Investigation of Trace Element Content in the Seeds,Pulp, and Peel of Mashui Oranges Using Microwave Digestion and ICP-MS Analysis

Fresh Mashui orange samples were pretreated with microwave digestion using an HNO₃-H₂O₂ system. The levels of Mg, K, Ca, Fe, Mn, Cu, Zn, As, Cd, and Pb in the seeds, pulp, and peel were then determined using inductively coupled plasma mass spectrometry (ICP-MS) combined with collision cell technology (CCT) and kinetic energy discrimination (KED). The standard curve coefficient of determinations of the ten tested elements were between 0.9995 and 0.9999. The instrument detection limit was between 0.112 ng/L and 3.05 ng/mL. The method detection limit was between 0.0281 and 763 ng/g. The average recovery rate was between 85.0 and 117%. The current results showed that Mashui oranges are rich in three elements, namely Mg, K, and Ca. The concentrations of K and Ca were significantly higher than that of Mg in the peel. The content of K was the highest in the seeds. Fe, Mn, Cu, and Zn had the second highest concentrations, and Fe was the highest in the seeds, while Cu was the lowest in the peel. As, Cd, and Pb (hazardous elements) had the lowest concentrations of all the tested elements.     

Mineral Elements in Root of Wild Saposhnikovia divaricata and Its Rhizosphere Soil

Mineral elements are important components of medicinal herbs, and their concentrations are affected by many factors. In this study, Ca, Mg, Na, K, Fe, Mn, Cu, and Zn concentrations in wild Saposhnikovia divaricata and its rhizosphere soil collected from seven locations at two different times in China were measured, and influences of rhizosphere soil on those minerals in plant were evaluated. The results showed that mean concentrations of eight minerals in plant samples decreased in the order: Ca > Mg > Na > K > Fe > Zn > Mn > Cu, and those in the soil samples followed the following order: Na > Fe > Ca > K > Mg > Mn > Zn > Cu. Mean concentrations of Ca, Na, Mg, and K in plants were higher than those in soils, while higher mean concentrations of the other four minerals were found in soils. It was found that there was a positive correlation of Mg, Na, and Cu concentrations in the plant with those in the soil respectively, but a negative correlation of Mn concentration in plant with that in the soil. Except Ca, K, and Mn, the other five minerals in plant were all directly affected by one or more chemical compositions of soil. The results also indicate that pH value and concentrations of total nitrogen, Mg, Mn, and Cu in soil had significant correlations with multimineral elements in plant. In a word, mineral elements uptake of S. divaricata can be changed by adjusting the soil fertility levels to meet the need of appropriate quality control of S. divaricata.     

Concentration Levels of Selected Metals in the Leaves of Different Species of Thyme (T. schimperi and T. vulgaris) Grown in Ethiopia

The contents of some selected metals Ca, Mg, Fe, Mn, Co, Cu, Zn, Ni, and Cd in different thyme leaf samples widely consumed in Ethiopia were determined by flame atomic absorption spectroscopy (FAAS) after acid digestion with 1:1 HNO₃/HClO₄ for 3 h at a temperature of 240°C by a Kjeldahl apparatus hot plate digester. The level of the nutrients in the four samples ranged from 1,239–2,517 μg/g, Ca; 1,524–1,786 μg/g, Mg; 728–2,517 μg/g, Fe; 37.7–114 μg/g, Mn; 2.59–4.3 μg/g, Co; 7.69–9.3 μg/g, Cu; 8.7–52 μg/g, Zn; and 9.83–14.2 μg/g, Ni; respectively. While the level of toxic metal Cd in the four samples ranged from 0.87–1.3 μg/g. The concentration of Ca was higher than the other metals in the three samples and Cd was the least of all the metals in the analyzed samples. The overall reproducibility of the method obtained from spiking experiment was within the range ±10%. This result will complement available data on food composition in Ethiopia.     

Concentration of essential and non-essential elements and carcinogenic / non-carcinogenic health risk assessment of commercial bee pollens from Turkey

BackgroundBee pollen, known as a natural super-food with valuable nutritional ingredients, is regarded as a good indicator of ecotoxic substances, such as potentially toxic elements (PTEs). Therefore, this study aims to examine the concentrations of selected PTEs (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Se, Sn, Sr, V, Zn) in bee pollen purchased from online markets in Turkey and perform a health risk assessment to identify the potential risk to consumers.MethodsThe quantitative analyses were conducted by inductively coupled plasma optical emission spectrometry (ICP-OES).ResultsThe mean values of essential PTEs in decreasing content order were Mg > Fe > Zn > Mn > Cu > Ni > Se > Cr > Mo >Co = V. Regarding the results of the study, daily consumption (40 g for adult or 20 g for children) of commercial bee pollen can recompense 20–35 % of daily Cu, Mn, Se requirements for children, adults, pregnant, and breastfeeding women. The decreasing content order of non-essential elements was Al > Sn > Sr > Ba > Pb > As. Cadmium and Hg concentrations were below the detection limits in all the samples. In terms of food and public health; detection of the PTEs concentrations is necessary to assess the quality and safety of bee pollen before consumption. According to the carcinogenic and non-carcinogenic risk assessments; commercial pollen consumption does not pose a health risk to either children or adults for the PTEs monitored in this study.ConclusionWe conclude that bee pollen is an ideal indicator for the monitoring of environmental pollution of PTEs and also a valuable source of essential elements. This study highlights the need to develop standards that regulate acceptable concentrations of PTEs.     

Multielement determination in small samples of human milk by inductively coupled plasma atomic emission spectrometry

Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used for routine analysis of small samples of human milk. The concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), phosphorus (P), and zinc (Zn) were determined in 203 milk samples from postpartum women at different stages of lactation after stepwise digestion in HNO₃, HCIO₄, and H₂O₂ under heat. Validation of the procedure was achieved using certified reference material of bovine liver (NBS 1577) with mean recoveries of 103.5%. The concentrations of the above elements in milk matrix were comparable with previously reported values. The analytical results from breast milk will provide reference information for mineral studies of Brazilian mothers and breast-fed infants.     

微波消解-FAAS法测定普通甘薯和紫甘薯中的金属元素

采用微波消解法处理普通甘薯和紫甘薯样品,运用火焰原子吸收光谱法测定其中的K、Ca、Mg、Fe、Mn、Zn、Cu 7种对人体有益的金属元素含量。结果表明,普通甘薯和紫甘薯中K、Ca、Fe、Mg元素含量较高,Mn、Zn、Cu元素含量较低,且7种金属元素含量在两者之间存在一定的差异,各元素在紫甘薯中的含量均比普通甘薯中含量高。方法的加标回收率介于98.5%～103.2%,相对标准偏差(RSD)不大于3.14%。可为普通甘薯与紫甘薯的品质评价提供理论参考。     

微波消解-FAAS法分析并比较旱芹(Apium graveolens L.)不同部位八种金属元素的含量

采用微波消解法处理旱芹根、茎、叶,并用火焰原子吸收法测定其中的Na、K、Ca、Mg、Fe、Mn、Zn、Cu 8种金属元素的含量。结果表明:旱芹中富含人体必需的Na、K、Mg、Fe、Ca等元素,各元素在不同部位含量有一定差异。Fe元素在旱芹根中含量为883.57μg.g-1,明显高于茎和叶;Ca、Zn和Mn元素在旱芹叶中的含量分别为11 103.74,214.04,88.07μg.g-1,明显高于茎和根;K、Na和Mg元素在旱芹茎中的含量高于根和叶中,Cu元素含量在各部位差异不大。方法的加标回收率为96.8%～105.8%,相对标准偏差(RSD)≤3.36%。     

Characterization and human health risk assessment of trace metal in PM10 in Bac Giang,short-term study in a developing province in Vietnam

Abstract

This study investigated the airborne concentration of PM₁₀ and 20 trace elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Na, Pb, Ti, V, Zn) in residential, industry, traffic road, coal mining, thermal power plant area of Bac Giang province. The average PM₁₀ concentration was highest at coal site, followed by traffic 1 sites, industrial sites and traffic 2 sites, the residential sites, and lowest at the power plant site located in mountain area. While Al, Ca, Fe, K, Mg, Na were the most abundant elements in all sampling sites, accounting for 73–96% of total obtained elements, the concentration of As, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn occupied from 2.9 to 23.2%. Noticeably, the concentrations of Cd were from 7 to 65 times higher than the concentration limit for Cd (0.1?ng/m³) according the World Health Organization (WHO). Although, the Hazard Index (HI values) of all metals were found to be within the safe level for both children and adults, the Carcinogenic Risk (CR) of Cr and As in all sites were closed to the acceptable levels for children, implying a potential carcinogenic risks of these metals.     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

人工饲养与野生川金丝猴体毛10种微量元素的含量及比较

测定了秦岭人工饲养(10只)和野生(14只)川金丝猴体毛中的10种微量元素含量。锌、铁、铜、钙、镁5种元素采用火焰原子吸收法;锰、铬、铅采用石墨炉原子吸收法;铝采用等离子光谱;硒经硝解后采用原子吸收法测定。结果表明,铬、锰、镁、铅、锌和硒的含量,人工猴极显著或显著高于野生猴;铁含量,人工猴极显著低于野生猴;钙、铜和铝的含量,人工猴与野生猴无显著差异。以人类毛发10种微量元素的正常范围为参照,人工猴铅、铬、锰与锌4种含量均显著超出正常范围的上限,属于严重超量。这可能与金丝猴饲养过程中添加营养制剂有关。     

Bioaccessibility and safety assessment of trace elements from decoction of “Zhebawei” herbal medicines by in vitro digestion method

Studies on in vitro bioaccessibility and safety assessment of 6 elements namely Fe, Zn, Cu, Mn, As and Cd in decoction of eight commonly consumed “Zhebawei” herbal medicines were carried out. The method was based on simulation of human digestion in the gastrointestinal tract. Total content and content in extracts from gastrointestinal phases were analyzed for these elements by inductively coupled plasma atomic emission spectrometer (ICP-AES). In decoction of all 8 herbal medicines, it was found that the total content and bioaccessible concentration of these elements varied considerably among the types of herb, and the total content of each element did not show linearity with their bioaccessible content of the corresponding element. There is no risk of adverse health effects resulting from overdose of Fe, Zn, Cu, and Mn for almost all individuals by ingesting recommended maximum daily dose of these eight herbal medicines. In terms of Cd only Ophitopogin japonicum had higher total concentration and bioaccessible content than the value of suggested limit (5.4 μg/d). For total As content, only Scrophularia ningpoensis and Corydalis yanhusuo did not meet the safety standard. However, regarding bioaccessible As contents, none of the eight herbal medicines exceeded the value of the daily permissible intake of As (0.12 mg). The risk of toxicity from an element in herbal medicine might be overestimated when the total concentration but not the bioaccessible content is taken into account. In vitro digestion method is rapid, relatively simple and inexpensive, which could be helpful in conducting experiments about safety assessment of an element in herbal medicines.     

茎瘤芥不同生长期植株营养特性及其与产量的关系

在涪陵区选取30个茎瘤芥种植农户,采用大田调查和室内化学分析方法,研究了茎瘤芥不同生长期（苗期、快速膨大期、采收期）叶片和茎瘤10种必需营养元素含量的变化特征及其与产量的关系。结果表明：茎瘤芥在整个生育期内,除K、S含量较高外,其余大、微量元素均在大多植物含量范围内;不同生育期茎瘤芥叶片、茎瘤中各养分含量变化具有明显的规律性,苗期叶片大量元素含量次序为N>K>Ca>P>S>Mg,快速膨大期和采收期叶片大量元素含量次序均为N>K>Ca>S>P>Mg,茎瘤中大量元素含量次序均为K>N>P>S>Ca>Mg,3个生长期叶片和茎瘤的微量元素含量,除快速膨大期茎瘤中略有不同（Fe>Zn>Mn>Cu）外,其余均为Fe>Mn>Zn>Cu;从苗期到快速膨大期再到采收期养分变化规律看,叶片中N、P、K、Fe、Cu和Zn含量呈降低趋势,而Ca、Mg、S和Mn则呈现先降低后升高的趋势,从快速膨大期到采收期茎瘤中除N、S、Fe和Cu元素呈降低趋势外,其余养分元素均呈上升趋势。从茎瘤芥不同器官养分含量高低看,快速膨大期和采收期叶片中N、P、K、Cu和Zn含量较茎瘤中低,而Ca、Fe和Mn含量的变化特点则相反,S和Mg差异较小,表明茎瘤芥不同部位对不同养分的敏感程度各异。相关分析表明,各生育期不同器官的Mg、Fe、Mn和Zn与产量呈显著或极显著的负相关关系,K、Cu与产量呈正的相关关系。通过逐步回归分析建立茎瘤芥各生育期植株营养元素与产量的回归预测模型,其中苗期叶片营养元素与产量的最优回归方程为Y= 36768 3583XK-6.328XFe-76.09XMn;快速膨大期叶片和茎瘤营养元素与产量的最优回归方程分别为Y=50458 21557XP 7925XCa-88092XMg-1145XCu和Y=32487 7294XK-116122XMg;采收期叶片和茎瘤营养元素与产量的最优回归方程分别为Y=36064 3413XK-30.15XFe和Y= 11791 7334XK-385XZn。因此,在茎瘤芥各生长期均应注意钾肥的合理施用,快速膨大期应重视磷肥的施用。而几种微量元素和镁素对茎瘤芥产量的负效应,则可通过增施充分腐熟的有机肥料加以调控。     

Effect of magnesium deficiency on enterocyte Ca, Fe, Cu, Zn, Mn and Se content

In previous studies based on indirect procedures, we reported that Mg deficit increased the bioavailability of a number of elements such as calcium, zinc, iron, copper, manganese and decreased selenium absorption. The present study was designed to verify these findings by direct methods. We investigated the effect of dietary magnesium deficiency on enterocyte Ca, Fe, Zn, Cu, Mn and Se concentrations. Male Wistar rats were fed a Mg-deficient diet (129 mg Mg/kg food) for 70 days. Whole enterocytes from the upper jejunum were isolated and Ca, Fe, Zn, Cu, Mn and Se were determined. The results were compared with findings in a control group that was pair-fed with an identical diet except that it covered this species's nutritional requirements for Mg (480 mg Mg/kg food). The Mg-deficient diet significantly increased enterocyte content of Ca, Fe, Zn, Cu and Mn; however, we found no significant changes in the Se content of these cells. These data support the results obtained by indirect methods.     

Serum Levels of Trace Elements and Heavy Metals in Patients with Acute Hemorrhagic Stroke

Trace elements are essential components of biological structures, but alternatively, they can be toxic at concentrations beyond those necessary for their biological functions. Changes in the concentration of essential trace elements and heavy metals may affect acute hemorrhagic stroke. The aim of this study was to measure serum levels of essential trace elements [iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), and magnesium (Mg)] and heavy metals [cobalt (Co), cadmium (Cd), and lead (Pb)] in patients with acute hemorrhagic stroke. Twenty-six patients with acute hemorrhagic stroke and 29 healthy controls were enrolled. Atomic absorption spectrophotometry (UNICAM-929) was used to measure serum Fe, Cu, Pb, Cd, Zn, Co, Mn and Mg concentrations. Serum Cd, Pb and Fe levels were significantly higher in patients with acute hemorrhagic stroke than controls (p < 0.001), while serum Cu, Zn, Mg and Mn levels were significantly lower (all p < 0.001). However, there was no significant difference between the groups with respect to serum Co levels (p > 0.05). We first demonstrate increased Cd, Pb, and Fe levels; and decreased Cu, Zn, Mg, and Mn levels in patients with acute hemorrhagic stroke. These findings may have diagnostic and prognostic value for acute hemorrhagic stroke. Further studies are required to elucidate the roles of trace elements and heavy metals in patients with acute hemorrhagic stroke.     

Minor and trace elements in human milk from Guatemala,Hungary, Nigeria,Philippines, Sweden,and Zaire

Concentrations of As, Ca, Cd, Cl, Co, Cr, Cu, F, Fe, Hg, I, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sn, V, and Zn were determined in human whole milk samples from Guatemala, Hungary, Nigeria, Philippines, Sweden, and Zaire; in most of these countries, three groups of subjects representing different socioeconomic conditions were studied. Analytical quality control was a primary consideration throughout. The analytical techniques used were atomic absorption spectrophotometry, atomic emission spectrometry with an inductively coupled plasma, colorimetry, electrochemistry, using an ion-selective electrode and neutron activation analysis. The differences between median concentrations of Ca, Cl, Mg, K, Na, and P (minor elements) were lower than 20% among the six countries. Among trace elements, concentrations observed in Filipino milk for As, Cd, Co, Cr, Cu, F, Fe, Mn, Mo, Ni, Pb, Sb, Se, and V were higher than for milk samples from other countries. The remaining five countries showed a mixed picture of high and low values. In the case of at least some elements, such as, F, I, Hg, Mn, Pb, and Se, the environment appears to play a major role in determining their concentrations in human milk. The nutritional status of the mother, as reflected by her socioeconomic status, does not appear to influence significantly the breast milk concentrations of minor and trace elements. Significant differences exist between the actual daily intakes observed in this study and current dietary recommendations made by, for example, WHO and the US National Academy of Sciences. These differences are particularly large (an order of magnitude or more!) for Cr, F, Fe, Mn, and Mo; for other elements, such as, Ca, Cu, Mg, P, and Zn, they amount to at least a factor 2. In the opinion of the present authors, these findings point to the need for a possible reassessment of the dietary requirements of young infants with respect to minor and trace elements, particularly for the elements Ca, Cr, Cu, F, Fe, Mg, Mn, Mo, P, and Zn.     

RETRACTED ARTICLE: CO<Subscript>2</Subscript> effects on plant nutrient concentration depend on plant functional group and available nitrogen: a meta-analysis

Elevated CO₂ is expected to lower plant nutrient concentrations via carbohydrate dilution and increased nutrient use efficiency. Elevated CO₂ consistently lowers plant foliar nitrogen, but there is no consensus on CO₂ effects across the range of plant nutrients. We used meta-analysis to quantify elevated CO₂ effects on leaf, stem, root, and seed concentrations of B, Ca, Cu, Fe, K, Mg, Mn, P, S, and Zn among four plant functional groups and two levels of N fertilization. CO₂ effects on plant nutrient concentration depended on the nutrient, plant group, tissue, and N status. CO₂ reduced B, Cu, Fe, and Mg, but increased Mn concentration in the leaves of N₂ fixers. Elevated CO₂ increased Cu, Fe, and Zn, but lowered Mn concentration in grass leaves. Tree leaf responses were strongly related to N status: CO₂ significantly decreased Cu, Fe, Mg, and S at high N, but only Fe at low N. Elevated CO₂ decreased Mg and Zn in crop leaves grown with high N, and Mn at low N. Nutrient concentrations in crop roots were not affected by CO₂ enrichment, but CO₂ decreased Ca, K, Mg and P in tree roots. Crop seeds had lower S under elevated CO₂. We also tested the validity of a “dilution model.” CO₂ reduced the concentration of plant nutrients 6.6% across nutrients and plant groups, but the reduction is less than expected (18.4%) from carbohydrate accumulation alone. We found that elevated CO₂ impacts plant nutrient status differently among the nutrient elements, plant functional groups, and among plant tissues. Our synthesis suggests that differences between plant groups and plant organs, N status, and differences in nutrient chemistry in soils preclude a universal hypothesis strictly related to carbohydrate dilution regarding plant nutrient response to elevated CO₂.     

Elemental distribution in tissue components of N2-fixing nodules of Psoralea pinnata plants growing naturally in wetland and upland conditions in the Cape Fynbos of South Africa

There is little information on in situ distribution of nutrient elements in N₂-fixing nodules. The aim of this study was to quantify elemental distribution in tissue components of N₂-fixing nodules harvested from Psoralea pinnata plants grown naturally in wetland and upland conditions in the Cape Fynbos. The data obtained from particle-induced X-ray emission revealed the occurrence of 20 elements (Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, Mo and Ba) in nodule components. Although, in upland plants, the concentrations of S, Fe, Si, Mn and Cu showed a steady increase from the middle cortex to the medulla region of P. pinnata nodules, in wetland plants, only S, Fe and Mn showed an increase in concentration from the middle cortex to the bacteria-infected medulla of P. pinnata nodules. By contrast, the concentrations of Cl, K, Ca, Zn and Sr decreased from middle cortex to nodule medulla. The alkaline earth, alkali and transition elements Rb, Sr, Y and Zr, never before reported in N₂-fixing nodules, were found to occur in root nodules of P. pinnata plants grown in both wetland and upland conditions.     

The Rengen Grassland Experiment: relationship between soil and biomass chemical properties, amount of elements applied, and their uptake

The Rengen Grassland Experiment (RGE) was established in the Eifel Mountains (Germany) on a low productive Nardetum in 1941. Since then, the following fertilizer treatments have been applied with a late two-cut system: unfertilized control, Ca, CaN, CaNP, CaNPKCl and CaNPK₂SO₄. We aimed to understand how concentrations of macro (N, P, K, Ca and Mg), micro (Cu, Fe, Mn and Zn) and trace (As, Cd, Cr, Ni and Pb) elements in the plant biomass were affected by long-term fertilizer application, soil chemical properties and biomass production. In 2008, biomass samples from the first cut (early July) and the second cut (mid-October) were collected and analyzed. The simultaneous application of N, P and K decreased nitrogen concentration in the aboveground biomass, but substantially increased biomass production. Late cutting management decreased forage quality in highly productive more than in low productive plant communities. The concentrations of P and K in the plant biomass were positively related to P and K application and, therefore, to plant available P and K concentrations in the soil. The concentrations of some micro (Fe, Mn and Zn) and trace (As, Cd, Cr, Ni and Pb) elements in the plant biomass were negatively correlated with the amount of elements supplied by fertilizers and biomass production, probably because of the dilution effect. Long-term fertilizer application resulted in the accumulation of macro (P, Ca and Mg), micro (Fe and Mn) and trace (As and Cr) elements in the soil, but in many cases this accumulation was not connected with an increase in the concentrations of these elements in the plant biomass. Nutritional status, as indicated by the biomass N:P ratio, was consistent with N or P limitation as indicated by the nitrogen and phosphorus nutrition indices. Furthermore, additional K (co-)limitation was indicated by the N:K and K:P ratios in the biomass from the NP treatment. The results from the RGE indicate that there is no simple positive relationship between the applied elements and their concentrations in the plant biomass.     

Spatial X-ray fluorescence micro-imaging of minerals in grain tissues of wheat and related genotypes

Main conclusion

Wheat and its related genotypes show distinct distribution patterns for mineral nutrients in maternal and filial tissues in grains. X-ray-based imaging techniques are very informative to identify genotypes with contrasting tissue-specific localization of different elements. This can help in the selection of suitable genotypes for nutritional improvement of food grain crops.

Abstract

Understanding mineral localization in cereal grains is important for their nutritional improvement. Spatial distribution of mineral nutrients (Mg, P, S, K, Ca, Fe, Zn, Mn and Cu) was investigated between and within the maternal and filial tissues in grains of two wheat cultivars (Triticum aestivum Cv. WH291 and WL711), a landrace (T. aestivum L. IITR26) and a related wild species Aegilops kotschyi, using micro-proton-induced X-ray emission (µ-PIXE) and micro-X-ray fluorescence (µ-XRF). Aleurone and scutellum were major storage tissues for macro (P, K, Ca and Mg) as well as micro (Fe, Zn, Cu and Mn) nutrients. Distinct elemental distribution patterns were observed in each of the four genotypes. A. kotschyi, the wild relative of wheat and the landrace, T. aestivum L. IITR26, accumulated more Zn and Fe in scutellum and aleurone than the cultivated wheat varieties, WH291 and WL711. The landrace IITR26, accumulated far more S in grains, Mn in scutellum, aleurone and embryo region, Ca and Cu in aleurone and scutellum, and Mg, K and P in scutellum than the other genotypes. Unlike wheat, lower Mn and higher Fe, Cu and Zn concentrations were noticed in the pigment strand of A. kotschyi. Multivariate statistical analysis, performed on mineral distribution in major grain tissues (aleurone, scutellum, endosperm and embryo region) resolved the four genotypes into distinct clusters.     

The contrasting effects of nutrient enrichment on growth,biomass allocation and decomposition of plant tissue in coastal wetlands

Background

Most studies focus on macronutrient of C, N and P and ignore other elements, which restrict our understanding on the strategy of plant nutrient adaption and nutrient cycling.

Methods

We investigated 14 element (C, N, P, S, K, Ca, Mg, Fe, Mn, Zn, Cu, Na, Al, and Ba) concentrations of green and senesced leaves in Quercus variabilis along the altitude in the Baotianman Mountains, China, and assessed their relationships with climate, soil, and plant functional traits.

Results

Leaf N,S and K increased with, C, Ca, Na, Fe, Mn, Cu and Ba decreased with, and P, Mg, Al, Zn and N:P did not change significantly with altitude. NRE and SRE increased with, and CRE decreased with altitude (p < 0.05). Among the 14 elements, nucleic acid-protein elements (N, K, S and P) were resorbed preferentially, compare to structural (Ca, Mn, and B) and enzymatic (C, Cu, Mg and Zn) that were discriminated against, and toxic (Al and Fe) elements that were totally excluded.

Conclusions

Q. variabilis can synergetically regulate green leaf multielement stoichiometry and nutrient resorption in responses to environment change. Deciduous plants may have a trade-off mechanism at the end of growing season to rebalance somatic nutrients.