共查询到20条相似文献,搜索用时 31 毫秒
1.
Aims
The aim of the present study was to predict kinetics of both Ni concentration in soil solution and leaf Ni mass for the Ni-hyperaccumulator Leptoplax emarginata cultivated on a fertilized and Ni-contaminated sandy topsoil.Methods
The 0-D (independent of space) one-site rate-limited desorption model proposed by Ingwersen et al. (J Environ Qual 35:2055–2065, 2006) was modified. The plant sink term of the model was approximated by the biophysical equation which assumes that the leaf nickel mass is equal to the triple product of the Intact Plant Transpiration Stream Concentration Factor for Ni IPTSCFNi (xylem:solution Ni concentration ratio), Ni concentration in solution and the volume of transpired water. The model input variables were the constant mean IPTSCFNi value, determined from independent leaf Ni accumulation kinetics, and the exponential law fitting the transpiration rate kinetics. Using the best calibration, the model was validated and a sensitivity analysis was carried out thereafter. Models were formulated as sets of ordinary differential equation systems which were solved using the fourth-order Runge–Kutta method.Results
The best model calibration was the joint parameter optimization: the two parameters of the Freundlich Ni adsorption isotherm and of the Ni desorption rate coefficient are obtained using the kinetics of Ni concentrations in the soil solutions for the reference unplanted Ni-contaminated topsoils. The model was validated reasonably well for both Ni concentration in soil solution and leaf Ni mass.Conclusions
The joint parameter optimization of the two parameters of the Freundlich nickel sorption isotherm and of the Ni desorption rate was successful whereas the Freundlich batch Ni sorption isotherm dramatically overestimated Ni sorption. This joint approach is therefore recommended for any plant metal uptake model. The 0-D one-site rate-limited desorption model linked to a biophysical coupled Ni and water uptake model reasonably validated the kinetics of both Ni concentration in solution and leaf Ni mass. This promising simplified model for predicting both metal concentration in solution and leaf metal mass for metal needs further validations in culture chambers and further improvements in order to use it in the field as a one-dimensional model, taking into account soil moisture dynamics. 相似文献2.
Interactive influence of light intensity and soil fertility on root-associated arbuscular mycorrhizal fungi 总被引:2,自引:0,他引:2
Guoxi Shi Yongjun Liu Nancy Collins Johnson Pål Axel Olsson Lin Mao Gang Cheng Shengjing Jiang Lizhe An Guozhen Du Huyuan Feng 《Plant and Soil》2014,378(1-2):173-188
Background and aims
Soil nutrients and light have major effects on the economics of arbuscular mycorrhizal (AM) symbioses. This study tests the main and interactive effects of soil fertility and light on AM fungal community.Methods
We conducted a 3 year mesocosm experiment with a full two factorial design: light (full light or shade) and soil fertility (unfertilized or fertilized), on the Qinghai-Tibetan Plateau. Plant traits, soil characteristics and the AM fungal communities inside roots and in soils were measured.Results
Shade reduced AM colonization of roots, fertilization reduced the hyphal abundance in the soil, and both factors reduced species richness of AM fungi inside plant roots. Fertilization exacerbated the negative impacts of shade on AM fungal abundance and diversity. We observed 15 phylotypes of AM fungi inside roots and ten morphotypes of AM fungal spores in the soil. Taxa responded differently to shade and fertilization and there was little congruence between the responses of fungi inside the roots and in the spore community.Conclusions
Our findings indicate that both shade and fertilization reduce the abundance of AM fungi, but the two factors have different effects on the quality of plant roots as habitat for AM fungi. 相似文献3.
Aims
Our goal was to assess how management and sward functional diversity affect nitrogen response efficiency (NRE), the ratio of plant biomass production to supply of available nitrogen (N) in temperate grassland.Methods
A three-factorial design was employed: three sward compositions, two mowing frequencies, and two fertilization treatments.Results
NRE was largely influenced by fertilization followed by mowing frequency and sward composition. NRE was larger in unfertilized than fertilized plots, in plots cut thrice than plots cut once per year, and in control swards than in monocot- or dicot-enhanced swards. Fertilization decreased NRE through decreases in both N uptake efficiency (plant N uptake per supply of available N) and N use efficiency (NUE, biomass produced per plant N uptake) whereas mowing frequency and sward composition affected NRE through N uptake efficiency rather than NUE. The largest NRE in the control sward with 70 % monocots and 30 % dicots attests that these proportions of functional groups were best adapted in this grassland ecosystem.Conclusions
Optimum NRE may not be a target of most farmers, but it is an appropriate tool to evaluate the consequences of grassland management practices, which farmers may employ to maximize profit, on environmental quality. 相似文献4.
5.
Kanehiro Kitayama 《Plant and Soil》2013,367(1-2):215-224
Background and aims
Tropical rain forests on deeply weathered soils are increasingly thought to be limited by phosphorus (P), where plants and associated organisms would demonstrate adaptations to efficiently recycle P using acid phosphatase from organic matter. The activities of soil and root acid phosphatase were investigated in nine tropical rain forests that demonstrated a 20-fold difference in the soil organic P pool on Mt. Kinabalu, Borneo.Methods
Acid phosphatase activity was measured at pH6.0 using p-nitrophenyl phosphate as substrate.Results
The specific phosphatase activity of tree roots on a soil-surface-area basis was significantly positively related with P-use efficiency of above-ground productivity, suggesting a physiological linkage between above and below-ground systems in the adaptation to P deficiency. The phosphatase activities of soils and roots were significantly negatively correlated with the pool size of soil organic P fractions, suggesting that demand for P determines phosphatase activities.Conclusions
It is suggested that tree roots and soil microbes develop more active phosphatases in response to the chronic shortage of soil P, which forms the basis for an important functional role for the efficient acquisition of P from soil organic matter. 相似文献6.
Aluminum tolerance of wheat does not induce changes in dominant bacterial community composition or abundance in an acidic soil 总被引:1,自引:0,他引:1
Chao Wang Xue Qiang Zhao Rong Fu Chen Hai Yan Chu Ren Fang Shen 《Plant and Soil》2013,367(1-2):275-284
Aims
Aluminum-tolerant wheat plants often produce more root exudates such as malate and phosphate than aluminum-sensitive ones under aluminum (Al) stress, which provides environmental differences for microorganism growth in their rhizosphere soils. This study investigated whether soil bacterial community composition and abundance can be affected by wheat plants with different Al tolerance.Methods
Two wheat varieties, Atlas 66 (Al-tolerant) and Scout 66 (Al-sensitive), were grown for 60 days in acidic soils amended with or without CaCO3. Plant growth, soil pH, exchangeable Al content, bacterial community composition and abundance were investigated.Results
Atlas 66 showed better growth and lower rhizosphere soil pH than Scout 66 irrespective of CaCO3 amendment or not, while there was no significant difference in the exchangeable Al content of rhizosphere soil between the two wheat lines. The dominant bacterial community composition and abundance in rhizosphere soils did not differ between Atlas 66 and Scout 66, although the bacterial abundance in rhizosphere soil of both wheat lines was significantly higher than that in bulk soil. Sphingobacteriales, Clostridiales, Burkholderiales and Acidobacteriales were the dominant bacteria phylotypes.Conclusions
The difference in wheat Al tolerance does not induce the changes in the dominant bacterial community composition or abundance in the rhizosphere soils. 相似文献7.
William S. Cuddy Brett A. Summerell Michelle M. Gehringer Brett A. Neilan 《Plant and Soil》2013,370(1-2):317-332
Background and aims
This study investigated the effect of cyanobacterial inoculants on salt tolerance in wheat.Methods
Unicyanobacterial crusts of Nostoc, Leptolyngbya and Microcoleus were established in sand pots. Salt stress was targeted at 6 and 13 dS m?1, corresponding to the wheat salt tolerance and 50 % yield reduction thresholds, respectively. Germinated wheat seeds were planted and grown for 14 (0 and 6 dS m?1) and 21 (13 dS m?1) days by which time seedlings had five emergent leaves. The effects of cyanobacterial inoculation and salinity on wheat growth were quantified using chlorophyll fluorescence, inductively coupled plasma-optical emission spectrometry and biomass measurements.Results
Chlorophyll fluorescence was negatively affected by soil salinity and no change was observed in inoculated wheat. Effective photochemical efficiency correlated with a large range of plant nutrient concentrations primarily in plant roots. Inoculation negatively affected wheat biomass and nutrient concentrations at all salinities, though the effects were fewer as salinity increased.Conclusions
The most likely explanation of these results is the sorption of nutrients to cyanobacterial extracellular polymeric substances, making them unavailable for plant uptake. These results suggest that cyanobacterial inoculation may not be appropriate for establishing wheat in saline soils but that cyanobacteria could be very useful for stabilising soils. 相似文献8.
Jian Jin Caixian Tang Roger Armstrong Clayton Butterly Peter Sale 《Plant and Soil》2013,368(1-2):315-328
Aims
The efficient management of phosphorus (P) in cropping systems remains a challenge due to climate change. We tested how plant species access P pools in soils of varying P status (Olsen-P 3.2–17.6 mg?kg?1), under elevated atmosphere CO2 (eCO2).Methods
Chickpea (Cicer arietinum L.) and wheat (Triticum aestivum L.) plants were grown in rhizo-boxes containing Vertosol or Calcarosol soil, with two contrasting P fertilizer histories for each soil, and exposed to ambient (380 ppm) or eCO2 (700 ppm) for 6 weeks.Results
The NaHCO3-extractable inorganic P (Pi) in the rhizosphere was depleted by both wheat and chickpea in all soils, but was not significantly affected by CO2 treatment. However, NaHCO3-extractable organic P (Po) accumulated, especially under eCO2 in soils with high P status. The NaOH-extractable Po under eCO2 accumulated only in the Vertosol with high P status. Crop species did not exhibit different eCO2-triggered capabilities to access any P pool in either soil, though wheat depleted NaHCO3-Pi and NaOH-Pi in the rhizosphere more than chickpea. Elevated CO2 increased microbial biomass C in the rhizosphere by an average of 21 %. Moreover, the size in Po fractions correlated with microbial C but not with rhizosphere pH or phosphatase activity.Conclusion
Elevated CO2 increased microbial biomass in the rhizosphere which in turn temporally immobilized P. This P immobilization was greater in soils with high than low P availability. 相似文献9.
Aims
Longleaf pine (Pinus palustris Mill.) is being restored across the U.S. South for a multitude of ecological and economic reasons, but our understanding of longleaf pine’s response to soil physical conditions is poor. On the contrary, our understanding of loblolly pine (Pinus taeda L.) root and shoot growth response to soil conditions is well established.Methods
We performed a comparative greenhouse study which modeled root length density, total seedling biomass, and the ratio of aboveground:belowground mass as functions of volumetric water content, bulk density and soil fertility (fertilized or not).Results
Root length density was about 35 % greater in longleaf pine seedlings compared to loblolly pine seedlings, and was reasonably well modeled (R 2?=?0.54) for longleaf pine by bulk density (linear), volumetric water content (quadratic), soil fertility, and the interactions of bulk density, volumetric water content, species, and soil fertility. The aboveground:belowground mass ratio (ABR) increased at both extremes of water content.Conclusions
This research indicates that young longleaf pine seedling root systems respond more negatively to extremes of soil physical conditions than loblolly pine, and compacted or dry loamy soils should be ameliorated in addition to normal competition control, especially on soils degraded by past management. 相似文献10.
Anna Belcarz Grażyna Ginalska Teodozja Pycka Aneta Zima Anna Ślósarczyk Izabela Polkowska Zofia Paszkiewicz Wojciech Piekarczyk 《Central European Journal of Biology》2013,8(6):534-548
Background
Unsatisfactory surgical handiness is a commonly known disadvantage of implantable granular bioceramics. To overcome this problem, β-1,3-glucan, biotechnologically derived polysaccharide, has been proposed as a joining agent to combine granular ceramics into novel compact and elastic composite. Hydroxyapatite/glucan elastic material was processed and evaluated as a potential bone void filler.Methodology
The procedure of composite formation was based on gelling properties of glucan. Its properties were studied using X-ray microtomography, SEM-EDS, FTIR spectroscopy, compression test and ultrasonic method. Sorption index was determined in phosphate buffered saline; bioactivity in simulated body fluid; sterility in growth broth and human blood plasma; implantation procedure in dog model.Results
HAp/glucan composite is sterilizable, flexible and self-adapting to defect shape. It exhibits bioactivity, good surgical handiness, high sorption index and profitable mechanical properties, resembling those of spongy bone. Results of pilot clinical experiment on animal (dog) patients of a local clinic of animal surgery suggested good healing properties of the composite and its transformation into new bone tissue within critical-size defect.Conclusions
The results obtained in this study confirm that flexible HAp/glucan composite has potential as a bone-substituting material. Promising results of pilot clinical experiment suggest that further in vivo experiments should be performed. 相似文献11.
David Solance Smith Jennifer A. Schweitzer Philip Turk Joseph K. Bailey Stephen C. Hart Stephen M. Shuster Thomas G. Whitham 《Plant and Soil》2012,352(1-2):243-251
Background and aims
Soils can act as agents of natural selection, causing differential fitness among genotypes and/or families of the same plant species, especially when soils have extreme physical or chemical properties. More subtle changes in soils, such as variation in microbial communities, may also act as agents of selection. We hypothesized that variation in soil properties within a single river drainage can be a selective gradient, driving local adaptation in plants.Methods
Using seeds collected from individual genotypes of Populus angustifolia James and soils collected from underneath the same trees, we use a reciprocal transplant design to test whether seedlings would be locally adapted to their parental soil type.Results
We found three patterns: 1. Soils from beneath individual genotypes varied in pH, soil texture, nutrient content, microbial biomass and the physiological status of microorganisms. 2. Seedlings grown in local soils experienced 2.5-fold greater survival than seedlings planted in non-local soils. 3. Using a composite of height, number of leaves and leaf area to measure plant growth, seedlings grew ~17.5% larger in their local soil than in non-local soil.Conclusions
These data support the hypothesis that variation in soils across subtle gradients can act as an important selective agent, causing differential fitness and local adaptation in plants. 相似文献12.
Mechanical properties and soil stability affected by fertilizer treatments for an Ultisol in subtropical China 总被引:3,自引:0,他引:3
Wei Yang Zhaoxia Li Chongfa Cai Zhonglu Guo Jiazhou Chen Junguang Wang 《Plant and Soil》2013,363(1-2):157-174
Background and aims
Soil mechanical properties are crucial for plant growth, soil erosion, tillage and traffic. The soil mechanical properties and stability of an Ultisol were determined in a 13-year fertilization experiment in subtropical China. The effect of organic matter on soil structure was also evaluated.Methods
The treatments include: unfertilized, mineral fertilized, mineral mixed with straw, and animal manure. Bulk soil strengths (shear strength and penetration resistance) were tested in field. Aggregate strengths (penetration resistance and tensile strength), water stability, organic carbon (OC), hot-water-extractable carbohydrate (HWEC) and some related factors were determined in laboratory.Results
Fertilizer increases aggregate penetration resistance, tensile strength, water stability and organic matter content in cultivated horizon (0–15 cm depth), especially at the 0–5 cm layer. OC and HWEC showed significantly regression relationships with aggregate water stability, porosity and water repellency for the whole soil profile (0–40 cm). Aggregate strengths also increased with OC and HWEC in cultivated horizon.Conclusions
Animal manure is most effective in improving soil structure while aggregate water stability is the most sensitive index of fertilizer management. Soil organic matter is a strong determinant of soil structure. Both OC and HWEC are good indicators of surface aggregate strengths and stability, and thus, soil quality in this region. 相似文献13.
14.
Aim
Highly alkaline soils (pH?>?9.0) may adversely affect agricultural crop productivity. Problems encountered include poor structure and nutrient deficiency. Research based on solution cultures suggests that aluminium (Al) phytotoxicity may occur in soils with pH?>?9.0, but little research has been undertaken on actual soils under controlled conditions. The nature of the Al species responsible and the pH regime of the soils when this occurs are unknown.Methods
The charge and species of Al responsible for this toxicity was investigated using Zeta Potential measurement, Nuclear Magnetic Resonance (NMR) spectroscopy, Al precipitation characteristics and electrical conductivity as a function of pH. An anion exchange resin was used to evaluate Al availability to plants at alkaline pH. To verify Al phytotoxicity, a pot experiment was performed with plants grown at near neutral and high pH, with and without Al.Results
The anionic aluminate species of aluminium was ubiquitous at highly alkaline pH, and was the dominant charged species at pH 9.2. Aluminium was phytotoxic at high pH, significantly reducing the stem and root development of field pea test plants over and above that caused by alkalinity alone. The effects of both alkalinity in general and aluminium in particular became noticeable at pH 9.0 and debilitating at pH?>?9.2.Conclusion
As this corresponds to the pH where aluminate becomes dominant, it is probably responsible for the phytotoxicity. 相似文献15.
Background and aims
Native shrub species of southern California have a long history of displacement by exotic annual herbs and forbs. Such invasions may be mediated by interactions with the microbial community and changes in the N cycle as a result of N pollution. However, the simultaneous effects of the soil microbial community status and N fertilization on dominant native and exotic plant species growth have not been thoroughly explored in this ecosystem.Methods
Three species of native shrubs and of exotic annuals were grown in an orthogonal two-factor greenhouse experiment. To assess the importance of the soil microbial community pre-sterilized soils were inoculated with sterilized or non-sterilized field soil; to assess the importance of N type pots were fertilized with nitrate, ammonium or glycine solutions. Plant shoot and root biomass was measured after harvesting.Results
The natives Artemisia californica and Eriogonum fasciculatum had lower growth in sterilized soil, suggesting microbial facilitation of these species, and E. fasciculatum higher growth with ammonia than either nitrate or glycine. Salvia apiana had equal growth under all conditions. The exotics Brassica nigra and Bromus madritensis grew equally in sterilized and unsterilized soil, and B. madritensis greater growth with ammonia fertilizer. Centaurea melitensis had greater growth in sterilized soil, and with either form of inorganic N.Conclusions
These results highlight the importance of the soil microbial community in contributing to relative success of native vs. exotic species, and could inform restoration approaches for these species. 相似文献16.
Effects of long-term temperature and nutrient manipulation on Norway spruce fine roots and mycelia production 总被引:2,自引:0,他引:2
J. Leppälammi-Kujansuu I. Ostonen M. Strömgren L. O. Nilsson D. B. Kleja S. P. Sah H.-S. Helmisaari 《Plant and Soil》2013,366(1-2):287-303
Aims and methods
The effects of changing climate on ectomycorrhizal (EcM) fine roots were studied in northern Sweden by manipulating soil temperature for 14 years and/or by fertilizing for 22 years. Fine root biomass, necromass, EcM root tip biomass, morphology and number as well as mycelia production were determined from soil cores and mesh bags.Results and conclusions
The fine root biomass and necromass were highest in the fertilized plots, following similar trends in the above-ground biomass, whereas the EcM root tip biomass per basal area decreased by 22 % in the fertilized plots compared to the control. Warming increased the fine root biomass, live/dead-ratio and the number of EcM root tips in the mineral soil and tended to increase the production of EcM mycelia. Greater fine root biomass meant more EcM root tips, although the tip frequency was not affected by fertilization or warming. Significantly higher specific root length of EcM root tips indicated an increased need for nutrients in warmed and in unfertilized plots. Better nutrient supply and warmer soil temperature provide a potential to increase the flow of carbon into the soil via increased fine root biomass, but the carbon balance also depends on root turnover. 相似文献17.
Effects of biochar amendment on root traits and contaminant availability of maize plants in a copper and arsenic impacted soil 总被引:1,自引:0,他引:1
Aoife Brennan Eduardo Moreno Jiménez Markus Puschenreiter José Antonio Alburquerque Christine Switzer 《Plant and Soil》2014,379(1-2):351-360
Background and aims
Biochar has been proposed as a tool to enhance phytostabilisation of contaminated soils but little data are available to illustrate the direct effect on roots in contaminated soils. This work aimed to investigate specific root traits and to assess the effect of biochar amendment on contaminant availability.Methods
Amendment with two different types of biochar, pine woodchip and olive tree pruning, was assessed in a rhizobox experiment with maize planted in a soil contaminated with significant levels of copper and arsenic.Results
Amendment was found to significantly improve root traits compared to the control soil, particularly root mass density and root length density. Copper uptake to plants and ammonium sulphate extractable copper was significantly less in the biochar amended soils. Arsenic uptake and extractability varied with type of biochar used but was not considered to be the limiting factor affecting root and shoot development.Conclusions
Root establishment in contaminated soils can be enhanced by biochar amendment but choice of biochar is key to maximising soil improvement and controlling contaminant availability. 相似文献18.
Background and aims
Interacting effects of atmospheric N deposition on the degree to which tree demand for other nutrients is met by soil supply has seldom been explored in Mediterranean-type ecosystems. We hypothesized that patterns for the relative availability of N and P in soils will be matched by variations in process rates related to soil organic P cycling and by shifts from N to P limitation of tree growth.Methods
We examined N/P relationships in Mediterranean-fir (Abies pinsapo) forests from two nearby regions differing in N deposition levels.Results
N pools and transformation rates and the contribution of organic fractions to the labile P pool in soils showed increasing trends toward the pollution source. Phosphomonoesterase activity (PME) in bulk soils, root PME per unit biomass (but not per unit soil volume) and biomass accumulation in P-fertilized root-in-growth cores incubated in situ were also the highest at the sites receiving elevated N deposition, indicating P limitation. In contrast, forest stands in the region farther from the pollutant source were N-limited (preferential root growth in N-rich soil microsites) and showed lower PME activities and higher total fine root biomass.Conclusions
In the forests under elevated N deposition, higher values for an overall indicator of soil N status matched with indications of an accelerated soil organic P subcycle and P-limitation of tree growth. 相似文献19.
Distribution and decline of endangered herbaceous heathland species in relation to the chemical composition of the soil 总被引:1,自引:0,他引:1
A. L. F. M. Houdijk P. J. M. Verbeek H. F. G. Van Dijk J. G. M. Roelofs 《Plant and Soil》1993,148(1):137-143
High atmospheric deposition of ammonium affects the physical and chemical status of the soil, increasing nitrogen availability, soil acidity and the mobilization of toxic metal ions. To investigate whether and how the decline of several herbaceous plant species in Dutch heathlands is associated with these processes, the chemical composition of the soil on which these species grow has been compared with the soil on which heathland species such asCalluna vulgaris (L.) Hull,Erica tetralix L. andMolinea caerulea (L.) Moench dominate. The discrimination between both soil types was primarily based on differences in pH (H2O), pH (NaCl) and the aluminium/calcium ratio in the waterextracts. Within the group of endangered herbaceous heathland species these soil parameters also varied. This led to a division into 4 groups of species: Dominating species growing on acid soils Herbaceous species growing together with dominating species on acid soils Herbaceous species growing together with dominating species on moderately acid soils Herbaceous species growing together with dominating species on weakly acid soils. This study indicated that, unlike the decline of heather species, the decline of herbaceous species is not likely to be due to increased competition from grass species as a result of eutrophication. Soil acidification and the changed mineral balance in the soil are most likely to be responsible for the decline of all three groups of herbaceous plant species. ei]R F Huettl 相似文献
u
20.