Zn In Lettuce Research Articles

INTENSITY OF ACCUMULATION OF HEAVY METALS IN RADISH AND LETTUCE GROWN IN CLOSED SOILS IN THE CONDITIONS OF THE FOREST STEPPE OF THE RIGHT BANK

One of the important tasks in vegetable production is the expansion of the range of vegetable crops in open and closed soil, which will ensure a constant supply of fresh vegetable products to consumers throughout the year. Lettuce and radish are among the many green vegetables that play an important role in solving this problem. In this work, the intensity of accumulation of heavy metals (Pb, Cd, Zn, Cu) in lettuce of the Record variety and radish of the Saxony variety in closed and open conditions of dark gray podzolized soil was studied. It was established that the concentration of Pb, Cd, and Zn in seeded lettuce grown under closed soil conditions was 1.5 times, 1.8 and 1.12 times lower, respectively, and in seeded radish by 1.5 times, 1.05 and 1, 23 times compared to similar products grown in open ground conditions. When growing lettuce and radish in closed soil conditions, the accumulation coefficient of Pb, Cd, Zn was lower by 2.0 times and 2.0 times, 1.8 times and 1.6 times, and 1.2 times and 1.2 times, respectively compared to similar products grown in open ground conditions. The coefficient of accumulation of Pb, Cd, Zn in lettuce grown in open ground was 2.0, 1.8, 1.12 times higher than that of lettuce grown in closed ground, respectively, and the coefficient of Pb accumulation in radish roots grown in open ground was 2.0 times higher than in the closed one, Cd concentration 1.6 times, Zn 1.2 times, and Cu 1.2 times, respectively. The research results showed that the hazard ratio of Pb in lettuce leaves and radish roots when grown in open ground was 1.5 times higher compared to similar vegetables grown in closed ground, the hazard ratio of Cd and Zn in lettuce leaves and radish roots grown under conditions of open soil was 1.8 and 1.06 times higher, respectively, compared to vegetables grown in closed soil, the hazard ratio of Cu in lettuce that was grown under closed soil conditions was 0.7 times higher compared to that grown in open soil. In radish roots, the risk factor of Cu was 1.5 times higher than in vegetables grown under open soil conditions.

Regulation of arsenite toxicity in lettuce by pyrite and glutamic acid and the related mechanism

Compared with the effect of a single substance on arsenic plant toxicity, the effect of coexisting pyrite and natural organic matter can better reflect actual environmental conditions. In this study, the interaction between pyrite and glutamic acid in arsenite solution was explored, the influence of pyrite and glutamic acid on arsenite plant toxicity was evaluated, and the metabolic regulation mechanism of pyrite and glutamic acid on the arsenite phytotoxic effect was clarified by metabolomics analysis. Combined pyrite and glutamic acid treatment fixed more arsenic by forming chemical bonds such as AsS, AsO, and As-O-OH in culture solution and reduced inorganic arsenic levels in plants. Compared with glutamic acid alone and pyrite alone, the combined treatment reduced the inorganic arsenic concentration in plants by 4.7 % and 40.0 %, respectively. The combined treatment limited plant ROS accumulation and maintained the leaf chlorophyll content by increasing SOD synthesis. Compared with the effect of As(III) alone, the chlorophyll content increased by 15.1–21.0 % on average under the combined treatment. The combined treatment promoted the absorption of Ca, Cu, Fe, Mo and Zn in lettuce, enhanced plant adaptation to As(III) and significantly improved plant nutritional quality. Compared with glutamic acid alone, the combined treatment increased the VC, fiber and protein contents by 128.9 %, 202.8 % and 36.7 %, respectively. Metabolomics analysis indicated that in the combined treatment group, the upregulation of tyrosine, pyruvate and N metabolism increased the plant chlorophyll content. The upregulation of S metabolism increases VC synthesis in plants and inhibits ROS accumulation, thus maintaining normal plant growth and development. The upregulation of glutathione and glycine metabolism enhances plant stress resistance. This study will provide a new way to scientifically and rationally evaluate the ecological risk of arsenic and regulate its toxicity.

Continuously applying compost for three years alleviated soil acidity and heavy metal bioavailability in a soil-asparagus lettuce system.

Soil acidification and heavy metal pollution are two common barrier factors threatening plant growth and agro-product quality. Applying manure compost is promising to alleviate soil acidity, while it may increase heavy metal accumulation in soil. In a 3-year field experiment, compost was applied for 12 consecutive harvest seasons at 15, 30, and 45 t ha−1 in a slightly acidic soil. Samples were taken at the twelfth season to examine the changes of soil properties, vegetable productivity, heavy metal accumulation and bioavailability in the soil-asparagus lettuce system. The results showed that the pH values of the topsoil were increased by 0.49–0.75 units in compost added soils compared with no compost control, soil organic matter (SOM) contents and cation exchange capacity (CEC) were increased by 34–101% and 43–44%, respectively. The soil nutrient contents were also increased in compost treatments. Continuously applying compost increased Cd, Cu, and Zn concentrations in topsoil by up to 32, 20, and 22% and decreased Pb by 10%, while soil available Cd and Zn concentrations were reduced by up to 54 and 86%, and available Cu was increased by 19–63%. The biomass of asparagus lettuce was increased by 30–59% in compost treatments, with Cd and Zn concentrations in the plant tissues reduced by 28–50% and 14–67%. Cu concentrations in the lettuce shoots were increased by 20–39%. The concentration factor and total uptake of Cd and Zn in lettuce were effectively reduced in compost treatments. Cd was more prone to be taken up, translocated and accumulated from soil to the lettuce plant than the other heavy metals. Continuously applying compost over 3 years increased soil pH, SOM, CEC, nutrient contents, and lettuce productivity, decreased Cd and Zn bioavailability in the soil-lettuce system, while posing a risk of increasing heavy metal accumulation in topsoil.

Photosynthetic Parameters and Growth of Rice, Lettuce, Sunflower and Tomato in an Entisol as Affected by Soil Acidity and Bioaccumulation of Ba, Cd, Cu, Ni, and Zn.

The bioaccumulation of trace elements (TEs) in crops consumed by humans can reduce food production as a consequence of photosynthetic damage in plants and cause several diseases in humans. Liming is a soil management strategy designed to alleviate soil acidity and mitigating these problems by reducing the TE bioavailability. In this study, we evaluated the effect of liming on photosynthesis, growth, and bioaccumulation of barium (Ba), cadmium (Cd), copper (Cu), nickel (Ni), or zinc (Zn) in lettuce (Lactuca sativa L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.), and tomato (Solanum lycopersicum L.) grown in a sandy Entisol. The crops were grown in either uncontaminated or contaminated Entisol, at two base saturation (BS%) ratios: 30% for all crops or 50% for rice and 70% for lettuce, sunflower, and tomato. The photosynthesis-related parameters varied depending on the metal and the crop, but in general, increasing BS% did not attenuate photosynthetic damage induced by Ba, Cd, Cu, Ni, and Zn in the crops. There was no strong correlation between the photosynthetic parameters and biomass production, which indicates that the suppression of biomass induced by Ba, Cd, Cu, Ni, or Zn is related to other metabolic disorders in addition to the impairment of CO2 assimilation or chlorophyll synthesis in the crops assayed, with the exception of Ni and Zn in lettuce. In conclusion, increasing BS% was not consistent in reducing Ba, Cd, Cu, Ni, and Zn accumulation in the edible parts of lettuce, rice, sunflower, and tomato grown in the sandy soil, which is probably related to the low capacity of this soil to control TE bioavailability.

Comparison of five extraction methods for evaluating cadmium and zinc immobilization in soil.

The remediation of soil contaminated with heavy metals is an ongoing environmental concern. Paddy soils contaminated with Cd and Zn were collected from around abandoned metals mines in Korea. Limestone and steel slag were mixed with the collected soil, as amendments for Cd and Zn immobilization. Sequential extraction, lettuce cultivation and five single extraction methods were carried out to assess the effects on Cd and Zn immobilization using amendments. The exchangeable fraction of Cd and Zn was decreased and Fe-Mn oxides fraction increased by stabilization using amendments. In addition, the accumulation of Cd and Zn in lettuce decreased in treated soil and indicated the Cd and Zn immobilization effect in soil by the amendments. The extractable Cd and Zn by CaCl2 and Mehlich-3 in the untreated soils were higher than that of treated soils, whereas Cd and Zn extraction by ethylenediaminetetraacetic acid (EDTA), diethylene tetramine penta-acetic acid (DTPA) and toxicity characteristic leaching procedure (TCLP) has a small or no difference between the untreated and treated soils. The extraction results by CaCl2 and Mehlich-3 methods present reasonable results for Cd and Zn immobilization in soil than EDTA, DTPA and TCLP methods. Therefore, the choice of appropriate extraction method is very important when there is the assessment of Cd and Zn immobilization efficiency.

Soil-plant transfer models for metals to improve soil screening value guidelines valid for São Paulo, Brazil.

In Brazil, there is a lack of combined soil-plant data attempting to explain the influence of specific climate, soil conditions, and crop management on heavy metal uptake and accumulation by plants. As a consequence, soil-plant relationships to be used in risk assessments or for derivation of soil screening values are not available. Our objective in this study was to develop empirical soil-plant models for Cd, Cu, Pb, Ni, and Zn, in order to derive appropriate soil screening values representative of humid tropical regions such as the state of São Paulo (SP), Brazil. Soil and plant samples from 25 vegetable species in the production areas of SP were collected. The concentrations of metals found in these soil samples were relatively low. Therefore, data from temperate regions were included in our study. The soil-plant relations derived had a good performance for SP conditions for 8 out of 10 combinations of metal and vegetable species. The bioconcentration factor (BCF) values for Cd, Cu, Ni, Pb, and Zn in lettuce and for Cd, Cu, Pb, and Zn in carrot were determined under three exposure scenarios at pH 5 and 6. The application of soil-plant models and the BCFs proposed in this study can be an important tool to derive national soil quality criteria. However, this methodological approach includes data assessed under different climatic conditions and soil types and need to be carefully considered.

Application of biosolids to soil affects Cu and Zn accumulation and antioxidant activity of lettuce (Lactuca sativa L.)

abstractThe application of biosolids to agricultural fields is becoming increasingly common. The effect of biosolids on the behavior of metals in different plants has been reported to be variable and ambiguous. A greenhouse experiment was conducted on a soil spiked with four rates of copper (Cu) (0, 50, 100, and 150 mg kg−1) and zinc (Zn) (0, 150, 300, and 450 mg kg−1) in lettuce culture. When Cu and Zn were spiked to anaerobically-digested biosolids, their availability in lettuce increased. Root and shoot fresh weight decreased due to a decrease in photosynthetic rate. superoxide dismutase (SOD) and peroxidases (POD) activity increased after the application of Cu and Zn. The bioavailability of Zn in lettuce was greater than that of Cu because of a higher transfer factor in plants and due to a higher endogenous Zn concentration.These results will allow for better fertilization management when biosolids are applied to tomato culture.

Use of in vitro digestion method and theoretical calculations to evaluate the bioaccessibility of Al, Cd, Fe and Zn in lettuce and cole by inductively coupled plasma mass spectrometry

Theoretical calculations of the binding energies of metal-polyphenols and metal-cellulose, as well as the hydration energies of metal-polyphenols were used to support the results obtained for the bioaccessibility of aluminium, cadmium, iron and zinc from four types of lettuce and one type of cole that were evaluated using an in vitro gastrointestinal digestion model and inductively coupled plasma-mass spectrometry. The bioaccessibility of Al found in the vegetables were less than 11% of the total Al content, whereas Cd exhibited average bioaccessibility of approximately 14% for the fresh samples and 41% considering the dried vegetables studied. However, the results indicated average bioaccessibility of 35% and 26% for Zn and average bioaccessibility of 19% and 21% for Fe in fresh and dried samples, respectively. The low bioaccessibility of Al is due to its strong binding with all of the vegetable components, whereas the low bioaccessibility of Fe and Zn are due to their interactions with phytates. Cd was observed to be the most bioaccessible element in the dried samples because of its weak interaction with other components in the vegetables.

Phosphate effect on the content of selected elements in a lettuce variety grown at a contaminated soil

The purpose of this study was to evaluate the efficiency of superphosphate fertilizer in remediating a contaminated soil with potentially toxic elements. For this, different phosphorus doses were used in a number of lettuce plants. The element concentrations determined in their leaves were compared with those found in control lettuce plants. Instrumental neutron activation analysis was the analytical technique used to determine element concentration in lettuce leave samples. The application of 250 mg kg−1 of P was the most effective treatment to reduce the concentrations of Br, Ca, Cd, Cl, Co, Cr, Fe, K, Mg, Mn, Sb and Zn in lettuce leaves.

시설재배지 토양 pH와 전함량 및 이동태 함량이 상추의 구리와 아연 흡수에 미치는 영향

Copper and Zinc are essential trace elements for all living organisms. When presenting in excess amount in soils, however they can be toxic to plants. In order to examine the transfer of Cu and Zn from soils to plants and to predict their contents in plants using soil factors, we investigated total and mobile contents of Cu and Zn in soils and their uptake by lettuce (Lactuca sativa L.) in plastic film houses. Total Cu and Zn contents in soils were 17.5∼65.9 mg kg -1 (mean: 39.3 mg kg -1 ) and 63.2∼200 mg kg -1 (mean: 137 mg kg -1 ), respectively. Mobile Cu and Zn contents in soils were (0.04)∼0.55 mg kg -1 (mean: 0.18 mg kg -1 ) and (0.05)∼2.62 mg kg -1 (mean: 0.47 mg kg -1 ), respectively. Soil pH ranged from 5.4 to 7.3 and OM from 24.1 to 59.9 g kg -1 . Mean Cu contents in leaves and roots of lettuce were 9.20 and 17.2 mg kg -1 , respectively which showed that Cu was accumulated mainly in root parts of lettuce and not easily transported to leaves. In contrast, Zn was fairly evenly distributed in leaves and roots with mean values of 54.5 and 56.7 mg kg -1 , indicating relative high mobility of Zn in lettuce. Transfer factors of Cu and Zn from soil total contents to roots and leaves of lettuce (TFStR and TFStL) were between 0.1 and 1, while transfer factors from soil mobile contents to roots and leaves (TFSmR and TFS mL) were between 10 and 1000. Transfer factors of Zn were higher than those of Cu, showing Zn was more easily absorbed by plants than Cu. Cu and Zn uptake was stronger influenced by soil pH and mobile contents than total contents and OM and could be significantly described by multiple regression equations including soil pH and soil mobile contents as variables.

INFLUENCE OF IRON-CHELATES ON TRACE ELEMENT UPTAKE FROM TWO CALCAREOUS SOILS AND THE ACTIVITY OF OXYGEN-SCAVENGING ENZYMES IN LETTUCE

A pot experiment was carried out to determine the ability of lettuce (Lactuca sativa cv. ‘Waldmann's dark green’) to acquire iron (Fe) from Fe-ethylenediaminedisuccinic acid [EDDS, both as an isomeric mixture, EDDS(mix), and (S,S)-EDDS], Fe-ethylenediaminetetraacetic acid (EDTA) and Fe-ethylenediimonobis(2-hydroxyphenyl)acetic acid (EDDHA) in two calcareous soils and consequent effect on the activity of reactive oxygen species scavenging enzymes. Probably due to the rapid biodegradation of [S,S]-EDDS, EDDS(mix) provided Fe to lettuce more efficiently. Iron-EDDS(mix) and Fe-EDDHA were equally efficient in increasing Fe concentration in lettuce. The activity of superoxide dismutase (SOD) was not affected by Fe deficiency and the activity of copper (Cu) and zinc (Zn) containing SOD (Cu/ZnSOD) was dependent on lettuce Zn concentration. Ascorbate peroxidase and guaiacol peroxidase activities were increased by Fe-EDDHA, probably due to the steady supply of Fe. Physiologically active Fe pool for lettuce was equally provided by Fe-EDDS(mix) and Fe-EDTA.

Cobertura do solo, produção de biomassa e teores de Mn e Zn de alface no sistema orgânico

O objetivo deste trabalho foi avaliar o efeito da cobertura do solo com aveia preta e manutencao da palha sobre o terreno, bem como cobertura do solo com filme de polietileno preto, sobre a producao de biomassa e teores de Mn e Zn em alface cultivada no sistema orgânico, por dois anos consecutivos. Utilizaram-se cinco tratamentos: solo sem cobertura, coberto com filme de polietileno preto, coberto com aveia acamada, coberto com aveia ceifada e solo coberto com aveia na sua forma natural, para o cultivo de tres cultivares de alface. O experimento seguiu delineamento experimental de blocos ao acaso, com quatro repeticoes e analise estatistica com parcelas subdivididas. Concluiu-se que o cultivo de alface em sucessao a aveia preta, sobre a palha, promoveu producao satisfatoria e apresentou adequados teores de manganes e zinco, equivalentes aqueles encontrados na literatura em diferentes sistemas de cultivo, e a cobertura do solo com plastico preto promoveu producao satisfatoria com maior acumulo de Zn no primeiro ano e menor de Mn no segundo.

Cobertura do solo, produção de biomassa e teores de Mn e Zn de alface no sistema orgânico

The goal of this research was to evaluate the effect of soil covering with black oat straw, as well as soil covered with black plastic, on the production of biomass and levels of Mn and Zn in lettuce produced in an organic system, over two consecutive years. Five treatments were used: soil without cover, covered with black plastic, covered with laying oats, covered with harvested oats, and covered with oat straw in natural form, for growing three cultivars of lettuce. A randomized blocks design was used in a split-plot system, with four replications. It was concluded that soil covered with oat straw promoted satisfactory lettuce production, as well as adequate Mn and Zn content in plants, equivalent to those found in studies conducted under different growing systems; the soil covered with black plastic promoted satisfactory production and higher Zn content after the first year, and lower Mn content after the second year.

Quantification of metal bioavailability for lettuce (Lactuca sativa L.) in field soils.

Understanding metal bioavailability of plants in soils requires, apart from physiological processes and symbiosis with arbuscular mycorrhizal fungi, the consideration of the chemical availability in the soil solution (the intensity of the toxic exposure) and the soil's capacity to supply the metal (capacity). In this contribution we report on the time-dependent accumulation of As, Cd, Cr, Cu, Ni, Pb, and Zn in lettuce (Lactuca sativa L.). Bioassays with 17 Dutch field soils and two artificially metal-contaminated soils were carried out. Phytotoxicity was observed in soils with pH (pore water) <4.8. Metal uptake is shown to be both metal- and soil-dependent and strongly depends on the amount of water the plant transpired and the available concentration in the water. No net accumulation of As, Pb, Ni, and especially Cr was observed in most soils tested. The latter observation is in agreement with findings of Zayed et al. (Planta, 1998 206:293-299), who reported that translocation of Cr from roots to shoots is extremely limited. Internal Cd levels in the plants varied greatly among soils, whereas plant tissue concentrations of Zn and especially Cu appear to be regulated at more or less fixed levels. The 0.01 M CaCl(2)-extractable metal pool provides the best descriptor for the capacity of the soil to supply Cd and Zn. This enabled the development of models that are suited to predict Zn and Cd uptake by lettuce in both field soils (weathered soils) and soils to which metal salts were added, which is common practice in toxicity testing of chemicals. It is concluded that of all metals included in this study, Cd is the metal of most concern due to bioaccumulation through the soil-plant-animal food chain as Cd is the only metal that might pose human or animal health risks at plant tissue concentrations that are not directly phytotoxic. Finally, application of the models for risk assessment purposes is discussed.

Sequential extraction of heavy metals in soils irrigated with wastewater

Different chemical forms of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) were determined in agricultural soils cultivated with lettuce and celery. These soils have been irrigated for several decades with nontreated wastewaters. The chemical forms of the metals were characterized by sequential extraction analysis in five steps, the extracting solutions of which contained 200 mg L‐1 nitrilotriacetic acid (NTA). The results showed that Cd, Pb, and Cu exhibited the highest values of extracted metal, and Cr exhibited the lowest value. Almost all of the metals in these soils are bound to iron oxides, followed by the metal complexed to organic matter. The form bound to manganese oxides is equally important to Co. Cadmium is the most mobile metal and its available forms account for 40% of the total extracted. When these metals were determined in plants, both shoots and roots, a greater concentration of Cr, Zn, and Cu was found in celery, and Cu, Ni, and Zn in lettuce, most of the metals being in roots. Only Cd and Co are similarly distributed in shoots and in roots. The relation between the metal contents in plants and the different fractions of the metal in soil was evaluated through linear correlations. Different results were obtained, the forms accounting for the metal in celery are those of the metal bound to iron oxides, while the metal content in lettuce would be related to the exchangeable, bound to manganese oxide, and carbonate forms.

INTERACTION OF THE YIELD RESPONSE SURFACE OF LETTUCE WITH HIGH AND TOXIC CONCENTRATIONS OF ZINC AND NICKEL

We germinated lettuce seeds in nutrient solutions with different high concentrations of Zn and Ni singly and together and estimated growth by measurement of root length at 120 h. The high concentration zone of the dose-response curve of lettuce to Zn consisted of a tolerance zone and one toxic phase. The toxicity threshold for Zn was 63 μeq L−1 Zn. In contrast, the dose-response curve for Ni had a tolerance zone, but the toxic zone comprised two phases of Ni toxicity, 20 μeq L−1 Ni, with 45 μeq L−1 Ni for the second phase. The two toxic phases for Ni were expressed both as a yield function and as a metabolic function where abrupt changes in the tissue concentration of Ca, Cd, and Na corresponded to changes in Ni status, as indicated in the dose-response curve developed from root length measurements. The response of lettuce to a matrix of both Zn and Ni concentrations was portrayed as a response surface. The Zn-Ni dose-response surface indicated that an interaction of Ni and Zn in lettuce occurred only when both metals were present at concentrations greater than their toxicity thresholds. The interaction of Zn and Ni was multiplical in form.