Resistance of 57 greenhouse-grown accessions of Lycopersicon esculentum and three cultivars to Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)     

Fabrício Alves Oliveira  Derly José Henriques da Silva  Germano Leão Demolin Leite  Gulab Newandram Jham  Marcelo Picanço 《Scientia Horticulturae》2009

The aim of this study was to evaluate resistance to Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) by antixenosis on 57 Lycopersicon esculentum Mill. accessions from the Horticultural Germplasm Bank (HGB) of Universidade Federal de Viçosa and by the three commercial cultivars (Santa Clara, Moneymaker and TOM-601) under greenhouse conditions. A randomized complete block design was used with three replications. Infestations with T. absoluta adults were performed weekly and the following characteristics were evaluated: number of small, large and total mines/leaf and % of leaves mined at days 60, 75 and 90 after planting. Low infestation occurred at days 60 and 75 but at day 90, infestation was sufficient to evaluate insect damage. Based on these data it was concluded that only accessions HGB-674 and HGB-1497 appeared to be the most promising. In addition, to determine possible chemical causes of resistance, hexane extracts were analyzed at day 90 by gas chromatography/mass spectrometry and the major peaks identified by a mass spectral database using similarity index. Nine hydrocarbons, viz., hexadecane, heptadecane, eicosane, tricosane, 2-methyltricosane, tetracosane, hexacosane, octacosane and triacontane were identified in the hexane extracts in many samples. Tricosane, tetracosane and hexacosane presented significant correlations with the leaves mined. Only tricosane presented a negative correlation with the number of small mines (r = −0.28), total number of mines (r = −0.27) and % of leaves mined (r = −0.22). However, tetracosane and hexacosane presented significant positive correlations (r = 0.25 and 0.24, respectively) with the % of leaves mined.  相似文献   

Contribution of microorganisms to the biofilm nutritional quality: protein and lipid contents     

C. FERNANDES da SILVA  E. BALLESTER  J. MONSERRAT  L. GERACITANO  W. WASIELESKY JR  P.C. ABREU 《Aquaculture Nutrition》2008,14(6):507-514

The nutritional quality of biofilm, a microbial community associated to an organic matrix, was evaluated in artificial substrate (polyethylene screen) in net cages during 30 days in the Patos Lagoon estuary, Southern Brazil. During this period, samples of biofilm were collected each 5 days for analysis of chlorophyll a, microorganisms abundance, dry weight, protein and lipid contents. During the study, chlorophyll a varied from 0.38 to 2.75 μg cm^?2; dry weight between 7.16 and 17.63 mg cm^?2; protein content from 0.43 to 1.76 mg cm^?2 and lipid concentration between 1.21 and 4.23 mg cm^?2. The variation of lipid in the biofilm was closely related to the abundance of free heterotrophic bacteria (34.25–56.54 × 10⁶ cells cm^?2), filamentous cyanobacteria (7.5–15.9 × 10⁶ filaments cm^?2), flagellates (6.92–12.89 × 10⁶ cells cm^?2) and mainly nematodes (29–1,414 organisms cm^?2), while protein content varied similarly to the abundance of unicellular centric diatoms (52.10–179.81 × 10³ cells cm^?2), and nematodes. This information will allow a better management of food supply to raised aquatic organism with the utilization of natural productivity in the culture systems, with considerable decrease in production costs.  相似文献   

Fragile ecosystems: Evaluation of Research and applications in the Neotropics. Edited by E. G. Farnworth and F. B. Golley. Report of the Institute of Ecology,Springer-Verlag,Soft cover DM19.20; US$7.80.     

C.S. Elton 《Biological conservation》1975,8(4):316

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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   

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