Diversity of genus Lasiodiplodia associated with perennial tropical fruit plants in northeastern Brazil          下载免费PDF全文

I. B. L. Coutinho  F. C. O. Freire  C. S. Lima  J. S. Lima  F. J. T. Gonçalves  A. R. Machado  A. M. S. Silva  J. E. Cardoso 《Plant pathology》2017,66(1):90-104

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Variation in pinewood nematode susceptibility among <Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait. provenances from the Iberian Peninsula and France     

María Menéndez-Gutiérrez  Margarita Alonso  Gabriel Toval  Raquel Díaz 《Annals of Forest Science》2017,74(4):76

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Valorization of Organic Wastes to Reduce the Movement of Priority Substances Through a Semiarid Soil     

Gabriel Pérez-Lucas  Nuria Vela  José A. Escudero  Ginés Navarro  Simón Navarro 《Water, air, and soil pollution》2017,228(3):119

In this work, we examined the effect of two different organic wastes, composted sheep manure and coir, on the sorption, persistence, and mobility of three pesticides (alachlor, chlorfenvinphos, and chlorpyrifos) included as priority substances in European Directive 2013/39/EU. With this aim, leaching studies were conducted using disturbed soil columns filled with a typical agricultural soil (hipercalcic calcisol) from a semiarid area (southeastern Spain) to determine their potential for groundwater pollution. The three compounds were found in leachates of unamended soil although in different proportions: 53% (alachlor), 9% (chlorfenvinphos), and 6% (chlorpiryfos). The addition of organic wastes significantly increased the sorption of the studied pesticides. As a consequence, the half-lives of the studied pesticides were higher in amended than in unamended soils. A marked reduction of the amount recovered in leachates was observed in the amended soils, except for chlorpiryfos, whose recoveries barely changed. According to their potential groundwater pollution calculated as the groundwater ubiquity score (GUS) index, alachlor and chlorfenvinphos show medium leachability while chlorpiryfos is unlikely to leach.  相似文献   

Foliar phosphorus fertilization of common bean complementing phosphate fertilization at sowing     

Rogério Nunes Gonçalves  Itamar Rosa Teixeira 《Journal of plant nutrition》2017,40(11):1580-1587

The objective of this study was to evaluate the response of common bean plants to phosphorus (P) applied to the leaves at different growth stages, as a complement to phosphate fertilization at sowing. The experiment followed the 2 × 7-factor randomized block design (RBD) with four replicates. The first factor was fertilization with P at the base with 60 and 120 kg ha^?1 of phosphorus pentoxide (P₂O₅). The second factor was the times and doses of P applied to the leaves: 0.5 or 1 kg ha^?1 of P₂O₅, at the V3 phenological stage; parceled in the following manner: 20% in V3, another 40% in R5 and 40% in R6, or 50% in R5 and 50% in R6; and one treatment with no P₂O₅ application to the leaves. P-based foliar fertilization increased P content in the grains of plants grown in soils with greater P availability. The lower common bean biomass production under scarce P availability was minimized by the foliar fertilization, as well as its productivity when 1 kg ha^?1 of P₂O₅ was applied to the leaves, 50% in the R5 phenological stage and 50% in R6. The highest productivity was obtained with the application of 0.5 kg ha^?1 of P₂O₅ to the leaves in the V3 phenological stage with the 120 kg ha^?1 dose at the base.  相似文献   

Gut pH as a limiting factor for digestive proteolysis in cultured juveniles of the gilthead sea bream (Sparus aurata)     

Márquez L  Robles R  Morales GA  Moyano FJ 《Fish physiology and biochemistry》2012,38(3):859-869

After the development of the gastric function in juvenile fish, dietary proteins enter a two-phase digestive process comprising an acidic gastric phase followed by an alkaline intestinal phase. However, the main gastric protease, pepsin, is strictly dependent on the existence of a low-enough environmental pH. In 20-g gilthead sea bream, Sparus aurata, the mean minimal gastric pH is close to 4.5, while the mean pH in the duodenal portion of the intestine was nearly fixed at 6.5. The mean maximal gastric content of HCl was approximately 20 microEq for a low-buffering diet. Gastric proteases were more severely affected than intestinal proteases when assayed at actual sub-optimal pH values, 4.5 and 6.5, respectively. When the gastric proteases of juvenile fish were pre-incubated with a citric acid buffer at pH 6.0, the activity at pH 4.5 was very low, whereas when they were pre-incubated with the same buffer at pH 3.0, the activity at pH 4.5 was significantly increased; this fact suggests a deficient activation of zymogens during the gastric digestion and points to a potential approach to improve protein digestion in juvenile gilthead sea bream.  相似文献   

Microbial Events in the Hindgut During Carbohydrate-induced Equine Laminitis     

Gabriel J. Milinovich  Athol V. Klieve  Christopher C. Pollitt  Darren J. Trott 《Veterinary Clinics of North America: Equine Practice》2010

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Short-term recovery of soil functional parameters and edaphic macro-arthropod community after a forest fire     

Sara C. Antunes  Nuno Curado  Bruno B. Castro  Fernando Gonçalves 《Journal of Soils and Sediments》2009,9(3):267-278

Background, aim and scope  Forest fires can result in severe economic and environmental consequences, and little is known about the ecological patterns and processes that may lead to the recovery of burnt areas. In the last decades, Portugal has been the Southern European country with the highest number of fire events and with the highest burnt area per hectare. With this work, we proposed to study the effect of a forest fire on the terrestrial ecosystem. More specifically, this work intended to evaluate the short-term recovery of several soil chemical, biochemical (microbial enzymatic activities) and biological (edaphic macro-arthropod community) variables in a burnt pine tree forest area. Methodology  Soil and macro-arthropod sampling was carried out in a burnt area (transects BI, BII and BIII) and in a neighbouring unburnt area (U) 3 and 8 months after the fire, coinciding with autumn and spring. Soil was collected for the determination of physical (pH and conductivity) and chemical parameters (moisture and organic matter) and soil enzymes (cellulase, acid phosphatase and nitrogen mineralisation rate). Edaphic macro-fauna was captured using pitfall traps. Results  Univariate and multivariate statistics revealed, overall, that burnt sites displayed lower acid phosphatase and cellulase activities and higher conductivity and pH values than the unburnt area. There was a recovery in the measured soil parameters between autumn and spring in the most interior parts of the burnt areas (BII and BIII), but the outer transect (BI, close to a road) still displayed considerable differences to the remaining burnt transects as well as to the unburnt area. A total of 47 macro-arthropod taxa were captured in both seasons, with Linyphiidae spiders (20.2%) and insect families Formicidae (13.4%) and Staphylinidae (11.9%) being the most abundant. Dominance by some taxa was overall stronger in the burnt than in the unburnt area, although dominant taxa varied between seasons. In autumn, the burnt area was dominated by ants and had also a high abundance of scavengers, carrion feeders and some ground active hunters. In spring, there was a general increase in taxa diversity, richness, and total catches; in the burnt area, there was a re-colonisation by several organisms sensitive to litter quality, such as isopods and pseudoscorpions, particularly in the outer transect (closest to the unburnt area). Discussion  Differences in soil parameters between burnt and unburnt areas were most likely due to the deposition of nutrient-rich alkaline ashes. However, low cellulase activity in the outer part of the burnt area (BI) indicated compromised microbial activity in both sampling seasons. Recovery of soil functional parameters was delayed in the outer zone of the burnt area because of (i) fire intensity in that area or (ii) proximity to the road (enhancing erosion and exposure to contaminants). The pattern of arthropod re-colonisation of the burnt area followed the inverse recovery pattern (from the outer zone to the inner zone), stressing the primary role of the adjacent unburnt area as a source of potentially colonizing organisms. Conclusions  Direct and indirect effects of fire on soil parameters (soil alkalinisation and nutrient enrichment) and edaphic fauna had a short-term persistence in the burnt area, and signs of recovery were evident 8 months after the fire (spring). The adjacent unburnt area seemed to act as an important source of arthropod colonisers. Recommendations and perspectives  More prolonged studies on the recovery of soil functional parameters and arthropod community structure are required to understand long-term re-colonisation patterns. Researchers and authorities should also endeavour in the implementation of measures that favour and protect survivors and new indigenous colonisers (microbes, plants and animals) after a forest fire.  相似文献   

Diagnosis of a field outbreak of Avian encephalomyelitis by enzyme-linked immunosorbent assay     

DR SHAFREN  GA TANNOCK  CJ MORROW 《Australian veterinary journal》1989,66(7):224-225

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Studies on the Ovarian Development in Zebu Cattle (Bos indicus)     

Gabriel K.  Mbassa 《Anatomia, histologia, embryologia》1989,18(2):143-149

In a study of 71 female foetuses, gonadal blastema was observed at 1.5 cm crown rump length (CRL). Oogonial cells entered the meiotic prophase at 3.5-6.0 cm CRL, which was arrested at the dictyotene stage to produce primary oocytes which formed primordial follicles. Primordial follicles were observed at 6-8 cm CRL. All germinal cells were at dictyotene by 20-24 cm CRL and follicles developed to primary and secondary stages. Folliculogenesis dominated further ovarian development and reached a peak between 32 and 35 cm CRL. In seven of the 12 foetuses measuring between 41 and 72 cm CRL, many follicles were atretic and some luteinized. The luteal bodies were composed of hypertrophied theca and granulosa cells with homogeneous and eosinophilic cytoplasm.  相似文献   

Comparison of the effectiveness of Milkofix, a preservative preparation, with traditional preservative agents in the determination of somatic cell count in milk samples using a fluoro-optic-electronic method]     

O Hanus  V Gencurová  B Gabriel  I Zvácková 《Veterinární medicína》1992,37(2):91-99

Milkofix (M), a health friendly preservative substance, to be used for milk sample preservation (Trzicky, 1990), was compared with other preservatives. Untreated milk samples (N) were tested against samples treated with sodium azide (A; 0.0085 g NaN3 and 0.0630 g NaCl), bronopol (B; 0.0100 g bronopol and 0.090 g NaCl), potassium dichromate (C; 0.0330 g K2Cr2O7 and 0.0670 g KCl) and Milkofix (M; 0.1250 g). The doses of the preservatives A, B, C and M are per 25 ml milk. The somatic cell counts (SB) were determined on a FOSSOMATIC 90 apparatus (FOSS ELECTRIC, DENMARK). In the treated milk samples taken from individual cows the values of SB counts were significantly higher than in N samples if determined within eight hours after sampling (Tab. I): in A higher by 18.6%, B by 26.3%, C by 26.4% and M by 24.3% (P less than 0.05). The significantly higher values of SB counts were recorded in bulk milk samples treated with preservatives in comparison with N samples immediately after sampling: in A by 6.0%, in B, C and M by 12.9% (P less than 0.01; Tab. II). After one-day storage of N samples at a temperature of 4 degrees C these differences are insignificant (P greater than 0.05), thus the results of N, A, B, C and M samples obtained after one-day storage at 4 degrees C can be taken as actual and mutually comparable.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献