| 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. |
- 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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| 3. |
- 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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| 4. |
- Barcenas-Moreno, Gema, et al.
(författare)
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Plant species influence on soil microbial short-term response after fire simulation
- 2014
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 374:1-2, s. 701-713
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Tidskriftsartikel (refereegranskat)abstract
- Plant species can influence fire intensity and severity causing different immediate and long-term responses on the soil microbial community. The main objective of this work was to determine the role of two representative Mediterranean plant species as soil organic matter sources, and to identify their influence on microbial response before and after heat exposure. A laboratory heating experiment (300 A degrees C for 20 min) was performed using soil collected under Pinus hallepensis (PIN) and Quercus coccifera (KER). Dried plant material was added before heating for a total of six different treatments: non-heated control samples amended with the original plant material (PIN0 and KER0); PIN samples heated with pine (PINp) or kermes oak litter (PINk); KER samples heated with kermes oak (KERk) or pine litter (KERp). Heated soils were inoculated with the original fresh soil and different microbial parameters related to abundance, activity and possible changes in microbial community composition and chemical soil parameters that could be conditioning microbial response were measured for 28 days after inoculation. The effect of heating on the soil microbial parameters studied was influenced to a small extent by the plant species providing fuel, being evident in soil samples taken under pine influence. Nevertheless heating effect showed marked differences when plant species influence on soil origin was analyzed. In general, samples taken under pine appear to be more negatively affected by heating treatment than samples collected under kermes oak, highlighting the importance of vegetation as a fresh organic matter source in soil ecosystems before and after fire.
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| 5. |
- Berg, Andreas, et al.
(författare)
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Transfer of fixed-N from N-2-fixing cyanobacteria associated with the moss Sphagnum riparium results in enhanced growth of the moss
- 2013
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Ingår i: Plant and Soil. - : Springer Verlag (Germany). - 0032-079X .- 1573-5036. ; 362:1-2, s. 271-278
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Tidskriftsartikel (refereegranskat)abstract
- Despite the general assumption that nitrogen fixed by associated cyanobacteria will be readily utilised for growth by the Sphagnum, no empirical evidence is available in the literature. Therefore the effects of nitrogen transfer from cyanobacteria associated with S. riparium were investigated. less thanbrgreater than less thanbrgreater thanCultivation of S. riparium with and without cyanobacteria was performed under laboratory conditions for 57 days. less thanbrgreater than less thanbrgreater thanWe show that nitrogen fixation by cyanobacteria associated with Sphagnum mosses, influences moss growth by transfer of fixed nitrogen to the moss. More than 35 % of the nitrogen fixed by cyanobacteria was transferred to the newly formed moss biomass and resulted in an increase in the growth of Sphagnum biomass compared to the controls. The variation in the increase of nitrogen content explained 76 % of the biomass increment. less thanbrgreater than less thanbrgreater thanHence, nitrogen fixation will have immediate effect on the carbon fixation by Sphagnum. This shows that factors regulating nitrogen fixation will have a direct effect on the role of Sphagnum dominated ecosystems with respect to carbon cycling.
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| 6. |
- Berggren Kleja, Dan, et al.
(författare)
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Fine root turnover and litter production of Norway spruce in a long-term temperature and nutrient manipulation experiment
- 2014
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 374, s. 73-88
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Tidskriftsartikel (refereegranskat)abstract
- The number and elongation of fine roots tended to be higher in WI and I compared to the other treatments, which may indicate nutrient shortage. Fine roots in the WFI treatment had the lowest median longevity and from three to fourfold higher below-ground litter production compared to WI, FI or I - higher soil temperature increased the litter input particularly into the mineral soil. Only fertilization increased the above-ground litter production. As warmer and more nutrient-rich soil significantly shortened the fine root lifespan and increased the litter input, the storage of carbon in boreal forest soil may increase in the future.
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| 7. |
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| 8. |
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| 9. |
- Blanck, Ylva-Li, et al.
(författare)
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Plant species richness in a natural Argentinian matorral shrub-land correlates negatively with levels of plant phosphorus
- 2011
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 345:1-2, s. 11-21
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to ascertain whether there is a relationship between plant species richness and plant-available N, P and water in an environment subject to little anthropogenic disturbance. To accomplish this we studied the vegetation in matorral shrub-lands in northern Patagonia, Argentina. Due to the variation in slope, precipitation and aspect between the sites water status was determined using the C-12/C-13 fraction, delta C-13, to investigate whether this was a confounding factor. The numbers of herb, shrub, liana and tree species were determined at 20 sites along an estimated precipitation gradient. Leaf P and N content and the delta C-13 of Berberis buxifolia were determined, as well as the soil P and N content at the different sites. A negative correlation was found between species richness and Berberis buxifolia foliar P concentration (52% of the species richness variation was accounted for), and a positive correlation was found between plant species richness and Berberis buxifolia foliar N: P ratios (54% of the species richness variation was accounted for). The relationship between species richness and foliar P was seen when all layers of vegetation were included (trees, lianas, shrubs and herbs). Foliar N showed no correlation with species richness, while soil extractable NH4 showed a weak positive correlation with the number of shrub layer species (lianas, shrubs and trees). The species richness of the shrub layer increased with decreasing values of delta C-13. Low soil P availability thus affects local species richness in the matorral shrub-lands of Patagonia in Argentina although the growth of vegetation in the area has been shown to be limited by N. We suggest that low P levels increase plant species richness because low soil P concentration is associated with a high P partitioning and high potential for niche separation.
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| 10. |
- Bokhorst, Stef Frederik, et al.
(författare)
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Impact of understory mosses and dwarf shrubs on soil micro-arthropods in a boreal forest chronosequence
- 2014
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 379, s. 121-133
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Tidskriftsartikel (refereegranskat)abstract
- Plant species and functional groups are known to drive the community of belowground invertebrates but whether their effects are consistent across environmental gradients is less well understood. We aimed to determine if plant effects on belowground communities are consistent across a successional gradient in boreal forests of northern Sweden.We performed two plant removal experiments across ten stands that form a 364-year post-fire boreal forest chronosequence. Through the removal of plant functional groups (mosses or dwarf shrubs) and of individual species of dwarf shrubs, we aimed to determine if the effects of functional groups and species on the soil micro-arthropod community composition varied across this chronosequence.Removal of mosses had a strong negative impact on the abundance and diversity of Collembola and Acari and this effect was consistent across the chronosequence. Only specific Oribatid families declined following dwarf-shrub species removals, with some of these responses being limited to old forest stands.Our results show that the impacts of plants on micro-arthropods is consistent across sites that vary considerably in their stage of post-fire ecosystem development, despite these stages differing greatly in plant productivity, fertility, humus accumulation and moss development. In addition, mosses are a much stronger driver of the micro-arthropod community than vascular plants.
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