Plant Zn Concentration Research Articles

Zinc phytotoxicity and cationic micronutrients contents in quinoa as influenced by high Zn levels and soil amendments

Contamination of soils with heavy metals (HMs) is a serious concern due to the non-biodegradability and accumulation of these metals in living organism. The aim of this study was to evaluate the effectiveness of fish scale powder, chitin, and chitosan in reducing zinc (Zn) accumulation of quinoa grown on Zn-polluted soil. A 3*4 factorial greenhouse trial was conducted with three levels of Zn contamination (0, 100, and 200 mg kg−1) and four types of amendment (control, and 0.15% of each fish scale powder, chitin, and chitosan). The quinoa seeds were sown in soil treated with Zn contamination and amendments. Results showed that application of amendments especially chitosan increased shoot and root dry weight and greenness index of quinoa leaf. While high soil Zn levels decreased cationic micronutrients uptake in quinoa shoot, chitosan addition desirably enhanced cationic micronutrients uptake in quinoa shoot. Overall, amendment addition significantly decreased Zn concentration and uptake in plant; the highest decrease was observed following the application of chitosan. Although the application of high Zn levels significantly increased the values of phytoextraction efficiency, application of chitin and chitosan significantly decreased it. The value of translocation factor was lower than one, demonstrating that a large amount of Zn was stabilized in the root tissues, while a small amount of this metal was transferred to aboveground parts of quinoa. Results of this study revealed that fish scales derivatives were effective in preventing Zn toxicity and at the same time increasing cationic micronutrients contents of quinoa grown on HMs-polluted soil.

Enzymatic alterations of soil and plant system on applied Zn sources, organics and microbial inoculants in zinc deficient calcareous and non-calcareous soils

The study aimed to investigate the impact of zinc (Zn) nutrition on enzymatic activity in soil and plant systems of zinc-deficient soils. Additionally, it aimed to understand the impact of solubilizer (such as Zinc Solubilizing Bacteria) and mobilizer (like AM Fungi) on enzyme activity and zinc nutrition in plants across calcareous and non-calcareous soil environments. A pot experiment was carried out with two different soils with three Zn sources (ZnSO4, ZnO and Zn-EDTA), organic manure (FYM) and microbial inoculants - Zinc Solubilizing Bacteria (ZSB) and Arbuscular Mycorrhizal Fungi (AM F). The DTPA-Zn and plant Zn content increased with applied sources of Zn. The microbial inoculants and FYM enhanced the use efficiency of all sources of Zn compared to unapplied treatments. Regarding soil enzyme activity, FYM and AM fungi played a major role which in turn altered the dehydrogenase (SDHA) and alkaline phosphatase (AlP) activities in both soils. The Zn sources and ZSB addition enhanced the plant enzyme activity. Calcareous soil recorded higher CA, SOD and alkaline phosphatase activities compared to non-calcareous soil the latter registered higher dehydrogenase activity and fruit Zn content.

Green chemistry routed sugar press mud for (2D) ZnO nanostructure fabrication, mineral fortification, and climate-resilient wheat crop productivity

Nanotechnology appears to be a promising tool to redefine crop nutrition in the coming decades. However, the crucial interactions of nanomaterials with abiotic components of the environment like soil organic matter (SOM) and carbon‒sequestration may hold the key to sustainable crop nutrition, fortification, and climate change. Here, we investigated the use of sugar press mud (PM) mediated ZnO nanosynthesis for soil amendment and nutrient mobilisation under moderately alkaline conditions. The positively charged (+ 7.61 mv) ZnO sheet-like nanoparticles (~ 17 nm) from zinc sulphate at the optimum dose of (75 mg/kg blended with PM (1.4% w/w) were used in reinforcing the soil matrix for wheat growth. The results demonstrated improved agronomic parameters with (~ 24%) and (~ 19%) relative increases in yield and plant Zn content. Also, the soil solution phase interactions of the ZnO nanoparticles with the PM-induced soil colloidal carbon (− 27.9 mv and diameter 0.4864 μm) along with its other components have influenced the soil nutrient dynamics and mineral ecology at large. Interestingly, one such interaction seems to have reversed the known Zn-P interaction from negative to positive. Thus, the study offers a fresh insight into the possible correlations between nutrient interactions and soil carbon sequestration for climate-resilient crop productivity.

The effect of phosphorus fertilizer under the influence of iron and zinc treatments on nutrient content and lettuce yield

Interaction between phosphorus (P), zinc (Zn), and iron (Fe) alters plant nutrient concentrations and nutritional quality. In this regard, there are a limited number of studies on P and micronutrient relations in lettuce plants. In this study, the effects of Zn and Fe applications on plant growth, concentrations, and contents of P, Zn, Fe, copper (Cu), and manganese (Mn) were determined in lettuce plants grown under increasing P rates. Lettuce plants grown under increasing P rates (0, 100, 200, and 400 mg kg−1 P) were treated with either sole or combined applications of 20 mg kg−1 Zn and 30 mg kg−1 Fe. Fresh and dry weights, P concentrations, and contents of lettuce were increased by P fertilization. With Zn and Fe applications, lettuce Fe contents were increased by medium P rates. Plant Zn contents were increased by P fertilization when the plant supplied Zn alone. Besides the highest P rate, Zn and Fe increased plant Zn content through P fertilization. Under no micronutrient condition, Cu concentration revealed insignificant changes, but its content was significantly increased by P application. Plant Mn concentration only increased by low P when the plant supplied Zn however Mn contents of lettuce were increased by P fertilization. In conclusion, even high P doses had no significant impact on Fe, Zn, Cu, and Mn concentrations in lettuce plants. Plant Zn concentrations increased when Zn was applied with Fe. Likewise, Cu increased but manganese declined. This emphasizes the importance of simultaneous Zn and Fe fertilizer application, especially in Zn biofortification research.

Effect of Iron and Urea Application on Iron Biofortification of Lentil (Lens culinaris Medik.)

ABSTRACT Agronomic biofortification with iron (Fe) may be a viable approach to combat the widespread deficiency of Fe in humans. Thus, the present study was conducted to examine the effect of Fe and urea foliar application on Fe biofortification in lentil (Lens culinaris Medik.). The field experiments were conducted at two locations viz. Ludhiana and Faridkot, India. Different treatment combinations of foliar spray of sole Fe (0.5% of FeSO4.7 H2O), sole urea (2% urea), and combined application of Fe and urea at flowering, pod formation, and flowering + pod formation stages along with unsprayed control were applied to lentil. The results of the study revealed that the combined foliar application of Fe and urea at flowering + pod formation stages was the most effective in enhancing grain yield, Fe and zinc (Zn) concentration in plants (at flowering as well as pod formation stage), stover and grain (whole and split). The highest Fe concentration in whole (36% higher over control) as well as split (32.9% higher over control) grain and protein content (21% higher over control) was obtained with foliar application of Fe + urea at flowering + pod formation stages. Conclusively, the combined foliar application of 0.5% FeSO4.7 H2O and 2% urea at flowering + pod formation stages may prove to be a feasible option for increasing grain yield and enrichment of lentils with Fe and Zn to combat micronutrient malnutrition in human populations.

Zinc Foliar Application Mitigates Cadmium-Induced Growth Inhibition and Enhances Wheat Growth, Chlorophyll Contents, and Yield.

Cadmium (Cd) is a toxic heavy metal that significantly threatens plants and the environment. Its toxicity in plants can result in various adverse effects, including reduced growth, altered metabolism, and cell damage. Cadmium can also interfere with nutrient uptake, particularly zinc (Zn), leading to Zn deficiency and further exacerbating Cd toxicity. On the other hand, foliar application of zinc might be a useful strategy to mitigate cadmium (Cd) toxicity in plants. Hence, a pot experiment was conducted with three replications. The wheat plants were treated with various concentrations of Zn as a foliar spray (control, 0.1, 0.2, 0.4, and 0.5%) in Cd-spiked soil in pots. The results showed that foliar use of Zn at 0.4 or 0.5% resulted in higher plant height, grain yield, and dry matter yield than the control group. Using Zn as foliar spray enriched shoot and grain Zn content while reducing Cd content in the shoot and grain. The leaf's electrolyte leakage (EL) decreased by 15.4, 29.8, 40.7, and 45.9% in the Zn 0.1%, Zn 0.2%, Zn 0.4%, and Zn 0.5% treatments, respectively, compared to the control treatment. Regarding superoxide dismutase (SOD) activity, Zn 0.5% treatment showed a decrease of 42.9% over control. Specifically, the Zn 0.1% showed a 27.2%, Zn 0.2% showed a 56.8%, Zn 0.4% showed a 91.1%, and Zn 0.5% showed a 133.7% increase in total chlorophyll content than control. Based on the results, it is recommended that 0.4% Zn solution may be used for foliar application for enhancing crop productivity and Zn concentration in plants under high Cd stress. Additionally, continued research on the mechanisms of cadmium uptake, transport, and detoxification in plants may lead to the identification of new targets for intervention.

Sepiolite, Palygorskite, and Triple Super Phosphate on the Uptake of Heavy Metals by Two Iranian Wheat Cultivars Inoculated With Piriformospora indica Fungus

Background and Purpose: Soil remediation in contaminated soils is an important factor of environmental research. This research evaluated the effect of sepiolite, palygorskite, and triple super phosphate (TSP) on decreasing the heavy metals uptake by wheat cultivars inoculated with Piriformospora indica (P. indica). Materials and Methods: Treatments included applying sepiolite, palygorskite (at the rate of 0% and 5% (W/W), and TSP (0% and 0.5% W/W) in the Pb- and Zn-polluted soil under cultivation of 2 wheat cultivars (Mihan and Pishgam cultivars) that inoculated with P. indica fungus. Plants were harvested after 90 days, and Pb and Zn concentrations in soils and plants were measured using atomic absorption spectroscopy. Furthermore, the catalase (CAT) enzyme activity was also measured. Results: With applying 5% (W/W) sepiolite and palygorskite, the plant Pb concentration was significantly reduced by 11.8%, while the plant Zn concentration increased by 13.9%. Plant Zn and Pb concentrations considerably increased and decreased following plant inoculation. However, plant cultivars showed different results. Our results showed that the Pb and Zn concentrations were lower in Mihan than in the Pishgam wheat cultivar. In addition, increasing soil Pb availability caused a significant increase in CAT enzyme activity. Soil contamination with heavy metals had a negative impact on plant root colonization. Conclusion: The interaction of plant cultivars and P. indica significantly affected plant heavy metal uptake by plants. However, environmental studies have found that applying organic amendments like nan-clays or TSP can reduce the absorption of Pb by plants.

Composition of some trace elements in wheat plant and soil

Zinc, copper, nickel, and manganese are essential nutrients for plants. However, excessive accumulation in the plant can lead to significant risks and problems in terms of human health after consumption. Also, the accumulation of chromium, cadmium and lead elements in plants can have a toxic effect on human health. This study aimed to determine the concentrations of copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), manganese (Mn), zinc (Zn), and lead (Pb) trace elements in wheat plants and soil. Mean trace element levels in soil samples taken from the city center Mn 556.9 mg kg-1, Ni 62.45 mg kg-1, Cr 24.98 mg kg-1, Zn 40.75 mg kg-1, Cu 17.25 mg kg-1, Pb 7.65 mg kg-1, Cd as 1.63 mg kg-1 and the average trace element levels in soil samples taken from villages Mn 418.7 mg kg-1, Zn 48.53 mg kg-1, Ni 32.34 mg kg-1, Cu 15.93 mg kg-1, Cr 13.7 mg kg-1, Cd 1.033 mg kg-1 was determined. Cd, Cr, and Pb concentrations were not detected in wheat samples. Average Cu (4.462 mg kg-1), Mn (30.03 mg kg-1), and Zn (20.39 mg kg-1) concentrations in wheat samples were determined at lower levels compared to soil samples. In the process of transporting trace elements from the soil to the plant, even if the plants are grown under the same conditions, the trace element levels accumulated in the plant may differ.

Essential trace elements in the African spider plant (Cleome gynandra). A case study in Molo Ward, Nakuru, Kenya

AbstractIn Kenya, cases of malnutrition and nutritionally related ailments have been on the rise. This calls for the search for food crops with vital trace elements. The aim of the current study was to use energy dispersive X‐ray fluorescence spectroscopy (EDXRF) to determine the concentrations of Zn, Fe, Cu, and Mn in the stems and leaves of the African spider plant (Cleome gynandra) in the context of nutrition. Stems and leaves of the African spider plant grown in the highland and in the lowland of Molo Ward, Nakuru, Kenya, were found to contain total available Zn in the range of 140 ± 50 to 230 ± 60 mg/kg, Fe in the range of 2200 ± 700 to 3900 ± 1700 mg/kg, Cu at 13 ± 3 to 16 ± 5 mg/kg, and Mn at 380 ± 120 to 400 ± 140 mg/kg. There was no significant difference in the average concentrations of the trace elements in the leaves and stems of the African spider plant from the lowland and highland regions of Molo Ward (p > 0.05). The concentrations of Zn, Fe, Cu, and Mn in the African spider plants is high enough to make it a nutritious traditional vegetable. Therefore, farmers should be encouraged and empowered to grow more vegetables.

Fe and Zn Metal Nanocitrates as Plant Nutrients through Soil Application.

Nanocitrates of iron (Fe) and zinc (Zn) in the form of plant nanonutrients were examined for their behavior in soil and the uptake of these by 20-day old groundnut (Arachis hypogaea) seedlings under greenhouse conditions. The Fe (0.04 to 0.008 mmol/kg of soil) and Zn (0.02 to 0.004 mmol/kg of soil) nanocitrates were applied to soil and compared with commercial counterparts (FeSO4, ZnSO4, nano-Fe, nano-Zn, Fe-EDTA, Zn-EDTA). The combined nanocitrate compositions were also formulated by physical means and characterized. The plant uptake of Fe and Zn was determined through atomic absorption spectrometry (AAS). All the treated plants showed good germination and higher vigor indexes compared to the control treatments. The highest available Fe and Zn soil contents after leaching were 150.5 and 18.9 mg/kg, respectively, in combined nanocitrate compositions, whereas in the control (untreated) soil, the Fe and Zn contents were 6.0 and 0.7 mg/kg, respectively. The plant's Fe content was 0.48 mg/pot for the combined nanocitrate composition, and that of the untreated plant sample was 0.02 mg/pot. The plant's Zn content was 82.3 μg/pot for pure zinc citrate, and the respective untreated-plant Zn content was 2.1 μg/pot. These values are better than those observed for commercial fertilizers. Additionally, no trend in promotional and antagonistic correlations between Fe and Zn in combined nanocitrates was observed in the studied period (20 days in duration). Among the 34 synthesized citrates, six nanocitrates show promising trends for evaluation under field conditions with higher stability.

Effect of soil texture and zinc oxide nanoparticles on growth and accumulation of cadmium by wheat: a life cycle study

Cadmium (Cd) is getting worldwide attention due to its continuous accumulation in agricultural soils which is due to anthropogenic activities and finally Cd enters in food chain mainly through edible plants. Cadmium free food production on contaminated soils is great challenge which requires some innovative measures for crop production on such soils. The current study evaluated the efficiency of zinc oxide nanoparticles (ZnONPs) (0, 150 and 300 mg/kg) on the growth of wheat in texturally different soils including clay loam (CL), sandy clay loam (SCL), and sandy loam (SL) which were contaminated with were contaminated with 25 mg/kg of Cd before crop growth. Results depicted that doses of ZnONPs and soil textures significantly affected the biological yields, Zn and Cd uptake in wheat plants. The application of 300 mg/kg ZnONPs caused maximum increase in dry weights of shoot (66.6%), roots (58.5%), husk (137.8%) and grains (137.8%) in CL soil. The AB-DTPA extractable Zn was increased while Cd was decreased with doses of NPs depending upon soil textures. The maximum decrease in AB-DTPA extractable Cd was recorded in 300 mg/kg of ZnONPs treatment which was 58.7% in CL, 33.2% in SCL and 12.1% in SL soil as compared to respective controls. Minimum Cd concentrations in roots, shoots, husk and grain were found in 300 mg/kg ZnONPs amended CL soil which was 58%, 76.7%, 58%, and 82.6%, respectively. The minimum bioaccumulation factor (0.14), translocation index (2.46) and health risk index (0.05) was found in CL soil with the highest dose of NPs. The results concluded that use of ZnONPs significantly decreased Cd concentration while increased Zn concentrations in plants depending upon doses of NPs and soil textures.

Mapping of DTPA Extractable Micronutrients in Sugarcane Soils of Sudhalagunta Sugar Factory, Andhra Pradesh, India – A GIS Approach

Sugarcane is the most important commercial crop grown in India and plays vital role in agricultural and industrial economy. In Andhra Pradesh, more than 50% of sugarcane is produced from Chittoor district for sugar and jaggery production. Sugarcane is heavy nutrient requirement crop and also removes considerable amount of nutrients through biomass. Continuous application of straight fertilizers, limited use of organic manures as well as non recycling of crop residues causes micronutrient deficiencies in soil. Keeping this in view, the present study was taken up to study the physico-chemical properties and DTPA extractable micronutrients and mapping of these nutrients. Soil samples along with geo reference coordinates were collected and analyzed for physico-chemical properties and DTPA extractable micronutrients (Fe, Mn, Zn and Cu). The digital soil maps for DTPA extractable micronutrients were generated with geo reference coordinates by using GIS approach. The analytical data of soils in Sudhalagunta sugar factory zone, Chittoor district showed that 80% of samples were slightly alkaline in reaction followed by 13% of samples were neutral in reaction. Regarding electrical conductivity, 16% of soils were slightly saline in nature. Among micronutrients, except DTPA-Zn, all cationic micronutrients were existed in above critical limit in this factory zone, 11% of soils showed Zn deficiency. Similar trend was noticed in plant Zn content. 18.4% of plant samples showed Zn deficiency. Remaining micronutrients were in sufficient range. Digital maps for DTPA - Fe, Mn, Zn and Cu have prepared.

Hemp Cultivation in Soils Polluted by Cd, Pb and Zn in the Mediterranean Area: Sites Characterization and Phytoremediation in Real Scale Settlement

Polluting activities affect, directly or indirectly, large areas of agricultural lands. Metal polluted soils could be managed by phytoremediation using hemp (Cannabis sativa L.). To know the phytoremediation capability of industrial hemp in metal polluted soils under semiarid environments, an experimental project with the support of local farmers was conducted in Sardinia (Italy). This work was carried out in three main steps: (i) identification and selection of the study sites, (ii) field trials, at local farms, both on contaminated and non-polluted sites, (iii) evaluation of heavy metals contents accumulated in the different parts of the plants. Five study sites were chosen. Three of them were severely polluted by heavy metals. Concentrations of Zn and Cd in plants generally were positively correlated with soil content and were different in each part of the plant. The higher values of Zn and Cd were detected in leaves of plants grown in polluted sites (Zn > 950 mg kg−1 and Cd > 6.8 mg kg−1). High values of Pb were also detected in plants grown in non-contaminated soils: this contamination may be due to atmospheric deposition related to polluting sources far to the cultivation.

Effect of EDTA chelate, cow manure, elemental sulfur application and Thiobacillus inoculant on Cd, Zn and Fe phytoremediation efficiency in a Cd-polluted soil

Background and Purpose: Phytoremediation efficiency of heavy metals is one of the important points in environmental studies. This research was conducted to investigate the effect of cow manure, elemental sulfur and EDTA on Cd uptake by Indian mustard in a Cd-polluted soil in the presence of Thiobacillus thiooxidans.
 Materials and Methods: Treatments consisted of applying cow manure (0, 5 and 10 g/kg soil), soil application of elemental sulfur (2 g/kg soil), and Cd-polluted soil (0 and 20 mg Cd/kg soil) with 1.5 mmol EDTA/kg soil in the presence of Thiobacillus spp. After 90 days, Indian mustard plant was harvested and plant Zn, Fe and Cd concentration was measured using atomic absorption spectroscopy. In addition, the soil microbial respiration was measured.
 Results: The use of 2 g/kg soil of elemental sulfur significantly increased the plant Cd concentration in the presence and absence of Thiobacillus by 14.2 and 11.7%, respectively. Adding cow manure to the soil at the rates of 5 and 10 g/kg soil significantly increased the plant Cd concentration by 15.7 and 18.1%, respectively. Also, the application of EDTA chelate at the rate 0f 1.5 mmol/kg soil significantly increased the Cd concentration of the plants grown in the Cd-polluted soil (20 mg Cd/kg soil) by 13.6%.
 Conclusion: The results of the present study showed that using elemental sulfur in the Cdpolluted soil can increase the Cd concentration of the plant which was cultivated in the soil amended with cow manure in the presence of Thiobacillus bacteria. However, the role of soil physic-chemical properties on phytoremediation efficiency cannot be ignored.

Nitrogen fertilisation affected zinc and selenium biofortification in silage maize

Context Biofortification of forage crops has become even more important, due to the improvement in livestock nutrition, but it has also had an indirect positive impact on the human diet. Aim This study investigated the effect of nitrogen and microelement (Zn and Se) fertilisation on yield and on the microelement composition of maize (Zea mays L.) silage. Methods Two field experiments were conducted using a two-factorial split-plot design with nitrogen fertilisation in three doses: 0, 120, 180 and 240 kg N/ha. The first experiment included foliar Zn fertilisation as the second factor (0, 1.5 kg Zn/ha and 1.5 kg Zn/ha + urea solution). The second experiment studied the effect of Se (10 g Se/ha). Key results Nitrogen fertilisation increased biomass yield, Cu and Mn concentration in silage maize. Application of Se and Zn did not affect the biomass yield, but it had a positive effect on Se and Zn concentration in plants. Zn and urea application in combination proved to be more efficient in increasing Zn concentration in plants when compared to Zn applied alone. Conclusions Nitrogen and fertilisation with Zn and Se can be a good tool in fodder plant biofortification because their application led to a yield increase (Zn), but at the same time to an improvement in the mineral composition of maize biomass, with essential elements (Zn and Se). Implications Although biofortification with 1.5 kg Zn/ha has achieved the concentration in maize biomass that can meet the nutritional needs of dairy cows, further research is needed to examine the adjuvant doses and forms of Zn to obtain high yields and Zn concentration in forage crops.

Determination of Poultry Manure and Plant Residues Effects on Zn Bioavailable Fraction in Contaminated Soil via DGT Technique.

A greenhouse experiment aimed to assess the effects of poultry manure, sorghum, and clover residues (0 and 15gkg-1) on the zinc (Zn) bioavailable fraction in contaminated calcareous soil using two chemical assays, including diffusion gradient in thin-films (DGT) and diethylene triamine pentaacetic acid-triethanolamine (DTPA-TEA), and a bioassay with corn (Zea mase L.). The results showed that poultry manure, clover, and sorghum residues application increased dissolved organic carbon (DOC) by 53.6 and 36.1, and 9.2%, respectively, and decreased soil pH by 0.42, 0.26, and 0.06 units, respectively compared to unamended soil. These changes resulted in increases of Zn effective concentration (CE) and DTPA-Zn, and plant Zn concentration as observed by the increase in exchangeable form of Zn. In the sorghum residues-amended soils, CE-Zn decreased by 29.5% compared to other treatments. The best correlations between corn metal concentrations and soil metal bioavailability were obtained for CE-Zn using the DGT technique, which also provided the best Zn bioavailability estimate. It is concluded that sorghum residues could be used to reduce the phytotoxicity risk of Zn in calcareous contaminated soil, and the DTPA method is the less robust indicator of Zn bioavailability than the DGT technique.

Effect of Zeolite Application and Seed Priming with Salicylic Acid on Decreasing the Cd Concentration of Inoculated Plant with Piriformospora indica Fungus under Drought Stress

Today, urban management seems necessary to remediate soils contaminated with heavy metals, especially in industrial regions. Thus, this research was done to evaluate the effect of zeolite and seed pre-treatment with salicylic acid on reducing the Cd sorption by ornamental sunflower under drought stress. Treatments (48 treatments) consisted of applying zeolite (0 and 5 % (W/W)) in the Cd (0 and 15 mg Cd (kg soil)-1) polluted soil under cultivation of ornamental sunflower that was inoculated with P.indica in normal and intensive drought stress condition. The plants seeds were pretreated with salicylic acid (0, 0.5 and 1 mM). After 90 days, plants were harvested and atomic absorption spectroscopy (Perkin-Elmer 3030) was used for determining the Pb and Zn concentration. Application of zeolite in the soil significantly decreased and increased the plant Cd and Zn concentration by 11.3 and 14.2%, respectively. Seed priming with salicylic acid at the rate of 1 mM significantly increased the plant Zn and Cd concentration by 12.7 and 14.2%, respectively. In addition, plant inoculation with P.indica significantly decreased the catalase (CAT) and ascorbate peroxidase (APX) enzyme activity which indicate the plant resistance to abiotic stress. However, drought stress had adverse effect on the Cd sorption by plants. Moreover, the CAT and APX enzymes activities were increased. The results of this study showed that applying zeolite and seed priming with salicylic acid had additive effects on decreasing the Cd sorption by ornamental sunflower that was inoculated with P.indica fungus under drought stress.

Interaction of different-sized ZnO nanoparticles with maize (Zea mays): Accumulation, biotransformation and phytotoxicity

This study aimed to investigate the biotransformation of ZnO nanoparticles (NPs) in maize grown in hydroponics for ecotoxicity assessment. Maize seedlings grown for 14 days were exposed to a solution of 9 nm ZnO NPs, 40 nm ZnO NPs, and ZnSO4 at a Zn concentration of 300 mg L−1 for 1, 3, and 7 days, respectively. The results of in-situ Zn distribution in maize (Zea mays) showed that 9 nm ZnO NPs could quickly enter the roots of maize and reach the center column transport system of the stem. The results of transmission electron microscopy combined with energy dispersive X-ray spectroscopy revealed that ZnO NPs were accumulated in the vacuoles of the roots, and then transformed and transported through vesicles. Simulated studies showed that low pH (5.6) played a critical role in the transformation of ZnO NPs, and organic acids (Kf = 1011.4) could promote particle dissolution. Visual MINTEQ software simulated the species of Zn after the entry of ZnO NPs or Zn2+ into plants and found that the species of Zn was mainly Zn2+ when the Zn content of plants reached 200–300 ppm. Considering that the lowest Zn content of the roots in treatments was 1920 mg kg−1, combination of the result analysis of root effects showed that the toxicity of roots in most treatments had a direct relationship with Zn2+. However, treatment with 9 nm ZnO NPs exhibited significantly higher toxicity than ZnSO4 treatment on day 1 when the Zn2+ concentration difference was not significant, which was mainly due to the large amount of ZnO NPs deposited in the roots. To the authors' knowledge, this study was the first to confirm the process of biotransformation and explore the factors affecting the toxicity of ZnO NPs in depth.

The Transcriptomic Profile of Watermelon Is Affected by Zinc in the Presence of Fusarium oxysporum f. sp. niveum and Meloidogyne incognita.

Zinc (Zn) accumulation and deficiency affect plant response to pests and diseases differently in varying pathosystems. The concentrations of Zn in plants aid in priming defense signaling pathways and help in enhanced structural defenses against plant pathogens. Studies are lacking on how concentrations of Zn in watermelon plants influence defense against two important soil-borne pathogens: Fusarium oxysporum f. sp. niveum (FON) and southern root-knot nematode (RKN, Meloidogyne incognita). In this study a comparative transcriptomics evaluation of watermelon plants in response to high (1.2 ppm) and low (0.2 ppm) levels of Zn were determined. Differential transcript-level responses differed in watermelon plants when infected with FON or RKN or both under high- and low-Zn treatment regimes in a controlled hydroponics system. Higher numbers of differentially expressed genes (DEGs) were observed in high-Zn-treated than in low-Zn-treated non-inoculated plants, in plants inoculated with FON alone and in plants inoculated with RKN alone. However, in the co-inoculated system, low-Zn treatment had higher DEGs as compared to high-Zn treatment. In addition, most DEGs were significantly enriched in hormone signal transduction and MAPK signaling pathway, suggesting an induction of systemic resistance with high-Zn concentrations. Taken together, this study substantially expands transcriptome data resources and suggests a molecular potential framework for watermelon-Zn interaction in FON and RKN.

Adaptive potential of Typha laxmannii Lepech to a heavy metal contaminated site

To study the adaptive potential of the plant Typha laxmannii Lepech. to heavy metal (HM) stress on the basis of analysis of its morphological and anatomical features under the conditions of an anthropogenically transformed ecosystem of the Don River Delta. The soils on the monitored plots are of the Fluvisol type. The soil characteristics and total concentrations of Mn, Ni, Cd, Cu, Zn, Pb and Cr in soils and cattail plants were analysed. Anatomical-morphological and electron-microscopic examinations revealed the toxic effect of HMs on the roots and leaves of T. laxmannii plants. The studied soils were found to contain high levels of the Zn, Cr, Pb and Cu. It was shown that the sources of Zn, Pb and Cu in the soils were anthropogenic in nature. The high Cr level in soils was due to the natural lithogenic factor. The contents of HM mobile forms in the soils exceeded the maximum permissible concentrations of Cd, Zn, Pb and Ni. An examination of communities of T. laxmannii grown in the impact zone revealed, proliferation anomalies. Ultrastructural studies of plants showed changes in cell membranes, as well as in the main cytoplasmic organelles. The revealed structural changes are assumed to contribute to a slowdown in the ontogenetic development of plants and a decrease in their morphometric parameters under anthropogenic pollution. No significant ultrastructure changes were observed in the roots compared with the leaves, which indicates their high adaptive potential.