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It is necessary to increase the agronomic use efficiency of urea to reduce ammonia volatilization and increase crop yield. However, relying solely on urea for the enhanced efficiency technologies development could harm fertilizer integrity, resulting in reduced application quality and fertilizer storage time. The authors aimed at developing and characterizing the physical, chemical, and physicochemical quality of a novel enhanced efficiency fertilizers, synthesized from urea plus boron (B), zinc (Zn), nickel (Ni), or molybdenum (Mo) addition, with or without N-(n-butyl) thiophosphoric triamide (NBPT) associated. Hygroscopicity, hardness, salt index (SI), pH, and thermogravimetric decomposition were the parameters evaluated. Fertilizer quality was assessed through microscopic X-ray fluorescence, microtomography, and scanning electron microscopy. Micronutrients were added by coating or granulation; they were homogeneously distributed over the fertilizer’s granules. The fertilizers’ hardness increased up to 86% with Zn coated compared with uncoated. Granulated urea with B, Zn, Ni, or Mo had greater internal porosity, which resulted in lower hardness. Boron and Zn addition to the fertilizers increased the hygroscopicity in average 388% and 473%, respectively, compared with hygroscopicity observed for urea. Moreover, hygroscopicity was increased by an average of 56% with NBPT addition. Micronutrients addition to the urea granules increased the SI, while thermal decomposition stages of urea were unaffected by micronutrients addition. Enhanced efficiency fertilizers require characterization before agronomic efficiency tests due to changes in their physical, chemical, and physicochemical properties. Unfavorable changes could harm granules integrity and application efficiency in the field, resulting in economic losses to the industry and farmers. [ABSTRACT FROM AUTHOR]

• We evaluated the effect of fertilization on plant growth and carbon isotopic composition. • We used dendrometers to assess tree growth in response to climate in Southern Brazil. • The tree growth of Pinus spp. was more responsive to rainfall and evapotranspiration. • Pinus caribaea var. hondurensis was more responsive to fertilization regime and showed higher water use efficiency compared to Pinus taeda. This study aimed to characterize the development of Pinus caribaea var. hondurensis and Pinus taeda grown under two fertilization regimes (fertilized and control treatments) at field-grown condition. The growth, climate-growth relation, and intrinsic water use efficiency (WUEi) of the trees were assessed by a combined analysis of cross-sectional area (CSA) increment, water balance and carbon isotope discrimination (Δ13C ‰). The effect of fertilization on tree growth regime was assessed using inventory data collected yearly over 8 years. Additionally, monthly data of wood increments, monitored in nonfertilized stands over a period of 6 years, were utilized for correlations with meteorological variables (air temperature, rainfall, vapor pressure deficit, solar radiation and potential and actual evapotranspiration). The growth of Pinus caribaea and P. taeda was strongly influenced by multiple meteorological variables related to water availability and evapotranspiration. Differences in carbon isotope composition between treatments revealed that fertilized Pinus spp. displayed higher Δ13C values in some years, indicating improved water uptake efficiency due to increased nutrient availability. Pinus caribaea outperformed P. taeda in wood productivity and exhibited a heightened responsiveness to fertilization. In general, P. caribaea was shown to be more water-use efficient than P. taeda , as it is able to use smaller amounts of water for greater wood production. [ABSTRACT FROM AUTHOR]

Abstract Lettuce (Lactuca sativa L.) is known to have high cadmium (Cd) concentrations in its shoots, which makes it necessary to protect against Cd toxicity. Understanding Cd-induced physiological responses in lettuce plants can contribute to the definition of useful strategies to decrease Cd uptake. This study aimed to gain new insights into Cd-induced stress by measuring Cd bioaccumulation, nutrient composition, anatomical and ultrastructural changes, and antioxidative metabolism in three lettuce genotypes characterized as having different degrees of Cd tolerance (Vanda = low, Lidia = medium and Stela = high). Plants were grown hydroponically with Cd concentrations of 0.0 and 0.1 or 0.5 μmol L−1, for 30 days. Cadmium uptake in the lettuce genotypes assayed is controlled by the root/shoot ratio, higher root/shoot ratios allowing greater Cd uptake. The Fe and Ni content increased in shoots of the genotype Lidia, which could be associated with a decrease in oxidative stress in chloroplasts due to superoxide dismutase (SOD) isozyme activity. Cadmium-induced oxidative stress is associated with de-structuring of the phloem and xylem in roots, and starch grain and plastoglobule accumulation in chloroplasts. Lettuce genotypes that presented higher SOD and ascorbate peroxidase (APX) activity presented better preserved anatomical structures. These results suggest that genotypes with less efficient antioxidant defence in the roots tend to take up more Cd, increasing root-to-shoot Cd translocation. Graphical abstract fx1 Highlights • Cd uptake by lettuce genotypes is linked with biomass partitioning. • Nutrient accumulation decreased in all genotypes, in response of Cd exposure, except for Fe and Ni in the genotype Lidia. • Plastoglobule accumulation is associated with Fe-SOD activity in the genotype Lidia. • Better-preserved xylem–phloem anatomy may be the result of increased APX and SOD activity in roots. [ABSTRACT FROM AUTHOR]

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[Display omitted] • Lime is recommended to Eucalyptus aimed to supply Ca and Mg contents to plant growth. • Lime increased pH of the topsoil in the first months after application. • In Eucalyptus plantation, high soil Cu and Zn contents were bound to organic matter fraction. • Lime increased Ca and Mg, while reduced Cu and Zn levels in Ferralsol and Eucalyptus grandis. • Copper plus zinc fertilization can improve plant growth when associated with liming. Brazil is a global reference in forest management for wood production (e.g., pulp and solid wood products), and large areas are planted mainly in acidic and poorly fertile soils, with a predominance of Eucalyptus species. Liming is widely adopted in acidic soils in humid tropical regions planted with Eucalyptus to increase the availability of some nutrients and supply Ca and Mg. However, liming decreases the availability of some micronutrients, such as Cu and Zn, depending on the lime content. Copper and Zn fertilization for Eucalyptus is usually intended to replace the amount of micronutrients extracted after wood harvesting. However, few studies have been carried out to investigate the combined effects of lime and Cu plus Zn application on forest plantations in tropical soils. Here, the effects of these factors on soil chemical-attributes, as well as nutrition, and growth performance of Eucalyptus grandis plantations were evaluated on a medium-textured Ferralsol. The stem volume yield improved after liming, regardless of the rate of application, and after Cu plus Zn fertilization. Liming increased soil pH and Ca and Mg availability and reduced Cu and Zn availability. Overall, liming reduced soil Cu and Zn contents in the residual-fraction, while increasing the fraction bound to organic-matter. High contents of Cu and Zn were linked to the organic-matter fraction in the soil under the Eucalyptus plantation. Eucalyptus trees grown in soils amended with lime had higher values for leaf area index and leaf Ca and Mg concentrations but showed reduced Cu and Zn concentrations. The combined application of lime and Cu plus Zn improved Eucalyptus growth, with the higher contribution of lime compared to Cu and Zn. In conclusion, the combined application of lime and Cu plus Zn is a useful strategy to provide balanced nutrition and optimize stem volume yields. [ABSTRACT FROM AUTHOR]

Low concentrations of selenium (Se) are beneficial for plant growth. Foliar Se application at high concentrations is toxic to plants due to the formation of reactive oxygen species (ROS). This study characterized Se toxicity symptoms using X-ray fluorescence (XRF) technique in response to foliar Se application in cowpea plants. Five Se concentrations (0, 10, 25, 50, 100 e 150 g ha−1) were sprayed on leaves as sodium selenate. The visual symptoms of Se toxicity in cowpea leaves were separated into two stages: I) necrotic points with an irregular distribution and internerval chlorosis at the leaf limb border (50–100 g ha−1); II) total chlorosis with the formation of dark brown necrotic lesions (150 g ha−1). Foliar Se application at 50 g ha−1 increased photosynthetic pigments and yield. Ultrastructural analyses showed that Se foliar application above 50 g ha−1 disarranged the upper epidermis of cowpea leaves. Furthermore, Se application above 100 g ha−1 significantly increased the hydrogen peroxide concentration and lipid peroxidation inducing necrotic leaf lesions. Mapping of the elements in leaves using the XRF revealed high Se intensity, specifically in leaf necrotic lesions accompanied by calcium (Ca) as a possible attenuating mechanism of plant stress. The distribution of Se intensities in the seeds was homogeneous, without specific accumulation sites. Phosphorus (P) and sulfur (S) were found primarily located in the embryonic region. Understanding the factors involved in Se accumulation and its interaction with Ca support new preventive measurement technologies to prevent Se toxicity in plants. Graphical abstract: Benefit and harmful effects of selenium to cowpea plants. Image 1 • Leaf chlorosis with necrotic spots is the main symptoms of Se toxicity in cowpea plants treated with 100 g Se ha-1. • Se distribution in the grain is homogeneous while P and S located in the embryo. • Foliar application of 50 g Se ha-1 increase the concentration of photosynthetic pigments and yield. • X-ray fluorescence (XRF) is an excellent tool for characterizing the toxicity and Se distribution in grains. [ABSTRACT FROM AUTHOR]

Selenium (Se) is considered a beneficial element to higher plants based on its regulation of antioxidative system under abiotic or biotic stresses. However, the limit of beneficial and toxic physiological effects of Se is very narrow. In the present study, the antioxidant performance, nutritional composition, long-distance transport of Se, photosynthetic pigments, and growth of Coffea arabica genotypes in response to Se concentration in solution were evaluated. Five Coffea arabica genotypes (Obatã, IPR99, IAC125, IPR100 and Catucaí) were used, which were grown in the absence and presence of Se (0 and 1.0 mmol L−1) in nutrient solution. The application of 1 mmol L−1 Se promoted root browning in all genotypes. There were no visual symptoms of leaf toxicity, but there was a reduction in the concentration of phosphorus and sulfur in the shoots of plants exposed to high Se concentration. Except for genotype Obatã, the coffee seedlings presented strategies for regulating Se uptake by reducing long-distance transport of Se from roots to shoots. The concentrations of total chlorophyll, total pheophytin, and carotenoids were negatively affected in genotypes Obatã, IPR99, and IAC125 upon exposure to Se at 1 mmol L−1. H 2 O 2 production was reduced in genotypes IPR99, IPR100, and IAC125 upon exposure to Se, resulting in lower activity of superoxide dismutase (SOD), and catalase (CAT). These results suggest that antioxidant metabolism was effective in regulating oxidative stress in plants treated with Se. The increase in sucrose, and decrease in SOD, CAT and ascorbate peroxidase (APX) activities, as well as Se compartmentalization in the roots, were the main biochemical and physiological modulatory effects of coffee seedlings under stress conditions due to excess of Se. • Excess Se does not cause visual toxicity in leaves of coffee seedlings. • Se increased the antioxidant metabolism and sugars compounds. • There was a genotypic variation of coffee plants for Se toxicity. • Sugars associated with antioxidant enzymes are effective biomarkers for Se toxicity in coffee plants. [ABSTRACT FROM AUTHOR]

Selenium (Se) at low concentration is considered benefit element to plants. The range between optimal and toxic concentration of Se is narrow and varies among plant species. This study aimed to evaluate the phenotypic, physiological and biochemical responses of four rice genotypes (BRS Esmeralda, BRSMG Relâmpago, BRS Bonança and Bico Ganga) grown hydroponically treated with sodium selenate (1.5 mM L−1). Selenium treated plants showed a dramatically decrease of soluble proteins, chlorophylls, and carotenoids concentration, resulting in the visual symptoms of toxicity characterized as leaf chlorosis and necrosis. Selenium toxicity caused a decrease on shoot and root dry weight of rice plants. Excess Se increased the oxidative stress monitored by the levels of hydrogen peroxide and lipid peroxidation. The enzymatic antioxidant system (catalase, superoxide dismutase, and ascorbate peroxidase) increased in response to Se supply. Interestingly, primary metabolism compounds such as sucrose, total sugars, nitrate, ammonia and amino acids increased in Se-treated plants. The increase in these metabolites may indicate a defense mechanism for the osmotic readjustment of rice plants to mitigate the toxicity caused by Se. However, these metabolites were not effective to minimize the damages on phenotypic traits such as leaf chlorosis and reduced shoot and root dry weight in response to excess Se. Increased sugars profile combined with antioxidant enzymes activities can be an effective biomarkers to indicate stress induced by Se in rice plants. This study shows the physiological attributes that must be taken into account for success in the sustainable cultivation of rice in environments containing excess Se. • Excess Se causes visual phytotoxicity in rice plants characterized as chlorosis. • Se increased the antioxidant metabolism, sugars and nitrogen compounds. • There was a genotypic variation of rice plants for Se toxicity. • Sugars associated with antioxidant enzymes are effective biomarkers for Se toxicity in rice plants. [ABSTRACT FROM AUTHOR]

Selenium (Se) is an essential element for human and animal, although considered beneficial to higher plants. Selenium application at high concentration to plants can cause toxicity decreasing the physiological quality of seeds. This study aimed to characterize the Se toxicity on upland rice yield, seed physiology and the localization of Se in seeds using X-ray fluorescence microanalysis (μ-XRF). In the flowering stage, foliar application of Se (0, 250, 500, 1000, 1500, 2000 g ha−1) as sodium selenate was performed. A decrease in rice yield and an increase in seed Se concentrations were observed from 250 g Se ha−1. The storage proteins in the seeds showed different responses with Se application (decrease in albumin, increase in prolamin and glutelin). There was a reduction in the concentrations of total sugars and sucrose with the application of 250 and 500 g Se ha−1. The highest intensities Kα counts of Se were detected mainly in the endosperm and aleurone/pericarp. μ-XRF revealed the spatial distribution of sulfur, calcium, and potassium in the seed embryos. The seed germination decreased, and the electrical conductivity increased in response to high Se application rates showing clearly an abrupt decrease of physiological quality of rice seeds. This study provides information for a better understanding of the effects of Se toxicity on rice, revealing that in addition to the negative effects on yield, there are changes in the physiological and biochemical quality of seeds. • Foliar Se application above 250 g ha-1decrease rice yield and physiological seed quality. • The highest Kα counts of Se were detected mainly in the endosperm and aleurone/pericarp. • Sulfur accumulation occurred in the same tissues and in the embryo region. • The μ-XRF was a great technique to map the distribution of Se in rice seeds. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) contamination has generated an environmental problem worldwide, leading to harmful effects on human health and damages to plant metabolism. Selenium (Se) is non essential for plants, however it can improve plant growth and reduce the adverse effects of abiotic stress. In addition, ethylene may interplay the positive effects of Se in plants. In order to investigate the role of ethylene in Se-modulation of antioxidant defence system in response to Cd-stress, we tested the hormonal mutant Epinastic (epi) with a subset of constitutive activation of the ethylene response and Micro-Tom (MT) plants. For this purpose, Se mineral uptake, Cd and Se concentrations, pigments, malondialdeyde (MDA) and hydrogen peroxide (H 2 O 2) contents, ethylene production, glutathione (GSH) compound, and superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-Px) activities were analysed in MT and epi plants submitted to 0.5 mM CdCl 2 and 1 μM of selenate or selenite. MT plants treated with both Se forms increased growth in the presence or not of 0.5 mM CdCl 2 , but not change epi growth. Both Se forms reduced Cd uptake in MT plants and cause reverse effect in epi plants. P, Mg, S, K and Zn uptake increased in epi plants with Se application, irrespective to Cd exposure. Chlorophylls and carotenoids contents decreased in both genotypes under Cd exposure, in contrast to what was observed in epi leaves in the presence of Se. When antioxidant enzymes activities were concerned, Se application increased Mn-SOD, Fe-SOD and APX activities. In the presence of Cd, MT and epi plants exhibited decreased SOD activity and increased CAT, APX and GR activities. MT and epi plants with Se supply exhibited increased APX and GR activities in the presence of Cd. Overall, these results suggest that ethylene may be involved in Se induced-defence responses, that triggers a positive response of the antioxidant system and improve growth under Cd stress. These results showed integrative roles of ethylene and Se in regulating the cell responses to stressful-conditions and, the cross-tolerance to stress could be used to manipulate ethylene regulated gene expression to induce heavy metal tolerance. Image 1 • Selenium (Se) induced different responses in Cd stress-attenuation and growth between MT and epi plants. • Epi plants showed reduced Cd absorption and increased nutrient uptake with Se application. • MT and epi plants with Se supply exhibited increased APX and GR activities in the presence of Cd. • Ethylene is involved in Se induced-defence responses that triggers an improvement in antioxidant system under Cd stress. • Integrative roles of ethylene and Se regulates responses to Cd stress. [ABSTRACT FROM AUTHOR]