Trace element dynamics in soils and plant uptake

Lead Research Organisation: Rothamsted Research
Department Name: Unlisted

Abstract

Supplying micronutrients to plants is a vital function of soil. Trace elements such as Fe, Zn and Se are essential for human nutrition and deficiency of these elements is widespread in humans, particularly in developing countries. There is evidence from the Rothamsted Classical Experiments that the concentrations of essential trace elements in cereal grain have decreased significantly as a result of increased yield over the last four decades. Other trace elements such as As and Cd are non-essential and toxic. Soil may be contaminated with toxic trace elements from either geogenic or anthropogenic sources, resulting in increased transfer to food crops, which causes a serious concern for food safety. In contrast, some plant species or ecotypes possess unusual abilities to hyperaccumulate trace elements. These plants have potential for phytoremediation of contaminated soils and are also interesting models for studying trace element uptake. Trace elements are present in different chemical forms in soil depending on soil conditions. Soil factors and soil-plant interactions play a crucial role in determining the bioavailability of trace elements and their uptake by plants. Our hypothesis is that soil-plant interactions influence trace element speciation in the rhizosphere, which controls the bioavailability of trace elements to plants.

The objectives of this project are:
1) to quantify the dynamics of different chemical species of trace elements in soil using techniques such as HPLC-ICP-MS and synchrotron radiation X-ray absorption spectrometry in order to understand their bioavailability to plant uptake;
2) to investigate how plants modify trace element speciation in the rhizosphere; and
3) to characterise the uptake, efflux and accumulation of trace elements in both crop plants and hyperaccumulators in different soils and environmental conditions.

Organisations

Publications

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Ma R (2014) Impact of agronomic practices on arsenic accumulation and speciation in rice grain. in Environmental pollution (Barking, Essex : 1987)

 
Description 1) Rice is a main dietary source of the toxic metalloid arsenic. We have discovered that rice root takes up arsenite, the main form of arsenic in flooded paddy soils, efficiently through the silicon uptake pathway. Two silicon transporter proteins in rice, Lsi1 and Lsi2, are able to take up arsenite from the soil inadvertently. This is the first time that arsenite transporters have been identified in higher plants. Supplying silicon to rice plants significantly decreased arsenic accumulation in rice shoots.
2) Dimethylarsenate (DMA) is a major arsenic species in rice grain. We found that rice plants are not able to methylate inorganic arsenic. Instead, DMA is produced by microbial arsenic methylation in the soil and taken up by rice roots via the Lsi1 aquaporin. Flooding of paddy soil enhances microbial arsenic methylation and the proportion of DMA in rice grain.
3)Deficiencies of the micronutrients iron and zinc affect more than 2 billion people worldwide. Using the Rothamsted long-term experiments, we found that zinc and iron concentrations in wheat grain have decreased significantly since the mid1960s, corresponding to the introduction of the high-yielding short-straw cultivars. Comparison of old and modern wheat cultivars shows a decreasing trend of micronutrient concentrations in wheat grain with the time of cultivar introduction.
4)• We have developed methods to investigate the cellular and sub-cellular localization of trace elements, such as iron, zinc, selenium and arsenic, in plant tissues, based on synchrotron X-ray fluorescence and high resolution secondary ion mass spectrometry. Using these methods, we have identified key tissues and cell types for the sequestration of different trace elements in rice plants.
Exploitation Route 1) This research represents an important breakthrough in the understanding of arsenic uptake and metabolism in plants, and points to the way of mitigation of excessive arsenic accumulation in rice by the use of silicon fertilizers.
2) These findings represent new knowledge of the arsenic biogeochemistry in the paddy rice system and could be used to change the way farmers farm.
3) This finding indicates a need to increase micronutrient density in cereals through crop breeding and agronomic methods
4) The methods offer advanced tools for researchers to investigate how different trace elements are transported and stored in plants.
Sectors Agriculture, Food and Drink,Chemicals,Environment,Healthcare,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology,Other

URL http://www.pnas.org/content/105/29/9931
 
Description Our research findings have been used in numerous places in the FAO/WHO Codex Committee on Contaminants in Food "Discussion paper on the possibility to develop a code of practice for prevention and reduction of arsenic contamination in rice" 2013.
First Year Of Impact 2013
Sector Agriculture, Food and Drink
Impact Types Societal

 
Description Arsenic Speciation in castor bean 
Organisation University of Aberdeen
Country United Kingdom 
Sector Academic/University 
PI Contribution results show that free inorganic As, mainly As(III), was transported in the phloem of castor bean exposed to either As(V) or As(III), and that methylated As species were more mobile than inorganic As in the phloem
Start Year 2009
 
Description Arsenic speciation in castor bean 
Organisation University of Science and Technology of China USTC
Country China 
Sector Academic/University 
PI Contribution Our results show that free inorganic As, mainly As(III), was transported in the phloem of castor bean exposed to either As(V) or As(III), and that methylated As species were more mobile than inorganic As in the phloem.
Start Year 2009
 
Description Conceptual Models for Isotopic Fractionation Processes 
Organisation Paris Diderot University
Country France 
Sector Academic/University 
PI Contribution demonstrated that metal isotopes have great promise to identify the chemical processes controlling Cu and Zn uptake and translocation in plants and organisms in situ.
Start Year 2008
 
Description Distinguishing Diffusional and Plant 
Organisation Lancaster University
Country United Kingdom 
Sector Academic/University 
PI Contribution Our research suggests that diffusion limitation applies for uptake of Cd by both HA and NHA plants and for uptake of Ni by the HA. However, uptake of Ni by the NHA is not limited by diffusion and the biotic ligand model is probably appropriate.
Start Year 2008
 
Description Impact of sulphur fertilisation on crop response 
Organisation Origin Fertilisers
Country United Kingdom 
Sector Private 
PI Contribution results demonstrate complex interactions between S and Se involving both soil and plant physiological processes; S can enhance Se availability in soil but inhibit selenate uptake by plants
Start Year 2008
 
Description Impact of sulphur fertilisation on crop response 
Organisation Scottish Crop Research Institute (SCRI)
Country United Kingdom 
Sector Academic/University 
PI Contribution results demonstrate complex interactions between S and Se involving both soil and plant physiological processes; S can enhance Se availability in soil but inhibit selenate uptake by plants
Start Year 2008
 
Description Impact of sulphur fertilisation on crop response 
Organisation University of Castile-La Mancha
Country Spain 
Sector Academic/University 
PI Contribution results demonstrate complex interactions between S and Se involving both soil and plant physiological processes; S can enhance Se availability in soil but inhibit selenate uptake by plants
Start Year 2008
 
Description Impact of sulphur fertilisation on crop response 
Organisation Yara (UK) Ltd
Country United Kingdom 
Sector Private 
PI Contribution results demonstrate complex interactions between S and Se involving both soil and plant physiological processes; S can enhance Se availability in soil but inhibit selenate uptake by plants
Start Year 2008
 
Description Impact of sulphur fertilisation on crop response to Se fertilisation 
Organisation Velcourt Ltd
Department Velcourt R&D
Country United Kingdom 
Sector Private 
PI Contribution results demonstrate complex interactions between S and Se involving both soil and plant physiological processes; S can enhance Se availability in soil but inhibit selenate uptake by plants. Furthermore, no residual effect of Se fertiliser applied in year 1 was found on the following crop
Start Year 2008
 
Description Impact of sulphur fertilisation on crop response to selenium fertilisation 
Organisation Marks and Spencer
Country United Kingdom 
Sector Private 
PI Contribution results demonstrate complex interactions between S and Se involving both soil and plant physiological processes; S can enhance Se availability in soil but inhibit selenate uptake by plants. Furthermore, no residual effect of Se fertiliser applied in year 1 was found on the following crop
Start Year 2008
 
Description Localisation of iron in wheat grain 
Organisation University of Oxford
Country United Kingdom 
Sector Academic/University 
PI Contribution Iron was shown to be localised strongly in the phytin globoids in the aleurone cells and to a lesser extent in the cytoplasm around the starch granules in the endosperm
Start Year 2008
 
Description Micronutrients in wheat grain 
Organisation Hungarian Academy of Sciences (MTA)
Department Centre for Agricultural Research (ATK)
Country Hungary 
Sector Academic/University 
PI Contribution The results from this study are useful for developing micronutrient biofortification strategies.
Start Year 2008
 
Description Role of phytochelatins in regulating arsenic accumulation in rice grain 
Organisation Agricultural University of Hebei
Country China 
Sector Academic/University 
PI Contribution PC complexation of arsenite in rice leaves reduces As translocation from leaves to grains, and implicate that manipulation of PC synthesis might mitigate As accumulation in rice grain.
Start Year 2008
 
Description Role of phytochelatins in regulating arsenic accumulation in rice grain 
Organisation Chinese Academy of Sciences
Country China 
Sector Public 
PI Contribution PC complexation of arsenite in rice leaves reduces As translocation from leaves to grains, and implicate that manipulation of PC synthesis might mitigate As accumulation in rice grain
Start Year 2008
 
Description Selenium concentration and speciation in biofortified flour and bread 
Organisation Premier Foods Group Ltd
Country United Kingdom 
Sector Private 
PI Contribution Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.
Start Year 2008
 
Description Selenium concentration and speciation in biofortified flour and bread 
Organisation Quadram Institute Bioscience
Country United Kingdom 
Sector Academic/University 
PI Contribution Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.
Start Year 2008
 
Description Selenium concentration and speciation in biofortified flour and bread 
Organisation University of East Anglia
Country United Kingdom 
Sector Academic/University 
PI Contribution Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.
Start Year 2008
 
Description Selenium concentration and speciation in biofortified flour and bread 
Organisation University of Nottingham
Country United Kingdom 
Sector Academic/University 
PI Contribution Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.
Start Year 2008
 
Description Selenium in higher plants 
Organisation Chinese Academy of Sciences
Department Institute of Urban Environment
Country China 
Sector Academic/University 
PI Contribution understanding mechanisms for biofortification and phytoremediation
Start Year 2008
 
Description Selenium in higher plants 
Organisation Chinese Academy of Sciences
Department Research Center for Eco-environmental Sciences
Country China 
Sector Academic/University 
PI Contribution understanding mechanisms for biofortification and phytoremediation
Start Year 2008
 
Description Selenium in higher plants 
Organisation Colorado State University
Country United States 
Sector Academic/University 
PI Contribution understanding mechanisms for biofortification and phytoremediation
Start Year 2008
 
Description Selenium in higher plants 
Organisation University of Aberdeen
Department Institute of Biological and Environmental Sciences
Country United Kingdom 
Sector Academic/University 
PI Contribution understanding mechanisms for biofortification and phytoremediation
Start Year 2000
 
Description Sulphate transporters in wheat 
Organisation Nihon University
Country Japan 
Sector Academic/University 
PI Contribution S fertilizer application has a marked impact on Mo and Se distribution and accumulation, which is at least partially a result of altered gene expression of the sulfate transporter family
Start Year 2008
 
Description Sulphur nutrition on distribution of asparagine in wheat grain 
Organisation French National Institute of Agricultural Research
Country France 
Sector Academic/University 
PI Contribution It was found that S deficiency resulted in disproportional increases in the asparagine contents of white flour fractions, implying that optimisation of yield in a conventional milling system is not an appropriate strategy for processing grain from sulphur-deficient crops.
Start Year 2008
 
Description The role of root hairs in cadmium acquisition by barley 
Organisation China Agricultural University (CAU)
Country China 
Sector Academic/University 
PI Contribution investigated the role of root hairs in Cd acquisition from soil: Found that root hairs contribute significantly to Cd uptake by barley.
Start Year 2008
 
Description The role of root hairs in cadmium acquisition by barley 
Organisation University of Hohenheim
Country Germany 
Sector Academic/University 
PI Contribution Root hairs contribute significantly to Cd uptake by barley
Start Year 2009
 
Description The role of the rice aquaporin Lsi1 
Organisation Okayama University
Department Research Institute for Bioresources
Country Japan 
Sector Academic/University 
PI Contribution Lsi1 plays a role in arsenite efflux in rice roots exposed to arsenate. However, this pathway accounts for only 15?20% of the total efflux, suggesting the existence of other efflux transporters.
Start Year 2008
 
Description The role of the rice aquaporin Lsi1 
Organisation Xinjiang University
Country China 
Sector Academic/University 
PI Contribution Lsi1 plays a role in arsenite efflux in rice roots exposed to arsenate. However, this pathway accounts for only 15?20% of the total efflux, suggesting the existence of other efflux transporters.
Start Year 2008
 
Description mechanisms of zinc uptake by rice 
Organisation Cranfield University
Country United Kingdom 
Sector Academic/University 
PI Contribution We show ed with a mathematical model that, for realistic rates of secretion of the phytosiderophore deoxymugineic acid (DMA) by rice, and realistic parameters for the Zn- solubilizing effect of DMA in soil, solubilization and uptake by this mechanism is necessary and sufficient to account for the measured Zn uptake and the differences between genotypes
Start Year 2008
 
Description mechanisms of zinc uptake by rice 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution We showed with a mathematical model that, for realistic rates of secretion of the phytosiderophore deoxymugineic acid (DMA) by rice, and realistic parameters for the Zn-solubilizing effect of DMA in soil, solubilization and uptake by this mechanism is necessary and sufficient to account for the measured Zn uptake and the differences between genotypes.
Start Year 2008
 
Description mechanisms of zinc uptake by rice 
Organisation Japan International Research Center for Agricultural Sciences (JIRCAS)
Country Japan 
Sector Public 
PI Contribution We showed with a mathematical model that, for realistic rates of secretion of the phytosiderophore deoxymugineic acid (DMA) b rice, and realistic parameters for the Zn-solubilizing effect of DMA in soil, solubilization and uptake by this mechanism is necessary and sufficient to account for the measured Zn uptake and the differences between genotypes
Start Year 2008
 
Description models of isotope fractionation processes of Cu and Zn 
Organisation Paris Diderot University
Country France 
Sector Academic/University 
PI Contribution we clearly demonstrate that metal isotopes have great promise to identify the chemical processes controlling Cu and Zn uptake and translocation inplants and organisms in situ.
Start Year 2008
 
Description models of isotope fractionation processes of Cu and Zn in plants 
Organisation French National Institute of Agricultural Research
Country France 
Sector Academic/University 
PI Contribution demonstrated that metal isotopes have great promise to identify the chemical processes controlling Cu and Zn uptake and translocation in plants and organisms in situ.
Start Year 2008
 
Description models of isotope fractionation processes of Cu and Zn in plants 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution we demonstrated that metal isotopes have great promise to identify the chemical processes controlling Cu and Zn uptake and translocation in plants and organisms in situ.
Start Year 2008
 
Description models of isotope fractionation processes of Cu and Zn in plants 
Organisation Natural History Museum
Country United Kingdom 
Sector Public 
PI Contribution we demonstrated that metal isotopes have great promise to identify the chemical processes controlling Cu and Zn uptake and translocation in plants and organisms in situ.
Start Year 2008
 
Description models of isotope fractionation processes of Cu and Zn in plants 
Organisation UMR Eco&Sols
Country France 
Sector Academic/University 
PI Contribution demonstrated that metal isotopes have great promise to identify the chemical processes controlling Cu and Zn uptake and translocation in plants and organisms in situ.
Start Year 2008
 
Description 3rd International Symposium on Trace Elements and Health 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Invited speaker

no actual impacts realised to date
Year(s) Of Engagement Activity 2011
 
Description Annual Meeting of the Soil Science Society of America 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited speaker

no actual impacts realised to date
Year(s) Of Engagement Activity 2011
 
Description Cereal nutrients in decline 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Article in Stock and Land Magazine

no actual impacts realised to date
Year(s) Of Engagement Activity 2009
 
Description Fortify bread with Se to fight off cancer, urge experts 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Newspaper article on line

no actual impacts realised to date
Year(s) Of Engagement Activity 2009
 
Description How to beat depression with the right diet 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Article in the Independent. about including Selenium in the diet www.independent.co.uk/life-style/health-and-families/features/how-to-beat-depression

no actual impacts realised to date
Year(s) Of Engagement Activity 2009
URL http://www.cam.ac.uk
 
Description Low selenium in the British Diet could be corrected with new fertilisers 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact "Halting the Hidden Hunger Crisis"- British Science Festival 2009

no actual impacts realised to date
Year(s) Of Engagement Activity 2009
 
Description MINERAL-IMPROVED PRODUCTION FOR HEALTHY FOOD AND FEED 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited Keynote speaker, COST action FA0905, Lisbon

no actual impacts realised to date
Year(s) Of Engagement Activity 2011
 
Description Selenium could make Britain more healthy 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Article in The Telegraph online

no actual impacts realised to date
Year(s) Of Engagement Activity 2009
 
Description Should Se be added to our daily bread? 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Article in Science and Health Blog Mirror.co.uk

no actual impacts realised to date
Year(s) Of Engagement Activity 2009
 
Description Whats new in Zinc nutrition 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Sewage sludge applications to soil can increase grain Zn concentrations for at least 2 to 8 years after application Article in New Ag International Newsletter

no actual impacts realised to date
Year(s) Of Engagement Activity 2008
URL http://www.bris.ac.uk/news/2013/9606.html