Movement patterns of armado, Pterodoras granulosus, in the Paraná River Basin     

M. C. Makrakis  L. E. Miranda  S. Makrakis  D. R. Fernandez  J. O. Garcia  J. H. P. Dias 《Ecology of Freshwater Fish》2007,16(3):410-416

Abstract –  We studied the migratory behaviour of armado, Pterodoras granulosus , in the Paraná River Basin of Brazil, Paraguay and Argentina, during 1997–2005. This species invaded the Upper Paraná River after upstream dispersal was facilitated when Itaipu Reservoir inundated a natural barrier. Fish were tagged ( N  = 8051) in the mainstems of the Yacyreta and Itaipu reservoirs, bays of major tributaries, the Paraná River floodplain above Itaipu Reservoir, and below dams. In all, 420 fish were recaptured of which 61% moved away from the release area. Fish moved a maximum of 215 km (mean 42), and at a maximum rate of 9.4 km·day⁻¹ (mean 0.6). Of the 256 armados that moved away from the release site, 145 moved upstream towards unimpounded stretches of the Paraná River and 111 moved downstream into the reservoir and bays of its tributaries (maximum 150 km). Based on the observed migratory movements, we suspect that most of the reproductive output originates in tributaries to the reservoirs. The ability of this species to expand its range presents a conundrum by pitting fishery management interests against conservation needs. Maintenance of the important armado fisheries depends on the ability of the species to migrate freely to use spawning and nursery areas in reservoir tributaries and floodplains. However, its ability to migrate long distances can allow this non-native species the opportunity to invade most of the Upper Paraná River.  相似文献   

Dynamics of natural infection by Toxoplasma gondii in goat herds in the semiarid region of northeastern Brazil: transitional antibody observation     

Sousa  Larissa Nascimento  Batista  Samira Pereira  Silva  Samara Santos  da Silva  Rômulo Fylipe  Sarmento  Wlysse Ferreira  Mota  Rinaldo Aparecido  Brasil  Arthur Willian Lima  Amaku  Marcos  Feitosa  Thais Ferreira  Vilela  Vinícius Longo Ribeiro 《Veterinary research communications》2022,46(2):507-515

Veterinary Research Communications - This study aimed to describe the transmission of T. gondii in naturally infected goats in the semiarid region of northeastern Brazil, through evaluating the...  相似文献   

Antibacterial activity of Persea cordata stem barks     

Schlemper SR  Schlemper V  da Silva D  Cordeiro F  Cruz AB  Oliveira AE  Cechinel-Filho V 《Fitoterapia》2001,72(1):73-75

The antibacterial effects of extracts obtained from Persea cordata stem bark, employed in Brazil to treat infectious diseases, were studied. The ethyl acetate fraction of the hydroalcoholic extract showed activity against pathogenic bacteria which may justify the popular use of the plant.  相似文献   

Axial and radial water flow in the trunks of oak trees: a quantitative and qualitative analysis   总被引：1，自引：0，他引：1  

Granier A  Anfodillo T  Sabatti M  Cochard H  Dreyer E  Tomasi M  Valentini R  Bréda N 《Tree physiology》1994,14(12):1383-1396

Axial water flow in the trunks of mature oak trees (Quercus petraea (Matt.) Liebl. and Q. robur L.) was studied by four independent techniques: water absorption from a cut trunk, sap flowmeters, heat pulse velocity (HPV) and thermoimaging. Estimation of the total water flow with sap flowmeters, HPV and water absorption yielded comparable results. We concluded from dye colorations, thermograms and axial profiles of sap flow and heat pulse velocity that, in intact trunks, most of the flow occurred in the current-year ring, where early-wood vessels in the outermost ring were still functional. Nevertheless, there was significant flow in the older rings of the xylem. Total water flow through the trunk was only slightly reduced when air embolisms were artificially induced in early-wood vessels, probably because there was little change in hydraulic conductance in the root-leaf sap pathway. Embolization of the current-year vessels reactivated transport in the older rings.  相似文献   

北美红杉生态因子的研究状况   总被引：1，自引：0，他引：1  

王懿祥  白尚斌  耿云芬  祁荣频  邵金平  马显达 《西部林业科学》2002,1(1):23-26

北美红杉自然分布范围狭窄 ,通过 10 0多年的努力 ,北美红杉已在 2 0多个国家成功引种。许多学者对北美红杉的生态因子进行了大量的研究。为了解国内外的研究状况 ,从影响北美红杉分布和生长的光、温度、雾、土壤 4个重要的生态因子出发 ,结合该树种自然分布区的生态环境 ,对其研究成果进行了概括和分析  相似文献   

Nitrogen uptake from 15N-enriched fertilizer by four tree crops in an Amazonian agroforest     

Harald Dinkelmeyer  Johannes Lehmann  Andreas Renck  Lucerina Trujillo  Jose Pereira da Silva Jr  Gerhard Gebauer  Klaus Kaiser 《Agroforestry Systems》2003,57(3):213-224

Mixed tree cropping systems have been proposed for sustainable nutrient management in the humid tropics. Yet, the nutrient interactions between intercropped trees have not been addressed sufficiently. In the present study we compare the temporal and spatial patterns of the uptake of applied ¹⁵N by four different tree crops in a mixed tree cropping system on a Xanthic Ferralsol in central Amazônia, Brazil, during one year. Most of the N uptake occurred during the first two weeks. Very little N was recovered by peach palm (Bactris gasipaes), more by cupuassu (Theobroma grandiflorum) and annatto (Bixa orellana) and most by Brazil nut (Bertholletia excelsa). Due to tree pruning the total accumulation of applied ¹⁵N in the above-ground biomass of annatto decreased throughout the year. It remained constant in cupuassu and peach palm and increased in Brazil nut. Brazil nut showed an extensive root activity and took up more fertilizer N applied to neighboring trees than from the one applied under its own canopy in contrast to the other three tree crops. Therefore, trees with wide-spread root systems may not need to receive N fertilizer directly but can take up N applied to other trees in the mixed cropping system. This means that such trees may effectively decrease N leaching when intercropped with trees that have dormant periods or places with low N uptake, but also exert considerable resource competition.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

First report on Meloidogyne chitwoodi hatching inhibition activity of essential oils and essential oils fractions     

Jorge Miguel Silva Faria  Inês Sena  Bruno Ribeiro  Ana Margarida Rodrigues  Carla Maria Nobre Maleita  Isabel Abrantes  Richard Bennett  Manuel Mota  Ana Cristina da Silva Figueiredo 《Journal of pest science》2016,89(1):207-217

The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL^?1 and were further tested at lower concentrations. Dysphaniaambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC₅₀ values (<0.15 µL mL^?1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC₅₀ values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity.  相似文献   

A new Delta7,22 sterol from the bulbs of Autonoë madeirensis     

Paulo A  Dias C  Jimeno ML  Borges C  Nascimento J 《Fitoterapia》2005,76(7-8):765-767

The spectral data of a new Δ^7,22 sterol, 24S-ethyl-5α-cholesta-7,22E-dien-3α-ol β-galactopyranoside, isolated from the bulbs of Autonoë madeirensis, are reported.  相似文献   

Biochanin A triglycoside from Andira inermis     

da Silva BP  Velozo LS  Parente JP 《Fitoterapia》2000,71(6):663-667

A new isoflavonol triglycoside, biochanin A 7-O-beta-D-apiofuranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->6 )-beta-D- glucopyranoside (1), was isolated from Andira inermis roots in addition to the known compounds genistein 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside and lanceolarin.  相似文献   

Empirical models to predict LAI and aboveground biomass of Coffea arabica under full sun and shaded plantation: a case study of South of Minas Gerais,Brazil     

Priscila Pereira Coltri  Jurandir Zullo Junior  Vincent Dubreuil  Glaucia Miranda Ramirez  Hilton Silveira Pinto  Gustavo Coral  Camila Giorgi Lazarim 《Agroforestry Systems》2015,89(4):621-636

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