Hydrogen peroxide,iodine solution and methylene solution highly enhance the hatching rate of freshwater ornamental fish species     

João Chambel  Ricardo Costa  Mónica Gomes  Susana Mendes  Teresa Baptista  Rui Pedrosa 《Aquaculture International》2014,22(6):1743-1751

The aim of this study was to evaluate the effect of hydrogen peroxide, iodine solution (PVP) and methylene blue on eggs disinfection of three ornamental fish species, Danio rerio, Pterophyllum scalare and Gymnocorymbus ternetzi. The main idea was to create conditions to enhance the hatching rates. Eggs of each species were exposed to different concentrations of hydrogen peroxide (5, 10, 15 and 25 mg/L), PVP (0.25, 0.5, 0.75 and 1 mg/L) and methylene blue (0.5 1, 2 and 3 mg/L). The optimal doses ranged between species and chemicals: for G. ternetzi, the concentrations that high enhanced the hatching rate were 1 mg/L for the PVP treatment, 25 mg/L for the hydrogen peroxide treatment and 3 mg/L for methylene blue treatment; for P. scalare, the best results were achieved with 25 mg/L for hydrogen peroxide treatment and 3 mg/L for methylene blue treatment. By contrast, for all the different chemical did not increased the D. rerio hatching rate. Results showed that hydrogen peroxide and methylene blue are the most versatile, effective and safe to use in these species. On the other hand, PVP can be used but with many precautions due to very low safety margin. Results clearly show that the optimal concentration of chemicals for eggs disinfection is fish species dependent and it is completely wrong to extrapolate concentrations between different chemicals and fish species. Our study suggests that P. scalare can be used as a model in study of effectiveness of new chemicals with potential to disinfect water and increase hatching rates.  相似文献   

Biomass and Accumulation of Potassium,Calcium, and Magnesium in Gladiolus as Affected by Heat Units and Corm Size     

Lucina Gómez-Pérez  Martín Cadena-Zapata  Donita L. Cartmill  Andrew D. Cartmill  Adalberto Benavides-Mendoza 《Communications in Soil Science and Plant Analysis》2018,49(3):344-357

In México, gladiolus is an important crop cultivated in the central part of the country. In ornamental geophytes, the size of bulbs is a critical factor, impacting plant growth and quality. The objective of the present study was to model the accumulation of potassium (K), calcium (Ca) and Magnesium (Mg) in gladiolus plants as affected by corm size (3.5, 3.0 and 2.5 cm). Regardless of corm size, total dry mass of plants accumulated in three different stages. The initial stage occurred during the corm sprouting phase and continued through the vegetative phase, ending either shortly before (plants from 3.5 cm corms), at (plants from 3.0 cm corms) or shortly after (plants from 2.5 cm corms) the heading phase. The second stage, on which the plants exhibited a rapid dry mass accumulation, occurred shortly before or shortly after the heading phase, finishing with the elongation of the flowering stem. The third stage showed the highest dry mass accumulation rate, coinciding with the elongation of the flowering stem and ending at the blooming of the spike. To complete all the phenological phases, gladiolus required 1818 heat units regardless of corm size. Not considering the nutrients provided by the corm, gladiolus required a total of 6.33, 5.59 and 5.01 mmol plant^?1 of K, 2.22, 1.69 and 1.38 mmol plant^?1 of Ca and 2.49, 2.00 and 1.68 mmol plant^?1 of Mg when grown from 3.5, 3.0, and 2.5 cm corms. At the beginning of the vegetative phase, plants tended to increase Ca content at the expense of K, whereas the proportion of Mg remained unaffected, however, between the vegetative and heading phases, the proportion of Ca declined while that of K and Mg increased. At the end of the study, the proportion of K was much higher than that of Ca and Mg, whereas the proportion of Ca and Mg was similar.  相似文献   

Nitrogen mineralization indicators under semi-arid and semi-humid conditions: influence on wheat yield and nitrogen uptake     

Juan M. Martínez  Juan A. Galantini  Matías E. Duval  María Rosa Landriscini  Ramiro J. García  Fernando López 《Communications in Soil Science and Plant Analysis》2018,49(15):1907-1921

The objectives were i) to assess indicators for potential nitrogen (N) mineralization and ii) to analyze their relationships for predicting winter wheat (Triticum aestivum L.) growth parameters (yield and N uptake, N_up) in Mollisols of the semi-arid and semi-humid region of the Argentine Pampas. Thirty-six farmer fields were sampled at 0–20 cm. Several N mineralization indicators, wheat grain yield and N_up at physiological maturity stage were assessed. A principal component (PC) analysis was performed using correlated factors to grain yield and N_up. The cluster analysis showed two main groups: high fertility and low fertility soils. In high fertility soils, combining PCs in multiple regression models enhanced the wheat yield and N_up prediction significantly with a high R² (adj R² = 0.71–0.83). The main factors that explained the wheat parameters were associated with water availability and N mineralization indicator, but they differ according to soil fertility.

Abbreviations: N: nitrogen; SOM: soil organic matter; POM: particulate organic matter; SOC: soil organic carbon; SON: soil organic nitrogen; POM-C: particulate organic carbon; POM-N: particulate organic nitrogen; N_an: anaerobic nitrogen; N_hyd: hydrolyzable N; NO₃-N: cold nitrate; N₂₀₅: N determined by spectrometer at 205 nm; N₂₆₀: N determined by spectrometer at 260 nm; Pe: extractable P; N_up: wheat N uptake; NO₃-N: inorganic N in the form of nitrate; FR: fallow rainfalls (March-Seeding rainfall); FLR: flowering rainfalls (October-December rainfall); GFR: grain filling rainfall (November rainfall); CCR: crop growing season rainfall (June-December rainfall); PCA: principal component analysis; PC: principal component; MR: multiple regression  相似文献   

Peroxicoagulation and Solar Peroxicoagulation for Landfill Leachate Treatment Using a Cu–Fe System     

Luis A. Castillo-Suárez  Francisco Bruno-Severo  Violeta Lugo-Lugo  Mario Esparza-Soto  Verónica Martínez-Miranda  Ivonne Linares-Hernández 《Water, air, and soil pollution》2018,229(12):385

Leachates, particularly those from mature landfills, are difficult to treat by biological processes because of their high toxicity and low biodegradability. Therefore, the development of new treatment technology is necessary. The treatment of landfill leachate by peroxicoagulation and solar peroxicoagulation using a batch electrolytic reactor with a Fe cathode and a Cu anode is proposed. The tested operational variables included pH (2.8 and 8.2), current density (11 and 16 mA cm^?2), treatment time (5, 10, 15, 20, 25, and 30 min), and presence of solar ultraviolet (UV) light and were collected using a compound parabolic collector. The optimum conditions were a pH, current density, and treatment time of 2.8, 16 mA cm^?2, and 10 min, respectively. The presence of UV did not have a significant effect. The chemical oxygen demand and biochemical oxygen demand removed were 62.3% and 55.5%, respectively. The results of UV-visible absorption, fluorescence, and Fourier transform infrared spectroscopy measurements confirm the oxidation process.  相似文献   

Does the persistence of sweet chestnut depend on cultural inputs? Regeneration,recruitment, and mortality in <Emphasis Type="Italic">Quercus</Emphasis>- and <Emphasis Type="Italic">Castanea</Emphasis>-dominated forests     

Fernando Silla  Álvaro Camisón  Andrea Solana  Héctor Hernández  Guillermo Ríos  Miguel Cabrera  Dámaris López  Albert Morera-Beita 《Annals of Forest Science》2018,75(4):95

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Genetic diversity of the myrtle rust pathogen (Austropuccinia psidii) in the Americas and Hawaii: Global implications for invasive threat assessments          下载免费PDF全文

J. E. Stewart  A. L. Ross‐Davis  R. N. Graҫa  A. C. Alfenas  T. L. Peever  J. W. Hanna  J. Y. Uchida  R. D. Hauff  C. Y. Kadooka  M.‐S. Kim  P. G. Cannon  S. Namba  S. Simeto  C. A. Pérez  M. B. Rayamajhi  D. J. Lodge  M. Arguedas  R. Medel‐Ortiz  M. A. López‐Ramirez  P. Tennant  M. Glen  P. S. Machado  A. R. McTaggart  A. J. Carnegie  N. B. Klopfenstein 《Forest Pathology》2018,48(1)

Since the myrtle rust pathogen (Austropuccinia psidii) was first reported (as Puccinia psidii) in Brazil on guava (Psidium guajava) in 1884, it has been found infecting diverse myrtaceous species. Because A. psidii has recently spread rapidly worldwide with an extensive host range, genetic and genotypic diversities were evaluated within and among A. psidii populations in its putative native range and other areas of myrtle rust emergence in the Americas and Hawaii. Microsatellite markers revealed several unique multilocus genotypes (MLGs), which grouped isolates into nine distinct genetic clusters [C1–C9 comprising C1: from diverse hosts from Costa Rica, Jamaica, Mexico, Puerto Rico, and USA‐Hawaii, and USA‐California; C2: from eucalypts (Eucalyptus spp.) in Brazil/Uruguay and rose apple (Syzygium jambos) in Brazil; C3: from eucalypts in Brazil; C4: from diverse hosts in USA‐Florida; C5: from Java plum (Syzygium cumini) in Brazil; C6: from guava and Brazilian guava (Psidium guineense) in Brazil; C7: from pitanga (Eugenia uniflora) in Brazil; C8: from allspice (Pimenta dioica) in Jamaica and sweet flower (Myrrhinium atropurpureum) in Uruguay; C9: from jabuticaba (Myrciaria cauliflora) in Brazil]. The C1 cluster, which included a single MLG infecting diverse host in many geographic regions, and the closely related C4 cluster are considered as a “Pandemic biotype,” associated with myrtle rust emergence in Central America, the Caribbean, USA‐Florida, USA‐Hawaii, Australia, China‐Hainan, New Caledonia, Indonesia and Colombia. Based on 19 bioclimatic variables and documented occurrences of A. psidii contrasted with reduced sets of specific genetic clusters (subnetworks, considered as biotypes), maximum entropy bioclimatic modelling was used to predict geographic locations with suitable climate for A. psidii which are at risk from invasion. The genetic diversity of A. psidii throughout the Americas and Hawaii demonstrates the importance of recognizing biotypes when assessing the invasive threats posed by A. psidii around the globe.  相似文献   

Considering neighborhood effects improves individual dbh growth models for natural mixed-species forests in Mexico     

Gerónimo Quiñonez-Barraza  Dehai Zhao  Héctor M. De Los Santos Posadas  José J. Corral-Rivas 《Annals of Forest Science》2018,75(3):78

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When the ground cover brings guests: is <Emphasis Type="Italic">Anaphothrips obscurus</Emphasis> a friend or a foe for the biological control of <Emphasis Type="Italic">Tetranychus urticae</Emphasis> in clementines?     

María Antonia Gómez-Martínez  Josep A. Jaques  María Victoria Ibáñez-Gual  Tatiana Pina 《Journal of pest science》2018,91(2):613-623

Biological control of Tetranychus urticae Koch (Acari: Tetranychidae), a key pest of clementines, can be improved in this crop with the establishment of a ground cover of Festuca arundinacea Schreber (Poaceae). This cover houses an abundant and diverse community of predatory Phytoseiidae mites including Euseius stipulatus (Athias-Henriot), Neoseiulus barkeri Hughes, Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot and a dense population of the grass thrips Anaphothrips obscurus Müller (Thysanoptera: Thripidae) throughout the year. The aim of this study was to determine whether the presence of this thrips species could be related to the improvement in the biological control of T. urticae. Therefore, the capacity of the abovementioned phytoseiids to feed and reproduce on A. obscurus and their feeding preferences when T. urticae and A. obscurus were simultaneously offered, were analyzed. The results show that E. stipulatus, N. barkeri and N. californicus have a type II functional response when offered A. obscurus nymphs, whereas P. persimilis barely feeds on this thrips species. Furthermore, N. barkeri and N. californicus can reproduce feeding only on thrips. Regarding prey preference, the Tetranychus spp.-specialist P. persimilis preferably preyed on T. urticae, the generalists N. barkeri and E. stipulatus preferred A. obscurus, and the selective predator of tetranychid mites N. californicus showed no preference. Therefore, we hypothesize that the enhanced biological control of T. urticae observed could be related to A. obscurus becoming an alternative prey for non-specialist phytoseiids, without altering the control exerted by the T. urticae-specialist P. persimilis and likely reducing intraguild predation.  相似文献   

Geographic variation in pheromone component ratio and antennal responses,but not in attraction,to sex pheromones among fall armyworm populations infesting corn in Mexico   总被引：2，自引：0，他引：2  

Samuel Cruz-Esteban  Julio C. Rojas  Daniel Sánchez-Guillén  Leopoldo Cruz-López  Edi A. Malo 《Journal of pest science》2018,91(3):973-983

The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is one of the most important pests of corn in Latin America. This insect presents two strains with behavioural and genetic differences. In Mexico, both strains are present, and at least two different FAW populations have been reported within the corn-strain. The objective of this study was to gather evidence of whether pheromonal communication varies among different S. frugiperda populations infesting corn in Mexico. First, we investigated any qualitative or quantitative difference in the composition of sex pheromones among populations; second, we studied whether male antennal responses to pheromone components vary among populations; and, finally, we investigated whether males from a region can discriminate between a synthetic pheromone blend characteristic of their region and blends formulated with the ratio of pheromone compounds emitted by females from other populations. Sex pheromone components were sampled by solid-phase microextraction and identified by gas chromatography coupled to mass spectrometry. Females from all populations consistently released three compounds: (Z)-9-tetradecenyl acetate (Z9-14:OAc), (Z)-11-hexadecenyl acetate (Z11-16:OAc) and (Z)-7-dodecenyl acetate (Z7-12:OAc). Our results showed that Z9-14:OAc and Z7-12:OAc evoked the highest and most variable antennal responses among the populations studied compared to Z11-16:OAc. However, males did not discriminate between local pheromone blends and those formulated from other populations in a field test. These results show that although there is geographic variation in the ratio of pheromone components and in the peripheral reception of them, males were not differentially attracted to different pheromone blends in the field.  相似文献   

Analysis of tree interactions in a mixed Mediterranean pine stand using competition indices   总被引：1，自引：1，他引：0  

Nicolás Cattaneo  Andrés Bravo-Oviedo  Felipe Bravo 《European Journal of Forest Research》2018,137(1):109-120

Studying species interactions in mixed forests allows us to assess their potential benefits and adapt current silvicultural tools developed in monospecific stands to multi-specific stands. We analyzed tree interactions in a Pinus halepensis Mill. and Pinus pinea L. mixed plantation using individual tree neighborhood models and competition indices that accounted for symmetric and asymmetric competition, to analyze whether the growth of each species was better explained by symmetric or asymmetric competition. We also split the competition indices into their intra- and interspecific forms, to test for competition effects on growth change based on competitor identity. Finally, we analyzed whether P. halepensis and P. pinea trees had different growth responses to competition. When calculating competition indices, we explored how spatial information and size of competitor trees contributed to the quantification of the process. Competition measurements were optimized to more precisely describe interactions. Results showed that the inclusion of competition indices generated important improvements in growth models. The main mode of competition was symmetric, which could be related to water restrictions typical of the Mediterranean climate. Considering competitor identity did not improve the growth models, while measurement without discriminating competitors by species generated more parsimonious models. P. halepensis and P. pinea trees had similar growth responses to competition, indicating that the two species cope with competition in similar ways. However, P. pinea showed lower average growth than P. halepensis in the period analyzed. Results suggest that preventing the onset of intense interspecific competition processes could help slow down the long-term replacement of P. pinea by P. halepensis and could have benefits for silvicultural management in systems with two species that share ecological niches but are capable of generating different goods and services.  相似文献