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1.
Aims
The uptake and tolerance of antimonite [Sb(III)] and antimonate [Sb(V)] were investigated in two populations of Achillea wilhelmsii, one from strongly Sb-enriched mine soil, the other from uncontaminated soil, in comparison with non-metallicolous Silene vulgaris and Thlaspi arvense.Methods
Tolerance was assessed from root elongation and biomass accumulation after exposure to a series of concentrations of Sb(III) or Sb(V) in hydroponics.Results
For all the species Sb(III) was more toxic than Sb(V). S. vulgaris was the most Sb(III)-tolerant species, and A. wilhelmsii the most Sb(V)-tolerant one. There were no considerable interspecific differences regarding the root and shoot Sb concentrations. Sb(III) and Sb(V) tolerance and accumulation were not different between the metallicolous and the non-metallicolous A. wilhelmsii populations. Sb(III) uptake was partly inhibited by silicon. Sb(V) uptake was strongly inhibited by chloride.Conclusions
There is uncorrelated variation among species in Sb(V) and Sb(III) tolerance, showing that plants sequester Sb(V) and Sb(III) in different ways. Sb(V) seems to be taken up via monovalent anion channels, and Sb(III) via silicon transporters, at least in part. The relatively high Sb(V) tolerance in A. wilhelmsii seems to be a species-wide property, rather than a product of local adaptation to Sb-enriched soil.2.
Background and Aims
Below-ground translocated carbon (C) released as rhizodeposits is an important driver for microbial mobilization of nitrogen (N) for plants. We investigated how a limited substrate supply due to reduced photoassimilation alters the allocation of recently assimilated C in plant and soil pools under legume and non-legume species.Methods
A non-legume (Lolium perenne) and a legume (Medicago sativa) were labelled with 15N before the plants were clipped or shaded, and labelled twice with 13CO2 thereafter. Ten days after clipping and shading, the 15N and 13C in shoots, roots, soil, dissolved organic nitrogen (DON) and carbon (DOC) and in microbial biomass, as well as the 13C in soil CO2 were analyzed.Results
After clipping, about 50 % more 13C was allocated to regrowing shoots, resulting in a lower translocation to roots compared to the unclipped control. Clipping also reduced the total soil CO2 efflux under both species and the 13C recovery of soil CO2 under L. perenne. The 15N recovery increased in the shoots of M. sativa after clipping, because storage compounds were remobilized from the roots and/or the N uptake from the soil increased. After shading, the assimilated 13C was preferentially retained in the shoots of both species. This caused a decreased 13C recovery in the roots of M. sativa. Similarly, the total soil CO2 efflux under M. sativa decreased more than 50 % after shading. The 15N recovery in plant and soil pools showed that shading has no effect on the N uptake and N remobilization for L. perenne, but, the 15N recovery increased in the shoot of M. sativa.Conclusions
The experiment showed that the dominating effect on C and N allocation after clipping is the need of C and N for shoot regrowth, whereas the dominating effect after shading is the reduced substrate supply for growth and respiration. Only slight differences could be observed between L. perenne and M. sativa in the C and N distribution after clipping or shading. 相似文献3.
Background and aim
Root system activity is affected by abiotic stresses, which often creates spatial differences in root conditions. This is expected to influence plants ability to cope with suboptimal conditions.Methods
Changes in root system activity were determined as 15N root uptake in top and bottom layers of potted tomato plants (Solanum lycopersicum L.), after waterlogging the bottom layer for 24 h or 5 d. The plants were grown in peat-based media; non-compacted or highly-compacted, resulting in differences in gas diffusion, air permeability and oxygen availability.Results
The roots were affected by short-term waterlogging (24 h) by decreasing uptake in the bottom layer and increasing uptake in the pot top layer. Long-term waterlogging (5 d) decreased the 15N root uptake more in both layers. Root uptake recovered fast (within 6 h) after short-term waterlogging, whereas recovery of long-term waterlogged roots took more than 24 h, suggesting production of new root biomass. Despite affecting physical properties, medium compaction did not affect root uptake. Aboveground biomass was affected by waterlogging by increasing the dry matter percentage, decreasing nitrogen (N) percentage and increasing starch content.Conclusions
The results confirmed that root uptake in different layers of small pots could be distinguished by the 15N technique, which was applicable under potentially denitrifying conditions. The results demonstrated that during short-term stress in part of the root system plants increased uptake from the non-affected parts of the root system, probably as compensation for suboptimal conditions. 相似文献4.
Aims
Plants with precise root foraging patterns can proliferate roots preferentially in nutrient-rich soil patches. When nutrients are distributed heterogeneously, this trait is often competitively advantageous in pot experiments but not field experiments. We hypothesized that this difference is due to belowground herbivory under field conditions.Methods
We performed pot experiments using seedlings of Lolium perenne (a more precise root foraging species) and Plantago lanceolata (a less precise root foraging species). The experiment had a two-way factorial randomized block design, with nutrient distribution pattern (homogeneous or heterogeneous) and belowground herbivore (present or absent) as the two factors. Each pot contained one seedling of each species.Results
With no herbivore present, plant biomass was smaller in the heterogeneous nutrient treatment than in the homogeneous treatment in P. lanceolata, but not in L. perenne. Under homogeneous nutrient distribution, plant biomass was lower in both species with a herbivore present than with no herbivore. Under heterogeneous nutrient distribution, biomass reduction due to herbivory occurred only in L. perenne.Conclusions
Roots of the precise root foraging species were grazed more under the heterogeneous nutrient distribution, suggesting that the herbivore more efficiently foraged for roots in nutrient-rich soil patches. 相似文献5.
Richard W. Zobel 《Plant and Soil》2013,363(1-2):113-121
Aims
Determine if the root system of Lolium perenne L. (L perenne) is a continuous distribution of diameters, or a collection of discrete diameters classes.Methods
Plants from tillers of five clones were grown in a local soil amended with lime. Roots were excavated after they were grown in soil for 54 days, washed and imaged with both a commercial scanner (94 px mm?1) and a high resolution, locally built, imager (204 px mm?1). Images were converted to diameter class length data with WinRhizo.Results
Scanned images did not have enough resolution to accurately measure fine roots diameters (<0.09 mm diam.). Therefore the high resolution images were used. The diameter class length distributions (DCLD) of these images demonstrated diameter class clusters (meso diameter classes) which could be modeled with a non-linear Gaussian (normal) curve model. Recreating the whole root system from a compilation of the DCLD, regenerated from the three parameters of each of the Gaussian curves for the root system, produced a distribution visually identical to the original whole root system curve.Conclusions
L perenne root systems are a collection of meso diameter classes easily described by non-linear Gaussian models. The data set of the parameters from these models is much smaller than a WinRhizo data set, and can reconstruct the original whole system DCLD. 相似文献6.
Effects of soil acidity and water stress on corn and soybean performance under a no-till system 总被引:1,自引:0,他引:1
Helio Antonio Wood Joris Eduardo Fávero Caires Angelo Rafael Bini Danilo Augusto Scharr Adriano Haliski 《Plant and Soil》2013,365(1-2):409-424
Background and Aims
Field studies have demonstrated that aluminum (Al) toxicity is low in no-till systems during cropping seasons that have adequate and well-distributed rainfall. This study evaluated the performance of corn (Zea mays L.) and soybean (Glycine max L. Merrill) on an acid loamy soil under a long-term no-till system, in response to surface liming and as affected by genotypic tolerance to Al and water stress.Methods
A field trial examined the effect of surface application of lime (0, 4, 8, and 12 Mg ha?1) on no-till corn and soybean nutrition and yield. Trials were also carried out in undisturbed soil columns taken from the unlimed and limed plots. Two hybrids/cultivars of corn and soybean, one sensitive and the other moderately sensitive to Al were grown at two soil moisture levels with and without water stress (50 % and 80 % water filled pore space).Results
Alleviating soil acidity by liming improved nutrition and increased grain yields of corn and soybean. The benefits of liming on root length density, nutrient uptake and shoot biomass production of corn and soybean were more pronounced in Al-sensitive genotypes under water stress.Conclusions
The results suggest that plants exposed to drought stress under no-till systems are more affected by Al toxicity. 相似文献7.
Ching-Chih Chen Frieda Beauregard Benoît Côté Nicolas Bélanger François Courchesne William H. Hendershot 《Plant and Soil》2013,373(1-2):229-242
Background and Aims
Reduced availability of calcium (Ca) has been linked to maple forest decline. We therefore aimed at assessing the contribution of the different soil horizons to leaf Ca of competing beech (Fagus grandifolia Ehrh.) and sugar maple (Acer saccharum Marsh.) to better understand the dynamics of Ca uptake.Methods
Leaf Ca was partitioned using the Ca/Sr ratio approach in two mature forests of southern Quebec. A mass balance was also used at one site to validate the results obtained with the Ca/Sr approach.Results
The L and F horizons contributed most of the leaf Ca of beech and maple with likely small contributions from the upper B and/or H/Ahe horizons. Leaf Ca/Sr ratios of beech were however more variable than those of maple. Using a mass balance, the organic horizons and upper mineral soil horizons were found to provide ca. 80 and 20 % of tree Ca uptake, respectively.Conclusion
Beech and maple Ca uptake depth apportionment is on average similar but beech is likely more plastic in sourcing soil Ca. The low contribution of the mineral soil to leaf Ca at our sites can be linked to less favorable conditions for Ca uptake likely associated with low Ca/Al ratios. 相似文献8.
Shimpei Oikawa Hitomi Ehara Mika Koyama Tadaki Hirose Kouki Hikosaka Charles P. Chen Hirofumi Nakamura Hidemitsu Sakai Takeshi Tokida Yasuhiro Usui Toshihiro Hasegawa 《Plant and Soil》2017,413(1-2):231-242
Background and Aims
The effects of Sb(V), alone or combined with Se, on the growth and root development of plants are unknown. The aim of this study is to investigate the interaction between selenite and different forms of Sb and the effects on their uptake in rice and on rice root morphology.Methods
A hydroponic experiment was conducted that contained fourteen treatments. The treatment levels for Se were 0.5 and 1 mg L?1, and the treatment levels for Sb(III) and Sb(V) were 5 and 15 mg L?1.Results
Sb(V) alone significantly reduced the surface area, mean diameter and volume of the roots, whereas Sb(III) alone reduced the values of most parameters of root morphology. The addition of 1 mg L?1 Se significantly enhanced the surface area, number of medium roots, and Sb concentration in the roots subjected to 15 mg L?1 Sb(V), but it decreased the number of root forks, the number and proportion of fine roots, and the shoot Sb concentration under exposure to 15 mg L?1 Sb(III). When the plants were subjected to 1 mg L?1 Se, the addition of 15 mg L?1 Sb(III) markedly reduced the shoot and root Se concentrations and the number of root tips, root forks, and fine roots and increased the mean root diameter. However, the addition of Sb(V) did not significantly affect the root and shoot Se concentrations but significantly decreased the number of root forks and fine roots and increased the proportion of medium roots.Conclusions
Se and Sb(III) showed antagonistic effects on uptake in the shoots, but not in the roots, of paddy rice. A range of Se concentrations could stimulate the uptake of Sb in both the shoots and roots of paddy rice exposed to Sb(V).9.
Non-destructive estimation of root mass using electrical capacitance on ten herbaceous species 总被引:1,自引:0,他引:1
Background and Aims
Characteristically baseline levels of Sb in the environment are low, but problematic local elevation trends arise from anthropogenic activities such as mining and incineration. Arsenic (analog of Sb) accumulation by rice can be reduced by iron (Fe) plaque. A hydroponic experiment was conducted to investigate whether Fe plaque could reduce the uptake and translocation of different Sb species in different rice cultivars.Methods
After Fe plaque on rice roots was induced in solution containing 0, 0.2, 0.4, 0.7, 1.2, 2.0?mM Fe2+ for 24?h, seedlings were transferred into nutrient solution with 20?μM Sb(V) or Sb(III) for 3?d.Results
About 60–80% (Sb(III) treatment) and 40–60% (Sb(V) treatment) of the total Sb accumulated in Fe plaque. There was a significant correlation between the concentrations of Sb and Fe on the root surface. A similar relationship was observed in roots and shoots. Cultivar (Jiahua 1) formed the most Fe plaque, had the highest Fe associated Sb sequestration but the lowest Sb concentration in the root interior.Conclusions
Fe plaque may act as a ‘buffer’ for Sb(V) and Sb(III) in the rhizosphere, and cultivars played an important role in the different species Sb uptake and translocation. 相似文献10.
Selenium accumulation in durum wheat and spring canola as a function of amending soils with selenite, selenate and or sulphate 总被引:3,自引:0,他引:3
Aims
A comparison was performed between plant species to determine if extractable, rather than total soil Se, is more effective at predicting plant Se accumulation over a full growing season.Methods
Durum wheat (Triticum turgidum L.) and spring canola (Brassica napus L.) were sown in potted soil amended with 0, 0.1, 1.0, or 5.0 mg kg?1 Se as SeO4 2? or SeO3 2?. In addition, SeO4 2?-amended soils were amended with 0 or 50 mg kg?1 S as SO4 2?. Soils were analyzed for extractable and total concentration of Se ([Se]). Twice during the growing season plants were harvested and tissue [Se] was determined.Results
Plants exposed to SeO3 2? accumulated the least Se. Fitted predictive models for whole plant accumulation based on extractable soil [Se] were similar to models based on total [Se] in soil (R2?=?0.73 or 0.74, respectively) and selenium speciation and soil [S] were important soil parameters to consider. As well, soil S amendments limited Se toxicity.Conclusions
Soil quality guidelines (SQGs) based on extractable Se should be considered for risk assessment, particularly when Se speciation is unknown. Predictive models to estimate plant Se uptake should include soil S, a modifier of Se accumulation. 相似文献11.
Aims
During the first days after harvest of Lolium perenne L., N remobilized from roots and stubble forms the main N source for regrowth. Low N uptake from the soil during this period may lead to N loss if N fertilizer is applied too soon. Furthermore, temporary N deprivation has been found to stimulate root growth. We therefore hypothesized that a strategic delay in N application after harvest may improve N-use efficiency of L. perenne grassland by increasing root biomass and reducing N loss.Methods
In a laboratory and field experiment with L. perenne, we delayed N fertilizer application after harvest for 0, 3, 6, 9 and 12 days, repeated this for up to six harvest cycles, and determined effects on herbage yield, herbage N uptake and root biomass.Results
In both experiments, delaying N application for up to 12 days had no significant effect on root biomass or total herbage N uptake, but it significantly reduced total herbage yield in the laboratory experiment. Total yield tended to be highest when N application was delayed for 3 days. Two growth periods in the field experiment showed significantly higher N uptake when N application was delayed, possibly due to rainfall-induced N losses in the treatments with shorter delay.Conclusions
Our results do not provide evidence that delaying N application improves N-use efficiency of L. perenne grassland by increasing root biomass. However, strategic timing of N fertilizer application based on rainfall forecasts could contribute to improve N-use efficiency by reducing N losses from leaching and denitrification.12.
K. Pirhofer-Walzl J. Eriksen J. Rasmussen H. Høgh-Jensen K. Søegaard J. Rasmussen 《Plant and Soil》2013,371(1-2):313-325
Background and aims
We carried out field experiments to investigate if an agricultural grassland mixture comprising shallow- (perennial ryegrass: Lolium perenne L.; white clover: Trifolium repens L.) and deep- (chicory: Cichorium intybus L.; Lucerne: Medicago sativa L.) rooting grassland species has greater herbage yields than a shallow-rooting two-species mixture and pure stands, if deep-rooting grassland species are superior in accessing soil 15N from 1.2 m soil depth compared with shallow-rooting plant species and vice versa, if a mixture of deep- and shallow-rooting plant species has access to greater amounts of soil 15N compared with a shallow-rooting binary mixture, and if leguminous plants affect herbage yield and soil 15N-access.Methods
15N-enriched ammonium-sulphate was placed at three different soil depths (0.4, 0.8 and 1.2 m) to determine the depth dependent soil 15N-access of pure stands, two-species and four-species grassland communities.Results
Herbage yield and soil 15N-access of the mixture including deep- and shallow-rooting grassland species were generally greater than the pure stands and the two-species mixture, except for herbage yield in pure stand lucerne. This positive plant diversity effect could not be explained by complementary soil 15N-access of the different plant species from 0.4, 0.8 and 1.2 m soil depths, even though deep-rooting chicory acquired relatively large amounts of deep soil 15N and shallow-rooting perennial ryegrass when grown in a mixture relatively large amounts of shallow soil 15N. Legumes fixed large amounts of N2, added and spared N for non-leguminous plants, which especially stimulated the growth of perennial ryegrass.Conclusions
Our study showed that increased plant diversity in agricultural grasslands can have positive effects on the environment (improved N use may lead to reduced N leaching) and agricultural production (increased herbage yield). A complementary effect between legumes and non-leguminous plants and increasing plant diversity had a greater positive impact on herbage yield compared with complementary vertical soil 15N-access. 相似文献13.
14.
David M. Deery John B. Passioura Jason R. Condon Asitha Katupitiya 《Plant and Soil》2013,368(1-2):483-492
Aims
To determine soil water diffusivity, D(θ), on undisturbed field soil at medium to low water content (suction range from 10 to 150 m of water), for the purpose of modeling the uptake of water by plant roots.Methods
The method is based on the analysis of one-step outflow induced by a turbulent stream of dry air over the exposed end of a soil core, with the other end of the core enclosed. The outflow is measured through time as the change in the weight of the core as it sits on a recording balance. D(θ) is calculated by deconvoluting the measured outflow function.Results
Over the suction range of 10 to 150 m of water, D(θ) calculated on the undisturbed soil ranged from 20?×?10?9 to 10?×?10?9 [m2?s?1], substantially higher than other published estimates over this range in suction.Conclusions
These unusually large values cast doubt on the view that flow of water to roots limits uptake of water from the targeted subsoil. 相似文献15.
Dynamics of plant metal uptake and metal changes in whole soil and soil particle fractions during repeated phytoextraction 总被引:2,自引:0,他引:2
Aims
Phytoextration of metal polluted soils using hyperaccumulators is a promising technology but requires long term successive cropping. This study investigated the dynamics of plant metal uptake and changes in soil metals over a long remediation time.Methods
A soil slightly polluted with metals (S1) was mixed with highly polluted soil (S4) to give two intermediate pollution levels (S2, S3). The four resulting soils were repeatedly phyto-extracted using nine successive crops of Cd/Zn-hyperaccumulator Sedum plumbizincicola over a period of 4 years.Results
Shoot Cd concentration decreased with harvest time in all soils but shoot Zn declined in S1 only. Similar shoot Zn concentrations were found in S2, S3 and S4 although these soils differed markedly in metal availability, and their available metals decreased during phytoextraction. A possible explanation is that plant active acquisition ability served to maintain plant metal uptake. Plant uptake resulted in the largest decrease in the acid-soluble metal fraction followed by reducible metals. Oxidisable and residual fractions were less available to plants. The coarse soil particle fractions made the major contribution to metal decline overall than the fine fractions.Conclusion
Sedum plumbizincicola maintained long term metal uptake and the coarse soil particles played the most important role in phytoextraction. 相似文献16.
Aims
This study aimed to identify amino acids that could act as chelators in enhancing absorption and translocation capabilities of a rare earth element (REE) lanthanum and yttrium in a non-hyperaccumulator plant.Methods
We analysed correlations between amino acid, La and Y concentrations in xylem saps of the REE hyperaccumulator Phytolacca americana L., to identify functional amino acids in long-distance transportation processes. These were used as chelators to observe the efficacy of La uptake and translocation in REE non-hyperaccumulator tomato seedlings. Pot culture experiments were conducted using modified Hoagland solution artificially contaminated with REEs.Results
Eighteen xylem sap amino acids were identified and measured in the xylem sap, using reversed-phase high-performance liquid chromatography. Aspartic acid, asparagine, histidine and glutamic acid may be related to xylem La and Y long-distance transportion in P. americana L. Extraneous aspartic acid, asparagine, histidine and glutamic acid enhanced La absorption in the whole tomato, compared with La alone. Moreover, the whole tomato La content increased by 449 μg and 139 μg in the presence of aspartic acid and asparagine as compared to P. americana L. Tryptophan insignificantly affected La uptake and translocation in tomato seedlings.Conclusions
Aspartic acid and asparagine could potentially promote remediation of La contamination in soil when used as a chelator. 相似文献17.
Jeffrey M. Warren Hassina Bilheux Misun Kang Sophie Voisin Chu-Lin Cheng Juske Horita Edmund Perfect 《Plant and Soil》2013,366(1-2):683-693
Background and aims
Knowledge of plant water fluxes is critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolving root water transport dynamics has been a particularly daunting task. Our objectives were to demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings using neutron imaging.Methods
Seedlings were propagated for 1–3 weeks in aluminum chambers containing sand. Pulses of water or deuterium oxide were then tracked through the root systems by collecting consecutive radiographs during exposure to a cold-neutron source. Water flux was manipulated by cycling on a growth lamp to alter foliar demand for water.Results
Neutron radiography readily illuminated root structure, root growth, and relative plant and soil water content. After irrigation there was rapid root water uptake from the newly wetted soil, followed by hydraulic redistribution of water through the root system to roots terminating in dry soil. Water flux within individual roots responded differentially to foliar illumination based on supply and demand of water within the root system.Conclusions
Sub-millimeter scale image resolution revealed timing and magnitudes of root water uptake, redistribution within the roots, and root-shoot hydraulic linkages—relationships not well characterized by other techniques. 相似文献18.
19.
Sally Nordlund Andersen Dorte Bodin Dresbøll Kristian Thorup-Kristensen 《Plant and Soil》2014,378(1-2):59-72
Aims
To investigate root competition in a legume/non-legume mixture, and how root growth of the legume is affected by the competition at increasing nitrogen (N) supply.Methods
Red beet (Beta vulgaris L.) and red clover (Trifolium pratense L.) were grown in transparent rhizotron tubes either in mixture or as sole crop at N supplies of 0, 75 or 150 kg ha-1. The root growth was evaluated by the root intensity on the rhizotron surface, root depth and plant uptake of 15N injected into the soil at the deeper part of the red clover root system.Results
Competition with red beet decreased clover root intensity in deeper soil layers compared to clover grown as sole crop. The difference between clover in sole crop and in mixture was not evident at the highest N supply because the root growth of clover in sole crop appeared to be lowered at high N level. Increased N supply increased the dominance of red beet, but generally did not alter the root growth and distribution of the two species grown in mixture.Conclusions
Clover root growth and rooting depth were inhibited by competition with red beet but the effect was not enhanced by increased N supply; hence the increased dominance of red beet at higher N level was likely due to its increased growth and competitiveness for other soil resources. 相似文献20.
Fertilizer N uptake of paddy rice in two soils with different fertility under experimental warming with elevated CO2 总被引:1,自引:0,他引:1
Hong-Shik Nam Jin-Hyeob Kwak Sang-Sun Lim Woo-Jung Choi Sun-Il Lee Dong-Suk Lee Kwang-Seung Lee Han-Yong Kim Sang-Mo Lee Miwa Matsushima 《Plant and Soil》2013,369(1-2):563-575