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1

Nitrogen deposition influences the allelopathic effect of an invasive plant on the reproduction of a native plant: Solidago canadensis versus Pterocypsela laciniata

100%
Wang C., Liu J., Xiao H., Zhou J., Du D.
Polish Journal of Ecology
|
2017
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tom 65
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nr 1
This study aims to gain insights into the allelopathic effects (by using leaf extracts) of the notorious invasive Solidago canadensis L. on seed germination of the associated Pterocypsela laciniata (Houtt.) C. Shih under different nitrogen (N) forms added: inorganic (NO3--N and NH4 -N), organic (urea-N), and mixed N (a mixture of the three N forms at 1:1:1 ratio). Among the two used concentrations of S. canadensis leaf extracts the higher exhibited inhibitory allelopathic effects on seedling height and biomass, germination potential, germination index, and vigor index of P. laciniata. N demonstrated positive effects on seed germination of P. laciniata. The effects of mixed and organic N on the seedling biomass of P. laciniata were more pronounced than those of inorganic N and control treatment. The vigor index of P. laciniata under mixed N was significantly higher than those under single N form and control treatment. Thus, organic and mixed N showed higher ecological effects on seed germination of P. laciniata than inorganic and single N form. All N forms could alleviate the inhibitory allelopathic effects of S. canadensis on seed germination of P. laciniata. Overall, the inhibitory allelopathic impact of S. canadensis on seed germination of native species may be attenuated under increased and diverse N deposition, thus it could prevent its further invasion.
2

Interactive effects of nitrogen and water addition on competitive hierarchies between early- and late- successional plant species

100%
Jiang L., Lan Z., Liu G., Kardol P.
Polish Journal of Ecology
|
2014
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tom 62
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nr 4
Increased nitrogen (N) and water availability, resulting from global changes or ecosystem management, were predicted to promote plant productivity and change community composition through shifts in competition hierarchies. So far, however, it still remains unclear how competitive interactions respond to N and water additions, which will be important to understand how plant community composition changes. To test plant competition ability in different successional stages under N and water addition treatments, a pot experiment under field conditions was performed. Six dominant plant species, three early-successional species, Artemisia lavandulaefolia, Artemisia capillaris, and Pennisetum centrasiaticum versus three late-successional species, Stipa krylovii, Leymus chinensis, and Artemisia frigida, were grown in monocultures and in two-species mixtures under factorial combinations of N and water addition treatments. We found that (1) there were interactive effects of N addition, water addition and interspecific competition on plant biomass; (2) For a given species, competitive abilities were correlated with biomass difference of neighboring species; (3) N and water additions interactively increased competition intensity and shifted species competitive hierarchies; (4) Late- successional species had stronger competitive abilities in the N addition treatment, whereas early-successional species had stronger competitive abilities after water addition or N + water addition. Our results show that N and water additions increased the intensity and impact of interspecific competition on plant growth, which has great implications for community structures. Since interspecific differences in competitive abilities were not well explained by species biomass, species identity, such as plant functional traits, should be included to predict the impact of increased N and water availability on plant communities and ecosystem functions.
3

Nitrate reductase activity as an indicator of nitrate fixation and assimilation by tropical forest species on St.Thomas Island

100%
Krywult M., Klich M.
Fragmenta Floristica et Geobotanica
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2000
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tom 45
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nr 1-2
4
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Effects of nitrogen deposition on growth and relationship of Robinia pseudoacacia and Quercus acutissima seedlings

84%
Ding W., Wang R., Yuan Y., Liang X., Liu J.
Dendrobiology
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2012
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tom 67
Increased nitrogen deposition and biological invasions may be two crucial consequences of global change. Exotic plants often have adverse effects on native plants. However, there are reports of occasional positive interaction between them. Increased nitrogen deposition enhances nitrogen availability in soil, which may facilitate the growth of some exotic plant and decrease the competitive advantage of native plants because of their adaptation to low-nutrient environments. Consequently, increased nitrogen deposition may regulate the relationship between exotic and native plants. A greenhouse experiment was, thus, conducted to examine the effects of increased nitrogen deposition on the relationship between the native Quercus acutissima and the exotic Robinia pseudoacacia, which are both widely distributed in North China. Seedlings of both species were grown in monoculture and mixture arrangements in a pot experiment with different nitrogen addition levels (i.e., 0, 2, 5, and 10 g N m–2 a–1). Nitrogen addition altered the biomass partitioning of Q. acutissima and R. pseudoacacia seedlings, with more biomass allocated to leaves and less to roots. Although R. pseudoacacia seedlings always had growth predominance over Q. acutissima seedlings, Q. acutissima was not threatened by R. pseudoacacia at the four levels of nitrogen addition during the three-month duration of the experiment. A positive interaction between the seedlings of R. pseudoacacia and Q. acutissima was found, and increased nitrogen deposition did not affect the positive interaction. Further studies are necessary to determine whether or not R. pseudoacacia is harmful to native ecosystems and should be limited for forestation in North China.
5

Impact of extra nitrogen on ecological stoichiometry of Alpine grasslands on Tibetan Plateau: meta-analysis

84%
Zhang H. R., Sun W., Li S. W., Han F. S., Yu C. Q., Zhang X. Z., Wang J. S., He Y. T., Zhong Z. M.
Polish Journal of Ecology
|
2018
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tom 66
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nr 4
The general impact of extra nitrogen on ecological stoichiometry was examined in alpine grasslands on the Tibetan Plateau. Extra nitrogen increased the ratio of nitrogen to phosphorus (N:P ratio) in leaves and aboveground parts of plants by 43.4% and 32.7%, respectively. In contrast, extra nitrogen reduced the ratio of carbon to nitrogen (C:N ratio) in leaves by 30.6%. Extra nitrogen decreased soil C:N ratio by 9.1% in alpine meadows, but increased soil C:N ratio by 3.4% in alpine steppes. Extra urea had a stronger positive impact on aboveground vegetation N:P ratio than did extra ammonium nitrate. Extra urea rather than ammonium nitrate decreased aboveground vegetation C:N ratio and soil C:N ratio. The impact of extra nitrogen on aboveground vegetation N:P ratio was positively correlated with latitude, mean annual temperature and precipitation, nitrogen application rate and accumulated amount, but negatively correlated with elevation, duration and aboveground vegetation N:P ratio of the control plots. The impact of extra nitrogen on leaves N:P ratio was positively correlated with nitrogen application rate and accumulated amount. The impact of extra nitrogen on leaves C:N ratio was positively correlated with latitude, but negatively correlated with mean annual temperature and precipitation, nitrogen application rate, accumulated amount, duration and leaves C:N ratio of the control plots. Therefore, nitrogen enrichment caused by human activities will most likely alter element balance and alpine plants from nitrogen limitation to phosphorus limitation. This effect may weaken with time, and increase with climatic warming, increased precipitation and nitrogen input rate.
6
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Impact of ship-borne nitrogen deposition on the Gulf of Finland ecosystem: an evaluation

84%
Raudsepp U., Laanemets J., Maljutenko I., Hongisto M., Jalkanen J.-P.
Oceanologia
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2013
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tom 55
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nr 4
7
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Impact of the emissions of international sea traffic on airborne deposition to the Baltic Sea and concentrations at the coastline

84%
Hongisto M.
Oceanologia
|
2014
|
tom 56
|
nr 2
8
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Effect of increased nitrogen depositions and drought stress on the development of young Norway spruce Picea abies (L.) Karst. stands

67%
Palatova E.
Dendrobiology
|
2004
|
tom 51 Supplement
The effects of drought stress, stress by increased nitrogen depositions and the combined effect of the two stress factors on the growth of Norway spruce Picea abies (L.) Karst. were studied in two stands. The drought stress was induced by reducing atmospheric precipitations by 60% and the increased nitrogen depositions were simulated by repeated applications of ammonium sulphate at a rate corresponding to 100 kg N ha–1 year–1. All stress factors under study affected the height increment of the above-ground part, the length and colour of needles, and the biomass, vertical distribution, functionality and mycorrhizal infection of fine roots. The root system responded to the simulated stresses right from the the very first year of their action, exhibiting a greater damage than the above-ground part of the plant. Drought acted as a stress factor stronger than the nitrogen depositions themselves. The strongest impact was recorded in the simultaneous influence of the stress factors.
9

Nitrogen deposition and flux through birch stands [Betula pubescens Ehrh.] in the Kampinos National Park [Central Poland]

67%
Kram K. J.
Polish Journal of Ecology
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2008
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tom 56
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nr 4
605-612
Nitrogen flow through birch stand canopies was studied in the Kampinos National Park (large forested area with inland dunes and wetlands close to Warsaw) during the growing seasons (April-October) of 2005–2006. The amount of nitrogen deposition including main forms like NO₃, NH₄, organic N and the aerosolgaseous fraction of deposition were estimated as well as the influence of birch canopies on this process. Because a method of “artificial foliage” allows to measure an aerosol-gaseous fraction of deposition a gradient of rain collectors equipped with artificial foliage of known surfaces were used. The results were compared with amounts of nitrogen measured in the throughfall of three birch forests. All stands (age 20–50 years) were rather similar, but stand II has smaller LAI (Leaf Area Index = 2.5 m² m⁻²) than stands II and III (3.8 and 3.9 m² m⁻²). It was found that nitrogen deposition in the Kampinos National Park is rather high – 1.6 kg ha⁻¹ month⁻¹. Ammoniumnitrogen made almost half of this value, organic nitrogen – over one third, and nitrate-nitrogen constituted the rest. Aerosol-gaseous input significantly made the deposition increased only in the case of nitrate-nitrogen, but deposition of ammonium- and organic nitrogen were similar and independent of catching leaf area. All fractions of nitrogen were effectively taken up during their passing through birch canopies (57% of nitrogen deposition was retained). Generally two thirds of deposited ammonium-nitrogen, more than half of organic N, and one third of nitratenitrogen were taken up by birch canopies. However, uptake efficiency of all N forms was lower for stand with smallest leaf area with no statistically significant retention of organic N.
10
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Content available

Variability of the marine boundary layer parameters over Baltic Sea sub-basins and their impact on nitrogen deposition

67%
Hongisto M.
Oceanologia
|
2011
|
tom 53
|
nr (1-TI)
The variability of the marine boundary layer parameters over the Baltic Sea and its sub-basins and their impact on the 6 h, monthly or seasonal deposition of oxidized nitrogen compounds was studied using results of the Hilatar chemistrytransport model, the 6th hour forecasts of the HIRLAM weather prediction model and meteorological measurement data. The monthly load of oxidized nitrogen was highest in the winters of 1993–1995 and 2000, and lowest in 1996–1997 and 2005; no trend was detected. Short-time correlations were low, but a significant correlation of the monthly deposition with the NAO index and ice-season was found over northern sub-basins.
11
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Metody fizyczne stosowane w monitoringu zanieczyszczeń powietrza w Puszczy Białowieskiej

67%
Wojcik J., Malzahn E.
Acta Agrophysica
|
2012
|
tom 19
|
nr 2
W pracy przedstawiono metodykę stosowaną w monitoringu zanieczyszczeń powietrza w Puszczy Białowieskiej, gdzie zlokalizowana jest sieć 7 punktów pomiarowych, w których mierzone jest stężenie w powietrzu zanieczyszczeń gazowych (depozycja sucha) i skład chemiczny opadów atmosferycznych (depozycja mokra). Pomiary wykonywane są według jednolitej metodyki stosowanej w europejskim i krajowym monitoringu lasu. Opisano metodę pasywną pomiaru zanieczyszczeń gazowych oraz metody badań opadów atmosferycznych, w tym metodę chromatografii jonowej (IC) oraz optycznej spektrometrii emisyjnej z plazmą wzbudzoną indukcyjnie (ICP-OES). Przedstawiono ocenę poziomu i trendów zmian oraz rozkładu przestrzennego depozycji całkowitej siarki i azotu na obszarze Puszczy Białowieskiej w latach 2002-2010.
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