Zn In Grain Research Articles

Genotypic variation in the response of soybean to elevated CO2.

The impact of elevated CO2 (eCO2) on soybean productivity is essential to the global food supply because it is the world's leading source of vegetable proteins. This study aimed to understand the yield responses and nutritional impact under free-air CO2 enrichment (FACE) conditions of soybean genotypes. Here we report that grain yield increased by 46.9% and no reduction in harvest index was observed among soybean genotypes. Elevated CO2 improved the photosynthetic carbon assimilation rate, leaf area, plant height, and aboveground biomass at vegetative and pod filling stages. Besides the positive effects on yield parameters, eCO2 differentially affected the overall grain quality. The levels of calcium (Ca), phosphorous (P), potassium (K), magnesium (Mg), manganese (Mn), iron (Fe), boron (B), and zinc (Zn) grain minerals decreased by 22.9, 9.0, 4.9, 10.1, 21.3, 28.1, 18.5, and 25.9% under eCO2 conditions, respectively. Soluble sugars and starch increased by 9.1 and 16.0%, respectively, phytic acid accumulation increased by 8.1%, but grain protein content significantly decreased by 5.6% across soybean genotypes. Furthermore, the antioxidant activity decreased by 36.9%, but the total phenolic content was not affected by eCO2 conditions. Genotypes, such as Winsconsin Black, Primorskaja, and L-117, were considered the most responsive to eCO2 in terms of yield enhancement and less affected in the nutritional quality. Our results confirm the existence of genetic variability in soybean responses to eCO2, and differences between genotypes in yield improvement and decreased sensitivity to eCO2 in terms of grain quality loss could be included in future soybean selection to enable adaptation to climate change.

Peningkatan Kadar Zn Beras Pecah-Kulit pada Sistem Penggenangan Berselang Melalui Aplikasi Pupuk Kandang Diperkaya Zn Heptahidrat

Zn levels in rice are essential for maintaining consumer health. However, Zn deficient plants can reduce levels of Zn in grains and the ability of plants to express their genetic potentials. This study examines the use of cow manure enriched with Zn heptahydrate on increasing Zn levels of broken skin rice. The experiment was arranged in a randomized single factor group design with seven levels of manure dose treatment, namely: 0; 2.5; 5, 7.5, 10, 12.5, 15 tons ha-1, with 3 replications. Spacing was 30 cm x 30 cm with a size of 3 m x 4 m. The parameters observed were plant growth, the weight of 1,000-grain, percentage of empty grain, production, Zn and protein contents of the brown rice. The collected data were analyzed using analysis of variance with a confidence interval of 5%, followed by the Duncan test of 5%. The results showed that the application of cow manure with a dose of 10 tons ha-1 enriched by 5 kg ha-1 Zn heptahydrate could increase the number of productive tillers, weight of 1,000-grains, production, Zn and protein contents of the brown rice as well as suppress the grainy rice grain of Mekongga variety of lowland rice on the intermittent flooding.
 
 Keywords: brownrice, cow manure, irrigation system, Zn heptahydrate

Utilization of Molecular Markers for Rice Breeding

Rice is the staple food for more than half of the world's population. Rice production in 2050 must increase by at least 50% to keep up with the population growth. Efforts to increase rice production continue using various strategies. Breeders apply multiple approaches including application of molecular markers in developing varieties better than the previous ones. Since the discovery of the restriction fragment length polymorphism (RFLP) markers in 1980s and the development of polymerase chain reaction (PCR) method, many types of molecular markers have been developed and applied to various crops including rice. Various molecular approaches to map genetic loci associated with rice superior traits were conducted. The mapped loci are very useful for rice breeding purposes. This paper reports the results of mapping and breeding economically important traits in rice, mainly those related to abiotic stresses, agronomic traits, yield, and yield quality. These included characters of semidwarf stature, aromatic grain, high yield potential, eating quality, higher Zn and Fe grain, more tolerant to abiotic stresses, such as salinity, drought, phosphate deficiency, Al toxicity and Fe toxicity, submergence, as well as early maturity character. The mapped characters can be transferred using marker-assisted backcrossing (MABC) method into cultivated rice genotypes well-adopted by farmers. Several countries including Indonesia have benefited from this breeding method, and Indonesia have released several rice varieties developed through MABC. These include rice varieties such as Code, Angke, Inpari 30, Inpari Blas, Inpari HDB, Bio Patenggang Agritan, and Bioni 63 Ciherang Agritan

Influence of zinc sulfate concentration in baths on the structure, morphology and tribocorrosion properties of Fe-Zn alloy coating

To address the glazing issue of impregnated diamond bit in drilling hard and compact rock formations, Fe-Zn alloys were electrodeposited from acid sulfate baths and the surface morphology , phase composition, microhardness and tribocorrosion property of the deposits were studied. As the ZnSO 4 concentration increased from 0 g/L to 20 g/L, the morphology of deposits changed from fine-grained clusters to triangular based pyramids, and finally to granular grains. α phase, η phase and a mixture of α phase and η phase were identified in Fe-Zn coatings. And the microhardness of the deposits is influenced by the Zn content and grain size of Fe-Zn alloy. Furthermore, tribocorrosion behaviors of the deposits were investigated in NaCl solutions by electrochemical measures (potentiodynamic polarization, electrochemical current noise) with an abrasion-corrosion rig. Results of tribocorrosion tests showed that the primary form of the material loss was pure mechanical wear , except the deposit obtained at 20 g/L ZnSO 4 , whose mass loss due to corrosion-induced abrasion contributed most to its total material loss. The degradation mechanism of Fe-Zn deposits was also detailed in this paper. • Fe-Zn alloy was electrodeposited from an acid bath with improved stability. • The morphology of Fe-Zn deposits changed with the variation of phase structure. • Fe-Zn coating with 20% Zn provided the best combination of hardness and mass loss. • The wear mechanism of Fe-Zn deposits in silica slurry with NaCl was discussed.

Validation of Genes Affecting Rice Grain Zinc Content Through Candidate Gene-Based Association Analysis.

Several key genes governing Zn homeostasis and grain zinc content (GZC) have been functionally characterized. However, the effects of these genes in diverse breeding populations have not been evaluated; thus, their availability in breeding is unclear. In this study, the effects of 65 genes related to rice zinc responses on GZC were evaluated using two panels of breeding lines, and the superior haplotypes were identified. One panel consisted of mega varieties from the International Rice Research Institute (IRRI), South Asia, and Southeast Asia (SEA), and the other panel is breeding lines/varieties from South China (SC). In addition, a multiparent advanced generation intercross (MAGIC) population, named as DC1, was also employed. Three analytical methods, single-locus mixed linear model (SL-MLM), multilocus random-SNP-effect mixed linear model (mrMLM), and haplotype-based association analysis (Hap-AA), were applied. OsIDEF1 (which explained 12.3% of the phenotypic variance) and OsZIFL7 (8.3–9.1%), OsZIP7 (18.9%), and OsIRT1 (17.9%) were identified by SL-MLM in SEA and SC, respectively, whereas no gene was significantly associated with GZC in DC1. In total, five (OsNRAMP6, OsYSL15, OsIRT1, OsIDEF1, and OsZIFL7, 7.70–15.39%), three (OsFRDL1, OsIRT1, and OsZIP7, 11.87–17.99%), and two (OsYSL7 and OsZIP7, 9.85–10.57%) genes were detected to be significantly associated with GZC in SEA, SC, and DC1 by mrMLM, respectively. Hap-AA indicated that Hap1-OsNRAMP5, Hap5-OsZIP4, Hap1-OsIRT1, Hap3-OsNRAMP6, Hap6-OsMTP1, and Hap6-OsYSL15 had the largest effects for GZC in SEA, whereas Hap3-OsOPT7, Hap4-OsIRT2, Hap4-OsZIP7, Hap5-OsIRT1, and Hap5-OsSAMS1 were the most significant in the SC population. Besides, superior alleles were also identified for the significant genes. The genes significantly associated with GZC and their superior haplotypes identified in different panels could be used in enhancing GZC through molecular breeding, which could further address the problem of Zn malnutrition among rice consumers.

Soil Zn Fertilization and Inoculation with Arbuscular Mycorrhizal Fungus and Azotobacter Chroococcum Bacteria Affect the Cd Concentration and Zn Bioavailability in Bread Wheat Grown in a Cd-spiked Soil

ABSTRACT Wheat is the main staple crop in Iran and thus of critical importance in human nutrition. This study was conducted to investigate the effect of individual and co-inoculation of azotobacter chroococcum bacteria (A. chroococcum) and a species (Rhizophagus irregularis) of arbuscular mycorrhizal fungi (AMF) on improving the nutritional quality of bread wheat grain. We performed a pot experiment, in which the effects of R. irregularis and A. chroococcum inoculation, and zinc (Zn) fertilization [0, 4.4, and 8.8 mg (kg)−1] to cadmium (Cd)-spiked soil on increasing the Zn bioavailability and reducing the Cd concentration of wheat grains were tested. Inoculation with A. chroococcum increased the rate of root colonization by R. irregularis. Root colonization with AM fungus significantly reduced the grain Cd concentration especially after co-inoculation with A. chroococcum and soil application of ZnSO4 fertilizer. Mycorrhized plants, compared to non-mycorrhized plants had considerably higher grain concentrations of phosphorous (P) and nitrogen (N), which were affected by the application rate of ZnSO4 and co-inoculation with A. chroococcum. The response of grain Zn concentration to mycorrhization was dependent on the rate of Zn fertilization and inoculation with A. chorococum. Single inoculation with R. irregularis increased the concentration of phytic acid (PA) and also the molar ratio of PA:Zn in grains, which may have resulted in reduced Zn bioavailability. In contrast, double inoculation of plants with R. irregularis and A. chroococcum reduced the molar ratio of PA:Zn especially after application of ZnSO4. This study suggests that dual inoculation of wheat plants with A. chroococcum and R. irregularis together with Zn fertilization may enhance the nutritional quality of wheat grains.

Effect of sulphur and zinc management on yield, quality and nutrient uptake in pearl millet (Pennisetum glaucum) – lentil (Lens culinaris) crop sequence

A field experiment was conducted at Panwari village of Agra district during Kharif and rabi season of 2015-16 and 2016-17 to study the effect of sulphur and zinc management on yield, nutrient uptake and residual soil fertility under pearl millet (Pennisetum glaucum) – lentil (Lens culinaris Medikus) crop sequence. Four levels each of sulphur and zinc were evaluated under randomized block design with three replications. Both the nutrients were applied to pearl millet and their direct and residual response was ascertained to pearl millet and lentil in sequence. Pooled results indicated that grain and stover yield of pearl millet improved significantly with increasing levels of S up to 20 kg S ha-1 over control. An increase of 17.0 and 16.5 % in grain and stover yield was recorded with 20 kg S ha-1 over control. Similarly, grain and stover yield of pearl millet increased significantly with Zn and maximum grain (3.46 t ha-1 ) and stover (8.19 t ha-1 ) yields were recorded with 4 kg Zn ha-1 . The content and yield of protein in both the crops increased significantly with the addition of S and Zn over control. The residual effect of S in lentil was significant at 40 kg S ha-1 and grain and straw yield increments were to the extent of 18.6 and 15.8 per cent, respectively. The residual effect of 6 kg Zn ha-1 on succeeding lentil crop produced 16.7 and 14.0 % higher grain and straw yield over control, respectively. Application of S and Zn showed significantly beneficial effect on S and Zn uptake by pearl millet and succeeding lentil crop over control. Nitrogen and P uptake by both the crops also improved significantly with these elements over control

High Soil Phosphorus Application Significantly Increased Grain Yield, Phosphorus Content but Not Zinc Content of Cowpea Grains

To ameliorate the impact of soil phosphorus (P) deficiency on cowpea, the use of P-based fertilizers is recommended. Plant zinc (Zn) is an essential nutrient required by plants in a wide range of processes, such as growth hormone production and metabolism. However, a negative association between plant Zn content and high P application has been reported in some crops. There are few reports about soil P application and plant Zn content relationship on cowpea. Thus, this study investigated the response of cowpeas to three P rates in the screenhouse (0, 1.5, and 30 mg P/kg) and field (0, 10, and 60 kg P2O5/ha) and their effects on plant P and Zn content, biomass, and grain yield. In the screenhouse, shoot and root dry weights, and shoot P and Zn content were measured. Shoot dry weight, grain yield, grain P, and Zn contents were determined from field plants. Higher rates of P led to increased shoot biomass and grain yield of the field experiment but were not associated with a significant change in shoot or grain Zn content. There was not a significant correlation between grain yield and Zn content in high soil P (p < 0.05). The effect of higher P application on reduced plant Zn contents may be genotype-dependent and could be circumvented if genotypes with high Zn content under high soil P are identified.

Selenium uptake and grain nutritional quality are affected by nitrogen fertilization in rice (Oryza sativa L.).

The effects of selenium in rice grain composition depend on the soil nitrogen supply. Selenium and nitrogen have the potential to modify rice grain composition; however, it is unclear how the combined effect of Se and nitrogen affects the grain nutritional quality of rice. In our study, grain Se concentration was positively associated with the increased availability of nitrogen in soil. The accumulation of Se in grain of rice plants treated with Se combined with nitrogen was accompanied by an increase in expression of NRT1.1B, a rice nitrate transporter and sensor, in root. Moreover, Se potentiates the response of nitrogen supply in expression of sulfate transporter OsSULTR1.2, phosphate transporter OsPT2 and silicon transporter OsNIP2.1 in root, thereby increasing root Se uptake capacity. The combination of Se with high nitrogen increased the concentrations of protein, carbohydrates, Se, Mo and Mg, but decreased concentrations of Fe, Mn, Cu and Zn in grain. Overall, our results revealed that many of the effects of Se in rice grain composition are due to a shift in the nitrogen status of the plant.

The effect of zinc shape on its corrosion mitigation as an anode in aqueous Zn/MnO2 battery

• Developing of Zn powder and dust electrode for aqueous Zn/MnO 2 battery. • Zn powder with grain sizes >500 µm attenuate its corrosion and dissolution in NH 4 Cl solution. • Assembling of Zn powder or dust (anode) with electrolytic (EMD) or nanostructured (NMD) MnO 2 (cathode) in Zn/MnO 2 cell. • Zn powder (>500 µm)/NMD cell yields a highest output voltage of 1.646 V. • Specific energy (109.722 mWh/g) and the lowest voltage drop of 0.7% after 2 h of discharge. This work gives an insight into how zinc (Zn) anode in the Zn/MnO 2 batteries is corroded depending on its shape (in the form of powder or dust), and how such shape can play a role to attenuate the Zn corrosion and dissolution during an electrochemical process. Indeed, the corrosion of Zn anodes in powder and dust shape was investigated in ammonium chloride aqueous NH 4 Cl solution using open circuit potential (OCP) plot, linear polarization (LP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods. The electrodes were also observed by scanning electron microscopy (SEM) and analyzed using X-ray diffraction (XRD). The results show that the corrosion rate significantly depends on Zn grain size and surface area. In addition, the SEM observations showed clearly some corrosion features on the surface of Zn grains. Furthermore, the XRD analysis confirms the formation of a corrosion layer constituted of ZnO and adsorbed Zn(NH 3 ) 2 Cl 2 molecules. These electrodes, with two distinct shapes, were used as anodes in assembled Zn/MnO 2 batteries with two types of MnO 2 cathode namely nanostructured manganese dioxide (NMD) and electrolytic manganese dioxide (EMD). Discharge tests showed high performance for Zn/MnO 2 cell based on Zn powder (>500 µm) as anode and NMD as a cathode in NH 4 Cl electrolyte, with an output voltage of 1.65 V and specific energy of 109.72 mWh/g after 2 h under 1 mA. Moreover, this cell is the most stable with a voltage drop as low as 0.7% after 2 h of continuous discharge. Such results demonstrate that the assembled Zn/MnO 2 can be used for low cost and high-performance battery with a specific structure and shape of both anode and cathode materials.

Zinc biofortification of bread winter wheat grain by single zinc foliar application

Wheat grain Zn concentration has important implications for Zn dietary intake in humans. Zn biofortification of wheat by Zn foliar application has been recognized as an efficient tool to enhance grain Zn level. In Serbia, wheat is a staple crop, and no attention is paid to wheat grain as a source of Zn. For the first time, we investigated the effect of Zn foliar application on grain Zn concentration and yield of high-yielding local bread wheat cultivars in Serbia as potential to improve Zn intake in local population. Field experiments were conducted over two growing seasons at two sites located in Vojvodina Province. Zn was applied by spraying of 0.5% water solution of ZnSO4 at the end of flowering stage. Zn foliar application had no significant effect on grain yield. Significant increases of Zn grain concentration resulted from Zn treatment in all of five cultivars tested, ranging from 15 to 49%. No significant difference between the two sites was found in the mean increase in grain Zn concentration by Zn foliar application compared with the control. No correlation was found between grain yield and grain Zn concentration, implying that high grain yields common in intensive wheat production in Serbia do not limit Zn biofortification of grain by Zn foliar application. Zn biofortification of wheat grain by a single foliar spray at the end of the flowering stage can be recommended as an efficient tool to increase Zn intake in human population and prevent low dietary Zn intake.

Combination of High Zn Density and Low Phytic Acid for Improving Zn Bioavailability in Rice (Oryza stavia L.) Grain

BackgroundZn deficiency is one of the leading public health problems in the world. Staple food crop, such as rice, cannot provide enough Zn to meet the daily dietary requirement because Zn in grain would chelate with phytic acid, which resulted in low Zn bioavailability. Breeding new rice varieties with high Zn bioavailability will be an effective, economic and sustainable strategy to alleviate human Zn deficiency.ResultsThe high Zn density mutant LLZ was crossed with the low phytic acid mutant Os-lpa-XS110–1, and the contents of Zn and phytic acid in the brown rice were determined for the resulting progenies grown at different sites. Among the hybrid progenies, the double mutant always displayed significantly higher Zn content and lower phytic acid content in grain, leading to the lowest molar ratio of phytic acid to Zn under all environments. As assessed by in vitro digestion/Caco-2 cell model, the double mutant contained the relatively high content of bioavailable Zn in brown rice.ConclusionsOur findings suggested pyramiding breeding by a combination of high Zn density and low phytic acid is a practical and useful approach to improve Zn bioavailability in rice grain.

Improving Grain Micronutrient Content of Durum Wheat (Triticum turgidum var. durum) through Agronomic Biofortification to Alleviate the Hidden Hunger

Improvement of durum wheat grain quality through agronomic biofortification becomes a priority research area and an effective route to combat malnutrition. An experiment was conducted to evaluate the effect of micronutrient application to different varieties of durum wheat and seeding rate on final harvest grain quality under different growing locations. The treatments were arranged in split-split plot design where the varieties were assigned in the main plot, micronutrients into the subplots, and seeding rate into the sub-subplots. Each variety was sown at four levels of seeding rates and treated with ZnSO₄ and FeSO4 applied foliarly, both at a rate of 25 Kg ha−1 during flowering. Micronutrients were applied in the form of ZnSO₄ 7H2O and FeSO₄ 7H2O. The study confirmed that application of 25 Kg ha−1 ZnSO₄-containing fertilizer has increased mineral content from 33.04 mg Kg−1 to 56.73 mg kg−1. The tested durum wheat varieties significantly differ in their capacity to accumulate grain Zn and Fe concentrations. Higher amount of Zn (20 mg kg−1) and Fe (10 mg kg−1) were accumulated by the landrace 208304 than by Asassa, an improved commercial variety. Increasing seeding rate from 100–175 Kg ha−1 has reduced grain Zn and Fe concentrations. Grain mineral concentration was significantly lower at the Mekelle location than at the Melfa location. It can be concluded that foliar application of ZnSO₄ and FeSO4 to the landrace, acc.208304, combined with 125 Kg seeds ha−1 can produce better Zn and Fe denser durum wheat grain. This will help to combat the hidden hunger, especially in resource poor countries, where fortified foods are limited in access and unaffordable by small-scale farmers.

A thorough screening based on QTLs controlling zinc and copper accumulation in the grain of different wheat genotypes.

Excess trace metals may cause damage to human health due to the consumption of food grain grown in contaminated soils. This study was designed to understand the genetic mechanisms of copper (Cu) and zinc (Zn) accumulation in wheat grain under stressed environments. The differences of Cu/Zn contents in the grain among 246 wheat varieties were analyzed, and the wheat varieties with low or high accumulation of Cu and Zn in the safe range were also screened out. The accumulation of Cu and Zn in grains of "Chushanbao" was lowest, which could be used as a novel germplasm for wheat breeding under heavy metal stress. We found that Cu contents of wheat grain were significantly and positively correlated with Zn. The quantitative trait loci (QTLs) for grain Cu content (GCuC) and grain Zn content (GZnC) were detected by genome-wide association study (GWAS). Twenty-three loci affecting GCuC were identified on chromosomes 1A, 1D, 2A, 2B, 2D, 3A, 3B, 3D, 4A, 4B 4D, 5A, 6D, 7A, and 7B, explaining 2.6-5.8% of the phenotypic variation. Sixteen loci associated with the GZnC on 11 different chromosomes 1B, 2B, 2D, 3A, 3D, 4A, 4B, 5A, 5D, 6B, and 7D were detected, which could explain 2.7~6.6% of phenotypic variance. We also determined five associated loci on chromosomes 2B, 2D, 3A, 4B, and 5A were in pleiotropic regions affecting both GCuC and GZnC. This study would help in better understanding the molecular basis of Cu/Zn accumulation in wheat grain, and the associated markers may be useful for marker-assisted selection (MAS) breeding program.

Rice cropping system in semi-mechanized and traditional planting patterns in Northern Iran

Modifying the conventional rice cropping systems and creating innovative cropping techniques might be considered as a way to increase performance, reducing the environmental pollutants and, enhancing the productivity. Therefore, the present study was aimed to determine the different cropping systems and planting patterns of rice crop. Field trials were conducted in Babol region located in north of Iran during the periods of 2016 and 2017. The experiment was carried out as factorial based on a randomized complete blocks design (RCBD) with four replications. Five cropping systems including conventional, low-input, high-input, improved and organic systems were used as main plots. Two planting patterns (traditional and semi-mechanized) were considered as subplots, respectively. The findings displayed that the days from transplanting to tillering, panicle initiation and full maturity of rice in traditional method was significantly higher than semi-mechanized method. The no. of tiller per hill, no. of fertile tiller per hill, nutrients (N, P, K and Zn) harvest index and nutrient (N, P, K and Zn) unitization efficiency in semi-mechanized method was significantly greater than traditional method. Days from transplanting to panicle initiation in conventional system was higher than high-input, improved, low-input and organic systems, respectively. Days from transplanting to full maturity in conventional system was greater than high-input, improved, low-input and organic systems, respectively. Paddy yield (PY) in high-input system (4331 kg ha−1) was 6.07%, 19.44% and 28.52% greater than conventional, low-input and organic systems, respectively. PY in improved system (4293 kg ha−1) was 5.14%, 18.39% and 27.39% higher than conventional, low-input and organic systems, respectively. The most nutrients (N, P, K, Zn) grain and straw uptakes was obtained in high-input, improved and conventional systems. In contrast, nutrient utilization efficiency in organic system was significantly greater than low-input, improved, high-input and conventional systems, respectively. Therefore, it seems that by designing an innovative improved system, the production productivity can be enhanced and will be resulted in enhance of nutrients uptake and utilization efficiency in rice crop.

Two metallothionein genes highly expressed in rice nodes are involved in distribution of Zn to the grain.

A rice node is a hub for distribution of mineral elements; however, most genes highly expressed in the node have not been functionally characterized. Transcriptomic analysis of a rice node revealed that two metallothionein genes, OsMT2b and OsMT2c, were highly expressed in the node I. We functionally characterized these genes in terms of gene expression pattern, cellular and subcellular localization, phenotypic analysis of the single and double knockout mutants and metal-binding ability. Both OsMT2b and OsMT2c were mainly and constitutively expressed in the phloem region of enlarged and diffuse vascular bundles in the nodes and of the anther. Knockout of either OsMT2b or OsMT2c increased zinc (Zn) accumulation in the nodes, but decreased Zn distribution to the panicle, resulting in decreased grain yield. A double mutant, osmt2bmt2c, showed further negative effects on the Zn distribution and grain yield. By contrast, knockout of OsMT2b had a small effect on copper (Cu) accumulation. Both OsMT2b and OsMT2c showed binding ability with Zn, whereas only OsMT2b showed binding ability with Cu in yeast. Our results suggest that both OsMT2b and OsMT2c play an important role mainly in the distribution of Zn to grain through chelation and subsequent transport of Zn in the phloem in rice.

Phosphorus and Zinc Fertilization Improve Zinc Biofortification in Grains and Straw of Coarse vs. Fine Rice Genotypes

Continuous cropping of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) deplete soil fertility and reduce crop productivity as well as zinc (Zn) concentrations in rice grains and straw. Low Zn concentrations in rice grains have a negative impact on human health, while low Zn concertation in rice straw creates a nutritional problem for animals. The current high yielding rice varieties and hybrids remove large quantities of Zn from the soils, lowering the residual concentrations of soil Zn for the subsequent crop (e.g., wheat). Field experiments were conducted on farmers field in Malakand with the objective to evaluate the impact of various combinations of phosphorus (0, 40, 80, and 120 kg ha−1) and Zn levels (0, 5, 10, and 15 kg ha−1) on biofortification of Zn in grains and straw of rice genotypes [fine (Bamati-385) vs. coarse (Fakhre-e-Malakand and Pukhraj)]. The results revealed that Zn biofortification in rice genotypes increased with the integrated use of both nutrients (P + Zn) when applied at higher rates (80 and 120 kg P ha−1, and 10 and 15 kg Zn ha−1, respectively). The biofortification of Zn in both grains and straw was higher in the coarse than fine rice genotypes (Pukhraj > Fakhre-e-Malakand > Basmati-385). It was concluded from this study that the application of higher P and Zn levels increased Zn contents in rice parts (grains and straw) under the rice-wheat system. We also concluded from this study that Zn concentrations in rice grains and straw are influenced by plant genetic factors and Zn management practices.

Enhancing nutrient translocation, yields and water productivity of wheat under rice–wheat cropping system through zinc nutrition and residual effect of green manuring

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice–wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5 × 103 and 30.5 × 103 L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5 × 103, 47 × 103 and 13 × 103 L irrigation water per tonne wheat over residual effect of 5 kg Zn ha−1 through chelated Zn-EDTA as soil application, 2.5 kg Zn ha−1 through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering + flowering + grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.

Reexamination of Nucleation and Growth Behavior of Zn during Zincating on Al: Role of Nitric Acid Etching

Deposition of various coatings on Al surface is required for variety of functional applications such as for better corrosion resistance, improvement in conductivity, wear resistance etc. These coatings are normally applied on Al surface followed by well-known zincating process (galvanic displacement) in order to obtain subsequent adherent overlayer coatings. Adhesion of these overlayers depends on uniformity of Zn films on Al surface and researchers normally follow either single zincating or double zincating process to eliminate oxide layer interference. However, it has been established over the years that double zincating is a better technique in comparison to single zincating to produce a uniform Zn-films on Al surface. It is to mention here that Al substrate undergoes nitric acid dip followed by single zincating prior to double zincating and is a very important step. A quiet good amount of research has already been devoted to obtain various adherent coatings on Al and Al-alloys and to analyze the nucleation mechanism during single and double zincating processes. However, the underline mechanism of nitric acid etching and its role on subsequent Zn-nucleation is yet to be fully understood. In view of this, in the present study, a systematic effort has been made to elucidate the role of nitric acid etching followed by single zincating on Zn nucleation and growth mechanism during subsequent second zincating. For this, we have studied the time-dependent zinc nucleation on 99.95% pure Al during single as well as double zincating. These Zn-nucleation and growth behavior on Al surface was monitored using AFM, FESEM and FIB-cut cross section image investigations in detail. Difference in nucleation and growth pattern of Zn on Al during two zincating processes was analyzed. Apart from these, the porous surface obtained after nitric acid dissolution was investigated in depth under AFM and FESEM along with EDS. Non-gravimetric method such as Rutherford Backscattering Spectrometry (RBS) was used to determine the deposition rate of Zn during competitive galvanic deposition of Zn and alkaline dissolution of Al while zincating. The Zn grain size obtained from AFM image was verified by GIXRD analysis. Open circuit potential (OCP) was monitored during single as well as double galvanic displacement processes to understand Zn nucleation behavior and correlated with the morphological data. The observed results will be discussed in terms of electrochemical processes involved, change in chemical nature of the Al surface and porous layer formation due to nitric acid etching and thermodynamic supersaturation on Zn nucleation. Figure 1

Role of Integrated Nutrient Management and Agronomic Fortification of Zinc on Yield, Nutrient Uptake and Quality of Wheat

Phosphorus (P) and zinc (Zn) are essential plant nutrients, and their deficiency in soils and the antagonistic effect of P on Zn are important concerns world-over. Thus, a two-year (2012–13 to 2013–14) experimentation was carried out to assess grain yield, nutrient uptake and quality parameters of wheat by various levels of P and Zn. The results revealed that 50% recommended dose of P (RDP) through phospho-enriched compost (PEC) + 50% RDP through fertiliser and soil application of 12.5 kg ZnSO4.7H2O ha−1 + one foliar spray of 0.5% ZnSO4.7H2O recorded significantly higher grain yield (4.81 and 4.61 t ha−1, respectively), straw yield (7.20 and 6.92 t ha−1, respectively) and protein content (11.5% and 11.3%, respectively). The concentrations of Zn in grain (35.6%) and straw (57.3%) were not affected due to organic P application but 100% P through P fertilizer reduced the Zn content in the grains. Both soil and foliar application of Zn were found to be more promising in increasing Zn and Fe concentration in grains (37.5 and 30.9 mg kg−1, respectively) and straw (60.3 and 398 mg kg−1, respectively). Overall, the treatment combination of 50% RDP through PEC + 50% RDP through fertiliser and soil applied 12.5 kg ZnSO4.7H2O ha−1 + one spray of 0.5% Zn was beneficial in reducing antagonistic effect of P on Zn and increasing Zn and Fe concentration in wheat grain and, thus, could be used for improving the yield of Zn and Fe enriched wheat grains.