| 1. |
- Abd El-Daim, Islam Ahmed Moustafa, et al.
(författare)
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Improved heat stress tolerance of wheat seedlings by bacterial seed treatment
- 2014
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 379, s. 337-350
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate if rhizosphere bacteria can improve heat tolerance of wheat. MethodsWheat (Triticum aestivum) seeds of the cultivars Olivin and Sids1 were treated with Bacillus amyloliquefaciens UCMB5113 or Azospirillum brasilense NO40 and young seedlings tested for management of short term heat stress. ResultsBacterial treatment improved heat stress management of wheat. Olivin showed higher heat tolerance than Sids1 both with non-inoculated and inoculated seeds. Heat increased transcript levels of several stress related genes in the leaves, while expression was lower in inoculated plants but elevated compared with the control. Enzymes of the ascorbate-glutathione redox cycle were activated in leaves after heat challenge but showed a lower response in inoculated plants. Metabolite profiling distinguished different treatments dependent on analysis technique with respect to primary and secondary metabolites. Analysis of some plant stress regulatory genes showed that bacterial treatment increased transcript levels while effects of heat treatment varied. Conclusions: The improvement of heat tolerance by bacteria seems associated with reduced generation of reactive oxygen species (and consequently less cell damage), small changes in the metabolome while preactivation of certain heat shock transcription factors seems important. Seed inoculation with beneficial bacteria seems a promising strategy to improve heat tolerance of wheat.
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| 2. |
- Abiven, Samuel, et al.
(författare)
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Biochar amendment increases maize root surface areas and branching : a shovelomics study in Zambia
- 2015
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 395:1-2, s. 45-55
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Tidskriftsartikel (refereegranskat)abstract
- Positive crop yield effects from biochar are likely explained by chemical, physical and/or biological factors. However, studies describing plant allometric changes are scarcer, but may be crucial to understand the biochar effect. The main aim of the present study is to investigate the effect of biochar on root architecture under field conditions in a tropical setting. The presented work describes a shovelomics (i.e., description of root traits in the field) study on the effect of biochar on maize root architecture. Four field experiments we carried out at two different locations in Zambia, exhibiting non-fertile to relatively fertile soils. Roots of maize crop (Zea mays L.) were sampled from treatments with fertilizer (control) and with a combination of fertilizer and 4 t.ha(-1) maize biochar application incorporated in the soil. For the four sites, the average grain yield increase upon biochar addition was 45 +/- 14 % relative to the fertilized control (from 2.1-6.0 to 3.1-9.1 ton ha(-1)). The root biomass was approximately twice as large for biochar-amended plots. More extensive root systems (especially characterized by a larger root opening angle (+14 +/- 11 %) and wider root systems (+20 +/- 15 %)) were observed at all biochar-amended sites. Root systems exhibited significantly higher specific surface areas (+54 +/- 14 %), branching and fine roots: +70 +/- 56 %) in the presence of biochar. Biochar amendment resulted in more developed root systems and larger yields. The more extensive root systems may have contributed to the observed yield increases, e.g., by improving immobile nutrients uptake in soils that are unfertile or in areas with prolonged dry spells.
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| 3. |
- Affholder, Marie-Cecile, et al.
(författare)
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Can Cd content in crops be controlled by Se fertilization? A meta-analysis and outline of Cd sequestration mechanisms
- 2019
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 440, s. 369-380
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Tidskriftsartikel (refereegranskat)abstract
- Aim Cadmium mitigation in crops is a worldwide concern. Selenium application has been suggested as a potential solution to reduce cadmium concentration in plants, but published results were contradictory. We analysed literature data with respect to the effect of selenium addition on cadmium uptake and elucidated processes possibly involved.Method A meta-analysis was performed on data collected from previously published studies presenting cadmium concentration in plants subjected to selenium treatments. Metaregression random models were run to test the impact of different factors. In addition, soil and crop inventory data exemplifying the natural variation of Cd and Se in soil were evaluated.Results The results highlighted a significant reduction of cadmium concentration in crops after selenium addition. The reduction was dose-dependent for crops growing under aerobic, but not for plants cultivated under anoxic conditions such as rice. This suggests that different process can be involved.Conclusion We demonstrated the potential of selenium fertilization to mitigate cadmium uptake and highlighted that for non-rice species, the main process seems to take place in the soil, while mechanisms in roots restricting uptake may be involved for all crops. The inventory data also indicated an impact of natural soil Se on Cd contents in crops.
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| 4. |
- Agback, Peter, et al.
(författare)
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Root morphology and cluster root formation by seabuckthorn (Hippophae rhamnoides L.) in response to nitrogen, phosphorus and iron deficiency
- 2015
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 397, s. 75-91
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Tidskriftsartikel (refereegranskat)abstract
- The aims were to investigate effects of availability of nitrogen (N), phosphorus (P) and iron (Fe) on root properties of seabuckthorn (HippophaA << rhamnoides) and to test the hypothesis that seabuckthorn is able to form cluster roots (CRs).Two sources of seabuckthorn were used: the seabuckthorn cultivar BHi10726 originating from a breeding programme based on H.r. ssp mongolica and carried out in rich agricultural field soil in the black earth (chernozem) region of Russia and the seabuckthorn accession named Pk originating in a natural population of H.r. ssp turkestanica in the mountainous region of northern Pakistan. Three cultivation systems giving different water availabilities were used at two levels each of N, P and Fe. Root morphology of seedlings and clones was characterized and metabolite content in extracts of young and old CRs of Pk was analyzed by proton nuclear magnetic resonance spectroscopy.Availability of N affected growth and distribution of biomass between shoot and root, while P and Fe deficiency modified root system architecture towards more lateral roots. Densely positioned rootlets with a determinate type of growth consistent with the definition of CR were observed under low P and low Fe. Pk formed on average 12 CRs per plant, which was 3 to 4-fold higher compared to BHi10726 also when normalized per root length. Malate and glycine were most abundant of the organic acids and amino acids, respectively, and decreased in old CRs.Seabuckthorn has the ability to form cluster roots especially in Pk and under deficiency of P and Fe. The two sources of seabuckthorn with different histories showed distinctly different root system architectures. The high contents of malate and glycine and their decrease in old CRs may reflect roles in CR metabolism.
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| 5. |
- Ahonen-Jonnarth, Ulla, et al.
(författare)
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Effects of elevated nickel and cadmium concentrations on growth and nutrient uptake of mycorrhizal and non-mycorrhizal Pinus sylvestris seedlings
- 2001
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Ingår i: Plant and Soil. - 0032-079X .- 1573-5036. ; 236, s. 129-138
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Tidskriftsartikel (refereegranskat)abstract
- The effects of Ni and Cd on growth and nutrient uptake of mycorrhizal and non-mycorrhizal Pinus sylvestris L. seedlings were investigated in a pot experiment. Seedlings were either inoculated with Laccaria bicolor (Maire) Orton or left uninoculated before being planted in pots containing a mixture of sandy soil from the B-horizon of a coniferous forest, small stones and pure quartz sand. The pots were supplied with small amounts of a balanced nutrient solution every 24 h using peristaltic pumps. Nickel or Cd were added as chlorides to the nutrient solution at levels of 85 μM Ni (Ni 1), 170 μM Ni (Ni 2), or 8.9 μM Cd. Mycorrhizal colonisation of the roots was nearly 100% in the mycorrhizal treatments. The mycorrhizal seedlings grew significantly better than the non-mycorrhizal ones. The weight of mycorrhizal seedlings in the Ni 2 treatment was 29% lower than that of the mycorrhizal controls, but still 34% greater than that of the non-mycorrhizal seedlings not exposed to metals. There was an overall, statistically significant, negative effect of metals on plant yield. Mycorrhizal plants had lower root:shoot (R:S) ratios than non-mycorrhizal plants and the R:S ratio was increased by metal exposure, particularly in the non-mycorrhizal seedlings. Plant concentrations of Cd or Ni were not affected by mycorrhizal colonisation, but total uptake of Cd and Ni was higher in bigger mycorrhizal seedlings. Nickel decreased P concentration in all seedlings and Cd decreased P concentration in the non-mycorrhizal seedlings. Generally, the mycorrhizal seedlings grew better than non-mycorrhizal ones and had better P, K, Mg and S status. Root growth was not significantly affected by the metal treatments. The reduction in mean shoot growth of non-mycorrhizal plants, relative to the metal-free control, appeared higher than in mycorrhizal plants but was not statistically significant due to high variation in the non-mycorrhizal plants not exposed to metals. The main mycorrhizal effect was thus increased nutrient uptake and growth of the seedlings.
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| 6. |
- Andersen, Emil Alexander Sherman, et al.
(författare)
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Nitrogen isotopes reveal high N retention in plants and soil of old Norse and Inuit deposits along a wet-dry arctic fjord transect in Greenland
- 2020
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Ingår i: Plant and Soil. - : Springer. - 0032-079X .- 1573-5036. ; 455:1-2, s. 241-255
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Plant growth in the Arctic is often nutrient limited due to temperature constraints on decomposition and low atmospheric input of nitrogen (N). Local hotspots of nutrient enrichment found in up to 4000-year-old archaeological deposits can be used to explore the recycling and long-term retention of nutrients in arctic ecosystems.Methods: We investigated old Inuit and Norse deposits (known as middens) and adjacent tundra ecosystems along a wet-dry fjord gradient in western Greenland to explore the isotopic fingerprinting of plant and soil carbon and nitrogen (C-13/C-12 and(15)N/N-14) derived from human presence.Results: At all locations we observed a significant isotopic fingerprint in soil and plant N related to human deposits. This demonstrates a century-long legacy of past human habitation on plant and soil characteristics and indicates a surprisingly high N retention in these ecosystems. This is consistent with the significantly higher plant biomass in areas with archaeological deposits.Conclusion: Vegetation composition and N in plants and soils displayed marked differences along the wet-dry fjord gradient. Furthermore, the profound nutrient enrichment and organic matter accumulation in archaeological deposits compared to surrounding tundra demonstrates a century-long legacy of past habitation on plant and soil characteristics as well as efficient N cycling with surprisingly limited N loss.
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| 7. |
- Andrén, Olof, et al.
(författare)
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How can soil monitoring networks be used to improve predictions of organic carbon pool dynamics and CO2 fluxes in agricultural soils?
- 2011
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 338, s. 247-259
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Tidskriftsartikel (refereegranskat)abstract
- As regional and continental carbon balances of terrestrial ecosystems become available, it becomes clear that the soils are the largest source of uncertainty. Repeated inventories of soil organic carbon (SOC) organized in soil monitoring networks (SMN) are being implemented in a number of countries. This paper reviews the concepts and design of SMNs in ten countries, and discusses the contribution of such networks to reducing the uncertainty of soil carbon balances. Some SMNs are designed to estimate country-specific land use or management effects on SOC stocks, while others collect soil carbon and ancillary data to provide a nationally consistent assessment of soil carbon condition across the major land-use/soil type combinations. The former use a single sampling campaign of paired sites, while for the latter both systematic (usually grid based) and stratified repeated sampling campaigns (5-10 years interval) are used with densities of one site per 10-1,040 kmA(2). For paired sites, multiple samples at each site are taken in order to allow statistical analysis, while for the single sites, composite samples are taken. In both cases, fixed depth increments together with samples for bulk density and stone content are recommended. Samples should be archived to allow for re-measurement purposes using updated techniques. Information on land management, and where possible, land use history should be systematically recorded for each site. A case study of the agricultural frontier in Brazil is presented in which land use effect factors are calculated in order to quantify the CO2 fluxes from national land use/management conversion matrices. Process-based SOC models can be run for the individual points of the SMN, provided detailed land management records are available. These studies are still rare, as most SMNs have been implemented recently or are in progress. Examples from the USA and Belgium show that uncertainties in SOC change range from 1.6-6.5 Mg C ha(-1) for the prediction of SOC stock changes on individual sites to 11.72 Mg C ha(-1) or 34% of the median SOC change for soil/land use/climate units. For national SOC monitoring, stratified sampling sites appears to be the most straightforward attribution of SOC values to units with similar soil/land use/climate conditions (i.e. a spatially implicit upscaling approach).
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| 8. |
- Andresen, Louise C., et al.
(författare)
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Uptake of pulse injected nitrogen by soil microbes and mycorrhizal and non-mycorrhizal plants in a species-diverse subarctic heath ecosystem
- 2008
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 313:1-2, s. 283-295
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Tidskriftsartikel (refereegranskat)abstract
- N-15 labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of N-15 label in mycorrhizal and non-mycorrhizal plants and in soil microorganisms, in order to reveal probable differences in acquisition patterns between the two functional plant types and between plants and soil microorganisms. Three weeks after the label addition, with the N-15-forms added with same amount of nitrogen per square meter, we analyzed the N-15-enrichment in total soil, in soil K2SO4 (0.5 M) extracts and in the microbial biomass after vacuum-incubation of soil in chloroform and subsequent K2SO4 extraction. Furthermore the N-15-enrichment was analyzed in current years leaves of the dominant plant species sampled three, five and 21 days after label addition. The soil microorganisms had very high N-15 recovery from all the N sources compared to plants. Microorganisms incorporated most N-15 from the glutamic acid source, intermediate amounts of N-15 from the glycine source and least N-15 from the NH4+ source. In contrast to microorganisms, all ten investigated plant species generally acquired more N-15 label from the NH4+ source than from the amino acid sources. Non-mycorrhizal plant species showed higher concentration of N-15 label than mycorrhizal plant species 3 days after labeling, while 21 days after labeling their acquisition of N-15 label from amino acid injection was lower than, and the acquisition of N-15 label from NH4 injection was similar to that of the mycorrhizal species. We conclude that the soil microorganisms were more efficient than plants in acquiring pulses of nutrients which, under natural conditions, occur after e. g. freeze-thaw and dry rewet events, although of smaller size. It also appears that the mycorrhizal plants in the short term may be less efficient than non-mycorrhizal plants in nitrogen acquisition, but in a longer term show larger nitrogen acquisition than non-mycorrhizal plants. However, the differences in N-15 uptake patterns may also be due to differences in leaf longevity and woodiness between plant functional groups.
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| 9. |
- Asplund, Linnea, et al.
(författare)
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Proof of concept: Nitrogen use efficiency of contrasting spring wheat varieties grown in greenhouse and field
- 2014
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 374, s. 829-842
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Tidskriftsartikel (refereegranskat)abstract
- Major aims were to test and evaluate a new concept for assessment of nitrogen use efficiency (NUE) of crops by growing six spring wheat varieties in greenhouse and field environments. NUE was calculated with a plant based concept integrating the entire crop life history and separating plant characteristics from environmental factors affecting NUE. Specific hypotheses were tested related to the varieties' drought and nutrient fertilisation responses for NUE components, and coherence of those responses in field and greenhouse.The wheat (Triticum aestivum L.) cultivated varieties 'Diskett', 'Granary', 'Quarna', 'Stilett', 'Vinjett', and a Swedish landrace ('Dala') were grown in field and greenhouse environments in Central Sweden. Two fertilisation treatments were included in a field and greenhouse experiment, and in the greenhouse also drought. The NUE components N uptake efficiency (U-N), grain-specific N efficiency (E-N,E-g) and grain N concentration (C-N,C-g) were assessed.Drought reduced yield and NUE through E-N,E-g, and more so when drought occurred prior to anthesis than after anthesis. Effect of fertilisation treatment on NUE components was similar in the two set-ups, but there were fewer variety x fertilisation interactions in the field. U-N was higher in the field and E-N,E-g was higher in the greenhouse, while C-N,C-g and overall NUE were similar in the two environments. Ranking of varieties regarding NUE and U-N was similar in the greenhouse and field, but different regarding E-N,E-g and C-N,C-g.The NUE concept is a useful tool to describe and integrate important NUE components for crops grown in different treatments (nutrient fertilisation, drought) and experimental set-ups, i.e. greenhouse and field. Similar variety ranking in overall NUE across experimental set-ups indicates stable results in different environments.
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| 10. |
- Bahr, Adam, et al.
(författare)
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Nitrogen leaching and ectomycorrhizal nitrogen retention capacity in a Norway spruce forest fertilized with nitrogen and phosphorus
- 2015
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 390:1-2, s. 323-335
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Tidskriftsartikel (refereegranskat)abstract
- To estimate the production of external ectomycorrhizal mycelia (EMM) in Norway spruce forests with varying nitrogen (N) and phosphorus (P) levels, and to relate this to the N retention capacity of ectomycorrhizal fungi (EMF) and N leaching. Seasonal changes in EMF production (in ingrowth mesh bags) and soil water N (in suction lysimeters) were analyzed after fertilization with N or N combined with P. The EMF N retention capacity was estimated by the addition of isotopically labeled N to the mesh bags. No relationship was found between the seasonal variation in EMF growth and N leakage from the soil. However, in the mesh bags, the total assimilation of N-15 by EMF was almost halved by N fertilization, while twice as much N-15 leached through. We found a high specific N assimilation capacity per unit weight of EMF mycelia. This was unaffected by N fertilization, but the total assimilation of N by EMF was drastically reduced due to reduced production of EMM. However, N-retaining processes other than N assimilation by EMF must be taken into account to explain the losses of N after fertilization.
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