Micronutrient Accumulation Research Articles

Uptake, distribution, and remobilization of iron and zinc among various tissues of wheat–Aegilops substitution lines at different growth stages

Biofortification of wheat for higher grain iron and zinc is the most feasible and cost-effective approach for alleviating micronutrient deficiency. The non-progenitor donor Aegilops species had 2–3 times higher grain iron and zinc content than the wheat cultivars, whereas the wheat–Aegilops substitution lines mostly of group 2 and 7 chromosomes had intermediate levels of grain micronutrients. The non-progenitor Aegilops species also had the highest iron content and intermediate-to-highest zinc content in straw, lower leaves, and flag leaves at the pre-anthesis, grain-filling, and maturity growth stages. The micronutrients accumulation status is followed by wheat–Aegilops substitution lines and is the least in wheat cultivars indicating that the donor Aegilops species and their substituted chromosomes possess genes for higher iron and zinc uptake and mobilization. The grain iron content was highly positively correlated with iron content in the plant tissues. Most of the lines had much higher iron and zinc content in all tissues during grain-filling period indicating higher iron and zinc uptake from soil during this stage. Although iron and zinc contents are nearly similar in grains, there was much less zinc content in the plant tissues of all the lines suggesting that the Triticeae species take up less zinc which is mobilized to grains more effectively than iron.

Identification of QTL Underlying Seed Micronutrients Accumulation in ‘MD 96-5722’ by ‘Spencer’ Recombinant Inbred Lines of Soybean

Genetic mapping of quantitative trait loci (QTL) associated with seed nutrition levels is almost non-existent. The objective of this study was to identify QTLs associated with seed micronutrients (iron, Fe; zinc, Zn; bororn, B; manganese, Mn; and copper, Cu) accumulation (concentration) in a population of 92 F5:7 recombinant inbred lines (RILs) that derived from a cross between MD 96-5722 (MD) and ‘Spencer’. For this purpose, a genetic linkage map based on 5,376 Single Nucleotide Polymorphism (SNP) markers was constructed using the Illumina Infinium SoySNP6K BeadChip array. The RILs were genotyped using 537 polymorphic, reliably segregating SNP markers. A total of 23 QTLs for micronutrients Fe, Zn, B, Mn, and Cu have been identified and mapped on eight linkage groups (LGs) of the soybean genome. Five QTLs were detected for Fe (qIRO001- qIRO005) on LGs N, A1, K, J, and G. Seven QTLs for Zn (qZIN001-qZIN007) on LGs D1a (Chr 1), N (Chr 3), F (Chr 5), B2 (Chr 14), J (Chr 16), A1 (Chr 5), and K (Chr 9). Two QTLs for B (qBOR001 and qBOR002) were detected on LGs N and A1. Four QTLs were detected for Mn (qMAN001-qMAN004) on LGs N, A1, K, and J, and five QTLs were detected for Cu (qCOP001- qCOP005) on LGs N, A1, K, J, and G). It was observed that the four QTLs for Zn, Cu, Fe, and Mn on LGs N (Chr 3), LG A1 (Chr 5), and LG J (Chr 16) were clustered in a similar region of the linkage groups, suggesting possible shared physiological and genetic mechanisms. The QTLs detected in this study are novel and will contribute to our understanding of the genetic basis of seed mineral nutrition. This research would allow breeders to efficiently select for higher seed nutritional qualities to meet the seed industry and human and livestock nutritional needs.

Quantificação de nutrientes nos frutos de goiabeiras adubadas com subproduto da agroindústria processadora de goiabas

Information about the export of nutrients is important as it can help fertilization programs and nutrient replenishment. Whereas studies assessing the effects promoted by the application of by-products and residues are scarce, especially in perennial crops, the objective of this work was to evaluate the export of nutrients by fruits of guava trees fertilized with the by-product of the agro-processing industry of the fruit itself. A randomized block experimental design with five treatments and four replications was used, being the doses of by-product: zero, 9, 18, 27 and 36 t ha-1 (dry weight of the material). Annual applications of waste were made between 2006 and 2010. From the 2009 harvest, nutrient content analyses were carried out on the fruits and, together with the production, the accumulation of macro and micronutrients was calculated for three consecutive harvests. The application of the by-product of the guava processing industry influenced the export of nutrients by guava fruits. Nutrients exported in larger quantities, in descending order, were: K> N> P> S> Mg> Ca> Fe> Zn> Mn = Cu> B.

Nitrogen fertilizer effect in production, nutrient accumulation and nitrogen efficiency use of second ratoon sugarcane harvested without straw burning

Sugarcane harvest after straw burning implies rapid mineralization of biomass and greenhouse gas emissions. In this context, maintenance of sugarcane straw on the soil is as a new strategy to circumvent the harmful environmental effects, but imposes a new dynamic regarding nitrogen in the soil-plant system. This study sought to evaluate the effect of nitrogen fertilization on biomass production and nutrient accumulation in leaf (senescent and young) and stalks of sugarcane plant from the second sugarcane ratoon, variety SP 83-2847, harvested mechanically in 2007 after six years without straw burning for six years. This study adopted a randomized block design with five nitrogen doses application (0, 60, 120, 180 and 240 kg ha-1) in the form of ammonium nitrate and four replications. Nitrogen fertilization promoted an increase in leaf (senescent and young) and stalk production of the sugarcane plants. However, excess nitrogen decreased accumulation of macro and micronutrients and nitrogen use efficiency by sugarcane due to dilution effect. Although straw deposition on the soil surface of the sugarcane field had occurred for six years, but mineralization of organic matter from the straw did not provide sufficient nitrogen for the growth of sugarcane plants in control treatments, requiring nitrogen application via fertilization. There is a need to adopt new nitrogen fertilization strategies in order to increase nitrogen use efficiency for greater production of sugarcane.

Genome Wide Identification of Orthologous ZIP Genes Associated with Zinc and Iron Translocation in Setaria italica.

Genes in the ZIP family encode transcripts to store and transport bivalent metal micronutrient, particularly iron (Fe) and or zinc (Zn). These transcripts are important for a variety of functions involved in the developmental and physiological processes in many plant species, including most, if not all, Poaceae plant species and the model species Arabidopsis. Here, we present the report of a genome wide investigation of orthologous ZIP genes in Setaria italica and the identification of 7 single copy genes. RT-PCR shows 4 of them could be used to increase the bio-availability of zinc and iron content in grains. Of 36 ZIP members, 25 genes have traces of signal peptide based sub-cellular localization, as compared to those of plant species studied previously, yet translocation of ions remains unclear. In silico analysis of gene structure and protein nature suggests that these two were preeminent in shaping the functional diversity of the ZIP gene family in S. italica. NAC, bZIP and bHLH are the predominant Fe and Zn responsive transcription factors present in SiZIP genes. Together, our results provide new insights into the signal peptide based/independent iron and zinc translocation in the plant system and allowed identification of ZIP genes that may be involved in the zinc and iron absorption from the soil, and thus transporting it to the cereal grain underlying high micronutrient accumulation.

Aluminum in mineral nutrition of upland rice plants

Although upland rice plants have been historically considered to be tolerant to aluminum, they may have their growth prevented or decreased when cultivated on aluminum soils, besides having their uptake of water and nutrients negatively influenced. Thus, the objective of this work was to evaluate the content and accumulation of macro and micronutrients in upland rice plants submitted to aluminum toxicity. The experimental design chosen was the randomized block design, with four replications; and the treatments were five doses of aluminum (0; 370; 740; 1100 and 1480 ?mol L-1). The evaluations conducted were on the content and accumulation of macro and micronutrients in the shoot and root of the plants. Due to the interaction between aluminum and calcium, the decrease in calcium content and accumulation are the most important effects caused by aluminum on the mineral nutrition of upland rice plants. Aluminum has a high negative influence on mineral nutrition of upland rice plants, especially at its roots.

Accumulation, partitioning, and bioavailability of micronutrients in summer maize as affected by phosphorus supply

Abstract Decreased micronutrient concentration in cereal grains caused by excessive application of phosphorus (P) fertilizer may contribute to reduce their nutritional quality. To help correct this problem in maize grain, a 3-year field experiment was conducted to determine how P application rate affects micronutrient partitioning in maize shoots and other plant organs and micronutrient bioavailability in grain. Phosphorus application significantly decreased shoot zinc (Zn) and copper (Cu) concentrations at all growth stages but had no effects on shoot iron (Fe) and manganese (Mn) concentrations. As the P application rate increased, shoot Zn and Cu contents decreased, and shoot Fe and Mn contents increased. The ratios of pre-anthesis to post-anthesis mineral contents were not affected by P application rate except Zn. P application increased the percentage of Zn that was allocated to grain and decreased the percentage that was allocated to other tissues, but had no effects on the allocation of other micronutrients among tissues. The bioavailability of Zn, Cu, Fe, and Mn in grain decreased as P application rate increased. Overall, taking account of grain yield and nutrients concentration, P fertilizer rates should range from 12.5 to 25.0 kg P ha −1 under the local condition. It can be concluded that not only grain yields, but also nutritional quality, should be considered in assessing optimal P rates in maize.

Aluminum tolerance and micronutrient accumulation in cereal species contrasting in iron efficiency

ABSTRACTAluminum (Al) negatively interferes with the uptake or transport of different nutrients. The aim of our work was to compare the Al tolerance and micronutrient accumulation: iron (Fe), zinc (Zn) and manganese (Mn), in cereal species (winter wheat, spring wheat, winter rye, oats and barley) contrasting in Fe efficiency. Our previous screening in a calcareous soil showed that oats and barley were more Fe-efficient than spring wheat, winter wheat or winter rye. In Al stress conditions, both oats and barley exhibited more effectiveness in Fe acquisition and translocation from root to shoot in comparison to winter wheat, spring wheat and winter rye. Also, oats and barley responded to Al toxicity by less Al-retarded shoot biomass than other cereal species. A combination of tolerance mechanisms appears to have great importance for Al tolerance including mechanisms underlying Fe efficiency in cereal seedlings.

Effect of Alkali Solids Amendment on Sewage Sludge Aerobic Composting and the Potential of Related Products on Infertile Soil Amelioration

Aiming to evaluate the influence of alkali solids amendment on the sewage sludge aerobic composting and to declare the potential of related composts on infertile soil amelioration, sewage sludge and sawdust mixture were amended with straw biochar, hardwood biochar, fly ash and lime by 10% addition ratio in dry weight during the aerobic composting process; finally, potential of the related composts on the infertile soil amelioration was investigated by pot experiment. The results showed that the alkali solids amendment could prolong the thermophilic phase, and promote the composting material heat inactivation. Addition of straw and hardwood biochar facilitated more than 21.65% and 18.16% organic matter degradation. During the composting, the compost pH decreased at the beginning and then gradually increased before reached values of 6.78-7.33, while the fly ash and lime amendments could lead to higher pH values in the beginning stage. The alkali solids amendment reduced the salinity of the compost with final products EC lower than 3000 μS·cm-1. The addition of straw and hardwood biochar could increase the total nitrogen content by reducing the ammonia loss at the beginning, while the fly ash and lime amendments would result in ammonia loss in the beginning stage. Despite the composting variation, the contents of nitrate increased and the ammonium salt content decreased gradually. The biochar addition can accelerate the nitrate transformation while the fly ash and lime amendment had slight inhibitory effect on the nitrate transformation and plant germination. The pot experiment revealed that applying compost products could significantly improve the brassica growth, Cu and Zn micronutrients accumulation since the compost addition could increase the soil organic carbon content, as well as soil N, P, and K contents. Compared with the non-amended compost, the alkali solids amendment could slightly reduce the Cu and Zn micronutrients accumulation, while the fertile potentials were acceptable. The study indicated that straw and hardwood biochar were more suitable than fly ash and lime as compost amendment, and the related compost products had great potential on infertile soil amelioration.

Transcriptional, physiological and cytological analysis validated the roles of some key genes linked Cd stress in Salix matsudana Koidz

Salix matsudana Koidz. is a fast-growing tree species with high cadmium (Cd) tolerance, making it potentially suitable for phytoremediation. To further explore the molecular mechanisms of Cd accumulation and tolerance in S. matsudana, genome-wide transcriptome sequencing of the roots of S. matsudana, along with detection of intracellular Cd, analyses of Cd-induced physiological response and cytological toxicity was investigated. The transcriptome analyses revealed that 342 and 583 genes in the roots of S. matsudana exposed to Cd for 7days were up-regulated and down-regulated, respectively. These genes encode proteins involved in regulation and metabolism processes such as metal transport, antioxidant response, and Cd detoxification, as well as DNA replication and transcription, which suggest they play important roles under Cd stress. Physiological and cytological studies showed that low concentrations of Cd (10μM) can not cause obvious changes, but high concentrations of Cd (100μM) interfered with the accumulation of micronutrients, increased the activities of CAT, POD and SOD, reduced the contents of soluble protein and soluble carbohydrates significantly (p<0.05) and decreased the mitotic index (MI) and induced chromosomal aberrations in the root tip cells. The transcriptome results were consistent with the observed physiological and cellular changes. The identified Cd-responsive genes provide insights for the characterization of molecular mechanisms underlying Cd tolerance in S. matsudana.

Accumulation of nutrients and growth in castor bean plants

Information about nutrient uptake and accumulation by different crops during development stages allows iden­tifying periods of higher demand and an adequate fertilization management. An experiment under field condi­tions was carried out in order to evaluate macro and micronutrient accumulation in castor bean leaf tissue, as well as to identify nutrient uptake critical stages of this crop. Treatments were consisted of evaluation periods with samples collected every ten days until 160 days after emergence of crop. Castor bean plants showed higher macronutrient accumulation in descending order: N > K > Ca > S > Mg > P and the following micronutri­ents Fe > Mn > Zn > B > Cu > Mo. The highest accumulation rates of N, P and K nutrients occur from 20 to 110 days after emergence (DAE) with the highest N uptake from 30 to 40 DAE, remaining high until approximately 110 DAE. Regarding potassium, the highest uptake occurs between 40 and 50 DAE, with high uptake rates until approximately 110 DAE. The highest phosphorus uptake was between 80 and 90 DAE. The majority of macro and micronutrients were accumulated in leaves during most part of evaluation cycle.

Effects of Irrigation with Treated and Untreated Wastewater on Nutrient, Toxic Metal Content, Growth and Yield of Coriander ( Coriandrum sativum L.)

The study was conducted in Vidyaranyapuram area in the South West of Mysore, Karnataka. It was aimed to investigate the concentration of macronutrients and trace metals of arable soils and to compare by those irrigation with wastewater on soil and coriander plant (Coriandrum sativum L.), grown during its growth period. Twenty one samples each of water, soil and coriander plant were collected from different sites. Treatments included untreated wastewater (UWW); treated wastewater (TWW) and ground water (GW) as control. The used water sources when evaluated as irrigation water according to the FAO system of water quality classification were found suitable for use in leaching and irrigating the saline soils especially for short duration crops. The results indicated that use of wastewater for irrigation led to significant differences in mean values of pH, EC, N, P, Ca, Mg, Na, Mn, Cu, Zn, Cd, Ni, Pb and Cr of soil as compared to the control GW irrigated soil sample. N, P, K, Ca, Mg and Na contents also increase in leaves of coriander crop significantly higher than the GW irrigated control plants, irrigation with different proportions of wastewater showed significantly higher concentrations of heavy metals like Fe, Mn, Zn, Cu, Ni, Pb and Cr in leaf tissues of coriander crop, except for Cd and Co, as compared to the control treatment GW. The results indicated that irrigation of coriander with UWW and TWW affect negatively on growth and yield parameters of coriander; these effects could be attributed to accumulation of micronutrients and macronutrients in soil. These results suggest that UWW and TWW effluents of Vidyaranyapuram area not fit for be utilization as a important sources of water for irrigating coriander crop, as they show it did have significant harmful effects on crop productivity.

Bioaccumulation and health risks of heavy metals associated with consumption of rice grains from croplands in Northern India

ABSTRACTThe present study focused on micronutrients and nonessential toxic heavy metals quantification and their bio-concentration in soil–rice system in Haryana, India. Composite samples of rice grains and paddy fields' soil were collected, processed and analyzed for heavy metals. Nutrient and heavy metals' content of paddy fields' soil varied over a wide range, having highest Fe content followed by Cu > Cr > Pb > Ni > Zn > Co > Cd. Most of the metals viz. Fe, Zn, Cu and Co found profusely in rice grains were essential micronutrients. Bio-concentration factors (BCFs) in rice grains were in the following order: Zn (0.11) > Co (0.10) > Cu (0.08) = Cr (0.08) > Ni (0.02) > Pb (0.011) > Cd (0.009) > Fe (0.003), indicating higher accumulation of micronutrients than non-essential toxic heavy metals. Principal component analysis revealed three factors accounting for 70% of the total variance which supported correlation among electrical conductivity (EC)-Na, EC-cation exchange capacity (CEC), CEC-Na, pH-TOC, and BCFCu-BCFZn. Health risk indices anticipated that the grains are safe for consumption as non-carcinogenic hazard quotients were less than unity for all the studied heavy metals.

Nutrient accumulation at the initial growth of pitaya plants according to phosphorus fertilization

ABSTRACT The knowledge about the amount of nutrient uptake in pitaya plants helps the balanced fertilizer recommendation for the crop, providing adequate nutrition and contributing to the maximum expression of this species potential. This research was carried out in order to evaluate the growth, nutrient accumulation and efficiency of absorption, transportation and use of P by pitaya according to phosphorus fertilization. A randomized blocks design was used, with five doses of P (0 mg dm-3, 20 mg dm-3, 40 mg dm-3, 80 mg dm-3 and 160 mg dm-3) incorporated into the soil, with four replications, three pots per plot and one cutting per pot. Differences in the nutrient accumulation of all doses were evident in the pitaya shoots and roots, as well as in the efficiency of absorption, transport and use of P, according to phosphorus fertilization. The nutrient accumulation in the pitaya roots was ranked in the following order: N &gt; K &gt; Ca &gt; S &gt; P &gt; Mg &gt; Fe &gt; Mn &gt; Zn &gt; B ≥ Cu. For the shoots, the order was: K &gt; N &gt; Ca &gt; S &gt; Mg &gt; P &gt; Mn &gt; Fe &gt; Zn &gt; B ≥ Cu. The initial growth of pitaya plants was maximum with 81 mg dm-3 of P, in a Red-Yellow Dystrophic Latosol. The application of 44-67 mg dm3 of P to the soil promoted the highest accumulation of macro and micronutrients in the pitaya.

Natural Genetic Variation of Seed Micronutrients of Arabidopsis thaliana Grown in Zinc-Deficient and Zinc-Amended Soil.

The quality of edible seeds for human and animal nutrition is crucially dependent on high zinc (Zn) and iron (Fe) seed concentrations. The micronutrient bioavailability is strongly reduced by seed phytate that forms complexes with seed cations. Superior genotypes with increased seed Zn concentrations had been identified, but low micronutrient seed levels often prevail when the plants are grown in Zn-deficient soils, which are globally widespread and correlate with human Zn-deficiency. Here, seed Zn concentrations of Arabidopsis accessions grown in Zn-deficient and Zn-amended conditions were measured together with seed Fe and manganese (Mn), in a panel of 108 accessions. By applying genome-wide association, de novo candidate genes potentially involved in the seed micronutrient accumulation were identified. However, a candidate inositol 1,3,4-trisphosphate 5/6-kinase 3 gene (ITPK3), located close to a significant nucleotide polymorphism associated with relative Zn seed concentrations, was dispensable for seed micronutrients accumulation in Col-0. Loss of this gene in itpk3-1 did neither affect phytate seed levels, nor seed Zn, Fe, and Mn. It is concluded that large natural variance of micronutrient seed levels is identified in the population and several accessions maintain high seed Zn despite growth in Zn-deficient conditions.

New promising alien species of yacon (Smallanthus sonchifolia (Рoepp. et Еndl.) H. Robinson) for medicinal plant cultivation in Ukraine

Available to man source of bioactive compounds and minerals are plants. One of the promising crops is yakon that was introduced and put into culture in many countries. Perspective for Ukraine exotic species, which yakon belongs to, was recently started to grow in our country. The main area of yakon distribution is average latitude of South America. Due to the content of chlorogenic, coffee acids and other phenolic compounds in leaves yakon has antioxidant properties. Root tubers of yakon contain inulin — a polysaccharide that is easily absorbed by the body and serves as a substitute for sugar in the diets of diabetic patients. In recent years, scientists from different countries have been studying yakon hypoglycemic properties. Researchers worldwide proved that the content of important biologically active compounds and chemical composition of yakon grown under different conditions vary quite strongly. So our goal was to find the optimal soil and climatic conditions for growing exotic species and identify favorable conditions for the accumulation of macro and micronutrients. This paper defines the contents of 23 chemical elements in the leaves, roots, tubers and root peel of yakon. A high content of vital macro and trace elements, including selenium was found out. Gray forest ashed, roughly silty, easily loam soil was found to be the most suitable for growing exotic species new for Ukraine Polymnia sonchifolia Poepp. &amp; Endl., from which the highest yield — 3.5 kg weight of underground parts (root tubers and rootstock) of the plant was obtained.

Assessment of seasonal variation for air pollutant accumulation by Zizyphus tree under washing treatment.

A field study was carried out near Jeddah Industrial Zone to estimate the leaf impairment, physiological disorders, and air pollutant accumulation potential of Ziziphus tree. The experiment was triplicated in RCBD design with factorial arrangement having seasonality as the main plot and washing as subplot treatments along with the control. Accumulation of heavy metals and micronutrients in plant foliage varied significantly under the influence of seasons and washing treatments. The maximum accumulation of cadmium, chromium, nickel, and lead were perceived in summer season while the minimum was observed in winter. Contrarily, a greater acquisition of iron, copper, zinc, and manganese was observed in autumn. Washing significantly reduced the accumulation of Cd, Cr, Ni, and Pb by 58, 90, 80, and 96%, while Fe, Cu, Zn, and Mn by 89, 37, 60, and 93%, respectively. Leaf protein and nitrogen content illustrated a greater adjustment for pollutants by presenting a minimum variation (14-18% and 2-3%) to seasonality. In contrast, leaf area and stomatal aperture were significantly disturbed and resulted in minimum recovery under washing. Correlation analysis revealed a stronger negative interaction of heavy metal accumulation to leaf features while non-significant interaction was perceived for microelements. In conclusion, planting of Ziziphus trees along industrial areas may impede potential threats of toxic pollutants to human and ecosystem.

Spatially resolved analysis of variation in barley (Hordeum vulgare) grain micronutrient accumulation.

Genetic biofortification requires knowledge on natural variation and the underlying mechanisms of micronutrient accumulation. We therefore studied diversity in grain micronutrient concentrations and spatial distribution in barley (Hordeum vulgare), a genetically tractable model cereal and an important crop with widespread cultivation. We assembled a diverse collection of barley cultivars and landraces and analysed grain micronutrient profiles in genebank material and after three independent cultivations. Lines with contrasting grain zinc (Zn) accumulation were selected for in-depth analysis of micronutrient distribution within the grain by micro-proton-induced X-ray emission (μ-PIXE). Also, we addressed association with grain cadmium (Cd) accumulation. The analysis of >120 lines revealed substantial variation, especially in grain Zn concentrations. A large fraction of this variation is due to genetic differences. Grain dissection and μ-PIXE analysis of contrasting lines showed that differences in grain Zn accumulation apply to all parts of the grain including the endosperm. Cd concentrations exceeded the Codex Alimentarius threshold in most of the representative barley lines after cultivation in a Cd-contaminated agricultural soil. Two important conclusions for biofortification are: first, high-Zn grains contain more Zn also in the consumed parts of the grain; and second, higher micronutrient concentrations are strongly associated with higher Cd accumulation.

Quantitative Trait Loci and Inter-Organ Partitioning for Essential Metal and Toxic Analogue Accumulation in Barley.

The concentrations of both essential nutrients and chemically similar toxic analogues accumulated in cereal grains have a major impact on the nutritional quality and safety of crops. Naturally occurring genetic diversity can be exploited for the breeding of improved varieties through introgression lines (ILs). In this study, multi-element analysis was conducted on vegetative leaves, senesced flag leaves and mature grains of a set of 54 ILs of the wild ancestral Hordeum vulgare ssp. spontaneum in the cultivated variety Hordeum vulgare ssp. vulgare cv. Scarlett. Plants were cultivated on an anthropogenically heavy metal-contaminated soil collected in an agricultural field, thus allowing simultaneous localization of quantitative trait loci (QTL) for the accumulation of both essential nutrients and toxic trace elements in barley as a model cereal crop. For accumulation of the micronutrients Fe and Zn and the interfering toxin Cd, we identified 25, 16 and 5 QTL, respectively. By examining the gene content of the introgressions, we associated QTL with candidate genes based on homology to known metal homeostasis genes of Arabidopsis and rice. Global comparative analyses suggested the preferential remobilization of Cu and Fe, over Cd, from the flag leaf to developing grains. Our data identifies grain micronutrient filling as a regulated and nutrient-specific process, which operates differently from vegetative micronutrient homoeostasis. In summary, this study provides novel QTL for micronutrient accumulation in the presence of toxic analogues and supports a higher degree of metal specificity of trace element partitioning during grain filling in barley than previously reported for other cereals.

Chemical properties of a Haplustalf soil under irrigation with treated wastewater and nitrogen fertilization

ABSTRACT The objective of this research was to investigate the effects of irrigation with treated wastewater and nitrogen (N) fertilization on the chemical characteristics of a Haplustalf soil cultivated with cotton. An experiment was conducted in a greenhouse in a completely randomized design with four replicates, and arranged in a 5 x 4 factorial. Five doses of N fertilization (0, 45, 90, 135 and 180 kg ha-1) and four sources of irrigation water (freshwater, wastewater treated by an anaerobic reactor, wastewater treated by an anaerobic reactor and post-treated by intermittent sand filter in series, wastewater treated in a septic tank and post-treated by an intermittent sand filter) were tested. Irrigation was daily performed from July 2011 to January 2012 according to the water demand of cotton resulting in a water depth of 620 mm. It was found that, compared with the conventional management with freshwater irrigation, treated wastewater provides greater accumulation of micronutrient, potassium and sodium in the soil, increasing the risk of sodification in irrigated areas.