Tolerance of Plants to Toxicity Induced by Micronutrients

Micronutrient elements such as zinc, boron copper, iron, manganese, molybdenum, and chlorine are frequently responsible by the regulatory activity of the cell organelles, being nutrients that are absorbed and found in lower concentrations in plant tissues, they also contribute to supply the nutritional exigency of the plant. Study with Zea mays plants exposed to Zn toxicity + Si presented significant increases in stomatal conductance, net photosynthetic rate, transpiration rate, and water use efficiency, respectively, in comparison with treatment only with Zn. In relation to chlorophylls a, b and total and carotenoids presented non-significant increases, when compared to plants exposed to Zn toxicity. This study revealed the positive contribution of the Si on gas exchange and reduction of the negative effects provoked on chlorophylls and carotenoids in maize plants under Zn toxicity. Other results described that prolonged exposure to excessive Cu resulted in serious toxic effects on the rice seedlings. In contrast, Tre pretreatment has been shown to be beneficial in alleviating Cu toxicity, which was mainly attributed to the ability of Tre to restrict Cu uptake and accumulation to maintain Cu homeostasis, and to induce production of antioxidant and Gly enzymes to alleviate excessive Cu-triggered oxidative stress. Stress caused by the excessive supply of micronutrients to plants frequently promotes repercussions on oxidant system, inducing the overproduction of reactive oxygen species. The oxidative damage is a situation characterized by the large ROS accumulation and insufficient detoxification promoted by antioxidant enzymes, such as catalase and glutathione peroxidase. Different mechanisms have been proposed to explain the tolerance of plants to toxicity induced by micronutrients, as uses of other elements and substances, in which it can positively act with specific transporters, metal ion homeostasis and compartmentalization of micronutrients into the vacuole

Boron Supply and Water Deficit Consequences in Young Paricá (Schizolobium parahyba var. amazonicum) Plants

Boron (B) is a very important nutrient required by forest plants; when supplied in adequate amounts, plants can ameliorate the negative effects of abiotic stresses. The objective of this study was to (i) investigate gas exchange, (ii) measure oxidant and antioxidant compounds, and (iii) respond how B supply acts on tolerance mechanism to water deficit in young Schizolobium parahyba plants. The experiment employed a factorial that was entirely randomised, with two boron levels (25 and 250 µmol L-1, simulating conditions of sufficient B and high B, respectively) and two water conditions (control and water deficit). Water deficit induced negative modifications on net photosynthetic rate, stomatal conductance and water use efficiency, while B high promoted intensification of the effects on stomatal conductance and water use efficiency. Hydrogen peroxide and electrolyte leakage of both tissues suffered non-significant increases after B high and when applied water deficit. Ascorbate levels presented increases after water deficit and B high to leaf and root. Our results suggested that the tolerance mechanism to water deficit in young Schizolobium parahyba plants is coupled to increases in total glutathione and ascorbate aiming to control the overproduction of hydrogen peroxide and alleviates the negative consequences on electrolyte leakage and gas exchange. In relation to B supply, this study proved that sufficient level promoted better responses under control and water deficit conditions

Effect of phosphite supply in nutrient solution on yield, phosphorus nutrition and enzymatic behavior in common bean (Phaseolus vulgaris L.) plants

Abstract Aim of this study was to (i) understand the phosphite action used as P source on growth and grain yield, (ii) measure P concentration and accumulation in shoot and root, and (iii) evaluate enzymatic behaviour in common bean (Phaseolus vulgaris L.) plants grown in nutrient solution under phosphate starvation. Experimental design was completely randomised with 7 levels of phosphite (0, 16, 32, 64, 128, 256 and 512 µM) and 2 levels of phosphate (80 and 800 µM, corresponding to phosphate-starved plants and phosphatesufficient plants, respectively) in nutrient solution. Common bean plants were evaluated at 2 different growth stages: flowering and mature grain stages. For plants harvested at the mature grain stage, two more treatments (additional treatments) were added: -P = no P supply in nutrient solution; and +Phi = all the P (800 µM) from nutrient solution was supplied only as Phi. This study revealed that growth and grain yield in plants grown under phosphate starvation presented negative repercussions on these parameters, in which treatments with 64, 128, 256 and 512 µM of phosphite resulted in no-filled grains. Concentration and accumulation of P in shoot and root of phosphate-starved plants was increased with increasing phosphite levels in nutrient solution, but this additional P concentration did not convert into grain yield. The phosphite application in phosphate-starved plants promoted a decrease in acid phosphatase (EC 3.1.3.4.1) activity, while catalase (EC 1.11.1.6) activity was increased up to 32 µM of phosphite and was reduced at higher levels of phosphite

Corrigendum to: Advancement of Nitrogen Fertilization on Tropical Environmental

The nitrogen (N) fertilization synthetic or biological is primordial for food production worldwide. The consumption of N fertilizers in agricultural systems increased in exponential scale, mainly in developing countries. However, some negative points are associated to industrial N consumption; consequently the industry promoted ways to minimize N losses in production systems of tropical agriculture. Biological nitrogen fixation is a very important natural and sustainable process for the growth of leguminous plants, in which many micronutrients are involved, mainly as enzyme activators or prosthetic group. However, other mechanisms in the rhizosphere and molecular region still need to be clarified. Therefore, the aim of this chapter is to compile information about the historical and current affairs about the advances in N fertilization in tropical environments through a history from N fertilization worldwide, N balance in the main agricultural systems, introduction of alternative ways to avoid N losses, advances between BNF and micronutrients, as well as the effects of N absence in plant metabolisms. Biological nitrogen fixation is a very important natural process for the growth of leguminous plants, in addition many metallic nutrients, micronutrients, are involved in BNF metabolism, mainly as enzyme activators or prosthetic group. But other mechanisms in the rhizosphere and molecular region still need to be clarified

Proline but not Glutathione Actively Participates in the Tolerance Mechanism of Young <i>Schizolobium parahyba</i> var. <i>amazonicum </i> Plants Exposed to Boron Toxicity

Glutathione, a peptide frequently associated with the antioxidant mechanism of plants against reactive oxygen species, and proline, an amino acid whose function is related to cellular homeostasis, can both contribute to improve plant tolerance under situations of abiotic stress, such as boron toxicity. Aims of this research were to (i) quantify the oxidant and antioxidant compounds, (ii) evaluate the photosynthetic pigments, (iii) determine amino acids and PRO, and (iv) determine whether GSH and PRO contribute to the tolerance mechanisms in young Schizolobium parahyba var. amazonicum plants under B toxicity. This experiment tested five boron levels (25, 50, 100, 150 and 250 µM B), being evaluated physiological and biochemical variables. The values reported to proline levels presented significant variation for treatments with 50, 100, 150 and 250 µM B, with increases for the 150 and 250 µM B levels, being 45.2 and 52.4%, respectively. This study found that boron toxicity promoted similar behaviours in both the leaves and root, which included progressive increases in hydrogen peroxide, electrolyte leakage, amino acids and proline, and decreases in total glutathione, chlorophyll a, chlorophyll b and total chlorophyll, confirming that proline but not glutathione actively participates in the tolerance mechanism of young Schizolobium parahyba plants exposed to boron toxicity

How Different Na⁺ Concentrations Affect Anatomical, Nutritional Physiological, Biochemical, and Morphological Aspects in Soybean Plants: A Multidisciplinary and Comparative Approach

Soybean is a legume widely cultivated globally for its seeds, which are rich in oil and protein suitable for animal and human nutrition, and as a biofuel source. One of the main factors that limits production is soil salinity; currently there are an estimated 800 million hectares of agricultural land affected by salt stress worldwide. The aim of this research was to determine whether anatomical, morphological, nutritional, physiological, and biochemical parameters are negatively affected in soybean plants cultivated under different levels of salt stress. The experiment was randomized into five treatments (0, 50, 100, 150, and 200 mM Na+). Plants subjected to concentrations of 50 to 200 mM Na+ exhibited reductions in K (range 21% to 57%), Ca (range 38% to 63%), and Mg (range 20% to 41%) compared to controls (without Na+). Na+ stress progressively produced negative effects on photosynthetic machinery, gas exchange, and photosynthetic pigments, results clearly related to oxidative stress generated by the saline growth conditions. Interestingly, our study revealed that at concentrations up to 100 mM Na+ deposition of epicuticular wax occurred, the quantity and shape of the stomata changed, and the thickness of the leaf epidermis increased. Our broad-based, multidisciplinary, and comparative study proved that soybean plants suffer significant deleterious effects modulated by Na+ stress, mainly at concentrations above 100 mM Na+

Flúor: elemento potencialmente tóxico para plantas, animais e seres humanos.

The objective of this literature review demonstrates the negative action of fluoride as a toxic component in air, soil, plants and animals. Fluoride occurs naturally in the earth's crust, such as trace element in certain rocks and in the biosphere, with extreme reactivity. Some fluorine compounds such as elementary fluorine and hydrogen fluoride are much toxic and less found in the environment. One of the important aspects of this element is the F emission sources in the atmosphere, which are mainly aluminum industries, ceramics and fertilizers, the latter during the process of production of superphosphate. In soil it can be observed chemical effects caused by fluoride pollution before harming other organisms, thereby interfering indirectly on soil properties. The natural concentration of this element is 1m g kg-1. Fluoride is absorbed from the atmosphere by plants, especially by the leaves. In areas without emission of fluorine plants typically contain less than 10 mg kg-1 F in plant tissue. The gaseous fluoride penetrates the leaf tissue primarily through stomata, but also to a lesser extent through the cuticle and lenticels of branching. In mesophyll it migrates with the transpiration stream to the areas of leaf evaporation. In literature there are some reports on the behavior of F in the soil and the factors that influence its dynamics and how plants respond to certain concentrations of fluoride in their tissues, and some species that can be considered as bioindicators or pollution.Objetiva-se com esta revisão de literatura demostrar a ação negativa do flúor como componente tóxico na atmosférica, solo, planta e animais. O flúor ocorre naturalmente na crosta terrestre, como elemento traço em certas rochas e na biosfera, apresentando extrema reatividade. Alguns compostos de flúor, como flúor elementar e o fluoreto de hidrogênio, são muito tóxicos e menos encontrados no ambiente. Um dos aspectos importante sobre esse elemento são as fontes de emissão de F na atmosfera, que são principalmente as indústrias de alumínio, cerâmicas e fertilizantes, esta última durante o processo de produção dos superfosfatos. No solo são observados efeitos químicos causados pela poluição por flúor antes mesmo de ocorrer malefícios a outros organismos, interferindo assim de maneira indireta nas propriedades do solo. A concentração natural desse elemento encontra-se é 1m g kg-1 O flúor é absorvido da atmosfera pelas plantas, principalmente, pelas folhas. Em áreas sem emissão de flúor as plantas contêm, normalmente, menos de 10 mg kg-1 de F no tecido vegetal. O flúor em forma gasosa penetra no tecido foliar, sobretudo, através dos estômatos, mas também, em menor proporção, através da cutícula e lenticelas de ramificações. No mesofilo, migra com a corrente de transpiração para as zonas foliares de evaporação. Na literatura há alguns relatos sobre o comportamento do F no solo e os fatores que influenciam na sua dinâmica e como as plantas respondem a certas concentrações de flúor nos seus tecidos, assim algumas espécies que podem ser consideradas como plantas bioindicadoras ou de poluição

Impacts of soybean agriculture on the resistome of the Amazonian soil

Funded National Research Council (CNPq), Alliance Program for Education and Training—PAEC-OEA-GCUB 2017, within the scope of the Cooperation Agreement between the Organization of American States (OAS) and the Coimbra Group of Brazilian Universities (CGUB) and L’Oréal Brasil-UNESCOABC For Women in Science.Federal University of Pará. Institute of Biological Sciences. Center of Genomics and System Biology. Laboratory of Genomic and Bioinformatics. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Center of Genomics and System Biology. Laboratory of Genomic and Bioinformatics. Belém, PA, Brazil.Federal University of Minas Gerais. Institute of Biological Sciences. Belo Horizonte, MG, Brazil.Federal Rural University of the Amazon. Department of Soil Science. Paragominas, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Center of Genomics and System Biology. Laboratory of Genomic and Bioinformatics. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Pará. Institute of Biological Sciences. Center of Genomics and System Biology. Laboratory of Genomic and Bioinformatics. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Pará. Institute of Biological Sciences. Center of Genomics and System Biology. Laboratory of Genomic and Bioinformatics. Belém, PA, Brazil / Federal University of Minas Gerais. Institute of Biological Sciences. Belo Horizonte, MG, Brazil.Federal University of Pará. Institute of Biological Sciences. Center of Genomics and System Biology. Laboratory of Genomic and Bioinformatics. Belém, PA, Brazil.The soils of the Amazon are complex environments with different organisms cohabiting in continuous adaptation processes; this changes significantly when these environments are modified for the development of agricultural activities that alter the chemical, macro, and microbiological compositions. The metagenomic variations and the levels of the environmental impact of four different soil samples from the Amazon region were evaluated, emphasizing the resistome. Soil samples from the organic phase from the different forest, pasture, and transgenic soybean monocultures of 2–14 years old were collected in triplicate at each site. The samples were divided into two groups, and one group was pre-treated to obtain genetic material to perform sequencing for metagenomic analysis; another group carried out the chemical characterization of the soil, determining the pH, the content of cations, and heavy metals; these were carried out in addition to identifying with different databases the components of the microbiological communities, functional genes, antibiotic and biocide resistance genes. A greater diversity of antibiotic resistance genes was observed in the forest soil. In contrast, in monoculture soils, a large number of biocide resistance genes were evidenced, highlighting the diversity and abundance of crop soils, which showed better resistance to heavy metals than other compounds, with a possible dominance of resistance to iron due to the presence of the acn gene. For up to 600 different genes for resistance to antibiotics and 256 genes for biocides were identified, most of which were for heavy metals. The most prevalent was resistance to tetracycline, cephalosporin, penam, fluoroquinolone, chloramphenicol, carbapenem, macrolide, and aminoglycoside, providing evidence for the co-selection of these resistance genes in different soils. Furthermore, the influence of vegetation cover on the forest floor was notable as a protective factor against the impact of human contamination. Regarding chemical characterization, the presence of heavy metals, different stress response mechanisms in monoculture soils, and the abundance of mobile genetic elements in crop and pasture soils stand out. The elimination of the forest increases the diversity of genes for resistance to biocides, favoring the selection of genes for resistance to antibiotics in soils

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications