Zinc allocation and re-allocation in rice
Stomph, T.J. ; Jiang, W. ; Putten, P.E.L. van der; Struik, P.C. - \ 2014
Frontiers in Plant Science 5 (2014). - ISSN 1664-462X - 12 p.
developing wheat grains - aerobic rice - soil-zinc - zn - biofortification - remobilization - translocation - micronutrients - fertilization - nutrition
Aims: Agronomy and breeding actively search for options to enhance cereal grain Zn density. Quantifying internal (re-)allocation of Zn as affected by soil and crop management or genotype is crucial. We present experiments supporting the development of a conceptual model of whole plant Zn allocation and re-allocation in rice. Methods: Two solution culture experiments using 70Zn applications at different times during crop development and an experiment on within-grain distribution of Zn are reported. In addition, results from two earlier published experiments are re-analyzed and re-interpreted. Results: A budget analysis showed that plant zinc accumulation during grain filling was larger than zinc allocation to the grains. Isotope data showed that zinc taken up during grain filling was only partly transported directly to the grains and partly allocated to the leaves. Zinc taken up during grain filling and allocated to the leaves replaced zinc re-allocated from leaves to grains. Within the grains, no major transport barrier was observed between vascular tissue and endosperm. At low tissue Zn concentrations, rice plants maintained concentrations of about 20 mg Zn kg-1 dry matter in leaf blades and reproductive tissues, but let Zn concentrations in stems, sheath, and roots drop below this level. When plant zinc concentrations increased, Zn levels in leaf blades and reproductive tissues only showed a moderate increase while Zn levels in stems, roots, and sheaths increased much more and in that order. Conclusions: In rice, the major barrier to enhanced zinc allocation towards grains is between stem and reproductive tissues. Enhancing root to shoot transfer will not contribute proportionally to grain zinc enhancement.
Evaluation of the performance and limitations of empirical partition-relations and process based multisurface models to predict trace element solubility in soils
Groenenberg, J.E. ; Dijkstra, J.J. ; Bonten, L.T.C. ; Vries, W. de; Comans, R.N.J. - \ 2012
Environmental Pollution 166 (2012). - ISSN 0269-7491 - p. 98 - 107.
metal-ion binding - natural organic-matter - humic substances - heavy-metals - contaminated soils - complexation models - agricultural soils - assemblage model - cation-binding - zn
Here we evaluate the performance and limitations of two frequently used model-types to predict trace element solubility in soils: regression based “partition-relations” and thermodynamically based “multisurface models”, for a large set of elements. For this purpose partition-relations were derived for As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se, V, Zn. The multi-surface model included aqueous speciation, mineral equilibria, sorption to organic matter, Fe/Al-(hydr)oxides and clay. Both approaches were evaluated by their application to independent data for a wide variety of conditions. We conclude that Freundlich-based partition-relations are robust predictors for most cations and can be used for independent soils, but within the environmental conditions of the data used for their derivation. The multisurface model is shown to be able to successfully predict solution concentrations over a wide range of conditions. Predicted trends for oxy-anions agree well for both approaches but with larger (random) deviations than for cations.
Ni adsorption and Ni-Al LDH precipitation in a sandy aquifer: An experimental and mechanistic modeling study
Regelink, I.C. ; Temminghoff, E.J.M. - \ 2011
Environmental Pollution 159 (2011)3. - ISSN 0269-7491 - p. 716 - 721.
dissolution kinetics - nickel sorption - soil - zn - pyrophyllite - interface - clay - stability - minerals - gibbsite
Mining activities and industries have created nickel (Ni) contaminations in many parts of the world. The objective of this study is to increase our understanding of Ni adsorption and Nickel-Aluminium Layered Double Hydroxide (Ni-Al LDH) precipitation to reduce Ni mobility in a sandy soil aquifer. At pH =7.2 both adsorption and Ni-Al LDH precipitation occurred. In batch experiments with the sandy soil up to 70% of oxalate-extractable Al was taken up in LDH formation during 56 days. In a long term column experiment 99% of influent Ni was retained at pH 7.5 due to Ni adsorption (˜34%) and Ni-Al LDH precipitation (˜66%) based on mechanistic reactive transport modeling. The subsequent leaching at pH 6.5 could be largely attributed to desorption. Our results show that even in sandy aquifers with relatively low Al content, Ni-Al LDH precipitation is a promising mechanism to immobilize Ni. © 2010 Elsevier Ltd. All rights reserved.
Temporal dynamics in wheat grain zinc distribution: is sink limitation the key?
Stomph, T.J. ; Choi, E.Y. ; Stangoulis, J.C.R. - \ 2011
Annals of Botany 107 (2011)6. - ISSN 0305-7364 - p. 927 - 937.
developing seeds - transport - biofortification - endosperm - phloem - barley - zn - remobilization - deposition - manganese
Background and Aims - Enhancing the zinc (Zn) concentration in wheat (Triticum aestivum) grain is a breeding objective in order to improve human Zn nutrition. At enhanced plant Zn uptake, grain Zn levels do not increase proportionally and within the grain the endosperm Zn levels remain below grain Zn levels. This study analysed the temporal dynamics of Zn concentrations in grain tissues during grain filling to find major bottlenecks. Methods - Plants of two cultivars were grown at 1 and 5 mg Zn kg-1 soil. Individual panicles were harvested 7, 14, 24 or 34 d after their flowering or at maturity and seeds were dissected into constituting tissues, which were analysed for Zn and other minerals. Key Results - The Zn concentration of the crease was found to increase five- to nine-fold between 7 and 34 d after anthesis, while that of the endosperm decreased by 7 and 45 % when grown at 1 or 5 mg Zn kg-1, respectively. The Zn turnover rate (d-1) in the crease tissues was either independent of the Zn application level or higher at the lower Zn application level, and the Zn concentration increased in the crease tissues with time during grain filling while the turnover rate gradually decreased. Conclusions - There is significant within-seed control over Zn entering the seed endosperm. While the seed crease Zn concentration can be raised to very high levels by increasing external Zn supply, the endosperm Zn concentrations will not increase correspondingly. The limited transfer of Zn beyond the crease requires more research to provide further insight into the rate-determining processes and their location along the pathway from crease to the deeper endosperm
Characterization of soil heavy metal pools in paddy fields in Taiwan: chemical extraction and solid-solution partitioning
Römkens, P.F.A.M. ; Guo, H.Y. ; Chu, C.L. ; Liu, T.S. ; Chiang, C.F. ; Koopmans, G.F. - \ 2009
Journal of Soils and Sediments 9 (2009)3. - ISSN 1439-0108 - p. 216 - 228.
contaminated soils - flow-analysis - trace-metals - cadmium - rice - cd - cu - zinc - zn - pb
Ongoing industrialization has resulted in an accumulation of metals like Cd, Cu, Cr, Ni, Zn, and Pb in paddy fields across Southeast Asia. Risks of metals in soils depend on soil properties and the availability of metals in soil. At present, however, limited information is available on how to measure or predict the directly available fraction of metals in paddy soils. Here, the distribution of Cd, Cu, Cr, Ni, Zn, and Pb in 19 paddy fields among the total, reactive, and directly available pools was measured using recently developed concepts for aerated soils. Solid-solution partitioning models have been derived to predict the directly available metal pool. Such models are proven to be useful for risk assessment and to derive soil quality standards for aerated soils. Soil samples (0-25 cm) were taken from 19 paddy fields from five different communities in Taiwan in 2005 and 2006. Each field was subdivided into 60 to 108 plots resulting in a database of approximately 3,200 individual soil samples. Total (Aqua Regia (AR)), reactive (0.43 M HNO3, 0.1 M HCl, and 0.05 M EDTA), and directly available metal pools (0.01 M CaCl2) were determined. Solid-solution partitioning models were derived by multiple linear regressions using an extended Freundlich equation using the reactive metal pool, pH, and the cation exchange capacity (CEC). The influence of Zn on metal partitioning and differences between both sampling events (May/November) were evaluated. Total metals contents range from background levels to levels in excess of current soil quality standards for arable land. Between 3% (Cr) and 30% (Cd) of all samples exceed present soil quality standards based on extraction with AR. Total metal levels decreased with an increasing distance from the irrigation water inlet. The reactive metal pool relative to the total metal content is increased in the order Cr
Predictions of Spatially Averaged Cadmium Contents in Rice Grains in the Fuyang Vally P.R. China
Brus, D.J. ; Koopmans, G.F. ; Temminghoff, E.J.M. ; Japenga, J. ; Li, Z. ; Song, J. ; Yin, X. ; Yao, C. ; Zhang, H. ; Luo, Y. - \ 2009
Journal of Environmental Quality 38 (2009). - ISSN 0047-2425 - p. 1126 - 1136.
heavy-metals - contaminated soils - nutritional-status - organic-matter - winter-wheat - paddy soils - cd levels - zinc - zn - availability
Received for publication May 14, 2008. Soils in the Fuyang valley (Zhejiang province, southeast China) have been contaminated by heavy metals. Since rice (Oryza sativa L.) is the dominant crop in the valley and because of its tendency to accumulate Cd in its grains, assessment of the human health risk resulting from consumption of locally produced rice is needed. In this study, we used a regression model to predict the average Cd content in rice grains for paddy fields. The multiple linear model for log(Cd) content in rice grains with log(HNO3–Cd), pH, log(clay), and log(soil organic matter, SOM) as predictors performed much better (R2adj = 66.1%) than the model with log(CaCl2–Cd) as a single predictor (R2adj = 28.1%). This can be explained by the sensitivity of CaCl2–extracted Cd for changes in redox potential and as a result of the drying of the soil samples in the laboratory. Consequently, the multiple linear model was used to predict the average Cd contents in rice grains for paddy fields, and to estimate the probability that the FAO/WHO standard of 0.2 mg kg–1 will be exceeded. Eleven blocks had a probability smaller than 10% of exceeding this standard (safe blocks). If a lognormal distribution is assumed, 35 blocks had a probability larger than 90% (blocks at risk). Hence, risk reduction measures should be undertaken for the blocks at risk. For 27 blocks the probability was between 10 and 90%. For these blocks the uncertainty should be reduced via improvement of the regression model and/or increasing the number of sample locations within blocks.
Feasilbility of phytoextraction to remediate cadmium and zinc contaminated soils
Koopmans, G.F. ; Romkens, P.F.A.M. ; Fokkema, M.J. ; Song, J. ; Luo, Y.M. ; Japenga, J. ; Zhao, F.J. - \ 2008
Environmental Pollution 156 (2008)3. - ISSN 0269-7491 - p. 905 - 914.
hyperaccumulator thlaspi-caerulescens - metal-accumulating plants - polluted soils - heavy-metals - sandy soil - zn - cd - phytoremediation - rhizosphere - field
A Cd and Zn contaminated soil was mixed and equilibrated with an uncontaminated, but otherwise similar soil to establish a gradient in soil contamination levels. Growth of Thlaspi caerulescens (Ganges ecotype) significantly decreased the metal concentrations in soil solution. Plant uptake of Cd and Zn exceeded the decrease of the soluble metal concentrations by several orders of magnitude. Hence, desorption of metals must have occurred to maintain the soil solution concentrations. A coupled regression model was developed to describe the transfer of metals from soil to solution and plant shoots. This model was applied to estimate the phytoextraction duration required to decrease the soil Cd concentration from 10 to 0.5 mg kg¿1. A biomass production of 1 and 5 t dm ha¿1 yr¿1 yields a duration of 42 and 11 yr, respectively. Successful phytoextraction operations based on T. caerulescens require an increased biomass production.
Tree species effect on the redistribution of soil metals
Mertens, J. ; Nevel, L. Van; Schrijver, A. De; Piesschaert, F. ; Oosterbaan, A. ; Tack, F.M.G. ; Verheyen, K. - \ 2007
Environmental Pollution 149 (2007)2. - ISSN 0269-7491 - p. 173 - 181.
disposed dredged sediments - contaminated soils - temperate forests - heavy-metals - litter - land - cd - zn - cu - ecosystem
Phytostabilization of metals using trees is often promoted although the influence of different tree species on the mobilization of metals is not yet clear. Soil and biomass were sampled 33 years after planting four tree species (Quercus robur, Fraxinus excelsior, Acer pseudoplatanus, Populus `Robusta¿) in a plot experiment on dredged sediment. Poplar took up high amounts of Cd and Zn and this was associated with increased Cd and Zn concentrations in the upper soil layer. The other species contained normal concentrations of Cd, Cu, Cr, Pb and Zn in their tissues. Oak acidified the soil more than the other species and caused a decrease in the concentration of metals in the upper soil layer. The pH under poplar was lower than expected and associated with high carbon concentrations in the top soil. This might be assigned to retardation of the litter decomposition due to elevated Cd and Zn concentrations in the litter. Trees (33-year-old) growing on polluted dredged sediment have influenced the metal concentration in the upper soil layer and there was a significant tree species effect.
A feasibility test to estimate the duration of phytoextraction of heavy metals from polluted soils
Japenga, J. ; Koopmans, G.F. ; Song, J. ; Romkens, P.F.A.M. - \ 2007
International Journal of Phytoremediation 9 (2007)2. - ISSN 1522-6514 - p. 115 - 132.
hyperaccumulator thlaspi-caerulescens - contaminated soils - solubility control - organic-matter - cadmium - plants - zinc - zn - accumulation - pb
The practical applicability of heavy metal (HM) phytoextraction depends heavily on its duration. Phytoextraction duration is the main cost factor for phytoextraction, both referring to recurring economic costs during phytoextraction and to the cost of the soil having no economic value during phytoextraction. An experiment is described here, which is meant as a preliminary feasibility test before starting a phytoextraction scheme in practice, to obtain a more realistic estimate of the phytoextraction duration of a specific HM-polluted soil. In the experiment, HM-polluted soil is mixed at different ratios with unpolluted soil of comparable composition to mimic the gradual decrease of the HM content in the target HM-polluted soil during phytoextraction. After equilibrating the soil mixtures, one cropping cycle is carried out with the plant species of interest. At harvest, the adsorbed HM contents in the soil and the HM contents in the plant shoots are determined. The adsorbed HM contents in the soil are then related to the HM contents in the plant shoots by a log-log linear relationship that can then be used to estimate the phytoextraction duration of a specific HM-polluted soil. This article describes and evaluates the merits of such a feasibility experiment. Potential drawbacks regarding the accuracy of the described approach are discussed and a greenhouse-field extrapolation procedure is proposed.
Uptake and distribution of root-applied or foliar-applied 65Zn after flowering in aerobic rice
Jiang, W. ; Struik, P.C. ; Lingna, J. ; Keulen, H. van; Ming, Z. ; Stomph, T.J. - \ 2007
Annals of Applied Biology 150 (2007)3. - ISSN 0003-4746 - p. 383 - 391.
developing wheat grains - zinc uptake - zn - plants - accumulation - manganese - iron - cu - phytoremediation - nutrition
We investigated the uptake and distribution of zinc (Zn) either applied to the roots or to the leaves in rice during grain development. Plants of two aerobic rice cultivars were grown in a nutrient solution with either sufficient Zn or surplus Zn. Root treatment with 1 week`s supply of both 65Zn and unlabelled Zn was started at flowering or 15 days after flowering (DAF). Foliar treatment with 65Zn applied to the flag leaf or to senescent leaves was carried out at flowering. When 65Zn was applied to roots, plants continued to take up Zn after flowering, even beyond 15 DAF, irrespective of cultivar and Zn nutritional status of the plants. During the 1 week of supply of both 65Zn and unlabelled Zn, which either started at flowering or 15 DAF, the absorbed 65Zn was mainly distributed to roots, stem and grains. Little 65Zn was allocated to the leaves. Following a week of 65Zn supply directly after flowering, under sufficient Zn or surplus Zn, the proportions of total 65Zn uptake allocated to the grains continued to change during grain filling (9¿33%). This Zn mainly came from the roots but under sufficient Zn supply also from the stem. With 65Zn applied to leaves (either the flag leaf or the lowest senescent leaf), both cultivars showed similar Zn distribution within the plants. About 45¿50% of the 65Zn absorbed was transported out of the 65Zn-treated leaf. From that Zn, more than 90% was translocated to other vegetative organs; little was partitioned to the panicle parts and even less to the grains. These results suggest that in rice plants grown under sufficient or surplus Zn supply, most of the Zn accumulated in the grains originates from uptake by roots after flowering and not from Zn remobilisation from leaves
Iron, zinc and phytic acid content of selected rice varieties from China
Liang, J. ; Han, B.Z. ; Han, L. ; Nout, M.J.R. ; Hamer, R.J. - \ 2007
Journal of the Science of Food and Agriculture 87 (2007)3. - ISSN 0022-5142 - p. 504 - 510.
molar ratios - phytate - availability - nutrition - minerals - calcium - seeds - zn
Rice is the major Chinese staple food (per capita approx 250 g day-1) and, as such, is an important source of essential minerals. However, due to a number of factors the bio-availability of these minerals is limited. In this study, the variation of phytic acid (PA), iron (Fe) and zinc (Zn) levels in 56 varieties of Chinese rice was investigated. The samples included in this study were collected in proportion to the importance of the rice-growing regions in China. Fe levels showed the biggest variation (9-45 mg kg-1) and were not related with PA content or grain shape although growing locations were identified yielding higher (25.2 mg kg-1) and lower (14.2 mg kg-1) Fe levels. Zn showed a moderate variability (13-39 mg kg-1), which was narrower than for Fe, while broader than for PA (7.2-11.9 g kg-1). Zn content is correlated (R2 = 0.5; P <0.01) with PA content, and shows a relation with growing region and kernel shape. Variation of PA content is the least among the three components. Molar ratios of PA to Fe and Zn ranged from 15 to 105 and 27 to 67, respectively. The results of the mineral contents and PA content can be interpreted in terms of expected bio-availability. This study shows that the mineral bio-availability of Chinese rice varieties will be
The effect of long-term irrigation using wastewater on heavy metal contents of soils under vegetables in Harare, Zimbabwe
Mapanda, F. ; Mangwayana, E.N. ; Nyamangara, J. ; Giller, K.E. - \ 2005
Agriculture, Ecosystems and Environment 107 (2005)2-3. - ISSN 0167-8809 - p. 151 - 165.
sewage-sludge - effluent - zn - ni - cu
The magnitude of contamination, regulatory compliance and annual loadings of soils with copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), chromium (Cr) and lead (Pb) were determined at three sites in Harare where wastewater was used to irrigate vegetable gardens for at least 10 years. Heavy metal total concentrations (mg kg-1) in sandy and sandy–clay soils of pH 5.1–8.1 from all sites ranged from 7.0 to 145 for Cu, 14 to 228 for Zn, 0.5 to 3.4 for Cd,
Morphology, chemistry and distribution of neoformed spherulites in agricultural land affected by metallurgical point-source pollution
Leguedois, S. ; Oort, F. van; Jongmans, A.G. ; Chevalier, P. - \ 2004
Environmental Pollution 130 (2004)2. - ISSN 0269-7491 - p. 135 - 148.
smelter-contaminated soils - sequential extraction - exafs spectroscopy - speciation - lead - microprobe - france - metals - zn - pb
Metal distribution patterns in superficial soil horizons of agricultural land affected by metallurgical point-source pollution were studied using optical and electron microscopy, synchrotron radiation and spectroscopy analyses. The site is located in northern France, at the center of a former entry lane to a bunker of World War 11, temporarily paved with coarse industrial waste fragments and removed at the end of the war. Thin sections made from undisturbed soil samples from A and B horizons were studied. Optical microscopy revealed the occurrence of yellow micrometer-sizcd (Ap horizon) and red decamicroineter-sized spherulites (AB, B(1)g horizons) as well as distinct distribution patterns. The chemical composition of the spherulites was dominated by Fe, Mn, Zn, Pb, Ca, and P. Comparison of calculated Zn stocks, both in the groundmass and in spherulites, showed a quasi-exclusive Zn accumulation in these neoformed features. Their formation was related to several factors: (i) liberation of metal elements due to weathering of waste products, (ii) Ca and P supply from fertilizing practices, (iii) co-precipitation of metal elements and Ca and P in a Porous soil environment, after slow exudation of a supersaturated soil solution in more confined mineral media. (C) 2004 Elsevier Ltd. All rights reserved.