Zn Supply Research Articles

Suboptimal zinc supply affects the S-nitrosoglutathione reductase enzyme and nitric oxide signaling in Arabidopsis

The S-nitrosoglutathione reductase (GSNOR), a key regulator of nitric oxide (NO) signaling, requires zinc (Zn) cofactors for its catalytic activity. Possible changes in GSNOR function and NO signaling due to limited Zn supply and participation of GSNOR in response to Zn deficiency have not yet been examined. The wild-type Arabidopsis thaliana seedlings (Col-0) and the overproducer of GSNOR (35S::FLAG-GSNOR1) were grown in agar medium supplemented with 15 µM (full Zn), 1.5 µM (Zn/10) and 0 µM (Zn0) zinc sulfate. Limited availability of Zn in the nutrient medium during the experimental period resulted in a significantly reduced Zn content in the roots and shoots of Arabidopsis and altered the expression of Zn deficiency marker genes; however, the Zn content did not reflect Zn deficiency in the seedlings. GSNOR has no effect on the Zn limitation-induced reduction in the in planta Zn content. Suboptimal Zn supply results in a smaller but more active GSNOR protein pool in Col-0 A. thaliana. In 35S::FLAG-GSNOR1, overproduction possibly compensates for the negative effects of reduced Zn supply, resulting in unchanged GSNOR expression, protein abundance, and activity. Suboptimal Zn supply alters NO but did not modify peroxynitrite and hydrogen peroxide levels and exerts a pronitrant effect in the plant proteome. Overall, this is the first report to show that limited Zn supply affects the GSNOR enzyme at the gene and protein levels but not at the activity level and modifies reactive species levels and physiological nitroproteome in Arabidopsis.

Characterization of zinc uptake in seedlings of wheat cultivars differing in Zn-deficiency tolerance as affected by histidine

Knowledge of the characteristics of zinc (Zn) uptake by plant roots may help in understanding the reasons for variations in the Zn deficiency tolerance of plant cultivars. We investigated the apoplastic and symplastic Zn uptake and proton secretion by roots of three bread wheat genotypes (Triticum aestivum cvs. Rushan, Kavir, and Falat) and a durum wheat genotype (Triticum durum cv. Yavarus) under influence of histidine addition in a nutrient solution. Seedlings of wheat genotypes were planted in a nutrient solution containing 10 µM Zn with or without added 50 mM histidine (His). A control with no added Zn or histidine was also used. A significant variation was found among wheat genotypes in shoot Zn content and the characteristics of Zn uptake by roots. The addition of Zn enhanced shoot Zn content compared to the control while the effect of His was genotype-dependent. His addition in combination with Zn enhanced shoot Zn content in Rushan and Falat but not in Kavir and Yavarus compared with the only Zn supply treatment. For all wheat genotypes, the addition of Zn enhanced the total, apoplastic, and symplastic root Zn concentration compared to the control. The highest and lowest amounts of proton (H+) were secreted from the roots of Rushan and Yavarus genotypes, respectively. In all wheat genotypes except Falat, the combined addition of zinc and histidine enhanced root H+ secretion compared with the only supply of Zn. Higher plant Zn uptake was associated with a higher ability to secretion of H+ from roots and higher proportion of symplastic to apoplastic Zn.

Improved sputtering method to deposit high conducting doped ZnO films without substrate heating

Magnetron sputtering deposition with Zn supply was utilized to deposit Ga-doped ZnO (GZO) films to minimize acceptor-like crystalline defects. This deposition technique significantly increased the carrier concentration of GZO films. In addition, the impact of partial oxygen pressure on the deposition atmosphere on carrier concentration was remarkably reduced. As a result, the resistivity of the films decreased to as low as 4 × 10−4 Ωcm without the need for intentional substrate heating. Consequently, the deposition with Zn supply shows great potential for producing ZnO-based transparent conducting films with practically low resistivity on polymer substrates that have lower heat tolerance.

Mapping QTL for Mineral Accumulation and Shoot Dry Biomass in Barley under Different Levels of Zinc Supply.

Zinc (Zn) deficiency is a common limiting factor in agricultural soils, which leads to significant reduction in both the yield and nutritional quality of agricultural produce. Exploring the quantitative trait loci (QTL) for shoot and grain Zn accumulation would help to develop new barley cultivars with greater Zn accumulation efficiency. In this study, two glasshouse experiments were conducted by growing plants under adequate and low Zn supply. From the preliminary screening of ten barley cultivars, Sahara (0.05 mg/pot) and Yerong (0.06 mg/pot) showed the lowest change in shoot Zn accumulation, while Franklin (0.16 mg/pot) had the highest change due to changes in Zn supply for plant growth. Therefore, the double haploid (DH) population derived from Yerong × Franklin was selected to identify QTL for shoot mineral accumulation and biomass production. A major QTL hotspot was detected on chromosome 2H between 31.91 and 73.12 cM encoding genes for regulating shoot mineral accumulations of Zn, Fe, Ca, K and P, and the biomass. Further investigation demonstrated 16 potential candidate genes for mineral accumulation, in addition to a single candidate gene for shoot biomass in the identified QTL region. This study provides a useful resource for enhancing nutritional quality and yield potential in future barley breeding programs.

Lithium Bis(oxalate)borate Additive for Self‐repairing Zincophilic Solid Electrolyte Interphases towards Ultrahigh‐rate and Ultra‐stable Zinc Anodes

AbstractThe artificial solid electrolyte interphase (SEI) plays a pivotal role in Zn anode stabilization but its long‐term effectiveness at high rates is still challenged. Herein, to achieve superior long‐life and high‐rate Zn anode, an exquisite electrolyte additive, lithium bis(oxalate)borate (LiBOB), is proposed to in situ derive a highly Zn2+‐conductive SEI and to dynamically patrol its cycling‐initiated defects. Profiting from the as‐constructed real‐time, automatic SEI repairing mechanism, the Zn anode can be cycled with distinct reversibility over 1800 h at an ultrahigh current density of 50 mA cm−2, presenting a record‐high cumulative capacity up to 45 Ah cm−2. The superiority of the formulated electrolyte is further demonstrated in the Zn||MnO2 and Zn||NaV3O8 full batteries, even when tested under harsh conditions (limited Zn supply (N/P≈3), 2500 cycles). This work brings inspiration for developing fast‐charging Zn batteries toward grid‐scale storage of renewable energy sources.

Lithium Bis(oxalate)borate Additive for Self-repairing Zincophilic Solid Electrolyte Interphases towards Ultrahigh-rate and Ultra-stable Zinc Anodes.

The artificial solid electrolyte interphase (SEI) plays a pivotal role in Zn anode stabilization but its long-term effectiveness at high rates is still challenged. Herein, to achieve superior long-life and high-rate Zn anode, an exquisite electrolyte additive, lithium bis(oxalate)borate (LiBOB), is proposed to in-situ derive a highly Zn2+-conductive SEI and to dynamically patrol its cycling-initiated defects. Profiting from the as-constructed real-time, automatic SEI repairing mechanism, the Zn anode can be cycled with distinct reversibility over 1800 h at an ultrahigh current density of 50 mA cm-2, presenting a record-high cumulative capacity up to 45 Ah cm-2. The superiority of the formulated electrolyte is further demonstrated in the Zn||MnO2 and Zn||NaV3O8 full batteries, even when tested under harsh conditions (limited Zn supply (N/P≈3), 2500 cycles). This work brings inspiration for developing fast-charging Zn batteries toward grid-scale storage of renewable energy sources.

Cadmium and Zn hyperaccumulation provide efficient constitutive defense against Turnip yellow mosaic virus infection in Noccaea caerulescens

To understand the role of Zn and Cd in anti-viral defence, Zn/Cd hyperaccumulator Noccaea caerulescens plants grown with deficient (0.3 µM), replete (10 µM) and excess (100 µM) Zn2+ and Cd (10 µM Zn2+ + 1 µM Cd2+) were infected with Turnip yellow mosaic virus (TYMV). Gas exchange and chlorophyll fluorescence kinetics analyses demonstrated direct TYMV effects on photosynthetic light reactions but N. caerulescens was more resistant against TYMV than the previously studied non-hyperaccumulator N. ochroleucum. Virus abundance and photosynthesis inhibition were the lowest in the high Zn and Cd treatments. RNAseq analysis of 10 µM Zn2+ plants revealed TYMV-induced upregulation of Ca transporters, chloroplastic ZTP29 and defence genes, but none of those that are known to be strongly involved in hyperaccumulation. Synchrotron µ-XRF tomography, however, showed that Zn hyperaccumulation remained strongest in vacuoles of epidermal storage cells regardless of infection. This was in contrast to N. ochroleucum, where apoplastic Zn drastically increased in response to TYMV. These results suggest that the antiviral response of N. caerulescens is less induced by the onset of this biotic stress, but it is rather a permanent resistant state of the plant. Real-time qPCR revealed upregulation of ferritin in Zn10 infected plants, suggesting Fe deprivation as a virus defence strategy under suboptimal Zn supply.

Effect of trace element supply on plant growth and mineral nutrition of Cyclopia longifolia Vogel L. a Honeybush tea plant growing on a farmer's field in the Cape fynbos, South Africa

Cyclopia longifolia Vogel L. is endemic to the Cape fynbos, and cultivated for the production of Honeybush tea, a herbal beverage with health benefits and economic potential in the cosmetic and nutraceutical industries. In this study, field plants were supplemented with different levels of Cu, Mo, Mn and Zn using 0, 0.5, 1.0 and 1.5 mM solutions of Na2MoO4·2H2O and MnSO4·2H2O and 0, 1.0 and 1.5 mM solutions of ZnSO4·7H2O and CuSO4·5H2O in a split-application. Plant shoots were harvested at 300 days after fertilization for biomass determination and analysis of mineral nutrients. The results showed significantly increased shoot dry matter yield of C. longifolia in response to Mn, Cu, Zn and Mo supplementation under field conditions, and was highest at the 1.5 mM level of each applied micronutrient. These results suggest that field fertilization of Cyclopia plants can lead to increased plant growth and greater tea yield, in addition to overcoming nutrient mining from the annual harvests of plant shoots for making tea. Furthermore, supplying Mn, Zn, Cu and Mo to C. longifolia also significantly increased the concentrations and amounts of P, K, Ca, Mg, Cu, Zn, Mn and B in shoots relative to the zero controls, suggesting an increase in tea quality with trace element supplementation. However, the shoot concentrations of N and Fe were markedly reduced with increasing supply of Mn, Cu, Zn and Mo to C. longifolia plants, an indication of mineral-to-mineral antagonism in the plant rhizosphere.

Dissecting the promotional effect of zinc on cadmium translocation from roots to shoots in rice.

It is often expected that Zn decreases Cd accumulation in plants due to competition for the same transporters. Here, we found that increasing Zn supply markedly increased the root-to-shoot translocation of Cd in rice. RNA sequencing showed that high Zn up-regulated expression of genes involved in glutathione biosynthesis and metabolism and the Zn/Cd transporter gene OsHMA2, but down-regulated expression of genes related to Zn uptake. Knockout of the iron or Zn transporter genes OsIRT1, OsIRT2, or OsZIP9 did not affect the Zn promotional effect on Cd translocation. Knockout of the manganese/Cd transporter gene OsNRAMP5 greatly reduced Cd uptake but did not affect the Zn promotional effect. Variation in the tonoplast transporter gene OsHMA3 affected Cd translocation but did not change the Zn promotional effect. Knockout of the Zn/Cd transporter gene OsHMA2 not only decreased Cd and Zn translocation, but also abolished the Zn promotional effect. Increased expression of OsHMA2 under high Zn conditions supports the hypothesis that this transporter participates in the promotional effect of Zn on Cd translocation. The results also show that OsIRT1, OsIRT2, and OsZIP9 made only small contributions to Cd uptake under low Zn conditions but not under high Zn conditions, whereas the dominant role of OsNRAMP5 in Cd uptake diminished under low Zn conditions.

Solvation Modulation Enhances Anion‐Derived Solid Electrolyte Interphase for Deep Cycling of Aqueous Zinc Metal Batteries

AbstractStable Zn anodes with a high utilization efficiency pose a challenge due to notorious dendrite growth and severe side reactions. Therefore, electrolyte additives are developed to address these issues. However, the additives are always consumed by the electrochemical reactions over cycling, affecting the cycling stability. Here, hexamethylphosphoric triamide (HMPA) is reported as an electrolyte additive for achieving stable cycling of Zn anodes. HMPA reshapes the solvation structures and promotes anion decomposition, leading to the in situ formation of inorganic‐rich solid‐electrolyte‐interphase. More interestingly, this anion decomposition does not involve HMPA, preserving its long‐term impact on the electrolyte. Thus, the symmetric cells with HMPA in the electrolyte survive ≈500 h at 10 mA cm−2 for 10 mAh cm−2 or ≈200 h at 40 mA cm−2 for 10 mAh cm−2 with a Zn utilization rate of 85.6 %. The full cells of Zn||V2O5 exhibit a record‐high cumulative capacity even under a lean electrolyte condition (E/C ratio=12 μL mAh−1), a limited Zn supply (N/P ratio=1.8) and a high areal capacity (6.6 mAh cm−2).

Solvation Modulation Enhances Anion-Derived Solid Electrolyte Interphase for Deep Cycling of Aqueous Zinc Metal Batteries.

Stable Zn anodes with a high utilization efficiency pose a challenge due to notorious dendrite growth and severe side reactions. Therefore, electrolyte additives are developed to address these issues. However, the additives are always consumed by the electrochemical reactions over cycling, affecting the cycling stability. Here, hexamethylphosphoric triamide (HMPA) is reported as an electrolyte additive for achieving stable cycling of Zn anodes. HMPA reshapes the solvation structures and promotes anion decomposition, leading to the in situ formation of inorganic-rich solid-electrolyte-interphase. More interestingly, this anion decomposition does not involve HMPA, preserving its long-term impact on the electrolyte. Thus, the symmetric cells with HMPA in the electrolyte survive ≈500 h at 10 mA cm-2 for 10 mAh cm-2 or ≈200 h at 40 mA cm-2 for 10 mAh cm-2 with a Zn utilization rate of 85.6 %. The full cells of Zn||V2 O5 exhibit a record-high cumulative capacity even under a lean electrolyte condition (E/C ratio=12 μL mAh-1 ), a limited Zn supply (N/P ratio=1.8) and a high areal capacity (6.6 mAh cm-2 ).

Combined transcriptome and proteome analysis revealed the molecular regulation mechanisms of zinc homeostasis and antioxidant machinery in tobacco in response to different zinc supplies

Zinc (Zn) is an essential micronutrient for plants. Adequate regulation of Zn uptake, transport and distribution, and adaptation to Zn-deficiency stress or Zn-excess toxicity are crucial for plant growth and development. However, little has been done to understand the molecular responses of plants toward different Zn supply levels. In the present study, we investigated the growth and physiological responses of tobacco seedlings grown under Zn-completely deficient, Zn-limiting, Zn-normal, and Zn-4-fold sufficient conditions, respectively, and demonstrated that Zn deficiency/limitation caused oxidative stress and impaired growth of tobacco plants. Combined transcriptome and proteome analysis revealed up-regulation of genes/proteins associated with Zn uptake and distribution, including ZIPs, NAS3s, and HMA1s, and up-regulation of genes/proteins involved in regulation of oxidative stress, including SODs, APX1s, GPX6, and GSTs in tobacco seedlings in response to Zn deficiency/limitation, suggesting that tobacco possessed mechanisms to regulate Zn homeostasis primarily through up-regulation of the ZIPs–NAS3s module, and to alleviate Zn deficiency/limitation-induced oxidative stress through activation of the antioxidant machinery. Our results provide novel insights into the adaptive mechanisms of tobacco in response to different Zn supplies, and would lay a theoretical foundation for development of varieties of tobacco or its relatives with high tolerance to Zn-deficiency.

Evaluation of Zinc efficiency and some of nutritional and physiological responses of tomatoes cultivars

Zinc (Zn) is an enzyme cofactor involved in plant metabolism, required in auxin biosynthesis and membrane integrity required to maintain ion transport systems. Nonetheless, only a few studies have shown that Zn is efficient in tomatoes. Thus, the present study aimed to analyze the responses of several tomato cultivars to Zn application and classify the tomato cultivars that were efficient and responsive to Zn. This study utilized seven commercial lowland tomato cultivars (Tyrana, Permata, Mirah, Tombatu, Zamrud, Tymoti, and Ratna) and comprised five levels of Zn dose 0, 10, 20, 30, and 40 mg Zn kg−1, which is given in the form of ZnSO4 7 H2O. Based on the results of the analysis, the study revealed that the application of ZnSO4 up to 40 mg Zn kg−1 could increase the growth of tomato roots, while at a dose of 20 mg, Zn kg−1 could provide the most excellent physiological efficiency and utilization efficiency in tomato plants. The Tyrana and Permata cultivars are a group of cultivars that are efficient and responsive to Zn. This shows that both cultivars can grow under conditions of low Zn supply and response to Zn fertilizer.

Rational screening of metal coating on Zn anode for ultrahigh-cumulative-capacity aqueous zinc metal batteries

Aqueous zinc metal batteries feature intrinsic safety, but suffer from severe dendrite growth and water-derived side reactions. Many metal coatings have been explored for stabilizing Zn metal anode via a trial-and-error approach. Here, we propose an exercisable way to screen the potential metal coating on Zn anodes in view of de-polarization effect and dendrite-suppressing ability theoretically. As an output of this screening, cadmium (Cd) metal is checked experimentally. Therefore, symmetric Zn||Zn cells using Cd coated Zn (Zn@Cd) exhibit an ultra-long cycle life of 3500 h (nearly 5 months) at a high current density of 10 mA cm−2, achieving a record-high cumulative capacity (35 A h cm−2) compared to the previous reports. The full cells of Zn@Cd||MnO2 display a markedly improved cycling performance under harsh conditions including a limited Zn supply (N/P ratio = 1.7) and a high areal capacity (3.5 mA h cm−2). The significance of this work lies in not only the first report of Cd coating for stabilizing Zn metal anode, but also a feasible way to screen the promising metal materials for other metal anodes.

Сучасні уявлення про значущість забезпечення цинком при інфекційній патології в дітей

Zinc (Zn) is an essential trace element that is critical for growth, development and maintenance of immune function. Zn is an indispensable trace element for humans, which is part of more than 20 metalloenzymes, including DNA and RNA polymerase, phosphatase, carbonic anhydrase and some others. The cycle of cell development requires this trace element. The permeability of cell membranes is also related to Zn. It has antioxidant properties and delays the apoptosis of peripheral cells. The formation of immunity depends on the body’s supply of Zn, and its deficiency causes atrophy of the thymic-lymphatic system. Zn is part of insulin, accelerates the regeneration of the mucous layer of the intestines, increases the activity of enzymes of the brush border of enterocytes, increases the level of secretory antibodies and the intensity of cellular immunity. The provision of this element cannot but affect the course of various infectious pathologies. Purpose - by analyzing modern literature data, to find out the importance of Zn provision in infectious pathologies in children. It is analyzed a review of the literature on the pathogenetic role of Zn in the diagnosis, pathogenesis and treatment of infectious diseases, based on a search for articles in the Science, Medline and PubMed databases published from January 2017 to June 2021. An analysis of current literature has shown that Zn is an important micronutrient involved in the regulation of innate and adaptive immune responses. Zn is necessary to ensure the barrier function of membranes. It is involved in the modulation of the pro-inflammatory response. Zn homeostasis is essential for many aspects of the immune system, including hematopoiesis, cell maturation and differentiation, cell cycle progression, and proper immune cell function. Consequently, Zn deficiency leads to cell-mediated immune dysfunctions. Such dysfunctions lead to deterioration of the body's response to bacterial infection. Zn is known to modulate antiviral immunity. Due to zinc, the production of interferon-α is activated and its antiviral activity is increased. Studies show that during the infectious process there is a decrease in the concentration of zinc in the blood plasma. Such changes, on the one hand, provide the needs of immune protection factors, and on the other hand, reduce the availability of the trace element for pathogens. Conclusions. Zn is one of the important trace elements that plays a leading role in maintaining homeostasis and is an integral component of the pathogenesis of various pathological conditions of infectious origin. The most studied is Zn deficiency in infectious diarrhea in children, but studies have been conducted in developing countries with limited resources. No works studying the prevalence of Zn deficiency in Ukraine were found. No conflict of interests was declared by the authors.

Zinc Status of Horses and Ponies: Relevance of Health, Horse Type, Sex, Age, and Test Material

Little is known about the animal- and diet-related factors that could interfere with the plasma zinc (Zn) concentrations of equines. Additionally, the adequacy of plasma to reflect changes in the Zn intake is unclear. In the first part of this study, the plasma Zn concentrations of hospitalized horses and ponies (n = 538) were measured and evaluated for the impact of the age, sex, horse type, and internal diseases of the animals. In the second part, the effects of increasing dietary Zn chloride hydroxide and Zn methionine supplementations were assessed on the plasma and mane hair Zn concentrations of healthy horses (n = 2) and ponies (n = 8). Part 1: The age, sex, and horse type did not influence the plasma Zn concentrations. No effect of internal diseases was observed, with the exception of higher plasma Zn concentrations in animals with metabolic disorders compared to the control group (p < 0.05). Part 2: Both Zn supplements dose-dependently increased the Zn concentrations in the mane hair (p = 0.003), but not in the plasma of the horses and ponies. In conclusion, the plasma Zn concentrations were widely unaffected by nutritional and non-nutritional factors in equines, while mane hair samples better reflected the dietary Zn supply.

Zinc Effects on Antioxidative Enzymes and Nitrate Reductase Activity in Phaseolus vulgaris (Common Bean) Seedling

The present study analyses antioxidative enzymes and in vitro NR activity in common bean seedlings in response to ZnCl2 supply over the range of 0 – 1 mM concentrations. Bean seedlings were grown in plastic pots containing acid washed sand for 10 days and watered daily with ½ Strength Hoagland’s Solution containing 5 mM NH4NO3 as nitrogen source and desired concentration of ZnCl2. Zn supply increased seedling weight and shoot length at 0.001 mM whereas root length decreased at all concentrations.&#x0D; Amongst the antioxidative enzymes, super oxide dismutase (SOD) activity increased up to 0.1 mM significantly and then decreased at 1 mM in leaf tissue whereas in root tissue it decreased at 0.001 mM and then increased significantly. The catalase (CAT) activity increased at all the concentration being more prominent at 0.1 mM in leaf whereas in roots it increased substantially at 0.1 and 1 mM Zn. Ascorbate peroxidase (APX) activity in leaf increased at 0.1 mM but decreased at 0.001 and 1 mM, whereas in roots it decreased at all the concentration. Various in vitro activities of NR were analysed in response to Zn supply. The effect of Zn on NADH-NR is more substantial than MVH-NR at all the concentrations. Also NRmax and NRact increased at all the concentration of Zn being most prominent at 0.1 mM in leaf and at 1 mM in root tissue.

Zinc-Contained Alloy as a Robustly Adhered Interfacial Lattice Locking Layer for Planar and Stable Zinc Electrodeposition.

Stable zinc (Zn)/electrolyte interface is critical for developing rechargeable aqueous Zn-metal batteries with long-term stability, which requires the dense and stable Zn electrodeposition. Herein, an interfacial lattice locking (ILL) layer is constructed via the electro-codeposition of Zn and Cu onto the Zn electrodes. The ILL layer shows a low lattice misfit (δ= 0.036) with Zn(002) plane and selectively locks the lattice orientation of Zn deposits, enabling the epitaxial growth of Zn deposits layer by layer. Benefiting from the unique orientation-guiding and robustly adhered properties, the ILL layer enables the symmetric Zn||Zn cells to achieve an ultralong life span of >6000h at 1mA cm-2 and 1 mAh cm-2 , a low overpotential (65mV) at 10 mAh cm-2 , and a stable Zn plating/stripping for >90h at an ultrahigh Zn depth of discharge (≈85%). Even with a limited Zn supply and a high current density (8.58mA cm-2 ), the ILL@Zn||Ni-doped MnO2 cells can still survive for >2300 cycles.

Zinc Supply Affects Cadmium Uptake and Translocation in the Hyperaccumulator Sedum Plumbizincicola as Evidenced by Isotope Fractionation.

This study employs stable isotope analysis to investigate the mechanisms of cadmium (Cd) and zinc (Zn) interaction in the metal hyperaccumulating plant species Sedum plumbizincicola. To this end, the Cd and Zn isotope compositions of root, stem, leaf, and xylem sap samples were determined during metal uptake and translocation at different Cd and Zn concentrations. The enrichment of light isotopes of both elements in plants during uptake was less pronounced at low metal supply levels, likely reflecting the switch from a low-affinity to a high-affinity transport system at lower levels of external metal supply. The lower δ114/110Cd values of xylem sap when treated with a metabolic inhibitor decreasing the active Cd uptake further supports the preference of heavier Cd isotopes during high-affinity transport. The Δ66Znplant-initialsolution or Δ66Znplant-finalsolution values were similar at different Cd concentrations, indicating negligible interaction of Cd in the Zn uptake process. However, decreasing Zn supply levels significantly increased the enrichment of light Cd isotopes in plants (Δ114/110Cd = -0.08‰) in low-Cd treatments but reduced the enrichment of light Cd isotopes in plants (Δ114/110Cd = 0.08‰) under high Cd conditions. A systematic enrichment of heavy Cd and light Zn isotopes was found in root-to-shoot translocation of the metals. The Cd concentrations of the growth solutions thereby had no significant impact on Zn isotope fractionation during root-to-shoot translocation. However, the Δ114/110Cdtranslocation values hint at possible competition between Cd and Zn for transporters during root-to-shoot transfer and this may impact the transport pathway of Cd. The stable isotope data demonstrate that the interactions between the two metals influenced the uptake and transport mechanisms of Cd in S. plumbizincicola but had little effect on those of Zn.

Role of zinc in management of plant diseases: A review

Management of disease by using agrochemicals has possessed serious issues and threats to food safety and environment due to excess use. The management of diseases by enhancing resistance or tolerance through plant nutrition contributes to food safety as well as sustainable and integrated disease management. Further, these nutrients optimize yield. Utilization of nutrients in disease management requires the knowledge of their association with plant defence mechanisms. This review describes the association of Zinc (Zn) in developing a plant’s defence mechanism and reducing the severity of diseases. It was found that Zn plays an important role in the functioning of enzymes/proteins like alcohol dehydrogenase, superoxide dismutases, metallothionein and zinc-finger proteins involved in plants’ response to pathogens. Zn supply increases the expression of various antioxidant systems detoxifying the harmful level of free radicals upon infection. Zn enhances the signalling of various defence pathways like salicylic acid-dependent pathways and jasmonic acid/ethylene-dependent pathways as well as improves membrane integrity assisting in defence against pathogens’ attack. A deficiency of Zn makes a plant susceptible to infection due to a deprived condition while an excess level negatively impacts growth and defence due to toxicity. Thus, high and non-toxic levels of Zn supply can be beneficial in enhancing a plant’s defence responses which depend on the nature of the plant and its interaction with pathogens. This study provides a basis for the exploration of the negative relationship between nutrient management and plant diseases.