Nitrogen dynamics in soil solution under different land uses: Atlantic forest and cacao–cabruca system     

Jéssica Carneiro de Souza  Marilane Andrade Pereira  Eline Nayara Dantas da Costa  Daniela Mariano Lopes da Silva 《Agroforestry Systems》2018,92(2):425-435

In the southern region of Bahia, a large portion of the Atlantic Forest was occupied by the cacao–cabruca system, which is implemented after the complete removal of the understory vegetation without altering the canopy. The objective of this study was to determine the nitrogen concentration in the soil solution in two micro-basins; one with the cacao–cabruca system and one in the Atlantic forest in the southern region of the state of Bahia. Samples were collected weekly during two periods, from September to December 2012 and from April to June 2013, using sample extractors installed in the micro-basins at 15, 45 and 90 cm. The inorganic forms in the soil solutions were analyzed through ion chromatography, total nitrogen was analyzed using spectrophotometry and mineralization and nitrification rates were analyzed using the laboratory incubation method. Among the nitrogen forms analyzed in the cacao–cabruca soil solution, the dissolved organic nitrogen prevailed among the rain classes in the three depths. In the forest, nitrate predominated at 15 cm, while the organic nitrogen prevailed in the other depths. The highest mineralization and nitrification rates were recorded in the forest. Of the inorganic nitrogen forms analyzed in the soil, ammonium concentrations showed higher rates than nitrate in both areas. Low inorganic nitrogen concentrations in the cabruca soil solution are associated with low mineralization and nitrification rates. Thus we can conclude that even if some studies point towards the environmental efficiency of this system, there are differences in the N forms in the forest and cacao–cabruca areas.  相似文献   

The Effect of Contrasting Moistening Regimes on CO<Subscript>2</Subscript> Emission from the Gray Forest Soil under a Grass Vegetation and Bare Fallow     

V. O. Lopes de Gerenyu  I. N. Kurganova  D. A. Khoroshaev 《Eurasian Soil Science》2018,51(10):1200-1213

The effect of contrasting moisture regimes on the CO₂ emission from the gray forest soils (Haplic Luvisols (Loamic, Cutanic, Humic)) under a grass vegetation and bare fallow was studied in a field simulation experiment in June–September, 2015 (Moscow region). Two short soil droughts (53 and 34 days) and a long one (94 days) were simulated on plots isolated from precipitation. A variant with regular irrigation, where the soil moisture was maintained 60–70% of their water holding capacity, was used as a control. Over the whole observation period, the CO₂ emissions from the soils studied decreased by a factor of 1.8 compared to the control only in the variant with the grass vegetation under prolonged drought. During the first hours after irrigation of the dry plots, the soil respiration intensified due to the “Birch effect”. The magnitude of this effect was 84–104% in the soils under the grass vegetation and 114–133% in the fallow areas. Owing to this phenomenon, the total CO₂ emission from the soils subjected to two short droughts was equal to the CO₂ flux under regular moistening for the grass plots and exceeded it by almost 1.3 times for the fallow plots as compared to the control. However, the share of extra CO₂ flux induced by moistening of the dry soils did not exceed 8–10% of the total CO₂ emission over the whole observation period.  相似文献   

Estimated Reduction in Solids During Sheep Bedding Composting as a Function of the Composition of the Organic Fractions     

Marco Antonio Previdelli Orrico Junior  Ana Carolina Amorim Orrico  Débora Maurício Manarelli  Walter Renato Teixeira Lopes  Alice Watte Schwingel 《Compost science & utilization》2018,26(2):91-97

The different organic matter fractions of residues significantly impact the degradability of organic material in composting windrows. Based on that, this study aimed to find out the organic matter fractions that most impact the breakdown rate during composting, besides proposing models to estimate the solids reductions in sheep bedding composting windrows. To that end, 24 sheep beddings from different locations and varied composition were composted so as to ensure the representativeness of the sample. The models found for reduction in total (TS) and volatile (VS) solids as a function of compostable organic matter (COM) and organic matter resistant to composting (OMRC) were not significant. Lignin had correlation coefficients of ?0.6, ?0.89, and ?0.84 in relation to temperature, TS reduction, and VS reduction, respectively. The hemicellulose:lignin ratio was the parameter most correlated with temperature (0.69), TS reduction (0.91), VS reduction (0.92), and nitrogen (0.5), which led to more significant predictive models. It can be concluded that the hemicellulose:lignin ratio is the parameter that most impacts the breakdown of organic matter and nitrogen losses in sheep bedding composting windrows.  相似文献   

Genetic variation and phylogenetic relationships based on RAPD analysis in section Caulorrhizae, genus Arachis (Leguminosae)     

Marcos Aparecido Gimenes  Catalina Romero Lopes  Maria Leticia Galgaro  José Francisco Montenegro Valls  Gary Kochert 《Euphytica》2000,116(3):187-195

Wild Arachis germplasm includes potential forage species, such as the rhizomatous Arachis glabrata and the stoloniferous A. pinto and A. repens. Commercial cultivars of A. pintoi have already been released in Australia and in several Latin American countries, and most of these cultivars were derived from a single accession of A. pintoi (GK 12787). Arachis repens is less productive as a forage plant than is A. pintoi. However, it can be crossed with A. pintoi, and thus has good potential as germplasm for the improvement of A. pintoi. Arachis repens is also used as an ornamental plant and ground cover. Many new accessions of these two stoloniferous species are now available, and they harbor significant genetic variability beyond that available in the few older accessions, previously available. Therefore, these new accessions need to be conserved, documented and considered in terms of their potential for crop improvement and direct commercial use. Sixty-four accessions of this new germplasm were analyzed using RAPD analysis. Most of the accessions of A. repens grouped together into a clearly distinct group. In general, the accessions from the distinct valleys of the Jequitinhonha, São Francisco and Paranã rivers did not group together, suggesting there is not a tight relation between dispersion by rivers and the geographic distribution of genetic variation in these species.  相似文献   

The bone degenerative processes in senile fishes from Holocene Brazilian shell mounds          下载免费PDF全文

O Aguilera  I Rocha  M S Lopes  I Lima  R T Lopes  A S Machado  R B Guimarães  M A C Crapez  M C Tenório  A Nepomuceno 《Journal of fish diseases》2017,40(12):1869-1881

Zooarchaeological collections from shell mounds in Rio de Janeiro (2,470–4,632 cal BP) contain a high prevalence of swollen fish bones belonging to the Atlantic spadefish (Chaetodipterus faber), crevalle jack (Caranx hippos) and fat snook (Centropomus parallelus). Given the lack of knowledge of the bone degenerative process in senile fishes, this study analysed hyperostotic bone in zooarchaeological and modern specimens to obtain high‐resolution morphology and microstructure reconstruction. We used microCT as well as X‐ray diffraction to characterize the crystallographic changes associated with fish senility. Our results showed that trabecular microstructures in hyperostotic bones were consistent with estimated values of the per cent bone volume‐to‐total volume ratio (BV/TV) and were greater than 60% in cortical bone. Hyperostotic bones indicated a high radiograph density, and X‐ray diffractograms showed a decrease in hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂] and calcite (CaCO₃) neocrystallization. These crystalline and density changes revealed an advanced stage of fish senile and indicate the vulnerability of ageing fish populations.  相似文献   

Ultramorphological changes in gill rakers of <Emphasis Type="Italic">Astyanax altiparanae</Emphasis> (Characidae) kept in contaminated environments     

F. P. Lopes  B. F. Pereira  R. M. S. Alves  J. R. T. Valim  F. A. T. Figueiredo  D. L. Pitol  F. H. Caetano 《Fish physiology and biochemistry》2017,43(4):1033-1041

Most water bodies in Brazil, and in the world, are contaminated by some types of pollutants, ranging from sewage to metal/chemicals, carcinogenic products, and biodegradable detergents. Despite the extensive knowledge on their effects on fish biology and especially on gill morphology, research that concerns their impacts on gill rakers and implications in parameters such as food consumption cannot be found in the literature. Gill rakers are vital because, together with gills, they are responsible for the defense and protection of the organism and for selecting appropriate food for survival. When detergents, which can act as toxic chemical agents, get in contact with the body of the fish, they can cause severe effects that must be understood. Therefore, our study investigated ultramorphological changes in gill rakers of Astyanax altiparanae (Lambeth) caused by the exposure to biodegradable detergents. Fish were exposed to a 1 mg/L dilution of a mixture of detergents and pure water from an artesian well for 5 months. Results revealed that the first month of exposure to detergent caused dilation of chemical receptors in taste buds and the rise of a large number of orifices for mucus release among pavement cells in gill rakers, although only a small amount of mucus was found in fish exposed both to pure water and the detergent dilution. After 5 months, there was an increase in the dilation of these chemoreceptors, excess mucus on gill rakers of detergent groups, and the emergence of microbridges between microridges in pavement cells.  相似文献   

Oued Bouhlou: A new hope for the Moroccan pearl mussel          下载免费PDF全文

Ronaldo Sousa  Amílcar Teixeira  André Santos  Hassan Benaissa  Simone Varandas  Mohamed Ghamizi  Vincent Prié  Elsa Froufe  Manuel Lopes‐Lima 《水产资源保护:海洋与淡水生态系统》2018,28(1):247-251

Seaweed Blends as a Valuable Source of Polyunsaturated and Healthy Fats for Nutritional and Food Applications     

Francisca Marques  Diana Lopes  Elisabete da Costa  Tiago Conde  Andreia Rego  Ana Isabel Ribeiro  Maria Helena Abreu  Maria Rosrio Domingues 《Marine drugs》2021,19(12)

Seaweeds are considered healthy and sustainable food. Although their consumption is modest in Western countries, the demand for seaweed in food markets is increasing in Europe. Each seaweed species has unique nutritional and functional features. The preparation of blends, obtained by mixing several seaweeds species, allows the obtaining of maximum benefits and ingredients with single characteristics. In this work, five seaweed blends, commercially available and produced under organic conditions in Europe, were characterized. The proximal composition included contents of ash (20.28–28.68% DW), proteins (17.79–26.61% DW), lipids (0.55–1.50% DW), and total carbohydrates (39.47–47.37% DW). Fatty acid profiles were determined by gas chromatography–mass spectrometry (GC–MS), allowing quantification of healthy fatty acids, namely n-3 and n-6 polyunsaturated fatty acids (PUFA), and calculation of lipid quality indices. Each blend showed a characteristic PUFA content in the lipid pool (35.77–49.43% of total fatty acids) and the content in essential and healthy n-3 PUFA is highlighted. The atherogenicity (0.54–0.72) and thrombogenicity (0.23–0.45) indices evidenced a good nutritional value of lipid fractions. As nutritional and environmentally attractive products, the consumption of the studied seaweed blends can contribute to a healthy lifestyle.  相似文献   

Effect of experimental arginine supplementation on the growth,immunity and resistance of tilapia fingerlings to Streptococcus agalactiae     

Rafael Alves Vianna  Roberta Torres Chideroli  Arthur Roberto da Costa  Oswaldo Pinto Ribeiro Filho  Leandro Licursi de Oliveira  Juarez Lopes Donzele  Eduardo Arruda Teixeira Lanna  Daniela Dib Gonalves  Ulisses de Padua Pereira 《Aquaculture Research》2020,51(3):1276-1283

Streptococcosis causes serious economic losses to fish farms every year. A four‐week feeding trial was carried out to evaluate arginine (ARG) supplementation in the diet of Nile tilapia (Oreochromis niloticus) fingerlings challenged by Streptococcus agalactiae. Fish were fed with experimental diets containing five levels of supplementation with 1.39%, 1.76%, 1.97%, 2.18% or 2.39% analysed level of ARG. Each diet was randomly distributed in 30 tanks containing 20 fish/tank. After 30 days, no differences were observed in performance parameters, weight gain, daily weight gain, specific growth rate, feed intake or food conversion. After the performance assay, fingerlings were infected with 1.95 × 10⁸ CFU/fish of Streptococcus agalactiae. Mortality was verified daily, and the respiratory burst of leucocytes and nitric oxide production were measured at 0 hr, 24 hr, 7 days and 15 days after infection. The survival rate of the fish is compared using the Kaplan–Meier method, with values of 4.29%, 14.8%, 10.8%, 17.2% and 33.3% for the 1.39, 1.76, 1.97, 2.18 and 2.39 treatments respectively. A reduction in the mortality rate and a boost in the immune responses was observed in all the supplementations of ARG in the diet; however, the best survival rates were obtained in the treatments with 2.39% ARG as well as the most efficient immune responses.  相似文献   

Growth,mortality and reproductive traits of diploid and triploid Pacific oysters (Crassostrea gigas,THUNBERG, 1793) in Southern Brazil     

Emílio Mateus Costa Melo  Simone Sühnel  Ana Cristina Santos de Oliveira  Brenda de Oliveira Lopes  Gabriela Costa Bachi  Claudio Manoel Rodrigues De Melo 《Aquaculture Research》2020,51(9):3631-3640

This work aimed to evaluate the whole weight (g), shell height (mm), mortality (%) and reproductive aspects (condition index and histology) of triploid (3N) Pacific oysters (Crassostrea gigas) cultivated in southern Brazil. To accomplish this, a comparative experiment was performed with a diploid (2N) control group in two cultivation sites on Santa Catarina Island: North Bay (NB) and South Bay (SB). Whole weight, height and cumulative mortality were evaluated monthly for eight months and condition index (CI) for six months. Histological analysis was performed every two weeks for four months to investigate reproductive aspects. At the end of the experiment, whole weight and height were similar for 3N and 2N oysters. However, while more growth in whole weight and height was observed in the initial phase of cultivation in NB, such growth was not detected in SB until intermediate and final grow‐out phase. At harvest, cumulative mortality in 3N oysters was similar that in 2N oysters. The results suggest that diploid and triploid oysters grown in southern Brazil have similar developmental patterns based on whole weight and height, as well as reproductive cycle. In addition, cultivation sites have more influence on growth and mortality than ploidy levels.  相似文献