Zinc Concentration In Shoots Research Articles

Investigating the Efficiency of (Alhagi graecorum) Plant in Accumulating some Heavy Metals

This study aimed to investigate the efficiency of the alhagi plant in adsorbing and accumulating heavy metals in the plant that grows naturally on both sides of the highway extending between the cities of Diwaniyah and Baghdad, passing through the city of Hilla. Plants grow 50 meters away on the sides of the main highway. The results showed that the lead concentration in the shoot and root system was higher than the permissible limit. The highest lead concentration was in Baghdad’s soil, and the lowest was in Diwaniyah. It is attributed to the momentum and traffic density of the city of Baghdad. The cadmium concentration in the shoots was less than the permissible limit, while it was higher in the root shoots, and the highest concentration appeared in the soil of Baghdad city. The cadmium concentration was less concentrated than the rest of the studied elements, lead, zinc, and nickel. The results showed that nickel was less than the permissible limit in the vegetative and root system. The zinc concentration in shoots was higher than the permissible limit, except in the soils of Hilla and Diwaniya at the right and left sides, respectively, it was less than the permissible limit. As for its concentration in the root system, it was higher than the permissible limit, except for the soil of Al-Diwaniyah city on the right side. The concentrations of the studied elements in the root system were higher than in the shoot system. The results of the plant pollution standards showed that the values of the bio concentration factor and the bioaccumulation factor for all studied elements are less than the value of one, which means that the alhagi plant is not considered one of the plants that accumulate heavy elements. Therefore, it is of limited benefit for the vegetative reclamation of soils contaminated with the studied heavy elements, except for the zinc element, as its values were between 0.1-10, which indicates that the sedum plant is a moderate accumulation of the zinc element. The results also present that the values of the local transmission coefficient for all the studied elements are more significant than the value of one. It indicates the movement and transfer of all elements from the root to the vegetative system.

Diversity and activity of soil biota at a post-mining site highly contaminated with Zn and Cd are enhanced by metallicolous compared to non-metallicolous Arabidopsis halleri ecotypes.

Hyperaccumulators' ability to take up large quantities of harmful heavy metals from contaminated soils and store them in their foliage makes them promising organisms for bioremediation. Here we demonstrate that some ecotypes of the zinc hyperaccumulator Arabidopsis halleri are more suitable for bioremediation than others, because of their distinct influence on soil biota. In a field experiment, populations originating from metal-polluted and unpolluted soils were transplanted to a highly contaminated metalliferous site in Southern Poland. Effects of plant ecotypes on soil biota were assessed by measurements of feeding activity of soil fauna (bait-lamina test) and catabolic activity and functional diversity of soil bacteria underneath A. halleri plants (Biolog® ECO plates). Chemical soil properties, plant morphological parameters, and zinc concentration in shoots and roots were additionally evaluated. Higher soil fauna feeding activity and higher bacterial community functional diversity were found in soils affected by A. halleri plants originating from metallicolous compared to non-metallicolous ecotypes. Differences in community-level physiological profiles further evidenced changes in microbial communities in response to plant ecotype. These soil characteristics were positively correlated with plant size. No differences in zinc content in shoots and roots, zinc translocation ratio, and plant morphology were observed between metallicolous and non-metallicolous plants. Our results indicate strong associations between A. halleri ecotype and soil microbial community properties. In particular, the improvement of soil biological properties by metallicolous accessions should be further explored to optimize hyperaccumulator-based bioremediation technologies.

Effect of the combined addition of Zn and Pb on partitioning in sediments and their accumulation by the emergent macrophyte Schoenoplectus californicus.

Wetlands usually provide a natural mechanism that diminishes the transport of toxic compounds to other compartments of the ecosystem by immobilization and accumulation in belowground tissues and/or soil. This study was conducted to assess the ability of Schoenoplectus californicus growing in natural marsh sediments, with zinc and lead addition, to tolerate and accumulate these metals, taking account of the metal distribution in the sediment fractions. The Zn and Pb were mainly found in available (exchangeable) and potentially available (bound to organic matter) forms, respectively. The absorption of Zn and Pb by plants increased in sediments with added metals. Both metals were largely retained in roots (translocation factor<1). Lead rhizome concentrations only increased significantly in treatments with high doses of metal independently of added Zn. The addition of Zn increased its concentration in roots and shoots significantly, while its concentration in rhizomes only increased when both metals were added together. Zinc concentration in shoots did not reach the toxic level for plants. Zinc and Pb concentrations in roots were high, but they were not sufficient to reduce biomass growth.

Identification of a novel mitochondrial protein, short postembryonic roots 1 (SPR1), involved in root development and iron homeostasis in Oryza sativa

• A rice mutant, Oryza sativa short postembryonic roots 1 (Osspr1), has been characterized. It has short postembryonic roots, including adventitious and lateral roots, and a lower iron content in its leaves. • OsSPR1 was identified by map-based cloning. It encodes a novel mitochondrial protein with the Armadillo-like repeat domain. • Osspr1 mutants exhibited decreased root cell elongation. The iron content of the mutant shoots was significantly altered compared with that of wild-type shoots. A similar pattern of alteration of manganese and zinc concentrations in shoots was also observed. Complementation of the mutant confirmed that OsSPR1 is involved in post-embryonic root elongation and iron homeostasis in rice. OsSPR1 was found to be ubiquitously expressed in various tissues throughout the plant. The transcript abundance of various genes involved in iron uptake and signaling via both strategies I and II was similar in roots of wild-type and mutant plants, but was higher in the leaves of mutant plants. • Thus, a novel mitochondrial protein that is involved in root elongation and plays a role in metal ion homeostasis has been identified.

Sensitivity to zinc of Mediterranean woody species important for restoration

Heavy metals have increased in natural woodlands and shrublands over the last several decades as a consequence of anthropogenic activities. However, our knowledge of the effects of these elements on woody species is scarce. In this study, we examined the responses of six Mediterranean woody species to increasing levels of zinc in hydroponic culture and discussed the possible implications for the restoration of contaminated sites. The species used, Pinus pinea L., Pinus pinaster Ait., Pinus halepensis Mill., Tetraclinis articulata (Vahl) Mast., Rhamnus alaternus L. and Quercus suber L. represent a climatic gradient from dry sub-humid to semi-arid conditions. Zinc concentrations in shoots ranged from 53 μg g − 1 in Q. suber to 382 μg g − 1 in T. articulata and were well below the levels found in roots. Zinc inhibited root elongation and root biomass and changed the root length distribution per diameter class, but the magnitude of the effects was species-specific. Only P. halepensis and Q. suber showed toxicity symptoms in aboveground parts. Species more characteristic from xeric environments ( T. articulata, R. alaternus and P. halepensis) were more sensitive to zinc than species from mesic environments ( Q. suber, P. pinaster and P. pinea). According to the Zn responses and bioaccumulation, Q. suber P. pinea and P. halepensis are the best candidates for field trials to test the value of woody species to restore contaminated sites. None of the species tested seemed suitable for phytoremediation.

Resposta da aveia preta à aplicação de zinco em Latossolo Vermelho Distrófico

Despite the importance of zinc for the nutrition and production of crops, there is little information in about its effects on nutrition of black oat. Thus the present work aimed to study the effects of zinc applied to soil the growth and nutritional status of black oat. The experiment was conducted in a greenhouse using six doses of Zn (0, 15, 30, 60, 120 and 360 mg dm-3) arranged in a randomized design with four replications. The experimental unit was constituted by a pot with a capacity of 4 dm3, filled with 3 dm3 of an Oxisol sample (Zn = 0.1 mg dm-3) and 5 plants per pot. Thirty days after thinning the growth variables (height, stem diameter, number of tillers, leaf area), dry matter and zinc concentration in shoots were obtained. It was observed that the application of zinc to soil affected only the number of leaves and stem diameter of the plants. The highest Zn doses increased the content of this micronutrient in soil and plant, and reduced the growth of black oats. The critical levels of toxicity of zinc in soil and plant ware 135 mg dm-3 and 494 mg kg-1, respectively.

Calcium effects on changes in chlorophyll contents, dry weight and micronutrients of strawberry (Fragaria ×ananassaDuch.) plants under salt-stress conditions

Introduction . Today, approximately one-third of the world's irrigated lands suffer some degree of salinity. Although there are several reports about the effects of calcium treatments on strawberry growth and development under saline conditions, there are no reports demonstrating the effect on micronutrient concentrations of strawberry due to supplementary calcium applied to the salt-stressed plants. Consequently, we investigated the effects of high salinity levels, with application of supplementary calcium, on chlorophyll contents, dry weight and micronutrients of strawberry. Materials and methods . Strawberry (Fragaria × ananassa Duch.) plants cv. ‘Selva’ were grown in hydroponic culture in a heated greenhouse to investigate the effectiveness of calcium (Ca) added to nutrient solution applied to plants. Six treatments were applied: nutrient solution alone (= [N]); [N] + NaCl salt (35 mM) (= [NS]); [NS] + CaCl2 (5 mM); [NS] + CaCl2 (10 mM); [NS] + CaSO4 (5 mM); and [NS] + CaSO4 (10 mM). The effect of calcium (different forms and different concentrations) on chlorophyll contents and dry weight of salt-stressed plants was determined. Additionally, micronutrient contents were studied. Results . The results indicated that chlorophyll contents and plant dry weight were decreased by salinity. NaCl application increased Cu, Zn, Mn and Fe concentrations of root parts. In shoot parts, Cu accumulation decreased, while other elements increased. Supplementary calcium could ameliorate the negative effects of salinity on chlorophyll and dry mass production. However, micronutrient concentrations of plant parts as influenced by calcium had contradictory results: calcium induced high levels of zinc, manganese and iron concentrations in roots, but high levels of copper and zinc concentrations in shoots. Moreover, there were significant differences between calcium forms in their actions. Conclusion . Our results suggest that CaSO4 could be applied to improve the growth of salt-stressed strawberry plants.

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Abstracts of Nippon Dojo-Hiryogaku Zasshi

Assessing Zinc Thresholds for Phytotoxicity and Potential Dietary Toxicity in Selected Vegetable Crops

Heavy metal pollution in soils influences crop yield and quality, and metal accumulation in vegetables may pose a human health risk when consumed. Zinc (Zn), one of the heavy metals, is an essential element for plants, animals, and humans, but it is toxic at high levels. In this study, bioavailability of added Zn in a vegetable garden soil and critical Zn concentrations for phytotoxicity and potential dietary toxicity were determined for Chinese cabbage (Brassica chinensis L.), pakchoi (Brassica chinensis L.), and celery (Apiumg graveolens L.). Different Zn levels (0, 100, 200, 300, 400 mg kg−1 soil, supplied as ZnSO4·7H2O) were added to the soil samples, based on Zn adsorption-desorption characteristics of the soil, the availability of added Zn in the soil decreased with time, with minimal change after 10–12 weeks of incubation. The results from sand and soil culture experiments showed that shoot growth was significantly inhibited at Zn concentrations above 25 mg L−1 in nutrient solution or at DTPA-Zn above 170 mg kg−1 in the soil. The sensitivity to Zn toxicity differed among the three vegetable crops, changing in the order: celery>Chinese cabbage>pakchoi. Zinc concentration in shoots and edible parts varied with Zn supply levels and type of the vegetables. Negative correlations were noted between Zn concentrations in shoots and dry matter yields (r=0.90–0.98, P<0.01), the critical Zn concentrations in plant tissues at 10% reduction of biomass yield (PT10) were 173.1, 167.5, 144.2 and 222.2 mg kg−1 (DW) for Chinese cabbage, pakchoi, celery (stem) and celery (leaf), respectively. Zinc concentrations in the edible parts were positively correlated with available and total Zn in the soil (r=0.91–0.99, P<0.01). Based on the threshold of human dietary toxicity for Zn (20 mg kg−1), the critical concentrations of total and available Zn in the soil were 413 and 244 mg kg−1 for Chinese cabbage, 224 and 75 mg kg−1 for pakchoi, and 272 and 101 mg kg−1 for celery, respectively. These results indicate that some vegetable species like pakchoi might accumulate Zn in edible parts over human dietary toxic threshold before the dry matter yield reduction was observed.

539 Assessing Soil and Water Thresholds for Potential Dietary Zinc Toxicity in Selected Vegetable Crops

Vegetables play an important role in the human diet, and production in suburban areas has increased as populations have become more urbanized. However, heavy metal pollution of soils has enhanced in such areas, and metal accumulation in vegetables may pose a human health risk when consumed. Zinc is an essential micronutrient for plants and humans, but it is toxic to plants and humans at high levels. Although a maximum Zn tolerance for human health has been established for edible parts of vegetables (20 mg/kg DW), little information is available for predicting vegetable Zn concentration based on soil and water Zn levels. The objectives of this study were to determine the critical Zn concentrations in nutrition solution and soil to reach maximum Zn tolerance concentrations in Chinese cabbage, bok choy, and celery. Five Zn levels were used for both solution and soil culture experiments, with three replicates of each. Shoot growth was significantly inhibited at Zn concentrations above 50 mg/L in nutrition solution and above 180 mg/kg in soil. The sensitivity of crops to zinc toxicity, in term of shoot and root growth, decreased in the order: celery &gt; Chinese cabbage &gt; bok choy. Zinc accumulation in shoots and edible parts varied with Zn supply levels and type of vegetables. A negative correlation was noted between Zn accumulation and dry matter yields, with r-squared values of 0.980** for nutrient solution and 0.960* for soil culture. Zinc concentrations in shoots or edible vegetable parts were below 20 mg/kg (human health threshold) when they were grown at DTPA extractable Zn in the soil less than 75, 100, and 175 mg/kg for bok choy, celery, and Chinese cabbage, respectively.

Effect of iron plaque outside roots on nutrient uptake by rice (Oryza sativa L.). Zinc uptake by Fe-deficient rice

This solution culture study examined the effect of the deposition of iron plaque on zinc uptake by Fe-deficient rice plants. Different amounts of iron plaque were induced by adding Fe(OH)3 at 0, 10, 20, 30, and 50 mg Fe/L in the nutrient solution. After 24 h of growth, the amount of iron plaque was correlated positively with the Fe(OH)3 addition to the nutrient solution. Increasing iron plaque up to 12.1 g/kg root dry weight increased zinc concentration in shoots by 42% compared to that at 0.16 g/kg root dry weight. Increasing the amount of iron plaque further decreased zinc concentration. When the amounts of iron plaque reached 24.9 g/kg root dry weight, zinc concentration in shoots was lower than that in shoots without iron plaque, implying that the plaque became a barrier for zinc uptake. While rice plants were pre-cultured in −Fe and +Fe nutrient solution in order to produce the Fe-deficient and Fe-sufficient plants and then Fe(OH)3 was added at 20, 30, and 50 mg Fe/L in nutrient solution, zinc concentrations in shoots of Fe-deficient plants were 54, 48, and 43 mg/kg, respectively, in contrast to 32, 35, and 40 mg/kg zinc in shoots of Fe-sufficient rice plants. Furthermore, Fe(OH)3 addition at 20 mg Fe/L and increasing zinc concentration from 0.065 to 0.65 mg Zn/L in nutrient solution increased zinc uptake more in Fe-deficient plants than in Fe-sufficient plant. The results suggested that root exudates of Fe-deficient plants, especially phytosiderophores, could enhance zinc uptake by rice plants with iron plaque up to a particular amount of Fe.

Zinc and Cadmium Uptake by Hyperaccumulator Thlaspi caerulescens Grown in Nutrient Solution

AbstractPhytoremediation of heavy‐metal‐contaminated soils can be an inexpensive means to remove hazardous metals from soil. Two metallophytes, Thlaspi caerulescents (J. &amp; C. Presl, a Zn and Cd hyperaccumulator) from Prayon, Belgium, and a Zn‐tolerant ecotype of bladder campion [Silene vulgaris (Moench.) Garcke L.] from Palmerton, PA, were compared with tomato [Lycopersicon lycopersicum (L.) Karsten, metal intolerant] in nutrient solution to characterize Zn and Cd uptake and tolerance. Zinc and Cd were added to solutions at a 50:1 molar ratio to simulate concentrations often found on contaminated sites. Seven treatment concentrations were used, ranging (in half‐log increments) from 3.16 µM Zn + 0.063 µM Cd to 10000 µM Zn + 200 µM Cd. Thlaspi caerulescens showed much greater tolerance to Zn/Cd treatments than the other species, with toxicity stress only apparent at the 10000 µM Zn/200 µM Cd treatment. In this treatment, shoot concentrations of Zn and Cd were 33600 and 1140 mg kg−1, respectively. Thlaspi caerulescens was also more effective at translocating both Zn and Cd from solution to shoots. Zinc concentration in shoots of T. caerulescens was higher than the other species at all Zn/Cd treatments. Cadmium concentration in shoots of T. caerulescens were significantly higher than in bladder campion only at the 316 µM Zn/6.32 µM Cd treatment. This genotype of T. caerulescens may not hyperaccumulate Cd. However, extreme Zn and Cd uptake and tolerance is evident in T. caerulescens, with &gt;25000 mg Zn kg−1 and 1000 mg Cd kg−1 before yield is reduced. Results suggest that T. caerulescens may be a candidate for the phytoremediation of Zncontaminated soils.

Factors affecting zinc concentrations in plants grown in sludge‐amended soils

Abstract Endive (Chicorium endiviaL.), a crop tolerant of acid soil conditions, was grown in a loamy sand, a loam, and a silt loam in a greenhouse. The soils were treated with limestone and a high‐calcium sewage sludge and with five levels of Zn ranging from 0 to 800 mg.kg‐1. Limed soils were about pH 6 ‐ 6.5 compared to pH 4.5 ‐ 5 for unlimed soils. Zinc concentrations in shoots of endive grown in limed soils were less than those in unlimed soils. Sludge increased Zn concentrations in plants grown in the loam or silt loam but not in the loamy sand. The pH of the loamy sand was increased by the addition of sludge and may have limited Zn entry into the plants. A second addition of sludge enhanced Zn levels in plants, and the effects of the sludge appeared to be related to the resultant soil pH.