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Research was performed during the 2010 and 2011 growing seasons to investigate the effect of zeolites and zinc foliar application on the physiological characteristics of canola cultivars at different moisture regimes. A factorial split-plot experiment was performed on the basis of the randomized complete block design with three replications in the Seed and Plant Improvement Institute, Karaj, Iran. The treatments were as follows: (1) irrigation (I), complete (I1), and restricted (I2) at the pod formation stage, (2) zeolite (Z), 0 (Z1), and 15 t ha−1 (Z2), and (3) (Zn), zinc sulfate concentrations of 0%, 0.1%, and 0.2% (Zn1, Zn2, and Zn3) at the pod formation stage. These treatments were applied on Licord, RGS003, and Opera cultivars. Although applying Z and Zn had positive effects on the quality of canola, the highest performance and the best results were obtained using a combination of Z and Zn. The combined application of Z and Zn increased the relative water content, yield, and oil yield and decreased the stomatal resistance and canopy temperature. Therefore, with the low cost of natural Z and moderate Zn intake, these treatments can be used to enhance the performance of canola, especially in regions frequently subjected to water stress. [ABSTRACT FROM AUTHOR]

Mist-rooted 'Picual' olive cuttings growing in 1.1-L pots containing a mixture of washed sand and perlite were used to induce symptoms of phosphorus (P) deficiency and toxicity and to determine the nutritional status to which these symptoms occur. Plants were growing in a growth chamber at 25 °C day/15 °C night with a 14-hour photoperiod. From late spring to the autumn, plants were placed in a shade house protected from the rain. In the first experiment, plants received the application of 0, 100, 200, or 400 ppm P, and in the second experiment, 0, 12.5, 25, 50, 100, or 200 ppm P. Shoot growth was measured weekly and leaf samples were collected at different dates to determine P concentration. At the end of each experiment, plants were harvested and P was determined to obtain the P uptake by the plants. Phosphorus uptake efficiency (PUE) was estimated as PUE = (P uptake/P applied) 3 100. P content increased in plants with the amount of P applied, and accumulated mainly in the roots. Vegetative growth showed a quadratic response, indicating a reduction of growth at the lowers and highest doses of P application. Leaf P concentration below or above which shoot growth was reduced was 0.11% to 0.13%. Symptoms of P deficiency and toxicity were observed in only a few plants. Leaf P concentration of deficient plants was 0.025%, and that of toxicity 0.21%. Toxicity symptoms were similar to that of zinc (Zn) deficiency. PUE was very low, 1.34% to 4.45%, suggesting the low P requirements of the olive. [ABSTRACT FROM AUTHOR]

Iron (Fe) and zinc (Zn) are important micronutrients for plant growth and development. Zinc-regulated transporters and the iron-regulated transporter-like protein (ZIP) are necessary for the homeostatic regulation of these metal micronutrients. In this study, the physiological function of ZmZIP7 which encodes a ZIP family transporter was characterized. We detected the expression profiles of ZmZIP7 in maize, and found that the accumulation of ZmZIP7 in root, stem, leaf, and seed was relatively higher than tassel and young ear . ZmZIP7 overexpression transgenic Arabidopsis lines were generated and the metal contents in transgenic and wild-type (WT) plants were examined using inductively coupled plasma atomic emission spectroscopy (ICP-OES) and Zinpyr-1 staining. Fe and Zn concentrations were elevated in the roots and shoots of ZmZIP7- overexpressing plants, while only Fe content was elevated in the seeds. We also analyzed the expression profiles of endogenous genes associated with metal homeostasis. Both endogenic Fe-deficiency inducible genes and the genes responsible for Zn and Fe transport and storage were stimulated in ZmZIP7 transgenic plants. In conclusion, ZmZIP7 encodes a functional Zn and Fe transporter, and ectopic overexpression of ZmZIP7 in Arabidopsis stimulate endogenous Fe and Zn uptake mechanisms, thereby facilitating both metal uptake and homeostasis. Our results contribute to improved understanding of ZIP family transporter functions and suggest that ZmZIP7 could be used to enhance Fe levels in grains. [ABSTRACT FROM AUTHOR]

Vineyard sandy acid soils from South Brazil have experienced heavy metal contamination due to replacement of copper (Cu)-based by zinc (Zn)-based products to control foliar diseases. Thus, we evaluate physiological and nutritional status of black oat ( Avena strigosa Schreb.), a common interrow crop in vineyards from this region. Soil was collected in a natural field from Santana do Livramento, in Rio Grande do Sul, the southernmost state of Brazil. Black oat was cultivated for 30 days in a greenhouse with application of 0, 30, and 60 mg Cu kg −1 combined with 0, 15, 30, 60, 120, and 180 mg Zn kg −1 . After the trial period, dry matter accumulation of roots and shoots, Cu and Zn contents in roots and shoots, chlorophyll a fluorescence, photosynthetic pigments and catalase (CAT, EC 1.11.1.6) and peroxidase (POD, EC 1.11.1.7) activity were determined. Cu and Zn toxicity was evidenced by the decrease in plant growth of black oat as well as by the decrease of photochemical efficiency associated with the decrease in photosynthetic pigment content, especially with the highest doses of Cu and Zn. Furthermore, the activity of antioxidant enzymes (CAT and POD) was increased in intermediate doses of Zn, indicating the activation of the antioxidant system, but the stress condition in treatments with high levels of Cu and Zn was not reversed. [ABSTRACT FROM AUTHOR]

To determine whether the enhanced stress tolerance of ZnSO with NiSO-treated Mimulus guttatus Fischer ex DC. plants was associated with the glutathione (GR-GSH) system, we investigated the changes in glutathione redox state (reduced (GSH), oxidized (GSSG) forms, total reduced (GSHt) glutathione, and GSH/GSSG ratio) and in the enzymatic activities of glutathione reductase (GR) and peroxidatic glutathione S-transferases (GST). The 6-week-old plants were grown in water culture during 4 weeks on a modified Rorison's medium with ZnSO (50, 100, and 200 μM) and NiSO (20 and 80 μM) in a condition of separate or simultaneous supply of the components. Dry biomass accumulations of roots and shoots were not influenced by the examined treatments. The positive correlations between the total external concentrations of ZnSO and NiSO and the total Zn and Ni contents in roots and leaves were found. It was determined that the MDA content was higher in the ZnSO-treated plants than in the NiSO-treated ones. The supplementation of the ZnSO-treated plants with varied concentrations of NiSO decreased the Zn-induced increase in the MDA levels. The inverse proportionality between the MDA and pigment levels in leaves was found. The Zn-Ni interactions were shown to induce the decreases in the GR activity, the total peroxidatic GST activity, and the GSH/GSSG ratio in roots. However, in leaves, the GR activity and the GSH/GSSG ratio were significantly increased and the total peroxidatic GST activity was decreased. The supplementation of the ZnSO-treated plants with varied concentrations of NiSO restored the Zn-induced reduction in the GSHt levels in roots and decreased the Zn-induced increase in the GSSG levels in leaves, which resulted in more reduced state of the intracellular environment. It was likely to cause a decrease of the MDA level. Thus, our studies on the Zn−Ni interactions identified the antagonizing role of Ni in Zn toxicity by the GR-GSH system. [ABSTRACT FROM AUTHOR]

Galactinol synthase (GolS, EC 2.4.1.123), a key enzyme in the biosynthesis of raffinose family oligosaccharides (RFOs), plays roles in plant growth and developmental processes. The in vitro roles of GolS in plant responses against heavy metal stress are not well clarified. In the present study, a suppression-subtractive hybridization (SSH) cDNA library has been constructed using RNA extracted from wheat cultivar Jinan 18 treated with ZnCl as the tester and RNA from untreated seedlings as the driver. Sixteen expressed sequence tags (ESTs) highly homologous with known proteins associated with stress tolerance have been obtained. Among these, a 1000-bp cDNA sequence encoding GolS protein has been isolated and designated as TaGolS3. Real-time quantitative PCR (qPCR) analysis revealed that TaGolS3 was mainly expressed in young roots and upregulated by exogenous ABA treatment and several abiotic stresses, such as ZnCl, CuCl, low temperature, and NaCl. Subcellular localization analysis showed that TaGolS3 protein is a nuclear-localized protein. A detailed analysis of Arabidopsis and rice transgenic plants overexpressing TaGolS3 gene displayed that transgenic plants exhibited increased lateral root number, primary root length, plant survival rate, and plant height. Moreover, in comparison with the wild-type (WT) plants, the TaGolS3-overexpressing lines showed a higher expression of ROS-scavenging genes, activities of antioxidative enzymes, proline contents, and a lower level of malondialdehyde (MDA) contents and electrolyte leakage under zinc stress. These results confirmed the positive roles of TaGolS3 in improving plant tolerance to heavy metal stress, indicating a potential resource in the transgenic breeding to enhance heavy metal stress tolerance in crop plants. [ABSTRACT FROM AUTHOR]

We examined the germination and biochemical features of seeds of the threatened Brazilian species Dimorphandra wilsonii exposed to Zn. Although seed germination decreased with Zn exposure, the species was able to germinate even under high Zn doses (200 mg Zn l −1 ). Zn-toxicity was related to Zn-induced hydrogen peroxide (H 2 O 2 ) accumulation, although increased activities of the H 2 O 2 -scavenging enzymes catalase and ascorbate peroxidase allowed seed germination in the presence of Zn. Using electron transport chain (ETC) inhibitors, we located the primary reactive oxygen species (ROS) production sites in seeds exposed to 200 mg Zn l −1 . Rotenone (an inhibitor of mitochondrial ETC complex I) reduced H 2 O 2 concentrations in embryos of Zn-treated seeds while KCN (an inhibitor of mitochondrial ETC complex IV) and dicumarol (an inhibitor of the plasma membrane ETC) showed no effects. The activities of enzymes related to mitochondrial ETC (Complexes I–IV) were reduced and the pool of oxidized ubiquinone was greater in Zn-treated seeds. Mitochondrial ETCs therefore appear to be the main sites for Zn-induced ROS formation, and that metal appears to act upstream of Complex IV. These results suggest that Zn does not block electron flow in the mitochondrial ETC but directly modify ubiquinone sites in Complexes I and II, resulting in H 2 O 2 formation. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate whether exogenous application of salicylic acid (SA) and zinc (Zn) could regulate the activities of antioxidant enzymes and ameliorate the adverse effects of drought stress on wheat. Pot experiment was arranged in a Randomized Complete Block Design (RCBD) with two factors and three replications during the year 2013-2014 in Turkey. The control, drought, drought + SA and drought + Zn were first factor, and the wheat cultivars, Basribey and Ziyabey 98, were second factor. Drought stress at grain filling stage significantly decreased plant height, spike length, number of grains per spike, 1000 grain weight, chlorophyll content, relative water content but activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) under drought stress were increased. Both SA and Zn application had positive influence on all parameters in this experiment. The foliar application of Zn increased water use efficiency and thereby reduced the negative effects of drought stress. Besides the foliar application of salicylic acid regulated physiological processes in plants and alleviated the adverse effects of water stress. Results showed that SA and Zn could be used for improving wheat growth under drought stress. [ABSTRACT FROM AUTHOR]

Cumin (Cuminum cyminumL.), originated from East Mediterranean country of Egypt, is widely cultivated in Middle Eastern, Asia minor and South East Asian countries. Zn is an essential factor in tryptophan metabolism and affects auxin contents in plants. In order to evaluate effects of Zn on vegetative growth, grain yield and its components on cumin genotypes, a field experiment was carried out at the department of field crops Ankara University; Turkey using randomized complete blocks split plot design with four replications during 2011 growing season. Four amounts of Zn (0, 1.5, 3 and 4.5 kg ha-1) in the form of soil application, were allocated at main plots and six genotypes [Kashmar, Bardskan, Mashhad (Iranian-origin)], [Haymana, Turkman and Egebin, (Turkish-origin)] were assigned to sub plots. Analysis of variance results showed significant interaction of zinc levels and genotypes for traits like root heights, grain yield, total dry matter, number of branches per plant and grain essential oil (p<0.01). Applications of different Zn levels was better than control in grain yield and its components. The highest amount of grain yield and essential oil (3.64%) was recorded using 3kg ha-1Zn application. Grain yield had significant and positive correlation with plant height (r=0.95**) and root length (r=0.95**). Root length (3.59) and total dry maater (2.71), had the most positive direct effects and incontrast plant height (-1.63), number of branches per plant (-2.33) had negative direct effect on grain yield. At the regression model based on grain yield as a dependent variable, traits of plant height, root length, total dry matter, number of branches per plant and oil yield remained at the final model. Concerning essential oil constituents, β-terpinene was the major compound followed by p-cymene and β-pinene. Highest γ-terpinene content (49.14%) was recorded in Kashmar genotype using 3 kg ha-1Zn. [ABSTRACT FROM AUTHOR]

Key message: Predictability estimated through cross-validation approach showed moderate to high level; hence, genomic selection approach holds great potential for biofortification breeding to enhance grain zinc and iron concentrations in wheat. Abstract: Wheat ( Triticum aestivum L.) is a major staple crop, providing 20 % of dietary energy and protein consumption worldwide. It is an important source of mineral micronutrients such as zinc (Zn) and iron (Fe) for resource poor consumers. Genomic selection (GS) approaches have great potential to accelerate development of Fe- and Zn-enriched wheat. Here, we present the results of large-scale genomic and phenotypic data from the HarvestPlus Association Mapping (HPAM) panel consisting of 330 diverse wheat lines to perform genomic predictions for grain Zn (GZnC) and Fe (GFeC) concentrations, thousand-kernel weight (TKW) and days to maturity (DTM) in wheat. The HPAM lines were phenotyped in three different locations in India and Mexico in two successive crop seasons (2011-12 and 2012-13) for GZnC, GFeC, TKW and DTM. The genomic prediction models revealed that the estimated prediction abilities ranged from 0.331 to 0.694 for Zn and from 0.324 to 0.734 for Fe according to different environments, whereas prediction abilities for TKW and DTM were as high as 0.76 and 0.64, respectively, suggesting that GS holds great potential in biofortification breeding to enhance grain Zn and Fe concentrations in bread wheat germplasm. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) are soil bacteria that are able to colonize rhizosphere and to enhance plant growth by means of a wide variety of mechanisms. In the present study,Myristica yunnanensisandStenotrophomonas chelatiphagastrains were recognized as new records in Iran flora. According to the results, these strains significantly affected plants’ zinc and phosphorous contents which could be due to the production of phytosiderophore. Siderophore-producing bacteria increased canola zinc (Zn) content as strategy-I plant, while in maize, it can be said that probably the effect of phytosiderophore produced by plant on increasing root and shoot Zn content was more than siderophore produced by bacteria. These isolates could be used as bio-input for improving the plant productivity as a substitute to chemical fertilizers and also to correct the nutrient deficiencies in canola and maize for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Heavy metal contamination resulting from anthropogenic activities is one of the major environmental problems in the modern world. Progress toward creating modified plants that are more efficient in phytoremediation requires an understanding of the anatomical and ultrastructural changes involved in heavy metal accumulation. A large supply of zinc (Zn) is toxic for plants and can lead to functional and structural disorders. The present study investigates the anatomical and ultrastructural responses of Brassica napus (rapeseed) to excess Zn after long-term exposure. Results showed that Zn bioaccumulation in the roots and leaves of plants treated with 350 µM Zn2+ was severely increased, leading to a variety of anatomical and ultrastructural alterations in several cell types. Overall, although B. napus has been reported as a metal-accumulator species, our data revealed that B. napus cultivar Hayola 401 could not tolerate a high concentration of Zn and thus is not a good candidate for Zn phytoremediation. [ABSTRACT FROM AUTHOR]

Zinc (Zn) deficiency is a major problem in agricultural crops of many world regions. N metabolism plays an essential role in plants and changes in their availability and their metabolism could seriously affect crop productivity. The main objective of the present work was to perform a comparative analysis of different strategies against Zn deficiency between two plant species of great agronomic interest such as Lactuca sativa cv. Phillipus and Brassica oleracea cv. Bronco. For this, both species were grown in hydroponic culture with different Zn doses: 10 μM Zn as control and 0.01 μM Zn as deficiency treatment. Zn deficiency treatment decreased foliar Zn concentration, although in greater extent in B. oleracea plants, and caused similar biomass reduction in both species. Zn deficiency negatively affected NO 3 − reduction and NH 4 + assimilation and enhanced photorespiration in both species. Pro and GB concentrations were reduced in L. sativa but they were increased in B. oleracea . Finally, the AAs profile changed in both species, highlighting a great increase in glycine (Gly) concentration in L. sativa plants. We conclude that L. sativa would be more suitable than B. oleracea for growing in soils with low availability of Zn since it is able to accumulate a higher Zn concentration in leaves with similar biomass reduction. However, B. oleracea is able to accumulate N derived protective compounds to cope with Zn deficiency stress. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effectiveness of various treatments in correction of alone boron (B) and multiple B, zinc (Zn), and iron (Fe) deficiencies in olive table cultivar (Gemlik) in the southeastern Marmara region of Turkey. This work consisted of four field experiments which mainly included control, soil, and foliar applications of B alone and combinations with Zn and Fe. In experiment I, borax was applied alone foliarly and via soil. In the other three experiments, double and triple combinations of iron(II) sulfate heptahydrate (FeSO4.7H2O) and zinc sulfate heptahydrate (ZnSO4.7H2O) with borax were applied foliarly and via soil. Soil applications of the compounds were only performed in the first year of the experiments. However, the leaves and the fruits were sampled in the following year to estimate the residual effect of soil applications. Foliar applications were sprayed onto leaves twice and four times at two doses in consecutive years. Soil and foliar applications of borax increased leaf and fruit B concentrations. However, foliarly treated B was more effective than soil application. Four times foliar applications of boron in each season seemed to be appropriate treatment to maintain a sufficient B level in olive trees. Foliar applications of double and triple combinations of FeSO4.7H2O and ZnSO4.7H2O with borax increased significantly Fe and Zn concentrations in the leaves as well. Boron concentrations were dramatically higher in the fruits than in the leaves. These results clearly indicated the translocation of B from soil and treated leaves to the fruits. Therefore, fruit B concentration was more descriptive in the evaluation of the B nutrition level of olive trees. [ABSTRACT FROM AUTHOR]

Glyphosate is a widely used nonselective herbicide for the control of agricultural weeds. It is being increasingly used in glyphosate resistant genetically modified plants. However, there are few studies on its effects on the nutritional status of soybean, particularly on the uptake of zinc (Zn). Two experiments were conducted under field conditions in a Typic Quartzipsamment and an Orthic Ferralsol to investigate the effect of glyphosate application × Zn interaction on soil fertility, yield components, seed yield (SY), shoot dry weight (SDW) yield, and nutritional status of soybean. The five Zn rates 0, 3, 6, 9, and 12 kg ha−1were used in two soybean varieties [BRS 133 (conventional—NGM) and its essentially derived transgenic line BRS 245RR (GM), which was divided into: with (+Gly) and without (–Gly) glyphosate application. Only the P (phosphorus) and Zn available concentrations in the soil were impacted by Zn rates. However, the available P concentration only decreased in the soil planted with GM soybean. Mehlich 1 and diethylenetriaminepenta acetic acid–triethanolamine (DTPA–TEA), 7.3 extractants were effective to determine the available Zn. In the two crop sites, the number of pods per plant (NPP) and the SDW yield were affected by the interaction varieties × Zn. SY was influenced by the application of the herbicide, reducing a potential phytotoxic effect with the use of high rates. Regarding the nutrients, only the foliar calcium (Ca), boron (B), iron (Fe), and manganese (Mn) concentrations were negatively affected by glyphosate, and in the case of Zn, the difference occurred only between the varieties BRS 133 and BRS 245RR. [ABSTRACT FROM AUTHOR]

The role of fluorescent pseudomonads isolates (pf0, pf1, pf2, and pf3) and zinc (Zn) (0 and 5 mg kg−1soil) interactions in alleviating salinity in pistachio seedlings were investigated. The experiment was conducted following completely randomized design with three replicates. The results revealed that salinity decreased the growth parameters, while application of PGPR (plant growth-promoting rhizobacteria) and Zn increased these parameters. Application of PGPR significantly enhanced phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), Zn, Ca/sodium (Na), and K/Na contents, while decreased the accumulation of Na and chloride (Cl). Application of PGPR and Zn increased the phenolic compounds, sucrose, membrane stability index (MSI), and relative water content (RWC) but reduced the malondialdehyde (MDA) amount. A positive correlation was observed between Zn concentrations with seedling dry weights, phenolic compounds, MSI, and RWC contents. These results indicated that the combined application of PGPR and Zn could be a simple treatment for growth and establishment of pistachio seedlings under Zn deficiency and soil salinity. [ABSTRACT FROM AUTHOR]

In order to evaluate the combined effects of salinity stress and Zinc (Zn) applications on wheat growth, an experiment was conducted with the treatments included four Zn levels (0, 10, 20, and 40 mg/kg of dried soil) and three levels of sodium chloride (NaCl) salinity of irrigation water (0, 100, and 200 mM NaCl). Salinity caused a significant reduction in chlorophyll a and b content. The activity of catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR) was enhanced as salinity level was increased. The significant enhancement in concentration of sodium due to the salinity was alleviated by Zn addition. Potassium content was increased by Zn treatments. A substantial increase was observed in leaf Zn concentration as the applied level of Zn was increased. Overall, these results indicate some positive and negative interactions of salinity and Zn application, which could be helpful in management of the saline soil and water. [ABSTRACT FROM AUTHOR]

The 6-week-old seedlings of Scots pine ( Pinus sylvestris L.) showed high sensitivity to chronic exposure to zinc in hydroculture, which manifested in a significant inhibition of growth. Changes in the architecture of the root system and the suppression of its growth were shown to be the most striking effects of the toxic effect of zinc. Based on the data relating to the accumulation of zinc predominantly in the root system (by up to 35 times at 300 μM ZnSO 4 ) and to the reduction in its translocation into the aerial organs, we concluded that P. sylvestris is related to a group of plants that exclude zinc. The seedlings developed a manganese deficiency (revealed by a reduction in Mn content in the roots and needles of up to 3.5 times at 300 μM ZnSO 4 ) but not an iron deficiency (revealed by an increase in iron content of up to 23.7% in the roots and up to 42.3% in the needles at average). The absence of signs of oxidative stress under the effect of the zinc was detected as evidenced by the reduction in the content of malondialdehyde and 4-hydroxyalkenals in the seedling organs. The leading role of low molecular weight antioxidants in the prevention of oxidative stress in the seedling organs was suggested. Under the influence of zinc, a significant increase in the Trolox Equivalent Antioxidant Capacity of ethanol extracts of the seedling organs was found, which was caused by an increase in the total content of (+)-catechin and proanthocyanidins. [ABSTRACT FROM AUTHOR]

Diffusive gradients in thin films (DGT) have been used for the assessment of Zn phytoavailability. Phosphorus is of particular interest in soils having Zn toxicity because of the Zn-P interaction. A greenhouse study was carried out to assess the influence of different P rates on the Zn phytoavailability to sorghum-Sudan grass (Sorghum vulgare var. sudanese) in soil systems by DGT. Soil was amended with ZnSO4 at 0, 150, 300, 600, and 1200 mg Zn kg-1 in order to create various levels of Zn phytoavailability. Phosphorus was applied to soil at 0, 100, and 200 mg P kg-1 as KH2PO4. Plant nutrients were added as Hoagland's solution. In general, plant tissue Zn concentrations were elevated by increasing Zn concentration in soils, and they decreased by increasing P concentrations. However, this reduction was not found in C-DGT results. In other words, DGT did not predict the effects of P additions compared to Zn. P application decreased plant Zn concentrations and increased plant biomass yields. The highest relative yield in shoot tissue was with P200 x Zn150 treatment, while the lowest one was with P0 x Zn1200 treatment. In general, increasing P concentrations in the soil increased shoot yields relative to control, while increasing Zn concentrations decreased the relative shoot yields where no P was added. P addition might be an alternative strategy for remediation of Zn contaminated soil, since addition of P decreased Zn phytoavailability and enhanced plant growth. [ABSTRACT FROM AUTHOR]

The effect of nitrogen (N), sulfur (S), and zinc (Zn) fertilization on the yield quantity and selected qualitative parameters of broccoli was studied in an experiment carried out in Nitra (Slovak Republic) during 2011 and 2012. In this experiment, the following fertilization treatments were tested: control; N200S80 (fertilized to the supply level: 200 kg N ha-1 and 80 kg S ha-1); N200S100 (supply level: 200 kg N ha-1 and 100 kg S ha-1), and N200S100 Zn (supply level: 200 kg N ha-1 and 100 kg S ha-1 + foliar zinc application). Compared to the control treatment, higher broccoli yield was shown at all fertilized treatments. The most significant increase in yield quantity was found at N200S100Zn, i.e. about 59% higher than the control. Application of N200S100Zn was the most suitable fertilization from the standpoint of broccoli quality. The foliar Zn spraying led to a statistically highly significant increase of sulforaphane in broccoli (about 41.1%) compared to the control. The applied N and S fertilization tended to decrease the vitamin C content in broccoli (about 9.2%) against the control. On the other hand, Zn application resulted in a return of the vitamin C content, nearly to its level in control. The results confirmed the well-known fact that nitrogen fertilization leads to nitrate accumulation in vegetables. However, the results of this research indicate that nitrogen fertilization combined with zinc application should be expressed mainly by lower nitrate accumulation in the edible parts of broccoli. The experimental data are interesting, and in terms of growing vegetables for consumption with enhanced quality, promising. This is notable because the formation of many serious diseases is increasing. [ABSTRACT FROM AUTHOR]

The Biosolids from sewage sludge used in agriculture, because of its content from organic matter and nutritive elements, but still there are some caveats because of heavy metals and pathogens in the sludge, in aim to study the effect of adding gradual amounts from sludge in productivity of Diplotaxis erucoides, and accumulation of Zn and Cd in its tissues, the plant were planted for two years, Four treatments were used 5 replicate for each treatment: 0 (control), 20, 40, 60 ton/ hectare, respectively. Chemical and physical analysis for sludge and soil were done. height of plant ,amount of chlorophyll, number of inflorescence and fruits, and dry weight were measured. concentration of Zn and Cd in parts of plant were measured in all treatments, Results show that the productivity indicate positive correlation with amount of sludge. the dry weight increased significantly by 70% for Adding 60 ton/hectare in comparison with control. Concentration of Zn and Cd in the soil and plant still within permissible limit(Syrian specification). Diplotaxis erucoides accumulate Zn and Cd because of its concentration in steam higher than its concentration in roots. [ABSTRACT FROM AUTHOR]

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‘Shatangju’ mandarin creasing results is serious economic loss in many ‘Shatangju’ mandarin orchards. Based on developing accurate preventive strategies for creasing fruit, the creasing of eight-year-old ‘Shatangju’ ( Citrus reticulata Blanco cv. Shatangju) onto Poncirus trifoliate (L.) rootstock was investigated. It was treated twice with either Zn or Zn + NAA application in the fruit enlargement stage (18th and 27th of May, 2011), and Zn + NAA (18th and 28th of May, 2012), respectively. The Zn and Zn + NAA treatments at the fruit enlargement stage of ‘Shatangju’ significantly enhanced the levels of IAA, GA 3 , and tryptophan in the early peel development stage, promoted the growth and division of cells, decreased the range of peel hardness variation during fruit development, reduced creasing abnormalities in peel tissue, especially in albedo, postponed the peel thickness transition time of peel development, and significantly lowered the creasing fruit rate and cumulative abscission rate of ‘Shatangju’ mandarin. Compared with the control and Zn treatment, Zn + NAA treatment could be recommended in the fruit enlargement stage as a cultivation technique to lower the creasing fruit rate of Shatangju mandarin. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles (NPs) are considered an emerging contaminant when in high concentration, and their effects on crops and soil microorganisms pose new concerns and challenges. Arbuscular mycorrhizal (AM) fungi (AMF) form mutualistic symbioses with most vascular plants, and putatively contribute to reducing nanotoxicity in plants. Here, we studied the interactions between ZnO NPs and maize plants inoculated with or without AMF in ZnO NPs-spiked soil. ZnO NPs had no significant adverse effects at 400 mg/kg, but inhibited both maize growth and AM colonization at concentrations at and above 800 mg/kg. Sufficient addition of ZnO NPs decreased plant mineral nutrient acquisition, photosynthetic pigment concentrations, and root activity. Furthermore, ZnO NPs caused Zn concentrations in plants to increase in a dose-dependent pattern. As the ZnO NPs dose increased, we also found a positive correlation with soil diethylenetriaminepentaacetic acid (DTPA)-extractable Zn. However, AM inoculation significantly alleviated the negative effects induced by ZnO NPs: inoculated-plants experienced increased growth, nutrient uptake, photosynthetic pigment content, and SOD activity in leaves. Mycorrhizal plants also exhibited decreased ROS accumulation, Zn concentrations and bioconcentration factor (BCF), and lower soil DTPA-extractable Zn concentrations at high ZnO NPs doses. Our results demonstrate that, at high contamination levels, ZnO NPs cause toxicity to AM symbiosis, but AMF help alleviate ZnO NPs-induced phytotoxicity by decreasing Zn bioavailability and accumulation, Zn partitioning to shoots, and ROS production, and by increasing mineral nutrients and antioxidant capacity. AMF may play beneficial roles in alleviating the negative effects and environmental risks posed by ZnO NPs in agroecosystems. [ABSTRACT FROM AUTHOR]

Zinc (Zn) is an essential micronutrient for plants and animals. Unfortunately, deficiency of Zn in humans has increased on a global scale. The main reason of this micronutrient deficiency is dietary intakes of food with low Zn levels. Adoption of biofortification approaches would result in Zn enrichment of target tissue to a considerable extent. However, there is a basic need to understand Zn absorption mechanisms in plants prior to exploitation of such practical approaches. Zn absorption is a complex physiological trait which is mainly governed by Zn transporters and metal chelators of plant system. Plant growth stage, edaphic factors, season etc. also influence Zn efficiency of particular species. Molecular studies in Zn hyperaccumulators have already demonstrated the participation of specific Zn transporters, vacuolar sequestration and detoxification mechanisms in maintenance of Zn homeostasis. These have been described in detail in present review and provide opportunities for utilization in biofortification programmes. However, issues such as lesser bioavailability of Zn in target organ, uptake of toxic divalent cations (Cd, Ni, Pb, As etc.) along with Zn, sink activity and dilution in Zn concentration in response to sink number etc. in biofortified crops need further investigation. In order to design novel strategy in biofortification programmes, future researches should focus on physiological performance and yield penalties in concerned crop, metabolic load in term of organic acid production and crosstalk of Zn with other mineral nutrients under low and high Zn conditions. [ABSTRACT FROM AUTHOR]

Plants’ tolerance to salt stress is different among species, nevertheless, mineral nutrition might also affect it. A greenhouse experiment was conducted to evaluate the effect of Zinc (Zn) on salinity tolerance using a sigmoid response model in two wheat (Triticum aestivumL.) genotypes ‘Falat’ and ‘Bam’ with different salinity tolerances. The treatments consisted of three Zn rates (0, 5 and 10 mg Zn kg−1) and five levels of soil salinity (1.1, 6.5, 12.3, 18.7 and 25.1 dS m−1). The results showed that dry weight of straw and grain decreased, as salinity increased in both genotypes although this decrease in ‘Falat’ genotype was higher than that of ‘Bam’ genotype. Application of 10 mg kg−1Zn increased the dry weight by 25% (straw) and 32% (grain) in ‘Falat’ but 67% (straw) and 60% (grain) in ‘Bam’ as compared with the absence of added Zn. According to the fitted function, in the absence of Zn, grain production began to decline at ECe-values of 4.7 dS m−1in ‘Falat’ genotype, and 7.5 dS m−1in ‘Bam’ genotype. Application of Zn led to a decrease of salinity tolerance in ‘Falat’ genotype, but an increase in ‘Bam’ genotype. The study found that Zn application under saline conditions, depending on genetic differences of wheat genotypes, would have different effects on their tolerance to salinity. [ABSTRACT FROM PUBLISHER]

Malaysia is taking efforts to be self-sufficient in rice production. However, the country is facing low availability of Cu and Zn in its soils. Even though these elements are required in small quantities for normal plant growth, their role in maximising yield is very impressive. The present study was conducted to assess the micronutrient Cu and Zn contents in selected paddy soils of Malaysia. Investigations carried out showed that marine alluvium [Guar, Sedaka, Keranji, Kuala Kedah, Kangkong, Sedu, Rotan and Kundur (Kedah)] and reverine alluvium; [Chempaka, Lubok Itek, Lating, Batu Hitam and Machang soil series (Kelantan)] were low in Cu and Zn contents. All soils were acidic in nature, with their pH values ranging from 4.3 to 6.5. Based on the results, extractable Cu and Zn concentration of soil varied within the range of 0.09-1.70 and 0.51-2.10 mg kg-1 in the soil series of Kuala Kedah and Lubukltek, respectively. It was manifested that the micronutrient contents were below the critical level (Cu 0.1-1.0 mg kg-1 and Zn 0.5-3.0 mg kg-1) according to the method of extracting analysis; Mehlich-I. The sampling depth has shown a variation and the subsurface soil sampling exhibited lesser Cu and Zn contents as compared to the surface soil sampling. Findings of the research indicate that micronutrient deficiency occurs in the main rice regions of Malaysia, and this can be corrected by applying micronutrient fertiliser. [ABSTRACT FROM AUTHOR]

In two long-term field experiments the zinc (Zn)/cadmium (Cd) hyperaccumulatorSedum plumbizincicola (S. plumbizincicola)was examined to optimize the phytoextraction of metal contaminated soil by two agronomic strategies of intercropping with maize (Zea mays) and plant densities. Soil total Zn and Cd concentrations decreased markedly after long-term phytoextraction. But shoot biomass and Cd and Zn concentrations showed no significant difference with increasing remediation time. In the intercropping experiment the phytoremediation efficiency in the treatment “S. plumbizincicolaintercropped with maize” was higher than inS. plumbizincicolamonocropping, and Cd concentrations of corn were below the maximum national limit. In the plant density experiment the phytoremediation efficiency increased with increasing plant density and 440,000 plants ha−1gave the maximum rate. These results indicated thatS. plumbizincicolaat an appropriate planting density and intercropped with maize can achieve high remediation efficiency to contaminated soil without affecting the cereal crop productivity. This cropping system combines adequate agricultural production with soil heavy metal phytoextraction. [ABSTRACT FROM AUTHOR]

Three Cd and Zn hyperaccumulating plant speciesNoccaea caerulescensNoccaea praecoxandArabidopsis halleri(Brassicacceae) were cultivated in seven subsequent vegetation seasons in both pot and field conditions in soil highly contaminated with Cd, Pb, and Zn. The results confirmed the hyperaccumulation ability of both plant species, althoughA. hallerishowed lower Cd uptake compared toN. caerulescens. Conversely, Pb phytoextraction was negligible for both species in this case. Because of the high variability in plant yield and element contents in the aboveground biomass of plants, great variation in Cd and Zn accumulation was observed during the experiment. The extraction ability in field conditions varied in the case of Cd from 0.2 to 2.9 kg ha−1(N. caerulescens) and up to 0.15 kg ha−1(A. halleri), and in the case of Zn from 0.2 to 6.4 kg ha−1(N. caerulescens) and up to 13.8 kg.ha−1(A. halleri). Taking into account the 20 cm root zone of the soil, the plants were able to extract up to 4.1% Cd and 0.2% Zn in one season. However, cropping measures should be optimized to improve and stabilize the long-term phytoextraction potential of these plants. [ABSTRACT FROM AUTHOR]

Four field experiments were established at different locations to study the influence of Zn alone and combined Zn + Fe, Zn + B and Zn + Fe + B applications on leaf and fruit absorption levels by “Gemlik” table olive cultivar ( Olea europea L.) trees. The treatments of every experiment were consisted of control, soil and foliar applications. Soil applied Zn did not have an effect on Zn contents of either the leaves or the fruit in each year of the experiments. Every treatments of foliar applied Zn elevated sufficiently Zn contents of the leaves. Four times foliar application of each dose should be conducted due to more evident increases in the fruit Zn contents. Foliar applications of double and triple combinations of Zn with Fe and B increased significantly Zn, Fe and B concentrations in the olive trees. [ABSTRACT FROM AUTHOR]

The effect of soil and foliar Zn fertilization on two varieties of peanut's (Arachis hypogaea) yield and some yield components were examined in this study. Soil applications of Zn doses were 0, 10, 20 and 40 kg ha-1 whereas 0, 0.5, 1 and 1.5 kg ha-1 Zn were sprayed to leaves. Applications of dose amounts of Zn lead to remarkable increase in yield and 100-seed weight. The effect of Zn treatment found to be statistically important at P<0.01 levels. The highest yield was obtained at COM variety as 6580.0 kg ha-1 with 0.5 kg ha-1 Zn foliar application. The lowest yield was measured at NC-7 variety's control plot with 3660.0 kg ha-1 in 2007. Foliar application Zn was statistically determined to be important to NC-7 variety peanut's grain Zn concentration at P<0.05 levels in each year. The economic analyses revealed that 0.5 kg ha-1 foliar application of Zn provided maximum profit with 10271.2 USD Dollars ha-1. [ABSTRACT FROM AUTHOR]

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Plants growing on polluted soils need to control the bioavailability of pollutants to reduce their toxicity. This study aims to reveal processes occurring at the soil-root interface of Pistacia lentiscus L. growing on the highly Zn-contaminated tailings of Campo Pisano mine (SW Sardinia, Italy), in order to shed light on possible mechanisms allowing for plant adaptation. The study combines conventional X-ray diffraction (XRD) and scanning electron microscopy (SEM) with advanced synchrotron-based techniques, micro-X-ray fluorescence mapping (μ-XRF) and X-ray absorption spectroscopy (XAS). Data analysis elucidates a mechanism used by P. lentiscus L. as response to high Zn concentration in soil. In particular, P. lentiscus roots take up Al, Si and Zn from the rhizosphere minerals in order to build biomineralizations that are part of survival strategy of the species, leading to formation of a Si-Al biomineralization coating the root epidermis. XAS analysis rules out Zn binding to organic molecules and indicates that Zn coordinates Si atoms stored in root epidermis leading to the precipitation of an amorphous Zn-silicate. These findings represent a step forward in understanding biological mechanisms and the resulting behaviour of minor and trace elements during plant-soil interaction and will have significant implications for development of phytoremediation techniques. [ABSTRACT FROM AUTHOR]

Zinc (Zn) being an activator of certain enzymes, can regulate antioxidative activities and enhance the vase-life of cut-flowers. This greenhouse study on zinc nutrition of Oriental lily was performed with four levels of zinc, 0, 3, 6 and 9 mg Zn kg −1 of soil media, applied after two weeks of lily bulbs plantation. Maximum plant height, internodal distance, and leaf area were recorded at 6 mg Zn kg −1 soil media. Floral attributes, viz., flower-bud diameter, flower diameter, number of flowers per plant, stalk length, stalk diameter, fresh and dry weight of nine flowers per treatment also showed the maximum response at 6 mg Zn kg −1 . Earlier flower initiation, extended vase-life, lesser weight loss of flower, greater membrane integrity, content of chlorophyll and protein were recorded at 6 mg Zn kg −1 . Photosynthetic rate, transpiration rate, stomatal conductance, relative water contents and net assimilation rate were higher at 6 mg Zn kg −1 dosage. Antioxidant enzymes, viz., SOD, POD and CAT in cut-flowers also remained at the maximum with this medium dose of zinc. This study concludes that zinc applied at 6 mg kg −1 is suitable dose for enhancing the plant growth, floral vase-life and quality of lily cut-flower. [ABSTRACT FROM AUTHOR]

Field experiment was conducted at Central Institute of Medicinal and Aromatic Plants (CIMAP), Lucknow to evaluate the growth and yield of geranium and garlic in intercropping system. Maximum dry matter accumulation was noticed during 120-135 DAP. Dry matter accumulation in geranium paired sole was almost equal to geranium paired intercrop. Application of phosphorus at 40 kg P2O5 ha-1 and 30 kg ZnSO4 ha-1 significantly increased the dry matter accumulation of plants over control at all the stages of crop growth. Bulb yield of garlic was found to be increased with increase in the application of phosphorus up to 40 kg P2O5 ha-1 and zinc upto 30 kg ZnSOl ha-1. The essential oil yield of geranium pure crop significantly improved over essential oil yield of intercropped geranium . Uptake of Zn also increased significantly upto 40 kg P2O5 ha-1. Higher rates of P decreased the Zn uptake by the plants. Application of 30 kg ZnSO4 ha-1 showed a significant response on the herb and oil yield over no zinc application. The net return from geranium and garlic in paired intercropping system was Rs 2,58,564.95 being higher other cropping system. Thus intercropping garlic with geranium proved economical. [ABSTRACT FROM AUTHOR]

Increasing concentration of Cd in soil is of great concern due to risk of its entry into food chain. Zinc (Zn) being antagonist to Cd is an important micronutrient to ameliorate its toxic effects on plants and to limit its entry into food chain. A pot experiment was conducted using Cd contaminated soil (30 mg Cd kg −1 soil as 3CdSO 4 ·8H 2 O) to investigate the effect of soil and foliar applied Zn on physiological response and Cd concentration in wheat. In soil, Zn was applied at 15 and 30 mg Zn kg −1 soil as zinc sulfate (ZnSO 4 ·7H 2 O). For foliar applications, 3 and 6 g L −1 ZnSO 4 solution was sprayed on completing eight weeks of growth. Results indicated that Zn application could effectively improve physiological performance and mineral content of wheat grown on Cd contaminated soils. Among different Zn fertilization treatments, foliar application of 3 g L −1 ZnSO 4 solution recorded the maximum soluble proteins and the minimum grain-Cd concentration. Soil application of ZnSO 4 or foliar application at 6 g L −1 did not affect Cd concentration in grains. Zinc application through both the methods significantly increased phosphorus (P), potassium (K) and Zn concentrations in shoots. Concentration of P and K in grains showed positive relationship with that of Zn. In crux, present study suggests that foliar application of Zn at booting stage in a suitable concentration (3 g L −1 ZnSO 4 solution) can effectively ameliorate the adverse effects of Cd and decrease grain-Cd of wheat grown in Cd contaminated soil. [ABSTRACT FROM AUTHOR]

Understanding how complexes with amino acids in soil solution affect plant zinc (Zn) uptake may aid in optimising plant Zn nutrition. We investigated the influence of histidine and glycine in nutrient solution on apoplastic and symplastic uptake and root-to-shoot translocation of Zn in a triticale (x Triticosecale cv. Elinor) and a bread wheat cultivar (Triticum aestivum cv. Back Cross Rushan). Six-week-old seedlings of the two cultivars were transferred to a nutrient solution containing 20 μm Zn, to which 50 μm histidine, 50 μm glycine or no amino acids were added. Control plants were transplanted to nutrient solution with no Zn or amino acids. Higher concentrations of Zn were found in root and shoots of wheat and triticale plants supplied with Zn than in the control plants without Zn supply. Among the treatments with Zn supply, histidine enhanced, whereas glycine reduced, symplastic root Zn concentration in bread wheat. Both amino acids decreased the symplastic root Zn concentration but had no effect on apoplastic Zn in triticale. Both amino acid treatments also reduced Zn concentrations in the xylem sap of the two plant species compared with the treatment with Zn addition only. In bread wheat, the effect was stronger for glycine than for histidine; in triticale, it was the same for both amino acids. The concentration of Zn in xylem sap was always greater in wheat than in triticale. Addition of histidine to the nutrient solution increased the total amount of shoot Zn in triticale but not in bread wheat, compared with the treatment with Zn addition only, whereas glycine had no significant effect on total shoot Zn in either of the plant species. The results show that histidine, but not glycine, can enhance Zn uptake and translocation into the aboveground parts of triticale. We suggest that this ability of histidine was due to the formation of strong complexes with Zn. [ABSTRACT FROM AUTHOR]

Bryophytes are well-studied model systems for the investigation of uptake mechanisms and pollutant tolerance of plants. The moss Physcomitrella patens is among the most intensively studied organisms with regard to physiological and cellular pathways; however, direct ecological studies on metal stress are rare in this species. We conducted growth experiments on copper and zinc containing media for five and ten weeks, respectively in order to investigate the element and anion dependent metal uptake by energy—dispersive X-ray spectroscopy on a scanning electron microscope. We compared the uptake of metals to the growth and morphology of leaves and protonemata of P. patens . The metal content of both tissues was strongly correlated with availability of free metal cations. Differences between copper and zinc uptake included the limitation of zinc uptake found after five weeks for both tissues. No further sequestration of metal occurred after week five. The content of up to 1.3 wt% zinc and 0.4 wt% copper in the dry biomass correlated negatively to leafy gametophyte growth and to cell length in both tissues. No such correlation to protonema growth or cell width was found. The shortening of protonema cells exposed to zinc did not necessarily lead to decreased protonemal growth. This indicates a compensation of the shorter cells by increased cell division of the protonema filaments. [ABSTRACT FROM AUTHOR]

This study evaluated the tolerance and accumulation potential in the mangroveKandelia obovataunder moderate and high levels of external Zn. A greenhouse experiment was conducted to investigate the effects of a range of external Zn concentrations (0–400 mg L−1) on the growth of this species by counting the lateral root number and measuring the root length, leaf area, and total dry biomass. We also determined the Zn accumulation in plant tissues.K. obovatasurvived with external Zn concentrations of up to 400 mg L−1, although the excess metal resulted in a biomass reduction of 34%. A significant increase in antioxidant enzyme activities occurred in roots of plants under high-level Zn stress, suggesting thatK. obovataseedlings could tolerate up to 200 mg L−1zinc treatment. [ABSTRACT FROM AUTHOR]

Coating seeds can increase seed germination potential, to contribute to better plant development and increase the concentration of micronutrients in seeds. The aim of this study was to evaluate the effect of zinc on nutrition and growth of wheat (Triticum aestivum L.) seedlings from high and low vigor seeds treated with 0, 1, 2, 3, and 4 mL ZnSO4 kg-1 seed (plus a fungicide, a polymer, and water), and stored for six months in an environment with no temperature or relative humidity control. Stem and root dry matter, concentration and accumulation of zinc and the effect of the dosages of ZnSO4 on growth of wheat seedlings were evaluated in seedlings 20 d after germination. It was concluded the zinc applied to wheat seeds accumulates mainly in the seedling roots. Application of ZnSO4 to seeds caused higher accumulation and lower transport efficiency, and use of zinc in the measure that the dosage of the nutrient increased. [ABSTRACT FROM AUTHOR]

Although plants introduced for site restoration are pre-selected for specific traits (e.g. trace element bioaccumulation, rapid growth in poor soils), the in situ success of these plants likely depends on the recruitment of appropriate rhizosphere microorganisms from their new environment. We introduced three willow ( S alix spp.) cultivars to a contaminated landfill, and performed soil chemical analyses, plant measurements, and Ion Torrent sequencing of rhizospheric fungal and bacterial communities at 4 and 16 months post-planting. The abundance of certain dominant fungi was linked to willow accumulation of Zn, the most abundant trace element at the site. Interestingly, total Zn accumulation was better explained by fungal community structure 4 months post-planting than 16 months post-planting, suggesting that initial microbial recruitment may be critical. In addition, when the putative ectomycorrhizal fungi S phaerosporella brunnea and I nocybe sp. dominated the rhizosphere 4 months post-planting, Zn accumulation efficiency was negatively correlated with fungal diversity. Although field studies such as this rely on correlation, these results suggest that the soil microbiome may have the greatest impact on plant function during the early stages of growth, and that plant-fungus specificity may be essential. [ABSTRACT FROM AUTHOR]

In Arabidopsis thaliana, FORD (FERRIC CHELATE REDUCTASE DEFECTIVE 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A. halleri. We combined gene expression studies with the use of β-glucuronidase and green fluorescent protein reporter constructs to compare the expression profile and transcriptional and post-transcriptional regulation of FRD3 in both species. The AtFRD3 and AhFRD3 genes displayed a conserved expression profile. In A. thaliana, alternative transcription initiation sites from two promoters determined transcript variants that were differentially regulated by zinc supply in roots and shoots to favour the most highly translated variant under zinc-excess conditions. In A. halleri, a single transcript variant with higher transcript stability and enhanced translation has been maintained. The FRD3 gene thus undergoes complex transcriptional and post-transcriptional regulation in Arabidopsis relatives. Our study reveals that a diverse set of mechanisms underlie increased gene dosage in the A. halleri lineage and illustrates how an environmental challenge can alter gene regulation. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) is a primary staple cereal and significant source of mineral nutrients in human diets. Therefore, increasing concentration of the essential mineral, Zn, and decreasing concentration of the toxic mineral, Cd, could significantly improve human health. Because plant mechanisms for uptake and translocation of Cd and Zn are related, we assessed both Cd and Zn concentration to evaluate their independence in hard winter wheat germplasm. Grain Cd concentrations of some genotypes grown in Nebraska trials were above the Codex guidance level (0.2 mg kg-1), and highly repeatable differences in grain Cd were found between pairs of low and moderate-Cd commercial cultivars. Grain Cd concentration was predicted by Cd concentration in aboveground plant tissues at anthesis. However, grain Zn concentration was not predicted by Zn concentration in aboveground plant tissues. Genome-wide association scans using high-density single nucleotide polymorphism (SNP) markers identified Cdassociated SNPs on 5AL in a region homoeologous to the Cdu1 locus on 5BL in durum wheat (Triticum turgidum L. var. durum Desf.). Genetic regulation of grain cadmium concentration in bread wheat may be more complex than in durum wheat because epistatic interactions between SNP markers were identified, and SNP marker haplotypes were imperfect predictors of grain Cd phenotype. The SNP marker associations with Zn concentration were weak and inconsistent across trials, and Zn concentration was independent of 5AL markers. The independent genetic regulation of grain Cd and Zn concentrations indicates that breeding low Cd hard winter wheat genotypes without reducing Zn concentration has high potential for success. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the effect of zinc (Zn) application on cadmium (Cd) uptake of maize (Zea maysL.) grown in alkaline soil. Four doses of cadmium (Cd; 0, 2.5, 5, and 10 ppm) in the form of cadmium chloride and four doses of Zn (0, 10, 20, and 40 ppm) in the form of zinc sulfate were applied to the soils. Plants were harvested at the 45th day of their developments. The Cd amounts in shoots and roots were analyzed separately. Significant differences between Cd amounts in shoots and roots are obtained with the application of different Zn doses (P < 0.01). In all Cd levels, Zn application increases Cd in both shoots and roots relative to Cd contents of plants grown in the pots that not applied Zn. It is also found that Cd content of the roots is greater than that of shoots. [ABSTRACT FROM AUTHOR]

Wheat is a staple food of Indian population. Its nutritional and quality parameters have gained considerable importance over past few decades. In the present study, genotypic variation was studied in 100 advanced breeding lines developed for Indian peninsular zone by measuring phytic acid (PA), inorganic phosphate (IP), iron and zinc content in seeds and hundred kernel weight (HKW). Advanced breeding lines under investigation exhibited wide variation for the characters studied. The PA content ranged from 4.97 mg/g to 15.02 mg/g (mean of 9.58 mg/g). Iron and zinc content was in the range of 0.042 to 0.098 mg/g and 0.017 mg/g to 0.029 mg/g respectively. HKW ranged from 2.99 to 5.42 g. There was significant negative correlation between PA and HKW. Iron content showed very high genotypic coefficient of variation and heritability (h2bs) as compared to zinc content and other traits. Low heritability of IP content indicated the environmental influence on the trait. [ABSTRACT FROM AUTHOR]

Phosphate (Pi) is pivotal for plant growth and development. Pi deficiency triggers local and systemically regulated adaptive responses in Arabidopsis thaliana. Inhibition of primary root growth (PRG) and retarded development of lateral roots (LRs) are typical local Pi deficiency-mediated responses of the root system. Expression of Pi starvation-responsive (PSR) genes is regulated systemically. Here, we report the differential influence of iron (Fe) availability on local and systemic sensing of Pi by Arabidopsis. P-Fe- condition disrupted local Pi sensing, resulting in an elongated primary root (PR). Altered Fe homeostasis in the lpsi mutant with aberration in local Pi sensing provided circumstantial evidence towards the role of Fe in the maintenance of Pi homeostasis. Reporter gene assays, expression analysis of auxin-responsive genes (ARGs) and root phenotyping of the arf7arf19 mutant demonstrated the role of Fe availability on local Pi deficiency-mediated LR development. In addition, Fe availability also exerted a significant influence on PSR genes belonging to different functional categories. Together, these results demonstrated a substantial influence of Fe availability on Pi deficiency-mediated responses of ontogenetically distinct traits of the root system and PSR genes. The study also provided evidence of cross-talk between Pi, Fe and Zn, highlighting a complex tripartite interaction amongst them for maintaining Pi homeostasis. [ABSTRACT FROM AUTHOR]

Aims: This study investigates the response of metallicolous (M) and nonmetallicolous (NM) ecotypes of Dianthus carthusianorum L. to chronic multi-metal and acute Zn stress. Methods: Plants were cultivated on the Zn-Pb waste heap substrate and under Zn excess in hydroponics. Growth parameters as well as accumulation of organic acids and thiol peptides were determined as a function of metal accumulation. Results: When grown on the metalliferous substrate, the M plants showed less phytotoxicity symptoms, lower foliar metal (Zn, Pb, Cd) accumulation, higher malate and citrate but lower glutathione content than the NM plants. When exposed to Zn excess in hydroponics, the M ecotype was also more tolerant but accumulated more Zn in comparison with the NM ecotype, accompanied by greater malate and citrate concentrations in the shoots, which were however not affected by increasing Zn doses. No phytochelatins were detected under any experimental conditions. Conclusions: Both constitutive and adaptive tolerance was found in D. carthusianorum. Under chronic metal stress, enhanced tolerance results from restricted metal uptake to the shoots and probably from detoxification by organic acids; however, under acute Zn stress it is not related to diminished metal uptake or organic acids. Glutathione and phytochelatins are not implicated in adaptive metal tolerance. [ABSTRACT FROM AUTHOR]

The mutual effects of boron (B) and zinc (Zn) on growth, total chlorophyll (Chl), membrane permeability (MP), and nutrient content were investigated in peanut (Arachis hypogaeaL.). The soil was treated with five levels of B (0, 4, 8, 16, 32 mg kg−1) and three levels of Zn (0, 10, 20 mg kg−1). Plant growth was progressively depressed with increasing of B. However, Zn addition had an inhibitory effect on B toxicity and decreased growth reduction caused by excess B. In Zn-untreated plants, B and Zn contents were enhanced by increasing of B; moreover, both Zn and B addition enhanced Zn content. The Chl content decreased and MP increased, resulting from B toxicity; however, Zn addition partially ameliorated the adverse effects of B toxicity on Chl and MP. Increasing B enhanced phosphorus (P), potassium (K), calcium (Ca), iron (Fe), Zn, copper (Cu), and sodium (Na) contents in peanut shoots. [ABSTRACT FROM PUBLISHER]

Large areas of China have soils low in both available selenium (Se) and zinc (Zn). In order to investigate whether Se supplied as either selenate or selenite can increase germination and growth compared with low-Se controls we used broccoli, an important vegetable with anticancer effects, especially when biofortified with Se. Broccoli was grown under both Zn adequacy and Zn deficiency to determine whether interactions between these minerals affect plant growth. Selenite and selenate at a wide range of doses increased the speed and extent of germination. Both inorganic Se forms increased early root and shoot growth at low concentrations, with selenite having a stronger effect than selenate. A sand culture trial showed a similar growth increase due to low-dose Se under Zn deficiency but not under Zn adequacy. Conversely, at high Se levels, the results provided evidence from biomass, water use, photosynthesis and gas exchange that broccoli growth was inhibited at high Se levels, with selenite being more toxic than selenate. In this broccoli trial, the two Se forms were equally effective in increasing leaf Se concentration, whereas in most plants selenite is largely converted to organic Se forms and stored in the roots. This study suggests that Se, supplied either as selenate or selenite, may improve germination and growth in broccoli, especially on Zn-deficient soils. Field trials conducted on soils which are very low in both plant-available Se and Zn are needed. [ABSTRACT FROM PUBLISHER]