Iron supplementation in the diets of hybrid catfish (Ictalurus punctatus × I. furcatus) juveniles affected haematocrit levels and potentially decreased disease resistance to Edwardsiella ictaluri.

To prevent catfish idiopathic anaemia, diets fortified with iron have been adopted as a regular practice on commercial catfish farms to promote erythropoiesis. However, the effects of prolonged exposure of excess dietary iron on production performance and disease resistance for hybrid catfish (Ictalurus punctatus × I. furcatus) remains unknown. Four experimental diets were supplemented with ferrous monosulphate to provide 0, 500, 1000, and 1500 mg of iron per kg of diet. Groups of 16 hybrid catfish juveniles (~22.4 g) were stocked in each of 20, 110-L aquaria (n = 5), and experimental diets were offered to the fish to apparent satiation for 12 weeks. At the end of the study, production performance, survival, condition indices, as well as protein and iron retention were unaffected by the dietary treatments. Blood haematocrit and the iron concentration in the whole-body presented a linear increase with the increasing the dietary iron. The remaining fish from the feeding trial was challenged with Edwardsiella ictaluri. Mortality was mainly observed for the dietary groups treated with iron supplemented diets. The results for this study suggest that iron supplementation beyond the required levels does affect the blood production, and it may increase their susceptibility to E. ictaluri infection.

Mitigating cadmium accumulation and toxicity in plants: The promising role of nanoparticles.

Cadmium (Cd) is a highly toxic heavy metal that adversely affects humans, animals, and plants, even at low concentrations. It is widely distributed and has both natural and anthropogenic sources. Plants readily absorb and distribute Cd in different parts. It may subsequently enter the food chain posing a risk to human health as it is known to be carcinogenic. Cd has a long half-life, resulting in its persistence in plants and animals. Cd toxicity disrupts crucial physiological and biochemical processes in plants, including reactive oxygen species (ROS) homeostasis, enzyme activities, photosynthesis, and nutrient uptake, leading to stunted growth and reduced biomass. Although plants have developed defense mechanisms to mitigate these damages, they are often inadequate to combat high Cd concentrations, resulting in yield losses. Nanoparticles (NPs), typically smaller than 100 nm, possess unique properties such as a large surface area and small size, making them highly reactive compared to their larger counterparts. NPs from diverse sources have shown potential for various agricultural applications, including their use as fertilizers, pesticides, and stress alleviators. Recently, NPs have emerged as a promising strategy to mitigate heavy metal stress, including Cd toxicity. They offer advantages, such as efficient absorption by crop plants, the reduction of Cd uptake, and the enhancement of mineral nutrition, antioxidant defenses, photosynthetic parameters, anatomical structure, and agronomic traits in Cd-stressed plants. The complex interaction of NPs with calcium ions (Ca2+), intracellular ROS, nitric oxide (NO), and phytohormones likely plays a significant role in alleviating Cd stress. This review aims to explore the positive impacts of diverse NPs in reducing Cd accumulation and toxicity while investigating their underlying mechanisms of action. Additionally, it discusses research gaps, recent advancements, and future prospects of utilizing NPs to alleviate Cd-induced stress, ultimately promoting improved plant growth and yield.

The damage caused by Cd toxicity to photosynthesis, cellular ultrastructure, antioxidant metabolism, and gene expression in young cacao plants are mitigated by high Mn doses in soil.

Manganese (Mn) is one of the essential mineral micronutrients most demanded by cacao. Cadmium (Cd) is highly toxic to plants and other living beings. There are indications that Mn can interact with Cd and mitigate its toxicity. The objective of this study was to evaluate the action of Mn on the toxic effect of Cd in young plants of the CCN 51 cacao genotype, subjected to different doses of Mn, Cd, and Mn+Cd in soil, through physiological, biochemical, molecular, and micromorphological and ultrastructural changes. High soil Mn doses favored the maintenance and performance of adequate photosynthetic processes in cacao. However, high doses of Cd and Mn+Cd in soil promoted damage to photosynthesis, alterations in oxidative metabolism, and the uptake, transport, and accumulation of Cd in roots and leaves. In addition, high Cd concentrations in roots and leaf tissues caused irreversible damage to the cell ultrastructure, compromising cell function and leading to programmed cell death. However, there was a mitigation of Cd toxicity when cacao was grown in soils with low Cd doses and in the presence of Mn. Thus, damage to the root and leaf tissues of cacao caused by Cd uptake from contaminated soils can be attenuated or mitigated by the presence of high Mn doses in soil.

New insights in to the ameliorative effects of zinc and iron oxide nanoparticles to arsenic stressed spinach (Spinacia oleracea L.).

Nanotechnology is capturing great interest worldwide due to their stirring applications in various fields and also individual application of iron oxide nanoparticle (FeO-NPs) and zinc oxide nanoparticle (ZnO-NPs) have been studied in many literatures. However, the combined application of FeO and ZnO-NPs is a novel approach and studied in only few studies. For this purpose, a pot experiment was conducted to examine the plant growth and biomass, photosynthetic pigments, gas exchange attributes, oxidative stress and response of antioxidant compounds (enzymatic and nonenzymatic), sugars, nutritional status of the plant, organic acid exudation pattern As accumulation from the different parts of the plants in spinach (Spinacia oleracea L.) under the different As concentrations i.e., 0 (no As), 60 and 120 µM] which were primed with combined application of two levels of FeO-NPs (10 and 20 mg L-1) and ZnO-NPs (20 and 40 mg L-1). Results from the present study showed that the increasing levels of As in the soil significantly (P < 0.05) decreased plant growth and biomass, photosynthetic pigments, gas exchange attributes, sugars, and nutritional contents from the roots and shoots of the plants. In contrast, increasing levels of As in the soil significantly (P < 0.05) increased oxidative stress indicators in term of malondialdehyde, hydrogen peroxide, and electrolyte leakage, and also increased organic acid exudation patter in the roots of S. oleracea. The negative impact of As toxicity can overcome the combined application of ZnO-NPs and FeO-NPs, which ultimately increased plant growth and biomass by capturing the reactive oxygen species, and decreased oxidative stress in S. oleracea by decreasing the As contents in the roots and shoots of the plants. Research findings, therefore, suggest that the combined application of ZnO-NPs and FeO-NPs can ameliorate As toxicity in S. oleracea, resulting in improved plant growth and composition under As stress, as depicted by balanced exudation of organic acids.

Poultry litter and cover crops influence the agronomic performance and grain yield of wheat

The use of poultry litter as a source of nitrogen (N) and the decomposition of ground cover plants can be an alternative and N management strategy in the wheat crop, in succession. Therefore, the objective of this study was to evaluate the effect of isolated and/or intercropped cultivation of ground cover plants in autumn/winter and the use of poultry litter on some plant parameters and on the final yield of wheat grains. The experimental design was randomized blocks, in split plots, with three replications. The treatments in the plots were composed of isolated coverings Avena strigosa Schreb., Raphanus sativus L. and intercropping of A. strigosa + R. sativus and fallow as a control. In the subplots, the N managements in the wheat crop with 100% of the N recommendation via poultry litter, 100% of the N via mineral (urea), 50% via poultry litter + 50% mineral and the control, without N application. The management of nitrogen fertilization and the cover crops altered the yield components of the wheat crop. The use of poultry litter increased the final grain yield, being an alternative as a partial replacement, when associated with urea, or total N. Isolated crops R. sativus and A. strigosa + R. sativus intercropping significantly influenced agronomic performance and final grain yield.

Plant mineral nutrition and disease resistance: A significant linkage for sustainable crop protection.

Complete and balanced nutrition has always been the first line of plant defense due to the direct involvement of mineral elements in plant protection. Mineral elements affect plant health directly by modulating the activity of redox enzymes or improving the plant vigor indirectly by altering root exudates, and changing microflora population dynamics, rhizosphere soil nutrient content, pH fluctuation, lignin deposition, and phytoalexin biosynthesis. Nitrogen (N) is one of the most important macronutrients having a significant impact on the host-pathogen axis. N negatively affects the plant's physical defense along with the production of antimicrobial compounds, but it significantly alleviates defense-related enzyme levels that can eventually assist in systemic resistance. Potassium (K) is an essential plant nutrient, when it is present in adequate concentration, it can certainly increase the plant's polyphenolic concentrations, which play a critical role in the defense mechanism. Although no distinguished role of phosphorus (P) is observed in plant disease resistance, a high P content may increase the plant's susceptibility toward the invader. Manganese (Mn) is one of the most important micronutrients, which have a vital effect on photosynthesis, lignin biosynthesis, and other plant metabolic functions. Zinc (Zn) is a part of enzymes that are involved in auxin synthesis, infectivity, phytotoxin, and mycotoxin production in pathogenic microorganisms. Similarly, many other nutrients also have variable effects on enhancing or decreasing the host susceptibility toward disease onset and progression, thereby making integrative plant nutrition an indispensable component of sustainable agriculture. However, there are still many factors influencing the triple interaction of host-pathogen-mineral elements, which are not yet unraveled. Thereby, the present review has summarized the recent progress regarding the use of macro- and micronutrients in sustainable agriculture and their role in plant disease resistance.

Cowpea seeds from plants subjected to restricted-and full-irrigation regimes show differential phytochemical activity.

BACKGROUND: Water scarcity is responsible for losses in the yield of many plants and this is expected to continue due to climate change. However, cowpea which is known for its drought tolerance, is considered as a plant without limitations to climate change. A two-year experiment was conducted to evaluate the effect of water restriction on phenolic compounds, antioxidant capacity and leaf nutrients concentration of four cultivars of cowpea at different growth stages. At second leaf stage, two irrigation regimes were initiated (Water irrigation was applied after 75% and 55% of field capacity, as well watered and drought stress treatment, respectively).Plants samples were collectedat three stages(immature pod, immature seed and dry seed stage) for total phenol and flavonoids content, ortho-diphenols andantioxidant capacity measurement and leaves sampling for nutrients concentration. RESULTS: The results indicated that polyphenolic compounds and antioxidant capacity increased under drought conditions. However, in both irrigation regimes, immature pods had the higher polyphenolic compounds, antioxidant capacity and leaf nutrients concentration rather than immature seeds and dry seeds. Among the genotypes, ILC482 revealed the highest content of total phenolics and ortho-diphenols (6.9 and 3.57 mg GA g-1dry weight, respectively). In addition, nitrogen, phosphorus and magnesium concentration of leaves were higher in ILC482 genotype. Under drought stress, ILC482 maintained higher ABTS radical scavenging capacity (0.0083 mmol Trolox g-1dry weight) compared to other genotypes. CONCLUSIONS: It is suggested that drought stress affect the quality of cowpea productions through polyphenolic compounds, ABTS and DPPH radical scavenging capacity which can be used as a helpful strategy to save water in the regions where water is scare.

Plant Growth-Promoting Rhizobacteria Alleviate High Salinity Impact on the Halophyte Suaeda fruticosa by Modulating Antioxidant Defense and Soil Biological Activity.

Plant growth-promoting rhizobacteria (PGPR) are considered as bio-ameliorators that confer better salt resistance to host plants while improving soil biological activity. Despite their importance, data about the likely synergisms between PGPR and halophytes in their native environments are scarce. The objective of this study was to assess the effect of PGPR (Glutamicibacter sp. and Pseudomonas sp.) inoculation on biomass, nutrient uptake, and antioxidant enzymes of Suaeda fruticosa, an obligate halophyte native in salt marshes and arid areas in Tunisia. Besides, the activity of rhizospheric soil enzyme activities upon plant inoculation was determined. Plants were grown in pots filled with soil and irrigated with 600 mM NaCl for 1 month. Inoculation (either with Pseudomonas sp. or Glutamicibacter sp.) resulted in significantly higher shoot dry weight and less accumulation of Na+ and Cl- in shoots of salt-treated plants. Glutamicibacter sp. inoculation significantly reduced malondialdehyde (MDA) concentration, while increasing the activity of antioxidant enzymes (superoxide dismutase; catalase; ascorbate peroxidase; and glutathione reductase) by up to 100%. This provides strong arguments in favor of a boosting effect of this strain on S. fruticosa challenged with high salinity. Pseudomonas sp. inoculation increased shoot K+ and Ca2+ content and lowered shoot MDA concentration. Regarding the soil biological activity, Pseudomonas sp. significantly enhanced the activities of three rhizospheric soil enzymes (urease, ß-glucosidase, and dehydrogenase) as compared to their respective non-inoculated saline treatment. Hence, Pseudomonas sp. could have a great potential to be used as bio-inoculants in order to improve plant growth and soil nutrient uptake under salt stress. Indole-3-acetic acid concentration in the soil increased in both bacterial treatments under saline conditions, especially with Glutamicibacter sp. (up to +214%). As a whole, Glutamicibacter sp. and Pseudomonas sp. strains are promising candidates as part of biological solutions aiming at the phytoremediation and reclamation of saline-degraded areas.

Bioactive compounds and physical-chemical characteristics of two genotypes of peach trees submitted to nitrogen fertilization

Nitrogen, which is the primary nutrient peach trees need, may affect their fruit quality. Thus, this study aimed at evaluating the effect of nitrogen fertilization on two genotypes of peach trees, regarding their fruit quality, in three consecutive crops. The experiment was carried out in the experimental area that belongs to the Embrapa Clima Temperado, located in Pelotas, Rio Grande do Sul (RS), Brazil, from 2016, 2016, 2017 and 2018. Four doses of nitrogen (0, 60, 120 and 180 Kg ha-1) and two peach tree genotypes ('Cascata 1513' and 'Cascata 1067') were used. For the fruit, we evaluated epidermis color, pulp firmness, epidermis firmness, soluble solids concentration, titratable acidity, concentration of total phenolic compounds, anthocyanins and antioxidant activity. Fruit underwent physical, chemical and bioactive compound analyses. Results showed that the highest dose of nitrogen (180 Kg ha-1) applied to the soil retards fruit ripening, while no application of nitrogen fertilization brings fruit maturation forward. Nitrogen fertilization via soil does not favor anthocyanins in fruit. Doses of 60 and 120 Kg ha-1 of nitrogen are recommended because they lead to improvement in peach color, epidermis firmness and acidity. Peach tree genotypes influence soluble solids, juice pH, phenolic compounds and antioxidant activity of their fruit.

Nitrogen fertilisation impacts greenhouse gas emissions, carbon footprint, and agronomic responses of beet intercropped with arugula.

Although the response of plants to nitrogen (N) in conventional systems has been extensively described in the literature, there is a lack of information available to refine the strategic N fertilisation program required in intercropping systems to match the nutrient supply with crop demands and reduce environmental impacts on greenhouse gas emissions. Therefore, this study aims to investigate the effect of N management on the growth, production, quality, greenhouse gas emissions (GHG) and carbon footprint of a beet-arugula intercropping system during two growing seasons (winter and summer). The efficiency of N fertilisation in each season was assessed by the supply of 20 N doses, varying the amounts applied at planting and as a side dressing (0-80, 0-120, 0-160, 0-200, 0-240, 20-80, 20-120, 20-160, 20-200, 20-240, 40-80, 40-120, 40-160, 40-200, 40-240, 60-80, 60-120,60-160, 60-200 and 60-240 kg N ha-1). GHG emissions and carbon footprint were calculated and converted to CO2 equivalent (CO2 eq) utilising IPCC methodology. The height, total and marketable productivities of beet plants were 33, 31 and 34% higher in winter than in summer, respectively. Arugula plants achieved the highest performance (height, fresh mass and yield) in summer. Considering the environmental impact on global warming/climate change caused by the use of N fertilisers, total GHG emissions may range from 1723.9 to 3369.8 kg CO2eq ha-1 cycle-1 according to the N dose applied. However, based on the carbon footprint, the application of 60-120 kg N ha-1 at planting and as side dressing was the best N dose, since it reduced the carbon footprint (equivalent to 0.134 g CO2eq kcal-1 vegetables) without compromising crop yield.

Hydrogen sulphide and salicylic acid regulate antioxidant pathway and nutrient balance in mustard plants under cadmium stress.

Cadmium (Cd), a pervasive noxious heavy metal, is a key threat to agricultural system. It is rapidly translocated and has detrimental effects on plant growth and development. Hydrogen sulphide (H2 S) is emerging as a potential messenger molecule for modulating plant tolerance to Cd. Salicylic acid (SA), a phenolic signalling molecule, can alleviate Cd toxicity in plants. The present study investigated the mediatory role of H2 S (100 µM) and SA (0.5 mM), individually and in combination, in modulating antioxidant defence machinery and nutrient balance to impart Cd (50 µM) resistance to mustard. Accumulation of Cd resulted in oxidative stress (TBARS and H2 O2 ), mineral nutrient imbalance (N, P, K, Ca), decreased leaf gas exchange and PSII efficiency, ultimately reducing plant growth. Both H2 S and SA independently attenuated phytotoxic effects of Cd by triggering antioxidant systems, enhancing the nutrient pool, eventually leading to improved photosynthesis and biomass of mustard plants. The positive effects were more pronounced under combined application of H2 S and SA, indicating a synergistic relationship between these two signalling molecules in mitigating the detrimental effects of Cd on nutrient homeostasis and overall health of mustard, primarily by boosting antioxidant pathway. Our findings provide new insights into H2 S- and SA-induced protective mechanisms in mustard plants subjected to Cd stress and suggest their combined use as a feasible strategy to confer Cd tolerance.

Mineral nutrient signaling controls photosynthesis: focus on iron deficiency-induced chlorosis.

Photosynthetic organisms convert light energy into chemical energy stored in carbohydrates. To perform this process, an adequate supply of essential mineral elements, such as iron, is required in the chloroplast. Because iron plays a crucial role during electron transport and chlorophyll formation, iron deficiency alters photosynthesis and promotes chlorosis, or the yellowing of leaves. Intriguingly, iron deficiency-induced chlorosis can be reverted by the depletion of other micronutrients [i.e., manganese (Mn)] or macronutrients [i.e., sulfur (S) or phosphorus (P)], raising the question of how plants integrate nutrient status to control photosynthesis. Here, we review how improving our understanding of the complex relationship between nutrient homeostasis and photosynthesis has great potential for crop improvement.

Fertilization assures mineral nutrition but does not overcome the effects of Fe accumulation in plants grown in iron ore tailings.

The rupture of Fundão dam was the biggest environmental disaster of the worlds' mining industry, dumping tons of iron ore tailings into the environment. Studies have shown that the Fundão dam's tailings are poor in nutrients and have high Fe and Mn concentration. In this context, our objective was to evaluate the growth performance of two native tree species (Bowdichia virgilioides and Dictyoloma vandellianum) in two treatments: fertilized soil and fertilized tailings. We hypothesize that the high concentrations of iron and manganese in the tailings can impair the growth performance of plants by interfering with the absorption of nutrients made available through fertilization. Soil and tailings samples were collected in the municipality of Barra Longa (MG, Brazil), and then fertilized with mixed mineral fertilizer ("Osmocote Plus 15-9-12" at 7.5 g L-1). The experiment was conducted for 75 days in a greenhouse using 180 cm3 tubes. We evaluate chlorophyll content, maximal PSII quantum yield, root length, shoot length, root:shoot ratio, leaf area, specific leaf area and leaf area ratio, dry mass, macro- and micronutrients concentration in the tissues, and metal translocation factor. Although assuring the adequate levels of the main nutrients to plant growth (N, P, K, Ca, and Mg), the fertilization did not reverse the negative effect of tailing on these species. The high concentration of Fe in the tissues associated with less biomass production, lower plant height, smaller leaf area, bigger specific leaf area, and reduced chlorophyll content indicates a probable phytotoxic effect of iron present in the tailings for D. vandellianum. Our results base further field evaluations and longer experiments, which will facilitate the understanding of the performance of tree species submitted to tailings with fertilization. So far, this study suggests that B. virgilioides are more tolerant to excess Fe from the tailings of Fundão dam than D. vandellianum.

The Combination of Untargeted Metabolomics and Machine Learning Predicts the Biosynthesis of Phenolic Compounds in Bryophyllum Medicinal Plants (Genus Kalanchoe).

Phenolic compounds constitute an important family of natural bioactive compounds responsible for the medicinal properties attributed to Bryophyllum plants (genus Kalanchoe, Crassulaceae), but their production by these medicinal plants has not been characterized to date. In this work, a combinatorial approach including plant tissue culture, untargeted metabolomics, and machine learning is proposed to unravel the critical factors behind the biosynthesis of phenolic compounds in these species. The untargeted metabolomics revealed 485 annotated compounds that were produced by three Bryophyllum species cultured in vitro in a genotype and organ-dependent manner. Neurofuzzy logic (NFL) predictive models assessed the significant influence of genotypes and organs and identified the key nutrients from culture media formulations involved in phenolic compound biosynthesis. Sulfate played a critical role in tyrosol and lignan biosynthesis, copper in phenolic acid biosynthesis, calcium in stilbene biosynthesis, and magnesium in flavanol biosynthesis. Flavonol and anthocyanin biosynthesis was not significantly affected by mineral components. As a result, a predictive biosynthetic model for all the Bryophyllum genotypes was proposed. The combination of untargeted metabolomics with machine learning provided a robust approach to achieve the phytochemical characterization of the previously unexplored species belonging to the Bryophyllum subgenus, facilitating their biotechnological exploitation as a promising source of bioactive compounds.

Interplay between Coumarin Accumulation, Iron Deficiency and Plant Resistance to Dickeya spp.

Coumarins belong to a group of secondary metabolites well known for their high biological activities including antibacterial and antifungal properties. Recently, an important role of coumarins in plant resistance to pathogens and their release into the rhizosphere upon pathogen infection was discovered. It is also well documented that coumarins play a crucial role in the Arabidopsis thaliana growth under Fe-limited conditions. However, the mechanisms underlying interplay between plant resistance, accumulation of coumarins and Fe status, remain largely unknown. In this work, we investigated the effect of both mentioned factors on the disease severity using the model system of Arabidopsis/Dickeya spp. molecular interactions. We evaluated the disease symptoms in Arabidopsis plants, wild-type Col-0 and its mutants defective in coumarin accumulation, grown in hydroponic cultures with contrasting Fe regimes and in soil mixes. Under all tested conditions, Arabidopsis plants inoculated with Dickeya solani IFB0099 strain developed more severe disease symptoms compared to lines inoculated with Dickeya dadantii 3937. We also showed that the expression of genes encoding plant stress markers were strongly affected by D. solani IFB0099 infection. Interestingly, the response of plants to D. dadantii 3937 infection was genotype-dependent in Fe-deficient hydroponic solution.

Effects of Melatonin on Morphological Characteristics, Mineral Nutrition, Nitrogen Metabolism, and Energy Status in Alfalfa Under High-Nitrate Stress.

Melatonin is an indoleamine small molecular substance that has been shown to play an important role in the growth, development, and stress response of plants. The effects of melatonin on the morphological characteristics, mineral nutrition, nitrogen metabolism, and energy status in alfalfa (Medicago sativa L.) under high-nitrate stress were studied. The alfalfa plants were treated with water (CK), 200 mmol L-1 nitrates (HN), or 200 mmol L-1 nitrates + 0.1 mmol L-1 melatonin (HN+MT), and then were sampled for measurements on days 0 and 10, respectively. The results showed that the HN treatment resulted in a decrease in the morphological characteristics (such as shoot height, leaf length, leaf width, leaf area, and biomass), phosphorus, soluble protein (SP), nitrogen-related enzymes activities and gene relative expression, adenosine triphosphate (ATP), and energy charge (EC). It also caused an increase in nitrogen, sodium, potassium, calcium, nitrate-nitrogen ( NO 3 - -N), ammonium-nitrogen ( NH 4 + -N), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). However, these parameters were conversely changed in the HN+MT treatment. Besides, these parameters were closely related to each other, and were divided into two principal components. It reveals that melatonin plays an important role in modulating the morphology, mineral nutrition, nitrogen metabolism and energy status, thereby alleviating the adverse effects of high-nitrate stress and improving the growth of alfalfa.

Serum concentration of thyroxine and triiodothyronine in newborn calves from cows supplemented with barium selenate / Concentración sérica de tiroxina y triiodotironina en terneros recién nacidos de madres suplementadas con selenato de bario / Concentração de tiroxina e triiodotironina sérica em bezerros recém-nascidos de mães suplementadas com selenato de bário

Abstract Background: Barium selenate is an inorganic source of selenium (Se) used in prolonged-release preparations to treat selenium deficiency in bovines. Objective: To evaluate serum concentrations of triiodothyronine (T3) and thyroxine (T4) hormones in newborn calves from mothers supplemented with barium selenate during prepartum. Methods: Six black Frisian pregnant cows were supplemented with barium selenate subcutaneously during the last two months of gestation, until calving. Six cows were used as controls. All cows were subjected to a low Se diet, consisting of hay from natural pasture and commercial concentrate lacking Se. The Se balance was measured through the activity of erythrocyte glutathione peroxidase (GPx). Serum concentration of T3 and T4 in calves was determined by electrochemiluminescence. Results: Se supplementation during prepartum increased GPx activity in cows from day 45 post-supplementation (p<0.05). Calves from supplemented mothers showed higher average serum Se concentration than calves from non-supplemented mothers. The average concentration of T3 in the calves from supplemented mothers was lower in the first hour of life (p<0.05) compared with calves from mothers of the non-supplemented group. A decrease (p<0.05) in T4 serum concentrations was observed in both groups at seven days of age. Conclusions: Administration of barium selenate to cows during prepartum generates a reduction in serum concentration of T3 in the first hour of life of calves.

Resumen Antecedentes: El selenato de bario es una fuente inorgánica de selenio (Se) utilizada en preparaciones de liberación prolongada para corregir el estado de carencia de Se en bovinos. Objetivo: Evaluar las concentraciones séricas de triyodotironina (T3) y tiroxina (T4) en terneros recién nacidos de madres suplementadas durante el preparto con selenato de bario. Métodos: Seis vacas frisón negro con 7 meses de gestación fueron suplementadas vía subcutánea con selenato de bario dos meses previos a la fecha de parto. Otras seis vacas permanecieron como controles. Todas las vacas se mantuvieron con una dieta cuyo aporte de Se fue inferior a los requerimientos y consistió en heno de pradera natural y concentrado comercial sin Se. El balance de Se se midió usando la actividad eritrocitaria de glutatión peroxidasa (GPx) y las concentraciones de T3 y T4 en terneros mediante electroquimioluminiscencia. Resultados: La suplementación con Se aumentó la actividad de GPx en vacas desde el día 45 post suplementación (p<0,05). Los terneros de madres suplementadas mostraron una concentración sérica promedio de Se mayor que los terneros de madres no suplementadas. La concentración promedio de T3 de terneros de madres suplementadas fue menor en la primera hora de vida (p<0,05) que en terneros de madres no suplementadas. A los 7 días de edad hubo una disminución (p<0,05) en las concentraciones séricas de T4 en ambos grupos. Conclusión: La administración de selenato de bario en vacas preparto genera una disminución en la concentración sérica de T3 en la primera hora de vida del ternero.

Resumo Antecedentes: O selenato de bário é uma fonte inorgânica de selênio (Se) usada em preparações de liberação prolongada para corrigir o status de deficiência de Se em bovinos. Objetivo: Avaliar as concentrações séricas de triiodotironina (T3) e tiroxina (T4) em bezerros recém-nascidos de mães suplementadas durante o pré-parto com selenato de bário. Métodos: Seis vacas friesianas negras aos 7 meses de gestação foram suplementadas com selenato de bário por via subcutânea dois meses antes do parto. Seis outras vacas permaneceram como controle. Todas as vacas foram mantidas em uma dieta cuja contribuição de Se foi inferior aos requeridos e consistiram em feno natural da pradaria e concentrado comercial sem Se. O balanço de Se foi medido usando a atividade eritrocitária das concentrações de glutationa peroxidase (GPx) e T3 e T4 em bezerros por eletroquimiluminescência. Resultados: A suplementação com atividade de GPx aumentou em vacas a partir do dia 45 após a suplementação (p<0,05). Os bezerros de mães suplementadas apresentaram uma concentração sérica média de Se maior que os bezerros de mães não suplementadas. A concentração média de T3 dos bezerros das mães suplementadas foi menor na primeira hora de vida (p<0,05) do que nos bezerros das mães não suplementadas. Aos 7 dias de idade houve uma diminuição (p<0,05) nas concentrações séricas de T4 nos dois grupos. Conclusão: A administração de selenato de bário em vacas de parto gera uma diminuição na concentração sérica de T3 na primeira hora de vida do bezerro.

Effect of arsenic-contaminated irrigation water on growth and elemental composition of tomato and cabbage cultivated in three different soils, and related health risk assessment.

This study was carried out to determine the effect of arsenic on tomato and cabbage cultivated in sand, sandy silt, and silt soil, and irrigated with water containing arsenic at concentrations 0.05 and 0.2 mg/L. Increasing arsenic in irrigation water did not affect the photosynthetic machinery. The chlorophyll content index increased in case of all soils and was dependent on the soil nitrogen, phosphorous, and plant biomass. Arsenic concentrations of 0.05 and 0.2 mg/L did not display any phytotoxic symptoms other than reduction in biomass in some cases. In cabbage, arsenic treatment of 0.2 mg/L increased the overall plant biomass production, while in tomato there was a decrease in aerial part and fruit biomass. The biomass production of both plants treated with different concentrations of arsenic, in the three soils was in the following order: silt > sand > sandy silt. Increase of arsenic in the irrigation water resulted in increase in arsenic concentration in the root and aerial part of both plants, at the same cultivation parameters. But tomato fruits displayed a decrease in arsenic accumulation with higher arsenic treatment. In both plants, the arsenic concentration in the plant parts changed in the following order: root > aerial part > fruit. Cabbage accumulated approximately twenty-fold more arsenic in the edible part (0.10-0.25 mg/kg DW) as compared to tomato (0.006-0.011 mg/kg DW) and displayed a good correlation with soil extractable arsenic. When cabbage was cultivated in three different soils applying the same irrigation water, it accumulated arsenic in the following order: sand > sandy silt > silt (p < 0.001 at 0.05 mg/L and p < 0.01 at 0.2 mg/L arsenic treatment). In tomato, the difference in arsenic accumulation among different soil types was highly significant (p < 0.001) but the accumulation pattern varied with the arsenic treatment applied. Sandy soil with the lowest total soil arsenic (4.32 mg/kg) resulted in the highest arsenic concentration in both plants. Among all soils and plants, the transfer factors and bioaccumulation factors were higher in sandy soil, and in cabbage. The estimated daily intake and hazard quotient values for arsenic were lower than 1 in all cases, implying no non-cancerous health risks at the arsenic concentrations applied in our study. Among nutrients only P showed a slight decline with increasing arsenic concentration while all other elements (Mg, K, Ca, S, Si, Fe, Mn, Cu, Zn) did not display any significant changes.

Exploratory analysis in the evaluation of stress due to aluminum presence in Physalis angulata L. and multielement determination by microwave-induced plasma optical emission spectrometry (MIP OES).

The present work aimed to analyze the mineral nutrition of Physalis angulata L. under stress by aluminum in the nutrient solution. The treatments consisted of five different concentrations of aluminum in the nutrient solution (0, 0.04, 0.08, 0.12, and 0.16 mmol L-1) in the AlCl3 form. The plants were exposed to Al for 30 days. Subsequently, nutritional and aluminum analyses were performed on plant tissue. The data were submitted to analysis of variance (p < 0.05), and, in case of significance, the regression study was performed as well as hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used. The formation of four groups occurred, where we can observe the similarity and differences in the treatments between them. The separation of the treatments into groups reflected the heterogeneity of the treatments about the aluminum levels in the nutrient solution, evidencing its phytotoxicity level in Physalis angulata plants. Among the analyzed variables, P, K, Ca, Mg, Fe, Mo, and Zn were the most influential ones demonstrated by principal component analysis (PCA). The stress of 0.16 mmol L-1 of Al increased the phosphorus contents in the stems and roots and the potassium, copper, and molybdenum contents in all parts of the plants. In contrast, Al reduced the levels of calcium, magnesium, iron, and zinc in P. angulata plants. Iron being the micronutrient that showed the largest reduction, followed by zinc in the leaves. The highest levels of aluminum were found in the roots.

Macronutrient uptake, transport and use efficiency in seedlings of Pochota fendleri produced in different substrates / Eficiência de absorção, transporte e utilização de macronutrientes por mudas de Pochota fendleri produzidas em diferentes substratos

Seedlings produced in containers can be influenced by the materials used in the substrate, which affects the robustness of the plants and, indirectly, the time required for transplanting and for the plants to become established in the field. The aim of this study was to determine the chemical properties of different materials and on the absorption of macronutrients in Pochota fendleri seedlings (cedro-doce). The treatments were: sand (Sa), soil (So), sand+soil (Sa+So), and sand+soil+crushed Brazil nut capsules (Sa+So+CNC). The growth and macronutrient content were evaluated at 60 days after thinning. The amount of macronutrients in the substrate increased with the addition of crushed Brazil nut capsules. The use of different materials for the substrate, particularly Sa+So+CNC, had a positive influence on the morphological characteristics of seedlings, which ensuring high rates of establishment and survival after outplanting, making commercial reforestation with Pochota fendleri attractive.

As mudas produzidas em recipientes podem ser influenciadas pelos materiais utilizados no substrato, que afetam a robustez das plantas e, indiretamente, o tempo necessário para o transplante e o estabelecimento das plantas no campo. O objetivo deste estudo foi determinar as propriedades químicas de diferentes materiais e a absorção de macronutrientes em mudas de Pochota fendleri (cedro-doce). Os tratamentos foram: areia (Sa), solo (So), areia + solo (Sa + So) e areia + solo + casca de ouriço da castanha do Brasil triturada (Sa + So + CNC). O crescimento e o teor de macronutrientes foram avaliados 60 dias após o desbaste. A quantidade de macronutrientes no substrato aumentou com a adição de casca de ouriço da castanha do Brasil triturada. O uso de diferentes materiais para o substrato, principalmente o Sa + So + CNC, influenciou positivamente as características morfológicas das mudas, garantindo altas taxas de estabelecimento e sobrevivência após o plantio, tornando atraente o reflorestamento comercial com Pochota fendleri.