Zinc Efficiency Research Articles

Uptake of zinc from chelate-buffered nutrient solutions by wheat genotypes differing in zinc efficiency

Zinc-efficient Triticum aestivum (cv. Warigal) and Zn-inefficient Triticum turgidum conv. durum (cv. Durati) were grown in chelate-buffe red, complete nutrient solutions providing either deficient or sufficient Zn supply. When transferred to fresh chelatebuffered nutrient solutions containing a wide range of Zn supplies (0-1.28/rniol m3 Zn2+ activity) for 24-48 h, both genotypes increased net Zn uptake linearly with an increase in solution Zn2+ activities. Zincefficient Warigal accumulated Zn at a greater rate than Zn-inefficient Durati. The greater rate of net Zn uptake was observed by plants of both genotypes when pretreated at deficient Zn supply. Net loss of Zn to the solution was higher in plants pretreated with sufficient Zn and was inversely related to Zn 2+ activity in the external solution. When continuously supplied with 40nmolm~3 Zn2+, net Zn uptake by Zn-efficient Warigal was significantly greater than that of Zn-inefficient Durati, but the difference diminished with plant age. Shoot concentrations of Fe, Mn and Cu were higher when plants were grown at deficient than at sufficient Zn supply. The Zn-efficient genotype transported less Zn and Fe to shoots and had higher Fe concentration s in roots than the Zn-inefficient genotype, supporting the hypothesis that Zn efficiency may be connected with inefficient transport of Fe from roots to shoots and thus initiation of the Fe-deficiency response resulting in increased release of Zn- and Fe-binding phytosiderophores. It is concluded that differential Zn efficiency of wheat genotypes is at least partly due to a greater ability of efficient genotypes to accumulate Zn.

Root morphology of wheat genotypes differing in zinc efficiency

Abstract The root morphology (root length, diameter) of the three wheat genotypes (Triticum aestivum L. cvs Excalibur and Gatcher, and T. turgidum conv. durum (Desf.) McKay cv Durati) grown in zinc (Zn)‐deficient, sandy soil under controlled conditions has been measured by a root scanner coupled to a computer. Wheat plants were supplied with 0, 0.025, 0.05, 0.1, 0.2, or 0.4 mg Zn/kg soil. Excalibur has previously been identified as the Zn‐efficient genotype which can take up more Zn and has higher yield in soils with low plant‐available Zn. Durati is Zn‐inefficient and Gatcher an intermediate genotype with respect to Zn efficiency. Root and shoot dry matter significantly increased at 0.1 mg Zn/kg soil compared to the 0 Zn level. Zinc content in shoots was lower in Durati than in Excalibur and Gatcher at sufficient supply of Zn. Zinc applications had no significant effect on root morphology at two weeks after sowing. At that time, however, the Zn‐efficient genotype Excalibur developed a longer and thinner roots (greater proportion of fine roots with diameter <0.2 mm) than the less efficient Gatcher and Zn‐inefficient Durati. Hence, growing longer and thinner roots and having a greater proportion of thinner roots in the total root biomass early in the growth period may be the two characters associated with the Zn‐efficient genotypes.

Effects of herbicide chlorsulfuron on growth and nutrient uptake parameters of wheat genotypes differing in Zn-efficiency

Chlorsulfuron has been reported to induce and aggravate Zn and Cu deficiency in wheat when applied to crops grown on soils with low availability of these micronutrients. In the present study, the effect of chlorsulfuron on the growth of three wheat genotypes (Triticum aestivum L., cvs Excalibur and Gatcher, and T. turgidum conv. durum (Desf.) McKay cv Durati) differing in zinc efficiency was examined in Zn-deficient sandy soil fertilised with 0 or 0.8 mg Zn kg-1 soil. Excalibur has previously been identified as the Zn-efficient genotype which can take up more Zn and has higher yield in soils with low plant-available Zn, while Gatcher and especially Durati are Zn-inefficient genotypes. Chlorsulfuron reduced the shoot dry weight but not root dry weight. Zn concentration and content in shoots and roots were reduced by chlorsulfuron when applied with 0.8 mg Zn kg-1 soil. Copper concentration was reduced by Chlorsulfuron in roots but not in shoots. Chlorsulfuron reduced the growth rate of the third leaf, decreased the total length of roots (especially the length of fine roots with diameter ≤ 0.2 mm), and increased the average root diameter, more so in the Zn-inefficient genotype Durati than in the other two genotypes. Gatcher is the genotype most tolerant to chlorsulfuron among the three wheat genotypes judged by its root system being less affected by chlorsulfuron. Excalibur grew well at the three-leaf stage (growth rate of the third leaf was not significantly inhibited by chlorsulfuron) but not better than Gatcher later because of inhibition of root growth by chlorsulfuron. The results indicate that Zn-efficiency trait of plants may contribute to the tolerance to chlorsulfuron but still there are other mechanisms involved. The reduced content of Zn or Cu may be a consequence of reduced growth of plant roots and alteration of root geometry or morphology because the net uptake rates (based on root surface area) of these micronutrients were not reduced by chlorsulfuron.

Application of chelator-buffered nutrient solution technique in studies on zinc nutrition in rice plant (Oryza sativa L.)

It has been difficult to impose different degrees of Zn deficiency on Poaceae species in nutrient solution because most chelators which would control Zn to low activities also bind Fe3+ so strongly that Poaceae species cannot obtain adequate Fe. Recently, a method has been developed to provide buffered Fe2+ at levels adequate for rice using Ferrozine (FZ), and use of other chelators to buffer the other micronutrient cations. The use of Fe2+ buffered with FZ in nutrient solutions in which Zn is buffered with HEDTA or DTPA was evaluated for study of Zn deficiency in rice compared to a conventional nutrient solution technique. The results showed that growth of rice plants in FZ+HEDTA-buffered nutrient solution was similar to that in the conventional nutrient solution. Severe zinc deficiency symptoms were observed in 28-day-old rice seedlings cultured with HEDTA-buffered nutrient solution at Zn2+ activities < 10-10.6 M. With increasing free Zn2+ activities, concentrations of Zn, Fe, Cu, and Mn in shoots and roots were quite similar for the FZ+HEDTA-buffered nutrient solution and the conventional nutrient solution techniques. The percentages of water soluble Zn, Fe, Cu and Mn in shoots with HEDTA-buffered nutrient solution were also similar to those with the conventional solution. However, with DTPA-buffered nutrient solution, the rice seedlings suffered severe Fe deficiency; adding more FeFZ3 corrected the Fe-chlorosis but shifted microelement buffering. Further, much higher total Zn concentrations are required to provide adequate Zn2+ in DTPA-buffered solutions, and the contents of Mn and Cu in shoots and roots cultured with DTPA-buffered solutions were much higher than those with the conventional or HEDTA-buffered solutions. In conclusion, DTPA-buffered nutrient solutions are not suitable but the FZ/HEDTA-buffered nutrient solution technique can be used to evaluate genotypic differences in zinc efficiency in rice.

Electrocatalytic Epoxidation of Cyclohexene by Manganese(III) Porphyrin Using Electron Mediator

Abstract For an electrocatalytic oxidation of cyclohexene in an air-equilibrated acetonitrile solution containing (5,10,15,20-tetraphenylporphyrinato)manganese(III) as a catalyst, benzoic anhydride as an acylating reagent and 1-methylimidazole as a ligand to Mn porphyrin, the addition of the compounds such as Methylene Blue, Safranine-T, and viologens promotes the production of cyclohexene oxide. The result implies that these compounds act effectively as mediators for the electron transfer from electrode to Mn porphyrin because they have more negative reduction potential than Mn porphyrin. The faradaic efficiency reaches about 100% by the use of benzylviologen under an optimum condition. But, in the presence of methylene blue, the maximum faradaic efficiency gives low values of about 30%. On the other hand, cyclohexene oxide is also produced by the use of zinc powder as a reductant, but the utilization efficiency of zinc gives relatively low values of 30—40% regardless of the kind of the mediator. This result is ascribed to the irreversible reduction of the mediator and the direct reaction of oxomanganese complex, which is an intermediate in this epoxidation reaction, with zinc powder.

Efect of zinc and iron deficiency on phytos1derophore release in wheat genotypes differing in zinc efficiency

Abstract The effect of varied zinc (Zn) and iron (Fe) supply on the release of Zn and Fe mobilizing phytosiderophores from roots was studied in Zn‐efficient Aroona and Zn‐inefficient Durati wheat genotypes (Triticum aestivum cv. Aroona; T. durum cv. Durati) grown under controlled environmental conditions in nutrient solution for 25 days. Phytosiderophore release was determined by the measurement of Zn and Fe mobilizing capacity of root exudates from a Zn‐loaded resin and from freshly precipitated FeIII hydroxide as well as identification by HPLC analysis. Visual Zn‐deficiency symptoms, such as necrotic patches on leaves and reduction in shoot length, appeared first and more severely in Zn‐inefficient Durati, although the concentrations of total Zn in shoot and root tissues were the same in both genotypes. Zinc‐efficient Aroona responded to Zn deficiency by increasing phytosiderophore release usually after 10 days growth in nutrient solution, whereas the phytosiderophore release in Durati remained at a very low level during 25 days growth. In contrast, under Fe deficiency and also under both Fe and Zn deficiency, Aroona and Durati released similarly high amounts of phytosidero‐ phores. HPLC analysis of root exudates revealed that the same phytosiderophores were released under Zn as under Fe deficiency, 2'‐deoxymugineic acid (DMA) being the dominant phytosiderophore. Besides DMA, 3‐hydroxymugineic acid (HMA) could also be identified mainly, however, in root exudates of Zn and of Fe‐deficient Aroona. In Zn‐deficient Durati, both DMA and HMA were released in much lower amounts. The results demonstrate that phytosiderophore release can occur under Zn deficiency as well as under Fe deficiency, and enhanced release of phytosiderophores under Zn‐deficiency stress may be causally involved in Zn efficiency in genotypes of graminaceous species.

Efficiency of Erythrocyte Zinc Protoporphyrin/Heme Ratio in Classifying Microcytic Anemias

Efficiency of Erythrocyte Zinc Protoporphyrin/Heme Ratio in Classifying Microcytic Anemias

Indirect determination of phosphate by graphite furnace AAS.

Simple, rapid and highly sensitive indirect determination of phosphate was studied by graphite furnace AAS using the absorbance of zinc. This method is based on the phenomenon that the decrease of atomization efficiency of zinc is proportional to the concentration of phosphate. In order to increase the effect of phosphate on zinc atomization efficiency, the atomization temperature was lowered from optimum atomization temperature (1300°C) to 1000°C. The detectable lower concentration of phosphate was 4 ppb with relative standard deviation of 3.0% using the optimum concentration of zinc (50 ppb). Silicate ion had 2.1 times effect and sulfuric acid had one fifth times effect of the phosphate at the concentration of 20 ppb. Nitric acid had less than one tenth effect of phosphate. The effect of the mixture of phosphate and other salts agreed well with the total effects of each one.

Egg hatching and metamorphosis to protozoea of Penaeus chinensis (Osbeck) by removal of heavy metals from rearing systems with polymeric absorbent

The semi-static removal efficiency of copper, zinc, lead and cadmium ions at different concentration levels from rearing systems by using polymeric heavy metal absorbent (PHMA), was investigated. The removal efficiency was 89.3–97.0% for copper, 41.3–82.7% for zinc, 54.5–66.5% for lead and 42.3–59.0% for cadmium, respectively, after 17 h of absorption. The rates of egg hatching and metamorphosis from nauplii to protozoea of Penaeus chinensis (Osbeck) were significantly greater with PHMA than without. The results show that PHMA can remove copper, zinc, lead and cadmium ions at high concentration levels from seawater. At low concentration levels, the toxicity of heavy metal ions can be completely eliminated by PHMA, so that the rates of egg hatching and metamorphosis to protozoea of P. chinensis are raised.

Effectiveness of an Urban Runoff Detention Pond‐Wetlands System

The effectiveness of an urban detention system, composed of a detention pond and wetlands in series, in reducing constituent loads carried in runoff was determined. The detention pond was effective in reducing loads of suspended solids and suspended metals. Suspendedphase efficiencies for solids, lead, and zinc ranged between 42 and 66%. Nutrient efficiencies were variable, ranging for all species and phases, from less than 0 to 72%. The wetlands generally was effective in reducing both suspended and dissolved loads of solids and metals. Total (dissolved + suspended) solids, lead, and zinc efficiencies ranged between 41 and 73%. Efficiencies for total nitrogen and phosphorus were 21 and 17%, respectively. The system, by combining the treatment of the pond and wetlands, was very effective in reducing loads of most constituents. Total solids, lead, and zinc efficiencies ranged between 55 and 83%. Total nitrogen and phosphorus efficiencies were 36 and 43%, respectively.

AlGaAs grown by metalorganic chemical vapor deposition for visible laser

Doping efficiency of selenium hydride (for Se donors) to GaAs in metalorganic chemical vapor deposition was shown to be high and near unity, whereas that of sulfur hydride (for S donors) was nearly two orders lower. The difference was even greater with the addition of aluminum to grow AlxGa1−xAs. Doping efficiency of diethyl zinc (for Zn acceptors) was shown to be three to four orders lower than of Se. A higher partial flow ratio of arsenic to column III elements was necessary to grow high-quality layers of AlxGa1−xAs with larger x. Room-temperature cw operation of AlxGa1−xAs/AlyGa1−yAs double heterostructure visible (760–780 nm) lasers grown by MOCVD has been achieved. The planar lasers, with an oxide-insulated stripe structure 10 μm wide and 250 μm long showed a cw threshold current from 150 to 300 mA.

Fertilizer Zinc Efficiency in Flooded Calcareous Soils

AbstractEffect of Zn sources and methods of application on rice (Oriza sativa var. Giza 159) was studied in relation to organic matter application and to N source. In addition to laboratory investigations, a pot experiment was conducted with 65Zn‐labelled soil (Vertic Torrifluvents) and two field experiments with labelled and nonlabelled Zn fertilizers.Zinc oxide (ZnO) was superior to ZnSO4 in increasing grain yield and Zn content of flooded rice and in maintaining higher Zn concentration in the soil solution. With different methods of ZnSO4 application, rice yield and Zn uptake were in the order: applied to surface water 2 weeks after transplanting ≫ mixed with soil = surface applied to soil. The corresponding percentages of plant Zn derived from fertilizer and of Zn utilization from the applied fertilizer were 11.2, 8.46, and 6.26%; and 2.9, 1.4, and 1.0%, respectively. Effectiveness of organic matter in increasing yield and Zn content was greater when applied 2 weeks before transplanting than when applied at transplanting, as it decreased soil solution Zn during the first 2 weeks of anaerobic decomposition. The organic matter induced a temporary reduction in Zn content early in the season, but a good correlation was obtained between grain yield and Y leaf Zn at the midtillering and panicle initiation stages.With combined Zn and organic matter application, urea as a N source resulted in higher yielding and Zn content than (NH4)2SO4. Specific activity measurements showed that under nonflooded conditions rice was largely dependent on the Zn labile pool, while flooded rice was able to derive Zn from an additional source. Results generally indicate that formation of sphalerite (ZnS) may play a major role in controlling Zn solubility in flooded calcareous soils.

Dynamics of zinc-65 specific activity and total zinc in benthic fishes on the outer continental shelf off Central Oregon

The dynamics of 65Zn specific activity and total zinc in benthic fishes on the outer continental shelf off central Oregon (USA) were examined. A differential equation that relates specific activity of 65Zn in fish to that in fish food was used to estimate α's (zinc uptake-rate coefficients) for 3 different size classes of the flounder Lyopsetta exillis, a small predator of pelagic Crustacea, and for 1 size class of the flounder Microstromus pacificus, a large predator of infauna. The α's obtained for L. exilis were very close to the α obtained in the laboratory for the flounder Pleuronectes platessa. The α estimated for M. pacificus was very much smaller than the α's estimated for the other two species. A model that related α to predicted weight-specific feeding rates suggested that the smaller α of M. pacificus was caused by a low absorption efficiency of zinc from its prey. Sensitivity studies indicated that time histories of specific activity in the fishes are not sensitive to moderate changes in α. The negative correlation between specific activity in the diet and in the weight of L. exilis was the major cause of the negative correlative between specific activity and weight in this species. In M. pacificus, where composition of diet does not vary with size, specific activity was independent of weight. The time history of specific activity in M. pacificus was very much lower than those in the different size classes of L. exilis, a result caused mainly by the much lower specific activity of the prey of M. pacificus. Differences in specific activity among other benthic fishes were also correlated with differences in specific activity of their prey. The food-web dynamics responsible for these patterns are discussed. Variation in total zinc concentrations among species was small. Within species of flounder, zinc concentration varied only slightly or not at all with weight.

Effect of zinc on peritoneal macrophages in vitro

Rat peritoneal macrophages incubated in a medium with 10% autologous serum showed 50% inhibition of O2 consumption by 0.4 mM zinc only when activated by yeast. Zinc ions had no effect on resting macrophages. The inhibitory efficiency of zinc depended on the ratio of yeast particles to macrophages; with more activated cells, the inhibition was less. The multiple-shaped intact macrophages changed into rounded cells in the presence of 0.1 and 0.5 mM Zn2+ as shown by photomicrography and scanning electron microscopy. When the incubation medium was replaced by zinc-free medium, cells recovered and became irregularly shaped. The reversibility of zinc effect on cell morphology corresponded with uptake and release of zinc by macrophages. The presence of serum in the medium interfered with the magnitude of zinc uptake by macrophages. We conclude that besides already reported effects of zinc on mast cells, platelets, and granulocytes, zinc ions also inhibit some functions of macrophages.

Effect of Processing Variables on the Barrel Cathode Efficiency and Thickness Scatter of Small Zinc Plated Parts

SummaryThe effect of variations in current density, speed of rotation and barrel loading on plating efficiency and scatter of deposit thickness has been examined using a small horizontal barrel in a low cyanide zinc solution. It has been shown that cathode efficiency is not affected by current density but does depend on how full the barrel is with components and the speed of rotation of the barrel. Scatter of deposit thickness on the other hand is increased by an increase in the effective current density on the barrel load and is also affected by the rotational speed of the barrel but is not dependent on the size of the load in the barrel.

Evaluation of Application Methods Efficiency of Zinc and Iron for Canola(Brassica napus L.)

In order to evaluation of application method efficiency of zinc and iron microelements in canola, an experiment was conducted in the Agricultural Research Station of Eastern Azerbaijan province in 2008. The experimental design was a RCBD with eight treatments (F1: control, F2: iron, F3: zinc, F4: iron + zinc in the form of soil utility, F5: iron, F6: zinc, F7: iron+ zinc in the form of solution foliar application, and F8: iron + zinc in the form of soil utility and foliar application). Analysis of variance showed that there were significant differences among treatments on given traits, antioxidant enzymes activity, fatty acids percentage, plant height, seed weight to capitulum weight ratio, protein percentage, oil percentage, oil yield, 1000 seed weight, seed yield, nitrogen, phosphorous and potassium percentage of leaves, zinc and iron content of leaves and capitulum diameters. The highest seed yield, oil yield, oil percentage, 1000 seed weight, seed weight to capitulum weight ratio and protein percentage were obtained from the soil and foliar application of iron + zinc treatments (F8). Also, the highest amounts of nitrogen, phosphorous and potassium concentration in leaves were achieved from control treatment which was an indication of non-efficiency of iron and zinc on the absorption rate of these substances in the leaves. The correlation between effective traits on the seed yield, such as, capitalism diameter, number of seed rows in capitulum, seed weight to capitulum weight ratio and 1000 seed weight were positively significant. In general, foliar and soil application of zinc and iron had the highest efficiency in aspect of seed production. The comparison of the various methods of fertilization showed that foliar application was more effective than soil application. Also, micronutrient foliar application increased concentration of elements, especially zinc and iron. Antioxidant enzymes activity was different in response to treatments also the highest palmitoleic, oleic and myristic acid were observed in F6 and F7 treatments.

亜鉛電解における脱落過酸化鉛の挙動に関する研究

The layer of lead peroxide is formed on the anode during the electrodeposition of zinc. It was separated mechanically from anode and suspended in the zinc electrolyte. The variation of lead peroxide particle suspended in the electrolyte and the effects of various lead compounds such as lead oxide, lead sulphate formed by this decomposition to the zinc deposit was investigated.These results are as follows.(1) Lead peroxide is suspended in cohesive state by the cathodic reduction, but lead oxide or lead sulphate is in dispersive state in the electrolyte.(2) Lead peroxide is decomposed easily by the cathodic reduction, it is converted from yellow lead oxide to lead sulphate. This decomposition increases with the rise of temperature and the presence of cobalt ion in the electrolyte.(3) On the presence of lead peroxide, it is deposited mechanically with zinc and we obtained a loosely adherent sponge deposit. The current efficiency of zinc is much lower. Cathodic potential becomes more positive. The content of lead in, deposited zinc is high. These results are accelerated with. an increase of temperature or the presence of cobalt ion in the electrolyte.(4) On the presence of lead oxide or lead sulphate, when alone in the electrolyte, there are much less effect than that of lead peroxide to the zinc deposit. Zinc is obtained in a smooth deposit. The current efficiency of zinc is high. The content of lead in deposited zinc is lower than the case of lead peroxide. Cathodic potential becomes more negative.The effect on the variation of temperature is small. The effect of cobalt ion in the electrolyte is prevented.

Estimation of nitrogen by fumeless digestion. Part 1

(1) The incomplete reduction of nitrate (over 50 parts per million) in the chromo-sulphuric acid digest by zinc is traceable to the presence of the mercury salt in the digesting mixture. The mercury forms a coat of hydride around unattacked zinc and thus prevents further action with acid. (2) The interference of mercury can be eliminated and accurate estimates of nitrates in soils (upto 300 parts per million) obtained by adding extraquantity of sodium sulphite to the digest until a black precipitate is obtained. The suspension is then raised to boil and treated with zinc in the usual way. (3) The efficiency of zinc in reducing nitrate in the digest is traceable to the joint action of chromium and sulphite. On treatment of acid with zinc the latter forms hydrogen sulphide which is directly responsible for the removal of small quantities of nitrous acid that may be formed during reduction. The mechanism of the related processes has been discussed. (4) The commoner samples of reduced iron contain ferrous sulphide, so that the non-formation of nitrous acid during reduction of nitrate by that reagent is traceable to hydrogen sulphide. The ferrous salt present in solution behaves in a manner similar to the chromium salt and thus prevents loss of nitrogen during reduction.