In vivo analysis of metal distribution and expression of metal transporters in rice seed during germination process by microarray and X-ray Fluorescence Imaging of Fe, Zn, Mn, and Cu

To investigate the flow of the metal nutrients iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) during rice seed germination, we performed microarray analysis to examine the expression of genes involved in metal transport. Many kinds of metal transporter genes were strongly expressed and their expression levels changed during rice seed germination. We found that metal transporter genes such as ZIP family has tendency to decrease in their expressions during seed germination. Furthermore, imaging of the distribution of elements (Fe, Mn, Zn, and Cu) was carried out using Synchrotron-based X-ray microfluorescence at the Super Photon ring-8 GeV (SPring-8) facility. The change in the distribution of each element in the seeds following germination was observed by in vivo monitoring. Iron, Mn, Zn, and Cu accumulated in the endosperm and embryos of rice seeds, and their distribution changed during rice seed germination. The change in the patterns of mineral localization during germination was different among the elements observed.     

The expression of heterologous Fe (III) phytosiderophore transporter HvYS1 in rice increases Fe uptake,translocation and seed loading and excludes heavy metals by selective Fe transport

Many metal transporters in plants are promiscuous, accommodating multiple divalent cations including some which are toxic to humans. Previous attempts to increase the iron (Fe) and zinc (Zn) content of rice endosperm by overexpressing different metal transporters have therefore led unintentionally to the accumulation of copper (Cu), manganese (Mn) and cadmium (Cd). Unlike other metal transporters, barley Yellow Stripe 1 (HvYS1) is specific for Fe. We investigated the mechanistic basis of this preference by constitutively expressing HvYS1 in rice under the control of the maize ubiquitin1 promoter and comparing the mobilization and loading of different metals. Plants expressing HvYS1 showed modest increases in Fe uptake, root‐to‐shoot translocation, seed accumulation and endosperm loading, but without any change in the uptake and root‐to‐shoot translocation of Zn, Mn or Cu, confirming the selective transport of Fe. The concentrations of Zn and Mn in the endosperm did not differ significantly between the wild‐type and HvYS1 lines, but the transgenic endosperm contained significantly lower concentrations of Cu. Furthermore, the transgenic lines showed a significantly reduced Cd uptake, root‐to‐shoot translocation and accumulation in the seeds. The underlying mechanism of metal uptake and translocation reflects the down‐regulation of promiscuous endogenous metal transporters revealing an internal feedback mechanism that limits seed loading with Fe. This promotes the preferential mobilization and loading of Fe, therefore displacing Cu and Cd in the seed.     

Trace metal loss following whole-tree harvest of a northeastern deciduous forest, U.S.A.

We examined changes in the biogeochemistry of trace metals following a commercial whole-tree harvest (WTH) at the Hubbard Brook Experimental Forest in New Hampshire. Within 6 months after completion of the WTH, maximum streamwater concentrations of Ni, Cd, Ba, Sr, Mn, Zn and Fe increased two- to nine-fold. Streamwater concentration of Cu remained unchanged after harvest. Streamwater pH decreased from 5.2 to 4.5 after the harvest, and correlated strongly with trace metal concentrations except for Fe. The decrease in pH apparently resulted from increased nitrogen mineralization and nitrification following harvest. All streamwater metal concentrations (except Mn and Fe) in the disturbed watershed increased prior to the decrease in streamwater pH, suggesting that the loss of readily exchangeable metals, not increased mineral dissolution, was responsible for the initial increase in streamwater trace metal concentrations. In contrast, streamwater Mn concentrations did not increase until streamwater pH dropped to 4.5, due in part to increased mineral dissolution. Although pH related strongly to trace metal concentrations in the harvested watershed, it did not account for much of the variation in metal concentrations in the reference (W6) watershed. Annual flux of trace metals increased two- to eight-fold following WTH. Annual losses of Mn and Sr were 14% and 12%respectively of the forest floor pool for each element, and less than 10% of forest floor pools for all other elements. Except for Cd and Cu, annual trace metal losses in streamwater exceeded annual inputs in bulk precipitation.Deceased     

Adverse health effects in workers exposed to trace/toxic metals at workplace

Widespread use of metals in industrial activities has enhanced the occupational exposure to toxic metals as well as the health risks of metal hazards to humans. Elemental analysis in human tissues is the most common application of biological monitoring for screening, diagnosis and assessment of such exposures and risk. Among various biopsy materials, blood, hair, nail, teeth and body fluids may be used as bioindicators for this purpose. The present paper deals with the determination of Pb, Cr, Ni, Mn, Fe, Cu and Zn elemental concentration in workers exposed to these metals at workplace by atomic absorption spectrophotometry, with adequate quality control measures using hair as biopsy material. The study group includes the male workers such as welders, foundry man, fitter, hammer man, machine man, cupola man etc., besides office workers of locomotive workshop in Ajmer and surrounding areas exposed to different metals. Age and sex matched controls of persons working in the same area of work in offices etc. and not exposed to metal pollution were selected for valid comparison. It is proposed to validate the use of hair as a biological marker for assessing metal body burden of workers. In our study significant correlations have been found between skin disease and Cr, Mn, Fe, Cu; chest pain and Pb; hypertension and Cu, Mn; mental stress and Mn, Ni, Cu, Zn; liver problem and Ni; indigestion and Cr; Ni, diabetes and Cr, Mn, Ni; tuberculosis and Zn; breathing trouble and Cr, Mn, Fe, Ni, Zn. The advantages of choosing hair as a biopsy material are also given.     

Distribution of manganese and other biometals in <Emphasis Type="Italic">flatiron</Emphasis> mice

Flatiron (ffe) mice display features of “ferroportin disease” or Type IV hereditary hemochromatosis. While it is known that both Fe and Mn metabolism are impaired in flatiron mice, the effects of ferroportin (Fpn) deficiency on physiological distribution of these and other biometals is unknown. We hypothesized that Fe, Mn, Zn and/or Cu distribution would be altered in ffe/+ compared to wild-type (+/+) mice. ICP-MS analysis showed that Mn, Zn and Cu levels were significantly reduced in femurs from ffe/+ mice. Bone deposits reflect metal accumulation, therefore these data indicate that Mn, Zn and Cu metabolism are affected by Fpn deficiency. The observations that muscle Cu, lung Mn, and kidney Cu and Zn levels were reduced in ffe/+ mice support the idea that metal metabolism is impaired. While all four biometals appeared to accumulate in brains of flatiron mice, significant gender effects were observed for Mn and Zn levels in male ffe/+ mice. Metals were higher in olfactory bulbs of ffe/+ mice regardless of gender. To further study brain metal distribution, ⁵⁴MnCl₂ was administered by intravenous injection and total brain ⁵⁴Mn was measured over time. At 72 h, ⁵⁴Mn was significantly greater in brains of ffe/+ mice compared to +/+ mice while blood ⁵⁴Mn was cleared to the same levels by 24 h. Taken together, these results indicate that Fpn deficiency decreases Mn trafficking out of the brain, alters body Fe, Mn, Zn and Cu levels, and promotes metal accumulation in olfactory bulbs.     

Overexpression of METAL TOLERANCE PROTEIN8 reveals new aspects of metal transport in Arabidopsis thaliana seeds

• METAL TOLERANCE PROTEIN8 (MTP8) of Arabidopsis thaliana is a member of the CATION DIFFUSION FACILITATOR (CDF) family of proteins that transports primarily manganese (Mn), but also iron (Fe). MTP8 mediates Mn allocation to specific cell types in the developing embryo, and Fe re-allocation as well as Mn tolerance during imbibition. We analysed if an overexpression of MTP8 driven by the CaMV 35S promoter has an effect on Mn tolerance during imbibition and on Mn and Fe storage in seeds, which would render it a biofortification target.
• Fe, Mn and Zn concentrations in MTP8-overexpressing lines in wild type and vit1-1 backgrounds were analysed by ICP-MS. Distribution of metals in intact seeds was determined by synchrotron µXRF tomography.
• MTP8 overexpression led to a strongly increased Mn tolerance of seeds during imbibition, supporting its effectiveness in loading excess Mn into the vacuole. In mature seeds, MTP8 overexpression did not cause a consistent increase in Mn and Fe accumulation, and it did not change the allocation pattern of these metals. Zn concentrations were consistently increased in bulk samples.
• The results demonstrate that Mn and Fe allocation is not determined primarily by the MTP8 expression pattern, suggesting either a cell type-specific provision of metals for vacuolar sequestration by upstream transport processes, or the determination of MTP8 activity by post-translational regulation.

     

Soybean genotypic difference in growth, nutrient accumulation and ultrastructure in response to manganese and iron supply in solution culture

* BACKGROUND AND AIMS: The objective of this research was to characterize the physiology and cell ultrastructure of two soybean genotypes subjected to nutrient solutions with increasing concentrations of manganese (Mn) at two contrasting iron (Fe) concentrations. Genotypes 'PI227557' and 'Biloxi' were selected based on their distinctly different capacities to accumulate Mn and Fe. * METHODS: Bradyrhizobium-inoculated plants were grown in hydroponic cultures in a greenhouse. Nutrient solutions were supplied with Mn concentrations ranging from 0.3 to 90 microm, at either 5 or 150 microm Fe as FeEDTA. * KEY RESULTS: For both genotypes and at both Fe concentrations, Mn concentrations from 6.6 to 50 microm did not affect shoot, root and nodule mass, or leaf and nodule ureide concentration. Mn concentrations of 70 and 90 microm did not result in visible toxicity symptoms, but hindered growth and nodulation of 'Biloxi'. An Mn concentration of 0.3 microm was, however, deleterious to growth and nodulation for both genotypes, and caused an accumulation of ureides in leaves and major alterations in the ultrastructure of chloroplasts, nuclei and mitochondria, regardless of the Fe concentration. In 'PI227557', there was also a proliferation of Golgi apparatus and endoplasmic reticulum in the cytoplasm of leaf cells, and nodules showed disrupted symbiosomes lacking poly-beta-hydroxybutirate grains concomitantly with a proliferation of endoplasmic reticulum as well as arrested bacterial division. At 15 microm Fe, ferritin-like crystals were formed in the lumen of chloroplasts of 'PI227557' plants. For both genotypes, there was an antagonism between the Fe and Mn concentrations in leaves, the higher values of both microelements being detected in 'PI227557'. The absence of any detectable relationship between Fe or Mn and zinc, phosphorus and copper concentrations in leaves ruled out those micronutrients as relevant for Mn and Fe nutrition in soybeans. * CONCLUSIONS: The results confirmed the greater capacity of 'PI227557' for Mn and Fe accumulation than 'Biloxi' for most nutrient treatments. Hence, 'PI227557' may be a very useful genetic resource both in developing soybean cultivars for growth on low nutrient soils and in physiological studies to understand differing approaches to nutrient accumulation in plants.     

Quantitative trait loci affecting seed mineral concentrations in Brassica napus grown with contrasting phosphorus supplies

MethodsA population of 124 recombinant inbred lines derived from a cross between P-inefficient ‘B104-2’ and P-efficient ‘Eyou Changjia’ was used for phenotypic investigation and QTL analysis. Two-year field trials were conducted with two P treatments. Concentrations of mineral elements (P, Ca, Mg, Fe, Zn, Cu and Mn) in seeds were determined and QTLs were identified by composite interval mapping.ConclusionsThe accumulation of mineral elements in seeds is controlled by multiple genes. Common physiological and molecular mechanisms could be involved in the accumulation of several mineral elements, and genes involved in these processes in B. napus are suggested. These results offer insights to the genetic basis of seed mineral accumulation across different P levels in B. napus.     

Regulation of Mineral Redistribution in Pod-Bearing Soybean Explants

On the way from the roots to the seeds during reproductive developmentin soybean (Glycine max), a large proportion of the mineralspass through the leaves rather than travelling directly viathe xylem. This direct and indirect movement of mineral nutrientshas important implications for mineral redistribution, seeddevelopment and leaf senescence. Therefore, we have studiedthe role of cytokinin and mineral flux from the roots in regulatingmineral redistribution from the leaves to the seeds using explants,i.e. a leaf, a pod and a subtending stem segment, with theirbases immersed in treatment solutions. Thus, defined solutionscontaining cytokinin and/or minerals can be substituted forthe roots. When explants (excised at early-mid podfill) aresupplied H₂O only, leaf N, P, K, Mo, Mg, Zn, Fe, B, Cu, Ca,and Mn decline, ranging from 93% for Mo to 38% for Fe. In explantson H₂O, N, P, K, Mo, Mg, Zn, and Fe appear to be redistributedfrom the leaves to the seeds, while the B, Cu, Ca, and Mn lostfrom the leaves do not seem to move to the seeds. Although amixture of minerals resembling xylem sap can delay net lossof these elements from the leaves, it does not prevent the decreases.The cytokinin zeatin (4.6 µM) inhibits the loss of N,IC, Mo, Mg, Zn, Fe, B, Cu, Ca, and Mn from the leaves, but notthat of P. When combined with minerals, zeatin not only preventsthe loss of the minerals from the leaves but may even greatlyincrease them with the possible exception of Zn, Fe, and Cu.Supplying the mineral nutrient mixture increases the quantitiesof N, P, K, Mg, Cu, and B in the seeds but not Zn, Fe, Mn, Ca,and Mo. For those minerals, especially N, where zeatin inhibitsefflux from the leaves, it may reduce the amounts in the seeds,but it does not change P, K, Mg, and Ca. The accumulation andredistribution patterns of the different mineral nutrients showmany dissimilarities thereby suggesting differences in the controlof their distribution. Key words: Cytokinin, mineral transport, seed development, senescence     

Trace metal biomonitoring in the soil and the leaves ofQuercus ilex in the urban area of Naples

The concentrations of Pb, Cu, Fe, and Mn were analyzed in surface deposit and tissue ofQuercus ilex leaves from several sites of the urban area of Naples, exposed to different degrees of air pollution. These included some major roads with heavy traffic loads, squares, and three urban parks. The soil from the trunk base area ofQ. ilex trees in the same sites was also analyzed for total and available metal contents. Pb, Cu, and Fe contents in the surface deposit and leaf tissue were significantly higher (p<0.01) in leaves from roadside sites than in leaves from parks; significant correlations were found between deposit- and tissue-contents of Pb, Cu, and Fe. Mn content in leaves from roadside sites and in leaves from parks were similar and Mn content in the leaf deposit was irrelevant. Significant differences (p<0.001) in both total and available Pb and Cu soil content were found between sampling sites. Also for available Fe and Mn soil content differences among sites were relevant, although the highest values were measured in soil from urban parks. A positive correlation between leaf and soil metal content was found only for Pb, thus suggesting that trace metal contents of leaves directly depend on atmospheric depositions. Seasonal variations of Pb, Cu, and Fe were pronounced at a polluted site, whereas no relevant seasonal variation was observed at a control site; moreover, metal accumulation was high at the polluted site. Mn content and seasonal dynamics were comparable at control and polluted sites.     

Periodic changes in metal content in Fucus distichus thalli under polar day conditions

Variation of Mn, Fe, Ni, Cu and Zn contents in thalli of Fucus distichus was determined under conditions of polar days. The use of spectrum analysis allowed estimates comparisons of the interrelation of periodic changes in irradiance, temperature and tidal fluctuations and quasiperiodic changes in metal contents. The effect of the diel rhythm of irradiance correlated with the accumulation of all metals except for Zn. At the same time, the changes in Mn, Fe and Cu content were delayed in respect to changes in irradiance level. The phase shift for Fe was 1 h 56 min, for Cu – 3 h 41 min and for Mn – 5 h5 min. The change in Ni content, in contrast, was 11min ahead of the change in irradiance. During the experiment an increase in water temperature up to10 °C resulted in increases in the average Mn, Ni and Cu contents in the thalli and decreases in Fe and Zn concents. The periodicity of metal thallus content did not always correspond to a diurnal rhythm, and couldbe longer (Mn, Ni: 32 h; Fe: 36 h) or shorter (Mn, Ni, Zn: 16 h; Cu: 12 h; Zn: 20, 10 h). The ANOVA of these rhythms allows an estimate of the contribution of rising and falling tidal fluctuations to the changes in Cu, Mn and Ni contents. There was a higher metal content during a falling than a rising tide. Abbreviations SDLT – semidiurnal lunartide, CDLT – closed diurnal lunar tide. This revised version was published online in August 2006 with corrections to the Cover Date.     

Sorption and distribution of copper in unsaturated Pseudomonas putida CZ1 biofilms as determined by X-ray fluorescence microscopy

The spatial and temporal distribution of metals in unsaturated Pseudomonas putida CZ1 biofilms was determined using synchrotron-based X-ray fluorescence microscopy (XRF). It was found that Fe, Mn, and Ca were mainly distributed near the air-biofilm interface of a biofilm grown on 40 mM citrate, while there were two Fe-, Mn-, and Ca-rich layers within a biofilm grown on 10 mM citrate. The sorption of copper by biofilm grown in medium containing 10 mM citrate was rapid, with copper being found throughout the biofilm after only 1 h of exposure. Copper initially colocalized with Fe and Mn element layers in the biofilm and then precipitated in a 40-μm-thick layer near the air-biofilm interface when exposed for 12 h. Cu K-edge X-ray absorption near edge structure (XANES) analysis revealed that Cu was primarily bound with citrate within the biofilm, and the precipitate formed in the biofilm exposed to copper for 12 h was most similar to copper phosphate. LIVE/DEAD staining revealed that cells at the biofilm-membrane interface were mostly alive even when the copper concentration reached 80.5 mg copper g(-1) biomass. This suggests that the biofilm matrix provided significant protection for cells in this area. These results significantly improve our understanding of metal acquisition, transportation, and immobilization in unsaturated biofilm systems.     

Changes in elemental content in fronds of Azolla filiculoides due to arsenic accumulation

This study analyzed the accumulation of arsenic and its influence on the content of P, Mn, Fe, Cu, Zn, S, Ca, Cl, and K in fronds of Azolla filiculoides via X-ray fluorescence (XRF). Azolla was exposed to increased concentrations of sodium arsenate (0, 5, 10, 20, and 30 μg ml ^? 1) in Yoshida's nutrient solution. After 96 h, fronds were collected and taken to constant weight to calculate the relative growth rate (RGR), the biomass duplication rate, the bioaccumulation factor (BAF), and the elemental concentration via XRF analysis. By increasing As concentrations the RGR and BAF were reduced. The greatest accumulation of As in fronds was achieved at 20 μg As ml ^? 1, which did not show significant differences with the highest concentration. Accumulation of As in fronds diminished concentrations of Mn, Fe, Zn, S, Ca, and K, while the concentration of P remained low but unchanging. The P content was significantly lower than the As content, thus the As:P ratio in fronds enhanced as the As concentration increased. Concentrations of Cl and Cu were unaffected due to As. This is one of the first reports about the influence of As-accumulation on the elemental content in Azolla fronds.     

Trace metal content in the seagrass Cymodocea nodosa: Differential accumulation in plant organs

Differences in the accumulation of seven metallic elements, including micronutrients (Cu, Fe, Mn, Ni and Zn) and non-essential elements (Cd and Pb) among plant organs (leaves, roots and rhizomes) were examined in the seagrass Cymodocea nodosa. Samples were taken from two coastal bays (Catalonia, Western Mediterranean), with a total of nine sampling sites encompassing different levels of metal availability. Metal content was generally higher in uptake organs (leaves and roots) than in rhizomes. However, accumulation in leaves and roots varied between elements. While Cd, Mn and Zn preferentially accumulate in leaves, Fe and Pb accumulate in roots and Cu and Ni in both. There were common spatial (between sites) trends in Cd, Mn, Cu and Zn accumulation in the three organs. However, these spatial trends varied according to the organ considered in the case of Fe, Pb, and Ni. Therefore, assessment of within-plant variability is strongly recommended prior to the use of C. nodosa for biomonitoring purposes, at least for Fe, Pb, and Ni.     

Particle size and metal distributions in anaerobically digested pig slurry

Particle size distribution and trace element patterns were studied in a full-scale anaerobic digestion plant treating pig slurry. Mass balance was established for major (N, P, K, Ca, Fe, Mg and S) and minor (Al, Cu, Mn and Zn) elements. Most of the elements were conserved through the process but part of the P, Ca, Mg and Mn was deposited as crystals lining the digester. In the dry matter of the slurry, Cu and Zn occurred at between 170 and 2600 mg kg(-1) due to pig diet supplements. Analyses of particle size distributions in raw and digested slurries showed a general shift in distribution towards larger sizes due to degradation of small and easily degradable particles as well as formation of large microbial filaments. Graded sieving of digested slurry showed metals to be mainly present on 3-25 microm particles. Less than 2% Cu and Zn was removed by passage through a 250 microm rotary screen.     

Size dependent metal concentrations in two marine gastropod species

The effect of size on the accumulation of Cd, Cr, Cu, Mn, Ni, Fe and Zn in the muscle and viscera of the gastropodsMonodonta turbinata andCerithium vulgatum was investigated. The concentration of the essential metals Cr, Mn and Ni and the non-essential metal Cd decreased with increasing size in both of the species and tissues. The concentration of the essential metals Cu, Fe and Zn, showed a less constant relation with size.     

Plant Cd2+ and Zn2+ status effects on root and shoot heavy metal accumulation in Thlaspi caerulescens

* In this study we address the impact of changes in plant heavy metal, (i.e. zinc (Zn) and cadmium (Cd)) status on metal accumulation in the Zn/Cd hyperaccumulator, Thlaspi caerulescens. * Thlaspi caerulescens plants were grown hydroponically on both high and low Zn and Cd regimes and whole-shoot and -root metal accumulation, and root (109)Cd(2+) influx were determined. * High-Zn-grown (500 microm Zn) plants were found to be more Cd-tolerant than plants grown in standard Zn conditions (1 microm Zn). Furthermore, shoot Cd accumulation was significantly greater in the high-Zn-grown plants. A positive correlation was also found between shoot Zn accumulation and increased plant Cd status. Radiotracer (109)Cd root flux experiments demonstrated that high-Zn-grown plants maintained significantly higher root Cd(2+) influx than plants grown on 1 microm Zn. It was also found that both nickel (Ni) and copper (Cu) shoot accumulation were stimulated by high plant Zn status, while manganese (Mn) accumulation was not affected. * A speculative model is presented to explain these findings, suggesting that xylem loading may be one of the key sites responsible for the hyperaccumulation of Zn and Cd accumulation in Thlaspi caerulescens.     

Accumulation and Distribution of Nutrients in Fruits of Castor Bean (Ricinus communis L.)

The nutrition of developing fruits of Ricinus communis was studiednear Perth, Western Australia, where the species grows as aweed on poor sandy soil. Fruits required 60 days to mature anddehydration of the capsule began 20 days before the seeds ripened.Mature seeds accumulated 49 per cent of the fruit dry matterand over 80 per cent of its P, Zn and Cu, 50–80 per centof its Mg, N, Fe and Mn, 41–46 per cent of its S and Caand 11–21 per cent of its K and Na. Losses of nutrientsfrom capsules during fruit ripening were: Zn, 73 per cent, P,42 per cent, Cu, 23 per cent and Mn, 8 per cent. Dry matter,N, K, S, Ca, Mg, Na and Fe were not withdrawn from capsules.Apparent retranslocation from capsules could have provided from6–28 per cent of the Zn, Mn, P and Cu in mature seeds.Seeds from plants on poor sandy soil were small but had adequatelevels of nutrients when compared with those from plants growingon a fertile loam. Concentrations of all nutrients except P were higher in youngcapsules than in young seeds, but levels of N, P, Mg, Fe, Znand Cu were higher in mature seeds than in mature capsules.The intake of most nutrients by fruits was out of phase withdry matter accumulation, especially in capsules, and the elementsappeared to accumulate in fruit parts independently of eachother. Glutamine accounted for over 85 per cent of the amino-Nin phloem sap destined for fruits. Potassium made up over 90per cent of the inorganic cations in phloem exudate. Of theminor elements in the exudate, Fe was present at highest concentrationand Cu at the lowest. The results showed that retranslocation from the capsule madea very small contribution to the nutrition of seeds. It is suggestedthat R. communis would require a sustained supply of soil nutrientsto ensure maximum seed yield, partly due to the restricted retranslocationof most nutrients from capsules. Ricinus communis L., castor bean, mineral nutrition, translocation, retranslocation     

镉胁迫下草莓幼龄期叶、根矿质元素积累和分布的变化

采用水培实验,研究重金属镉对草莓幼龄期叶、根矿质元素含量和分布的影响。结果表明,高量镉降低草莓根中K、Ca、Mg、P、Cu、Zn、Mn、Fe的积累,叶片相应元素以及B、Mo含量也随镉浓度增大而呈降低趋势;但镉浓度较低时,K、Mg、P、Zn在叶、根中的含量均增加,而后才随镉处理浓度提高而降低。在镉胁迫下,同一元素在草莓叶、根之间的分布也受到影响,而且某些矿质元素含量间有显著相关性。     

Mobilisation of iron and manganese by plant-borne and synthetic metal chelators

Phytosiderophores released by roots of iron-deficient grasses mobilise Fe, Zn, Mn and Cu in calcareous soils. Mobilisation of Fe, Zn and Cu can be explained as the chelation of these metal cations by phytosiderophores. Mobilisation of Mn could not be so explained because phytosiderophores have a much smaller affinity for Mn than for Fe, Cu and Zn. Model experiments have been made with freshly precipitated Fe(OH)₃ and different soils to study the mobilisation of iron and manganese by plant-borne chelating phytosiderophores, the synthetic metal chelators DTPA and the microbial metal chelator sulphonated ferrioxamine B (FOB). Compared with the synthetic chelator DTPA, the plant-borne chelating phytosiderophores mobilised Fe very efficiently, but no change was observed in the Mn mobilisation by phytosiderophores.Different phytosiderophores, as well as the microbial metal chelator FOB, were used to compare the mobilisation of iron and manganese in a calcareous soil.