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1

Nutrient stoichiometric relations and biogeochemical niche in coexisting plants species: effect of simulated climate change

100%
Penuelas J., Sardans J., Ogaya R., Estiarte M.
Polish Journal of Ecology
|
2008
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tom 56
|
nr 4
613-622
Here we define a “biogeochemical niche” characterized by the species position in the multivariate space generated by its content not only of macronutrients like N, P or K, but also of micronutrients such as Mo, Mg and Ca, and trace toxic elements such as Pb and As. We then hypothesize that the flexibility of the species “biogeochemical niche” will influence the quality of plant tissue, which may have implications for herbivores, and will affect the species capacity to respond to disturbances and climate change and to adapt to the new climate conditions. We show with a simple multivariate procedure, a principal component analysis (PCA), first, that there is a strong differentiation in the total and relative (stoichiometry) content of the different elements in coexisting plant species, and, second, that there is species-specific plasticity in the response of this elemental composition to experimental climate change. The concentrations of foliar macro and micronutrients, as well as trace elements were measured in several tree species (Quercus ilex L., Phillyrea latifolia L. and Arbutus unedo L. in a Mediterranean broad leaf forest (Prades Mts) and in shrub species (Erica multiflora L., Globularia alypum L. and Dorycnium pentaphyllum Scop.) in a Mediterranean shrubland (Garraf Mts) in control plants and in plants grown in experimental drought and warming plots. The climate conditions were monitored during the period 1999–2005. During this period, in the Prades experiment the drought plots had on average a soil moisture content 9% lower than the control plots, whereas in the Garraf experiment the drought treatment led to a mean reduction in soil moisture of 21% and the warming treatment to 0.9ºC rise. The species with greater changes in biogeochemical niche under increased warming or drought, Arbutus unedo, Erica multiflora and Globularia alypum, were those that were also more affected in growth, photosynthetic capacity and other eco-physiological traits. The species differentiations indicate a strong biogeochemical niche, and that the changes in biogeochemical niche are probably an underlying factor in community structure shifts.
2

Soil C:P ratio along elevational gradients in Picea schrenkiana forest of Tianshan Mountains

84%
Cao Y., Wang Y., Xu Z.
Polish Journal of Ecology
|
2018
|
tom 66
|
nr 4
Forest soils potentially store a large pool of carbon and phosphorus. A deep understanding of the total carbon and phosphorus stock in forest soils is vital in the assessment of the nutrients dynamics in forest ecosystems. This study examined the effects of elevation, soil depth, and climatic variables, specifically mean annual temperature (MAT) and mean annual precipitation (MAP), on soil carbon and organic phosphorus in Schrenk's spruce (Picea schrenkiana) forest at Tianshan Mountains. Results showed that soil organic carbon (SOC) significantly increased while organic phosphorus decreased with elevation. Interestingly, carbon increased faster with increasing elevation in the alluvial horizon than in the leached horizon, demonstrating the important role of deep soils in carbon sequestration potential. SOC concentration decreased with soil depth, whereas phosphorus concentration initially decreased and then increased. SOC had no significant relationships with MAT and MAP, whereas phosphorus concentration decreased with MAT. Similar to the impacts of MAT and MAP on SOC, these two climatic variables also exerted no significant influence on C:P ratio.
3

Influence of branch death on leaf nutrient status and stoichiometry of wild apple trees (Malus sieversii) in the Western Tianshan Mountains, China

84%
Tao Y., Nuerhailati M., Zhang Y.-M., Zhang J., Yin B.-F., Zhou X.-B.
Polish Journal of Ecology
|
2020
|
tom 68
|
nr 4
4
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Redox control of photosynthetic acclimation in plants

84%
Pfannschmidt T.
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
|
2013
|
tom 94
|
nr 2
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
|
tom 66
|
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

Leaf nitrogen and phosphorus stoichiometry of plants from natural and restorable communities at lands used for Qinghai-Tibet Highway Construction, China

84%
Luo M. W., Mao L., Guo Z. G.
Polish Journal of Ecology
|
2014
|
tom 62
|
nr 2
Highway network construction is one of common factors contributing to alpine grassland degradation in the Qinghai-Tibet Plateau as well as other regions, resulting in big area land used for highway construction by abruptly removing the vegetation and topsoil on both sides of roadbed. Taking the Land Used for Qinghai-Tibet Highway Construction (LUQHC) produced in 1994 as an example, a field survey was conducted to investigate the leaf N, P stoichiometry of plants from natural communities and restorable communities by using all plants and same pairwise of species, because the natural vegetation restoration at LUQHC is driven by element availability to some extent. This study showed that plants were probably P-limited in study region and the variation of N:P ratio was closely related to leaf P concentration. Results of same pairwise of species showed that the leaf N, P and N:P ratio of plants from restorable communities were higher than those of adjacent natural communities, indicating that leaf N and P were simultaneously affected by the environment circumstance of LUQHC. However, results of all species showed that the environment factors only impacted on leaf N concentration. These showed that the plant in restorable communities suffered from more intense P-limited conditions than those in natural communities, and that the same pairwise of species sampling was better to acquire the N- or P-limitation status for plant in restorable communities than all species. This study also showed that phylogenetic variation (family and genus identity) was key factor affecting the variations of N, P stoichiometry.
7

Water- and N-induced changes in soil C:N:P stoichiometry and its implications for N limitation of a desert steppe species, Glycyrrhiza uralensis

84%
Huang J., Yu H., Zhang F., Li M., Lin H.
Polish Journal of Ecology
|
2016
|
tom 64
|
nr 2
Changes in precipitation patterns and the deposition of atmospheric nitrogen (N) increase the possibility of altering soil carbon (C):N:phosphorus (P) stoichiometry through their effects on soil C and nutrient dynamics, especially in water- and N-limited ecosystems. We conducted separate 2-year watering and N addition experiments, and examined soil C:N:P stoichiometry, relative growth rate, and leaf N resorption traits of Glycyrrhiza uralensis Fisch in a desert steppe of northwestern China. Our objectives were to determine how soil C:N:P stoichiometry responded to climate change, and its indications for plant growth and N resorption. The results showed that additional water increased N loss and thus decreased N availability, resulting in high N resorption from senescing leaves of G. uralensis. N addition increased N availability, consequently reducing plant N dependence on leaf resorption. High relative growth rates occurred with intermediate N:P and C:N ratios, while high N resorption occurred with a low N:P ratio but a high C:N ratio. Our results indicate that soil C:N:P stoichiometry also could be a good indicator of N limitation for desert steppe species. Altered soil C:N:P stoichiometry affects the N strategy of plants, and will be expected to further influence the structure and function of the desert steppe community in the near future.
8

Composition of guano produced by frugivorous, sanguivorous, and insectivorous bats

67%
Emerson J. K., Roark A. M.
Acta Chiropterologica
|
2007
|
tom 09
|
nr 1
Bat guano supports an assemblage of organisms that varies depending on the species of bat producing it. To determine whether these differences in community structure may be due to differences in guano composition, we analyzed guano from frugivorous (Pteropus rodricensis), sanguivorous (Desmodus rotundus), and insectivorous (Tadarida brasiliensis) bats. We found no differences among species in organic matter or lipid of guano. Desmodus guano contained more carbon (C) than Pteropus guano. The latter contained less nitrogen (N), and the former contained less phosphorous (P) than guano of the other two species. Pteropus guano had a higher C:N ratio, and Desmodus guano had higher N:P and C:P ratios than the other two species. These differences in guano composition suggest that guano from bats in different feeding guilds may affect ecosystem structure and dynamics differently.
9

Biomass fraction of graminoids and forbs in N-limited Alpine grasslands: N:P stoichiometry

67%
Zhang R., Gou X., Bai Y., Zhao J., Chen L., Song X., Wang G.
Polish Journal of Ecology
|
2011
|
tom 59
|
nr 1
It is known that the dominance of graminoid species is promoted by N addition; however, there has been relatively little effort to examine the pattern induced by natural N fertility. Since nutrie nt use e fficiency (NUE) is an important trait determining plant competitive ability, we expected that the species guild with higher NUE (lower nutrient content) may be more competitive on infertile soils. We explo red t he relationships between relative forbs biomass share , soil N and productivity by the linear regressi on analysis on a natural alpine meadow in northeast of Qinghai- Tibetan Plateau (3600 m a.s.l.). To test the variety of leaf N:P stoichiometry, paired t test and general linear model multivariate (GLM) analysis were also used. We f ound that the leaf N:P ratios of the whole community were below 13 in studied sites, which may be consistent with the N limitation on the veget ation. Graminoids re tained lower concentrations of leaf N and P than forbs in community on the Nlimited grassland. Consistent with our prediction, we found that the biomass fraction of graminoids declined with soil N content and aboveground production on the grassland. Different from the pattern along fertility gradients induced by N fertilization, our results showed that gr aminoids with lower internal nutrient content w ere able to resist low levels of nutrient availability on the natural alpine grassland when compared to forbs.
10

Voltage activated ion channels formed by a synthetic alpha-helical peptide: - Determination of channel stoichiometry and molecular modelling of peptide conformation

67%
Mellor I. R., Kerr I. D., Sansom M. S. P., Sukumar M., Balaram P.
Cellular and Molecular Biology Letters
|
1996
|
tom 01
|
nr 3
We designed and synthesized an 18 residue peptide (MS 18) similar to the channel forming fungal antibiotic alamethicin. MS18 formed ion channels in lipid bilayers exhibiting a low discrete conductance level of 55 pS and brief openings to many other conductance levels. Channel formation was markedly dependent on transbilayer voltage with macroscopic conductance increasing exponentially beyond an activation voltage. The activation voltage was higher for lower concentrations of peptide. The relationship between conductance, voltage and peptide concentration was used to calculate the mean number of peptide monomers forming the MS18 channel. This gave an estimate of 4 MS18 monomers per channel. Molecular modeling of MS18 revealed a predominantly α-helical structure.
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