Increase In Zn Uptake Research Articles

Biofertilizer effect of some zinc dissolving bacteria free and encapsulated on Zea mays growth

Crop nutrition depends on zinc for enzymatic, oxidative, and metabolic processes. In the current study 20 different bacteria were isolated from five soil samples collected from different fields in Egypt. Bacterial isolates were screened for their ability to solubilize insoluble zinc oxide and zinc carbonate. The ability of selected isolates to tolerate soluble zinc was determined using different concentrations of (ZnSO4). Three bacterial isolates were selected with efficiency in solubilizing zinc oxide and zinc carbonate while tolerating high levels of soluble zinc. Molecular identification by 16S rRNA sequencing of the chosen isolates identified them as B3 (Acinetobacter calcoaceticus), B5 (Bacillus proteolyticus) and C6 (Stenotrophomonas pavanii). Sodium alginate beads formulated with the isolated bacteria were tested for stability under different storage conditions for 3 months. A pot experiment was conducted to study and compare the effect of using chosen isolates as an in vivo Zn solubilizer with amended ZnCO3 either alone or embedded in beads as carrier in the soil and its effect on growth parameters of Zea mays after 2 months. There was an increase in Zn uptake in all treatments compared to the control. However, plants grown in a pot treated with ZnCO3 and Acinetobacter calcoaceticus showed the highest zinc content and plant dry weight as compared to the control. Finally, selected isolates in both free and encapsulated forms showed improved plant growth parameters and higher zinc content and can be applied as biofertilizers to enhance soil fertility.

Rhizobacteria improve rice zinc nutrition in deficient soils

The deficiency of zinc (Zn) in rice grown under partially reclaimed sodic soils is mainly because of the low solubility of Zn minerals. Augmenting the rhizosphere interaction with acclimatized native Zn solubilizing rhizobacteria (ZSB) can be a promising approach to cope with poor Zn nutrition of crops under deficient soils. This study was designed to isolate ZSB from the rhizosphere bacterial community of plants growing in soils of zinc mines and sodic environments and evaluate their performance in Zn nutrition of the rice. Isolates were assessed for in vitro Zn solubilization and identified by the amplified 16S rRNA gene using universal primers. The selected ZSBs were evaluated using a complete randomized block design with three replications for their response to Zn nutrition of rice in soils with high and low DTPA extractable Zn. The ZSB population was greater in rhizospheric soils of yellow sweat clover, rice, sorghum, and maize (6.2–10.3 × 103) than wheat (2.5 × 103). The Zn mine soils harbour a 2.96 times higher ZSB population than sodic soils. The ZSB population showed a strong negative correlation with the pH and EC of the soil (r > −0.90, p < 0.01). Bacillus paramycoides strain-1, B. paramycoides strain-2, B. cereus, and Enterobacter soli, isolated from rhizospheric soil; solubilized 228.4, 146.5, 174.6, and 334.0 μg mL−1 Zn from zinc oxide under in vitro conditions. However, rice plants showed a selective response in forging an association with inoculated ZSB. Only B. paramycoides strain-1 had exhibited a 17% increase in Zn uptake over uninoculated control. Inoculation with B. paramycoides strain-1 also caused a 22–24% increase in the water-soluble plus exchangeable fraction of Zn in deficient soils. This study concludes that using native rhizobacteria can be a practical option for managing Zn deficiency in alkaline soil conditions. The study also highlights the importance of soil native micronutrient levels in the success of the rhizobacteria –phytobionts interaction for crop nutrition.

Mitigation of Copper Stress in Maize (Zea mays) and Sunflower (Helianthus annuus) Plants by Copper-resistant Pseudomonas Strains.

Use of heavy metal (HM) resistant plant growth-promoting rhizobacteria (PGPR) is among the eco-friendly strategies to increase the resistance of crop plants against the HM stress. In this study, we investigated the effects of two copper (Cu)-resistant PGPR strains (Pseudomonas fluorescens P22 and Pseudomonas sp. Z6) on the growth and nutrition of maize (Zea mays) and sunflower (Helianthus annuus) plants grown in a Cu-contaminated soil under glasshouse conditions. Both PGPR strains significantly increased the plant vegetative parameters including shoot biomass, stem height and diameter, and chlorophyll (SPAD values) index in both crops. In both plants, the PGPR inoculations also significantly elevated the uptake of nutrients including potassium, phosphorus, calcium, magnesium (only by P. fluorescens P22), iron, zinc, manganese, and Cu. Magnitude of the nutritional effects varied between the PGPR strains, e.g., in sunflower, inoculation with P. fluorescens P22 and Pseudomonas sp. Z6 led to an increase in uptake of Zn by 42% and 114%, or Mn by 61% and 88%, respectively, in comparison with control plants. Improved performance of the inoculated plants can be attributed to the plant growth-promoting (e.g., production of auxin and siderophore, phosphate solubilization activities, etc.) and stress removal (e.g., production of ACC-deaminase to drop the ethylene level in stressed plants) properties of the PGPR strains, which were uncovered in our in vitro studies prior to the glasshouse experiment. Beside the plant growth-promoting traits of these PGPR strains, their high resistance to Cu toxicity seemed to be of particular importance for plant fitness improvement under Cu toxicity.

Toxicity effects of zinc on two marine diatoms, under varying macronutrient environment

Diatoms constitute one of the fundaments in the trophic food chains and are responsible for much of the bioaccumulation of heavy metals, in particular zinc, throughout the web of food chains. Chaetoceros calcitrans and Thalassiosira weissflogii are widely present as a dominant marine diatom in estuarine and coastal waters. The zinc uptake, its fractionation in subcellular structures and macromolecular compartments in two marine diatoms, C. calcitrans and T. weissflogii and trophic transfer under different macronutrient concentrations were investigated. The study reveals a significant interaction between macronutrients and metal uptake by the two diatom species. Increased cellular accumulation of zinc and N, P-limited condition were found to affect N, P and Si assimilation by diatoms negatively. Conversely, nitrogen (N) limitation inhibited the intracellular uptake of zinc. However, at higher concentration of zinc, the difference in zinc uptake between nutrient enriched condition (+NP) and nutrient limited (N or P) condition become smaller, indicating that the zinc uptake by diatoms is less dependent on N containing protein ligands at high Zn concentration. Nitrogen concentration in the medium was also found to affect the relative distribution of zinc in subcellular structures and macromolecular components. However, major portion of zinc was distributed in soluble substance and in the protein of the algal cells. The N limited condition facilitates the accumulation of zinc in cell organelles (insoluble substance) leading to increased toxicity. Trophic transfer of zinc was also measured by calculating percentage of metal retained in mussel, Perna viridis over the experiment period. Regardless of the algal species, the percentage of accumulation of zinc was found to be high in mussels fed with algal cells acclimated to nutrient enriched condition (31 and 38%). Our study therefore suggests that N enrichment may lead to an increase in Zn uptake and transfer in marine plankton.

Effects of nickel on zinc uptake and translocation in two wheat cultivars differing in zinc efficiency

Low availability of zinc (Zn) in soil can limit plant growth and yields. In soils with elevated nickel (Ni) concentrations, which can be due to anthropogenic and geogenic sources, Zn uptake by plants may be inhibited due to competition between the two elements. Here we used a hydroponic system to investigate short-term effects of a wide range of Ni concentrations on Zn uptake and translocation in two spring wheat cultivars at two different levels of Zn supply. Seedlings of the Zn efficient cultivar Back Cross Rushan and the Zn inefficient cultivar Kavir were grown for three weeks in Zn and Ni free nutrient solution and then exposed for two days to either 0, 1, 2, 10, 20, or 40μM Ni and either 400nM or 2μM Zn, before they were harvested. Increasing Ni had no influence on Zn uptake by Kavir at the low Zn level and even slightly enhanced it in Back Cross Rushan, which means that competition by Ni for uptake sites was irrelevant and suggests that Zn uptake was governed by a highly selective uptake system under these conditions. At the high Zn level, Ni had contrasting effects on the uptake of Zn in the two cultivars: Increasing Ni led to a strong increase in Zn uptake in Kavir as opposed to a slight decrease in Back Cross Rushan. The difference indicates that the two cultivars strongly differ in their low-affinity Zn uptake systems. Also the fraction of Zn translocated to the shoots differed between the two cultivars at high Zn supply, while they were very similar at the low Zn level. A strong decrease with increasing Ni solution concentration was observed in Kavir at the high Zn level, whereas there was little Ni dependence of root-to-shoot translocation in Back Cross Rushan. The findings suggest that differences in root Zn compartmentalization may be involved in the different Zn efficiencies of the cultivars.

Effect of Biosolid Amendments on the Metal and Nutrient Uptake and Spectral Characteristics of Five Vegetable Plants

The accumulation of metals and nutrients in biosolid-amended soils and the risk of their excess uptake by plants is a topic of great concern. This study examines the elemental uptake and accumulation in five vegetable plants grown on biosolid-applied soils and the use of spectral reflectance to monitor the resulting plant stress. Soil, shoot, root, and fruit samples were collected and analyzed for several elemental concentrations. The chemical concentrations in soils and all the plant parts increased with increase in applied biosolid concentrations. The Cu and Zn concentrations in the plant shoots increased in the order of collard<radish<lettuce<tomato<pepper. The Cu and Zn concentrations accumulated significantly in the fruits of the tomato plants compared to other plants. Among all the plants, the shoot concentration factor (SCF) of Zn was significantly higher for pepper plants, indicating increase in uptake of Zn. The shoot relative uptake index (SRUI) of Cu and Zn increased in the order of collard<radish<lettuce<tomato<pepper. The shoot dry weight and spectral reflectance of the radish plants in the near-infrared (NIR) region (800-1,300 nm) decreased significantly with increase in biosolid concentration compared to other plants. Increase in plant stress with increase in biosolid dose was evident in radish plants through significant reduction in Normalized Difference Vegetative Index (NDVI). This study indicates the potential use of spectral reflectance as a tool for the screening and monitoring of stress-sensitive plant species and their physiology and as a result, indirectly assesses the chemical concentrations in soils and plants.

Phytoextraction of soil cadmium and zinc by microbes-inoculated Indian mustard (Brassica juncea)

A pot experiment was carried out to evaluate the effect of Pseudomonas fluorescens and Trichoderma harzianum inoculation on the uptake of zinc (Zn) and cadmium (Cd) by Indian mustard (Brassica juncea) from the soil having three different concentrations of Zn (300, 600, 900 mg/kg) and Cd (5, 10, 15 mg/kg) separately. Microbial inoculation resulted in significantly better plant growth, available metal content and their uptake than control (without microbes). Available Zn was enhanced, ca.1.6- and 1.4-fold and Cd ca. 2.5- and 1.8-fold, by P. fluorescens and T. harzianum, respectively. P. fluorescens resulted in an increase in Zn uptake by 113.9, 51.9 and 58.4% and T. harzianum by 42.6, 32.1 and 33.9% over control from soils having 300, 600 and 900 mg Zn, respectively, while of the corresponding results for Cd were 110.2, 48.9 and 58.1% with P. fluorescens and 42.6, 30.9 and 33.4% with T. harzianum from soil having 5, 10 and 15 mg Cd, respectively, after 90 days of treatment. In general the rate of metal uptake was higher during the initial 30 days and declined later.

Effect of earthworms on the phytoremediation of zinc-polluted soil by ryegrass and Indian mustard

In this paper, the effects of earthworms on the growth and Zn uptake of ryegrass and Indian mustard in artificially Zn-contaminated soils were studied. Earthworm inoculation increased plant shoot biomass by 29–83% for ryegrass and by 11–42% for Indian mustard, respectively, as compared to the treatments without earthworms, while the roots’ biomass of both plants were increased much more than their corresponding shoots. Earthworms also increased shoot Zn concentrations in both ryegrass and Indian mustard, although the increases in ryegrass did not show significant difference. Except for soil without Zn contamination, the Zn contents of both ryegrass and Indian mustard roots were significantly increased by earthworm addition. Generally, Zn contents of roots were relatively higher than those of shoots for both plants, which were independent of earthworms inoculation. Earthworm increased soil bioavailable metal (diethylenetriamine-pentaacetic acid–Zn) (DTPA-Zn) concentrations, which resulted in a direct increase in Zn uptake by the plants, since a significant correlation was observed between the DTPA–Zn contents and plant Zn uptake. However, the main reason for the increase in plant Zn uptake under earthworm inoculation was probably the increase in dry matter production stimulated by earthworms.

Methods of cotton (Gossypium hirsutum) establishment and zinc fortification in cotton-based cropping systems: Direct and residual effect on onion (Allium cepa) and system productivity of cottononion cropping system

A field experiment was conducted during rainy (kharif) and winter (rabi) seasons of 201314 and 201415 at New Delhi, to evaluate the effect of 2 methods of cotton establishment (direct sowing and transplanting) and 5 zinc-levels (control, 2.5, 5.0, 7.5 kg Zn/ha and 0.5% zinc sulphate foliar spray at 60 and 90 days after planting ) on cotton (Gossypium hirsutum L.) and their residual and direct effect of 5.0 kg Zn/ha in place of foliar treatment on the succeeding wheat [Triticum aestivum (L.) emend. Fiori &amp; Paol.] and onion (Allium cepa L.) crop. In this re- search paper residual effect of treatments applied to cotton and direct effect of Zn on onion has been presented along with system productivity and resource-use efficiency. Productivity of cotton and onion was higher during 201314 than 201415. Onion recorded significantly higher economic parameters and nutrient uptake after trans- planted cotton than direct sown. Onion produced statistically similar growth and yield attributes, bulb yield, gross and net returns and nutrient uptake, due to direct application of 5.0 kg Zn/ha and residual effect of 5.0 and 7.5 kg Zn/ha to cotton, which were significantly superior to control and residual effect of 2.5 kg Zn/ha. Based on 2 years average, gain in net returns was 40,350, 43,200 and 47,950/ha due to residual effect of 5.0/7.5 kg Zn/ha and direct effect of 5.0 kg Zn/ha over control. Both residual and direct effect of Zn found to enhance the quality of bulb in terms of Zn enrichment and on an average 32.0, 31.8% and 36.2% increase in Zn uptake was recorded due to residual effect of 5.0/7.5 kg Zn/ha and direct effect of 5.0 kg Zn/ha respectively. Based on 2-years average, sys- tem productivity in terms of seed cotton equivalent yield (9.45 t/ha), production efficiency (27.0 kg/ha/day), eco- nomic efficiency (736.9 /ha/day) and irrigation water productivity (1.16 kg/m3) of transplanted cottononion crop- ping system was significantly greater than the direct sown cottononion system. Successive increase in Zn-levels caused significant increase in system productivity, production efficiency, economic efficiency and irrigation water productivity up to application of 5.0 kg Zn/ha. So based on the study it is concluded that in Bt cottononion crop- ping systems 5.0 kg Zn/ha to Bt cotton is sufficient to meet the zinc requirement of both the crop and transplanted cotton is better than direct sown cotton.

Responses of Zn assimilation by coastal plankton to macronutrients

We examined the Zn uptake in marine diatoms and its transfer to marine copepods under different nutrient‐replete and ‐deplete conditions. Zn uptake, quantified by measurements of both total cellular and intracellular Zn accumulation in two coastal diatoms (Thalassiosira pseudonana and Thalassiosira weissflogii), was greatly dependent on the ambient nitrogen conditions. Semicontinuous culture experiments demonstrated that diatom cells accumulated much less Zn with decreasing ambient nitrate concentration. The calculated Zn uptake rate decreased by 1.8 times in T. pseudonana and 1.5 times in T. weissflogii with a decrease in ambient N concentration from 176 µM to 17.6 µM. N‐starved cells also accumulated much less Zn compared with N‐enriched cells. The uptake rate decreased by 2.5–2.6 times when both diatoms were starved of N for 2 d. The intracellular partitioning of Zn in the diatom T. pseudonana was positively related to the ambient N level within the short‐term exposure period (5 h). P starvation, however, resulted in an increase in Zn accumulation in the diatoms, whereas Si starvation did not significantly affect the rate of Zn uptake in diatoms. The trophic transfer was quantified by measurement of Zn assimilation efficiency in two copepods (Calanus sinicus and Acartia spinicauda) feeding on diatoms with a different N quota. Assimilation generally increased with an increase in the N quota of the diatoms. In one experiment (C. sinicus feeding on diatom T. weissflogii), the influence of different N status in diatoms on Zn assimilation by copepods was statistically significant. In contrast, the elimination rate (physiological turnover rate) was independent of the N quota of the cells. Nitrogen enrichment may lead to an increase in Zn uptake and transfer in marine plankton. Our study therefore suggests that there is considerable interaction between macronutrients and Zn uptake by plankton in aquatic systems.

Mycorrhizal colonization and nutrient uptake of dry bean in manure and compost manure treated subsoil and untreated topsoil and subsoil

Eroded or leveled Portneuf silt loam soils (coarse‐silty mixed mesic Durixerollic Calciorthid) have been restored to topsoil productivity levels by manure application, but not by other organic sources such as cheese whey. In dry bean (Phaseolus vulgaris L. cv. Viva), only soil organic matter and Zn concentration of leaf tissue correlated with improved yields. Manure application could potentially increase or decrease mycorrhizal colonization depending on which factors dominate. Manured and unmanured soils from a long‐term field experiment were sampled and mycorrhizal spores were quantified, but there was no significant manure treatment effect on spore numbers. A greenhouse study was conducted to see if manure or composted manure freshly applied to subsoils would facilitate mycorrhizal colonization in dry bean roots compared to untreated topsoil or conventionally fertilized subsoil. Low level colonization (< 5%) was observed 21 days after planting and that increased to 58% by 56 days after planting. Roots grown on subsoil treated with manure or composted manure showed higher percent colonization than roots from untreated subsoil, but roots on topsoil had highest colonization. This increase in colonization was statistically significant for the last two sampling dates. Topsoil promoted the greatest percent colonization in early bean growth and this was reflected in greater Zn uptake during early growth stages. By day 56, plants grown in manured subsoil absorbed Zn equal to topsoil and at higher levels than the subsoil control. However, this increase in Zn uptake was not seen in plants grown in compost manured subsoil. A decrease in root and shoot weight was observed in the composted manure treatment and this seemed to decrease mycorrhizal efficiency. Uptake of other nutrients was either not related or was negatively related to mycorrhizal infection. The higher percent colonization of roots by mycorrhizal fungi stimulated by manure could explain the field observations of higher bean yield and Zn contents in dry bean in manured than in untreated subsoils.

Effect of potassium application on the transformation of zinc fractions in soil and on the zinc nutrition of wetland rice

AbstractThe effect of different levels of K application on the transformation of native as well as applied Zn fractions in a rice‐growing soil was studied under two moisture regimes viz. waterlogged and alternate waterlogged and saturation. Application of K caused an increase in the water‐soluble plus exchangeable, organically complexed and carbonates, and other acid‐soluble mineral fractions of native soil Zn. Application of K also caused an increase in the transformation of applied Zn into all the above three fractions of the element in soil. The above effects of K were more pronounced in soil under waterlogged than under alternate waterlogged and non‐waterlogged moisture regimes.The results of a greenhouse experiment showed that K application caused an increase in Zn uptake and per cent utilization of both native and added Zn by rice. This was attributed to the increase in the water‐soluble plus exchangeable and organically complexed forms of Zn in soil due to K application.

Interactions of zinc with banded and broadcast phosphorus fertilizer on the concentration and uptake of P, Zn, Ca and Mg in plant tissue of oilseed flax

Field experiments on four sites over 3 yr evaluated the effect of banded and broadcast applications of fertilizer P, with and without application of Zn on the tissue concentration and uptake by the plant of Zn, P, Ca, and Mg in oilseed flax (Linum usitatissimum L.). Residual effects of the P applications were also evaluated over five site-years. Banded applications of P tended to be more effective than either broadcast applications or residual P in increasing tissue concentration and uptake of P. Zinc application tended to decrease P concentration in the tissue where P levels were relatively high. When Zn was applied with banded P applications, it tended to reduce P uptake by the plant; when it was applied with broadcast P, it tended to increase P uptake by the plant. Changes in P uptake in response to Zn application generally reflected changes in dry matter production. When an increase in Zn concentration in the tissue or uptake by the plant occurred due to Zn applications, it was primarily when the Zn was applied with broadcast P fertilizer or where P had been broadcast the previous season. The increase in uptake of Zn generally reflected increased dry matter yield. Banded applications of P tended to produce lower tissue concentrations of Zn than did broadcast applications. Zinc concentration in the tissue also tended to be reduced by residual P from applications the previous season. Changes in Ca concentration in the tissue and uptake by the plant generally reflected changes in dry matter production. However, Mg concentration in the tissue and uptake by the plant were increased by P applications, particularly where P was banded. The increase in concentration in the tissue and uptake of Mg by the plant with application of P indicates that applications of P increase the ability of the plant to absorb Mg, presumably due to an effect on the absorption-translocation system within the plant. Key words: Flax, P placement, P, Zn, Ca, Mg

Cellular uptake of cadmium and zinc

CHO mutants, resistant to over 100-fold of a normally toxic level of extracellular cadmium have been used to examine the mutually antagonistic effect of Cd and Zn on their uptake. Cadmium uptake in these mutants is only 7-10% that of the parental cells. Zinc uptake in these mutants is equal to or greater than that in the wild-type cells. Results of kinetic studies on uptake indicated that the two metals interact by competitive inhibition. TheK m andK i values for Cd and/or Zn were different in some of the mutants and indicate multiple carriers may be involved in the transport of these metals. The reduction in Cd uptake and concomitant increase in Zn uptake contribute to the increased Cd resistance in these mutants.

Navy bean responses to zinc fertilizers

Abstract Experiments were conducted to study the effects of various Zn carriers and rates on the growth and Zn uptake of Sanilac navy beans. Plants were grown under greenhouse and growth chamber conditions for 2, 4, 6 or 8 weeks on a Wisner silty clay loam soil low in available Zn. Plant growth responded to the various Zn fertilizers except at 4 weeks where no response was obtained. Only ZnZnEDTA and ZnNa2EDTA increased growth at 2, 6 and 8 weeks while ZnSO4, ZnHEIDA, ZnNTA and Zn(NO3)2 did not give consistent responses at all of these periods. The Zn carriers did not influence uptake until 6 weeks after planting. Zinc rates began to influence plant growth at about the bloom stage, 6 weeks after planting with 2.0 kg/ha Zn as ZnNa2EDTA and 3.3, 6.6 and 13.2 kg/ha Zn as ZnSO4 giving higher responses than 0.7 or 1.3 kg/ha Zn as ZnNa2EDTA. The most consistent increase in Zn uptake at 2, 6 and 8 weeks was obtained with 6.6 and 13.2 kg/ha Zn applied as ZnSO4. No differences in uptake were obtained at 4 weeks be...