entire root systems and a broader range of P concentrations, showed that P effects were specific on nodulation and not a general stimulation via a plant growth effect. These results indicate that nodule initiation and nodule growth have a high P demand. The split-root assay, comprising seven combinations of two N and two P levels, showed that P could counteract systemic N inhibition of nodulation, but did not counteract N inhibition of nitrogenase activity.
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Nitrogen, Phosphorus, and the Ratio Between them Affect Nodulation in Alnus incana and Trifolium pratense
Symbiosis, 2000Co-Authors: Luis Gabriel Wall, Anna Hellsten, Kerstin Huss-danellAbstract:Nodulation of Alnus incana by Frankia was studied at three levels of N (ammonium nitrate, 0.071-7.1 mM N) combined with three levels of P (0.01-1.0 mM) in a factorial design. Nodulation of Trifolium pratense by Rhizobium leguminosarum bv. trifolii was studied in a partial factorial design. Plants were in growth pouches for 10.5 weeks. In general, the degree of N inhibition depended on the P level. In A. incana, high P level stimulated nodule number and nodule dry matter per plant and per plant dry matter or per root dry matter. High P also stimulated nodule size and nitrogenase activity. Effects on nodule number seemed to be largely explained by plant growth whereas P had more of a specific effect on nodule dry matter. The N/P ratio was important, and increased N levels inhibited nodulation at N/P ratios >7 but not at N/P ratios
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Regulation of nodulation in Alnus incana‐Frankia symbiosis
Physiologia Plantarum, 1997Co-Authors: Luis G. Wall, Kerstin Huss-danellAbstract:We have studied regulation of nodulation in Alnus incana (L.) Moench using double inoculations in plastic pouches and a slide technique to observe root hair deformation. Initially, the distribution of nodules between main and lateral roots appeared quite constant, independent of the concentration of inoculum (1 to 250 μg of crushed nodules plant−1). Susceptibility to infection after the second inoculation was restricted to lateral roots after the initial infections developed. When pre-existing nodules were excised before the second inoculation, subsequent nodules appeared to arise where infections had arrested at stages earlier than actual nodule emergence. We observed that root hairs formed postinoculation were very crowded and short with a pronounced deformation. No nodules were found later on this region of the root, suggesting a loss of susceptibility in this region. Split-root experiments with delays between inoculation of the first and second side of the root system showed irreversible, systemic inhibition of nodulation on the second side starting between 3 and 6 days after the inoculation of the first side. Only when compatible, infective strains were used in the first inoculation, was nodule formation inhibited after the second inoculation. We conclude that autoregulation of nodulation operates in Alnus incana and on a time scale similar to what is found in some legumes.
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Superoxide dismutase, catalase and nitrogenase activities of symbiotic Frankia (Alnus incana) in response to different oxygen tensions
Physiologia Plantarum, 1997Co-Authors: Gunnar Alskog, Kerstin Huss-danellAbstract:Presence and activity of the enzymes superoxide dismutase (SOD) and catalase were studied in Frankia in symbiosis with Alnus incana (L.) Moench. Analysis on native PAGE gels indicated that symbiotic Frankia contained an FeSOD and catalase. The activity of the enzymes was in the same range as reported for cultured Frankia. Attempts to characterize SOD by western blots with antisera from Escherichia coli and Azotobacter vinelandii did not give clear-cut results with the antibodies used. Alnus incana plants were grown with the root system in 5, 10, 21 or 40% 0 2 for up to 6 days. Nitrogenase activity, measured as ARA (acetylene reducing activity) dropped within 3 h when roots were exposed to low or high oxygen. At 40% 02 ARA was almost completely lost while at 5 and 10% 0 2 ARA decreased to 69 and 74% of the inital value, respectively. Nitrogenase activity recovered at all oxygen tensions. Recovery rates resembled the continuous increase in ARA in plants continuosly kept at 21% 02, and suggests that new vesicles with envelopes of appropriate thickness were formed. The ARA measurements confirm results from an earlier study where nitrogenase activity was measured as H2 evolution. There was a tendency for increased SOD and catalase activities in Frankia from root systems exposed to 40% O2 for 24 h but not earlier or later than this. When data from all experimental times were pooled, SOD activity increased significantly with increased oxygen tension whereas catalase activity decreased. Although ARA per plant varied with oxygen tension, there was no statistically significant correlation between ARA and SOD or between ARA and catalase. It seems that being linked to nitrogenase activity is only one role of SOD and catalase in this symbiotic Frankia.
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Fungal biomass in roots and extramatrical mycelium in relation to macronutrients and plant biomass of ectomycorrhizal Pinus sylvestris and Alnus incana
New Phytologist, 1995Co-Authors: Alf Ekblad, Håkan Wallander, Rolf Carlsson, Kerstin Huss-danellAbstract:summary We studied the effects of macronutrients on the production and distribution of fungal biomass and plant biomass in ectomycorrhizal (Paxillus involutus (Fr.) Fr.) or non-mycorrhiza] Pinus sylvestris L, and Alnus incana (L.) Moench. Fungal biomass was measured as ergosterol content in roots and extramatrical mycelium, Alnus infants was nodulated with Frankia. All six macronutrients were varied according to a two-level fractional factorial design, The plants were grown in pots during two growing periods in a growth chamber. Levels of N, P and sometimes K and interactions between them, had highly significant effects, whereas Ca. Mg and S had no significant effects. The production of extramatrical mycelial biomass peaked when P was low and other nutrients were high. This investment in extramatrical mycelium resulted in a 660%, higher biomass in mycorrhizal compared with non-mycorrhizal P. sylvestris at this nutrient regime. The proportion of fungal biomass in roots was stable in P. sylvestris hut more variable in A. incana. Alnus incana grew less when mycorrhizal then when non-mycorrhizal. The growth responses to mycorrhiza and to the different nutrient treatments were evident at the end of the first growing period. Non-mycorrhizal P. sylvestris did not respond to P limitation by a production of proportionally more roots. This might be a reflection of an obligate dependency on mycorrhiza for effective P uptake. By contrast, the root/shoot ratio in both mycorrhizal and non-mycorrhiza] P. sylvestris decreased strongly in response to increased N. The opposite root/shoot response was found in Alnus incana, and the ratio decreased strongly in response to increased P and increased in response to increased N.
Kerstin Hussdanell - One of the best experts on this subject based on the ideXlab platform.
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nitrogen phosphorus and the ratio between them affect nodulation in Alnus incana and trifolium pratense
Symbiosis, 2000Co-Authors: Luis Gabriel Wall, Anna Hellsten, Kerstin HussdanellAbstract:Nodulation of Alnus incana by Frankia was studied at three levels of N (ammonium nitrate, 0.071-7.1 mM N) combined with three levels of P (0.01-1.0 mM) in a factorial design. Nodulation of Trifolium pratense by Rhizobium leguminosarum bv. trifolii was studied in a partial factorial design. Plants were in growth pouches for 10.5 weeks. In general, the degree of N inhibition depended on the P level. In A. incana, high P level stimulated nodule number and nodule dry matter per plant and per plant dry matter or per root dry matter. High P also stimulated nodule size and nitrogenase activity. Effects on nodule number seemed to be largely explained by plant growth whereas P had more of a specific effect on nodule dry matter. The N/P ratio was important, and increased N levels inhibited nodulation at N/P ratios >7 but not at N/P ratios <7. In T. pratense, high P level counteracted the inhibition of high N on nodule number and nitrogenase activity. The fact that N effects on nodulation and nitrogenase activity depend on P level should encourage more detailed work on effects of nutrient interactions on nodulation, both in actinorhizal plants and in legumes.
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regulation of nodulation in Alnus incana frankia symbiosis
Physiologia Plantarum, 1997Co-Authors: Luis G. Wall, Kerstin HussdanellAbstract:We have studied regulation of nodulation in Alnus incana (L.) Moench using double inoculations in plastic pouches and a slide technique to observe root hair deformation. Initially, the distribution of nodules between main and lateral roots appeared quite constant, independent of the concentration of inoculum (1 to 250 μg of crushed nodules plant−1). Susceptibility to infection after the second inoculation was restricted to lateral roots after the initial infections developed. When pre-existing nodules were excised before the second inoculation, subsequent nodules appeared to arise where infections had arrested at stages earlier than actual nodule emergence. We observed that root hairs formed postinoculation were very crowded and short with a pronounced deformation. No nodules were found later on this region of the root, suggesting a loss of susceptibility in this region. Split-root experiments with delays between inoculation of the first and second side of the root system showed irreversible, systemic inhibition of nodulation on the second side starting between 3 and 6 days after the inoculation of the first side. Only when compatible, infective strains were used in the first inoculation, was nodule formation inhibited after the second inoculation. We conclude that autoregulation of nodulation operates in Alnus incana and on a time scale similar to what is found in some legumes.
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nitrogen fixation by Alnus incana and nitrogen transfer from a incana to pinus sylvestris influenced by macronutrients and ectomycorrhiza
New Phytologist, 1995Co-Authors: Alf Ekblad, Kerstin HussdanellAbstract:The aims of this study were to evaluate the effect of macronutrients on nitrogen fixation in mycorrhizal and non-mycorrhizal grey alder (Alnus incana (L.) Moench), and to evaluate the effect of ect ...
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distribution of biomass and nitrogen among plant parts and soil nitrogen in a young Alnus incana stand
Botany, 1992Co-Authors: Kerstin Hussdanell, Helene OhlssonAbstract:Grey alder, Alnus incana (L.) Moench, was inoculated with the local source of Frankia and planted in nitrogen-poor soil in northern (63.8°N, 20.3°E) Sweden. Each alder root system was enclosed in a...
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n2 fixation in a young Alnus incana stand based on seasonal and diurnal variation in whole plant nitrogenase activity
Botany, 1992Co-Authors: Kerstin Hussdanell, Per-olof Lundquist, Helene OhlssonAbstract:N2 fixation by grey alder, Alnus incana (L.) Moench, was studied in the field during two growing seasons in northern Sweden. Alders were planted in a nitrogen-poor soil. Each alder had its root sys...
Per-olof Lundquist - One of the best experts on this subject based on the ideXlab platform.
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Carbon cost of nitrogenase activity in Frankia-Alnus incana root nodules
Plant and Soil, 2005Co-Authors: Per-olof LundquistAbstract:The carbon cost of nitrogenase activity was investigated to determine symbiotic efficiency of the actinorhizal root nodule symbiosis between the woody perennial Alnus incana and the soil bacterium Frankia. Respiration (CO2 production) and nitrogenase activity (H2 production) by intact nodulated root systems were continuously recorded in short-term assays in an open-flow gas exchange system. The assays were conducted in N2:O2, thus under N2-fixing conditions, in all experiments except for one. This avoided the declines in nitrogenase activity and respiration due to N2 deprivation that occur in acetylene reduction assays and during extended Ar:O2 exposures in H2 assays. Two approaches were used: (i) direct estimation of root and nodule respiration by removing nodules, and (ii) decreasing the partial pressure of O2 from 21 to 15% to use the strong relationship between respiration and nitrogenase activity to calculate CO2/H2. The electron allocation of nitrogenase was determined to be 0.6 and used to convert the results into moles of CO2 produced per 2e− transferred by nitrogenase to reduction of N2. The results ranged from 2.6 to 3.4 mol CO2 produced per 2e−. Carbon cost expressed as g C produced per g N reduced ranged from 4.5 to 5.8. The result for this actinorhizal tree symbiosis is in the low range of estimates for N2-fixing actinorhizal symbioses and crop legumes. Methodology and comparisons of root nodule physiology among actinorhizal and legume plants are discussed.
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Nitrogenase activity in Alnus incana root nodules. Responses to O2 and short-term N2 deprivation.
Plant physiology, 2000Co-Authors: Per-olof LundquistAbstract:O 2 and host-microsymbiont interactions are key factors affecting the physiology of N 2 -fixing symbioses. To determine the relationship among nitrogenase activity of Frankia - Alnus incana root nodules, O 2 concentration, and short-term N 2 deprivation, intact nodulated roots were exposed to various O 2 pressures (pO 2 ) and Ar:O 2 in a continuous flow-through system. Nitrogenase activity (H 2 production) occurred at a maximal rate at 20% O 2 . Exposure to short-term N 2 deprivation in Ar:O 2 carried out at either 17%, 21%, or 25% O 2 caused a decline in the nitrogenase activity at 21% and 25% O 2 by 12% and 25%, respectively. At 21% O 2 , nitrogenase activity recovered to initial activity within 60 min. The decline rate was correlated with the degree of inhibition of N 2 fixation. Respiration (net CO 2 evolution) decreased in response to the N 2 deprivation at all pO 2 values and did not recover during the time in Ar:O 2 . Increasing the pO 2 from 21% to 25% and decreasing the pO 2 from 21% to 17% during the decline further decreased rather than stimulated nitrogenase activity, showing that the decline was not due to O 2 limitation. The decline was possibly due to a temporary disturbance in the supply of reductant to nitrogenase with a partial O 2 inhibition of nitrogenase at 25% O 2 . These results are consistent with a fixed O 2 diffusion barrier in A. incana root nodules, and show that A. incana nodules differ from legume nodules in the response of the nitrogenase activity to O 2 and N 2 deprivation.
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n2 fixation in a young Alnus incana stand based on seasonal and diurnal variation in whole plant nitrogenase activity
Botany, 1992Co-Authors: Kerstin Hussdanell, Per-olof Lundquist, Helene OhlssonAbstract:N2 fixation by grey alder, Alnus incana (L.) Moench, was studied in the field during two growing seasons in northern Sweden. Alders were planted in a nitrogen-poor soil. Each alder had its root sys...
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N2 fixation in a young Alnus incana stand, based on seasonal and diurnal variation in whole plant nitrogenase activity
Canadian Journal of Botany, 1992Co-Authors: Kerstin Huss-danell, Per-olof Lundquist, Helene OhlssonAbstract:N2 fixation by grey alder, Alnus incana (L.) Moench, was studied in the field during two growing seasons in northern Sweden. Alders were planted in a nitrogen-poor soil. Each alder had its root system enclosed in an open-ended cylinder that was closed with a gas-tight lid around the stem base to serve as cuvette during nitrogenase activity (acetylene reducing activity) measurements. To follow the seasonal variation, nitrogenase activity was measured at noon on 15 occasions for each alder in 1987 and on 15 occasions in 1988. Diurnal variation in nitrogenase activity was studied at six occasions, but no obvious pattern in the diurnal variation was found. Nitrogenase activity began shortly after leaf emergence at the very end of May, increased in June, stayed high although with some variation through July and August, declined during September, and was zero in early October. Cumulative nitrogenase activity over the season was converted to cumulative N2 fixation after determination of molar ratio nitrogenase a...
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Immunological studies of glutamine synthetase in Frankia-Alnus incana symbioses
FEMS Microbiology Letters, 1992Co-Authors: Per-olof Lundquist, Kerstin Huss-danellAbstract:We have investigated the presence and form of glutamine synthetase (GS) in Frankia vesicle cluster preparations of two actively nitrogen-fixing Frankia-Alnus incana root-nodule symbioses and in cultured Frankia sp. strain CpI1 (HFP070101). The symbioses contained Frankia CpI1 or the local source of Frankia. We used Western-blot analysis with antisera raised against three types of GS. In symbiotic Frankia GS protein was not detected at a significant level when either antisera against Rhodospirillum rubrum GS or antisera against Rhizobium meliloti GSII were used. In cultured Frankia CpI1 GSI was detected both when grown with NH4+ or N2 as nitrogen source, and GSII was detected when grown on N2. Antiserum raised against the nodule-specific GSn1 of Phaseolus vulgaris crossreacted with a 43-kDa polypeptide corresponding to plant GS in root-nodule extracts from Alnus, and with a 41-kDa polypeptide corresponding to GSII in cultured Frankia CpI1 grown on N2. We conclude that both GSI and GSII are repressed in symbiotic Frankia and that NH4+ produced through nitrogen fixation is assimilated by the plant in Frankia-Alnus incana symbioses. It thus appears that vesicle formation, synthesis of nitrogenase and synthesis of GS are separately regulated in symbiotic Frankia and that the plant has to supply symbiotic Frankia with organic nitrogen in some form in addition to the carbon.
Todd M. Hurd - One of the best experts on this subject based on the ideXlab platform.
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comparison of nitrogen solute concentrations within alder Alnus incana ssp rugosa and non alder dominated wetlands
Hydrological Processes, 2004Co-Authors: Todd M. Hurd, Dudley J. RaynalAbstract:This study examined differences in nitrogen solutes and groundwater flow patterns between a riparian wetland dominated by the N2-fixing shrub, Alnus incana ssp. rugosa, and an upstream coniferous forested riparian wetland along a stream of the Adirondack Mountains, where some surface waters are susceptible to nitrogen excess. Channel water NO3 � was up to 16µmol l � 1 greater in the alder reach, with peaks following maxima in groundwater dissolved inorganic nitrogen (DIN). NO3 � at 25 cm depth was 30 µmol greater in the alder than in the conifer reach in April, and 24 µmol l � 1 greater than channel water and 30 µmol l � 1 greater than that of 125 cm groundwater in June. Dissolved organic nitrogen and NH4 C concentrations increased between 25 and 75 cm depths in both wetlands during the growing season. Inorganic nitrogen increased between the hillslope and stream in both wetlands, with the greatest increases in the alder reach during the dormant season. Greatest subsurface DIN (120 µmol l � 1 ) occurred at 75 cm in the alder reach, within 1 m of the stream, between November (120 µmol l � 1 NH4 C ) and a January thaw (60 µmol l � 1 each of NH4 C and NO3 � ). Concentrations of deeper groundwater at 125 cm during this period were lower (10–30 µmol l � 1 ). Lateral flow from the stream channel occurred in the alder reach during the dormant season, and channel water contribution to groundwater was correlated strongly to NO3 � at 25 cm. These results indicate that nitrification is stimulated in the presence of alders and oxidized exchange flow, producing NO3 � that may contribute to elevated channel water NO3 � during periods of peak flow. Copyright 2004 John Wiley & Sons, Ltd.
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Comparison of nitrogen solute concentrations within alder (Alnus incana ssp. rugosa) and non‐alder dominated wetlands
Hydrological Processes, 2004Co-Authors: Todd M. Hurd, Dudley J. RaynalAbstract:This study examined differences in nitrogen solutes and groundwater flow patterns between a riparian wetland dominated by the N2-fixing shrub, Alnus incana ssp. rugosa, and an upstream coniferous forested riparian wetland along a stream of the Adirondack Mountains, where some surface waters are susceptible to nitrogen excess. Channel water NO3 � was up to 16µmol l � 1 greater in the alder reach, with peaks following maxima in groundwater dissolved inorganic nitrogen (DIN). NO3 � at 25 cm depth was 30 µmol greater in the alder than in the conifer reach in April, and 24 µmol l � 1 greater than channel water and 30 µmol l � 1 greater than that of 125 cm groundwater in June. Dissolved organic nitrogen and NH4 C concentrations increased between 25 and 75 cm depths in both wetlands during the growing season. Inorganic nitrogen increased between the hillslope and stream in both wetlands, with the greatest increases in the alder reach during the dormant season. Greatest subsurface DIN (120 µmol l � 1 ) occurred at 75 cm in the alder reach, within 1 m of the stream, between November (120 µmol l � 1 NH4 C ) and a January thaw (60 µmol l � 1 each of NH4 C and NO3 � ). Concentrations of deeper groundwater at 125 cm during this period were lower (10–30 µmol l � 1 ). Lateral flow from the stream channel occurred in the alder reach during the dormant season, and channel water contribution to groundwater was correlated strongly to NO3 � at 25 cm. These results indicate that nitrification is stimulated in the presence of alders and oxidized exchange flow, producing NO3 � that may contribute to elevated channel water NO3 � during periods of peak flow. Copyright 2004 John Wiley & Sons, Ltd.
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Formation of cluster roots in Alnus incana ssp. rugosa and other Alnus species
Canadian Journal of Botany, 1996Co-Authors: Todd M. Hurd, Christa R. SchwintzerAbstract:Small numbers of cluster roots were found on older roots of Alnus incana ssp. rugosa (speckled alder) shrubs in the field at 2 of 11 sites. Cluster roots also formed infrequently in speckled alder grown hydroponically in complete nutrient solution. No cluster roots formed in solutions lacking P or Fe. Small numbers of cluster roots also formed in Alnus glutinosa grown hydroponically in the presence of P but not in its absence. In contrast, Alnus rubra produced small numbers of cluster roots in the absence of P but not in its presence. No cluster roots formed in Alnus viridis ssp. crispa. Cluster roots are probably not important for nutrient uptake in speckled alder because they form infrequently both in the field and in hydroponic culture. Keywords: Alnus incana ssp. rugosa, Alnus glutinosa, Alnus rubra, Alnus viridis ssp. crispa, cluster roots, proteoid roots.
Dudley J. Raynal - One of the best experts on this subject based on the ideXlab platform.
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comparison of nitrogen solute concentrations within alder Alnus incana ssp rugosa and non alder dominated wetlands
Hydrological Processes, 2004Co-Authors: Todd M. Hurd, Dudley J. RaynalAbstract:This study examined differences in nitrogen solutes and groundwater flow patterns between a riparian wetland dominated by the N2-fixing shrub, Alnus incana ssp. rugosa, and an upstream coniferous forested riparian wetland along a stream of the Adirondack Mountains, where some surface waters are susceptible to nitrogen excess. Channel water NO3 � was up to 16µmol l � 1 greater in the alder reach, with peaks following maxima in groundwater dissolved inorganic nitrogen (DIN). NO3 � at 25 cm depth was 30 µmol greater in the alder than in the conifer reach in April, and 24 µmol l � 1 greater than channel water and 30 µmol l � 1 greater than that of 125 cm groundwater in June. Dissolved organic nitrogen and NH4 C concentrations increased between 25 and 75 cm depths in both wetlands during the growing season. Inorganic nitrogen increased between the hillslope and stream in both wetlands, with the greatest increases in the alder reach during the dormant season. Greatest subsurface DIN (120 µmol l � 1 ) occurred at 75 cm in the alder reach, within 1 m of the stream, between November (120 µmol l � 1 NH4 C ) and a January thaw (60 µmol l � 1 each of NH4 C and NO3 � ). Concentrations of deeper groundwater at 125 cm during this period were lower (10–30 µmol l � 1 ). Lateral flow from the stream channel occurred in the alder reach during the dormant season, and channel water contribution to groundwater was correlated strongly to NO3 � at 25 cm. These results indicate that nitrification is stimulated in the presence of alders and oxidized exchange flow, producing NO3 � that may contribute to elevated channel water NO3 � during periods of peak flow. Copyright 2004 John Wiley & Sons, Ltd.
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Comparison of nitrogen solute concentrations within alder (Alnus incana ssp. rugosa) and non‐alder dominated wetlands
Hydrological Processes, 2004Co-Authors: Todd M. Hurd, Dudley J. RaynalAbstract:This study examined differences in nitrogen solutes and groundwater flow patterns between a riparian wetland dominated by the N2-fixing shrub, Alnus incana ssp. rugosa, and an upstream coniferous forested riparian wetland along a stream of the Adirondack Mountains, where some surface waters are susceptible to nitrogen excess. Channel water NO3 � was up to 16µmol l � 1 greater in the alder reach, with peaks following maxima in groundwater dissolved inorganic nitrogen (DIN). NO3 � at 25 cm depth was 30 µmol greater in the alder than in the conifer reach in April, and 24 µmol l � 1 greater than channel water and 30 µmol l � 1 greater than that of 125 cm groundwater in June. Dissolved organic nitrogen and NH4 C concentrations increased between 25 and 75 cm depths in both wetlands during the growing season. Inorganic nitrogen increased between the hillslope and stream in both wetlands, with the greatest increases in the alder reach during the dormant season. Greatest subsurface DIN (120 µmol l � 1 ) occurred at 75 cm in the alder reach, within 1 m of the stream, between November (120 µmol l � 1 NH4 C ) and a January thaw (60 µmol l � 1 each of NH4 C and NO3 � ). Concentrations of deeper groundwater at 125 cm during this period were lower (10–30 µmol l � 1 ). Lateral flow from the stream channel occurred in the alder reach during the dormant season, and channel water contribution to groundwater was correlated strongly to NO3 � at 25 cm. These results indicate that nitrification is stimulated in the presence of alders and oxidized exchange flow, producing NO3 � that may contribute to elevated channel water NO3 � during periods of peak flow. Copyright 2004 John Wiley & Sons, Ltd.
