Compatibility relations between the edible carrot Daucus carota and D. pusillus, a related wild species from the Argentinian Pampas     

Elsa L. Camadro  Miguel A. Cauhépé  Philipp W. Simon 《Euphytica》2008,159(1-2):103-109

To establish the feasibility of hybridization between the wild carrot species Daucus pusillus Michx. (2n = 2x = 22; 2n = 2x = 22 and 20), collected in the pampas grasslands of Argentina, and the edible carrot, Daucus carota L. (2n = 2x = 18), controlled pollinations were attempted on the plant. Due to the difficulties encountered, flowers of 12 accesions and three commercial cultivars were excised from individual plants and pollinated in Petri dishes following an incomplete diallel design. After processing, the pollinated pistils (four to six per genotypic combination) were observed under a microscope with UV light. Pollen tubes reaching the ovaries and/or the ovules (compatible relation) were observed in six out of nine D. pusillus × D. pusillus and seven out of 18 D. pusillus × D. carota genotypic combinations. In the eight D. carota × D. pusillus genotypic combinations, only ungerminated pollen, pollen not adhered to the stigmas or pollen tubes overlapping the stylar tissue were observed. Additional flowers were pollinated in a sample of compatible genotypic combinations and the pollinated pistils were in vitro culture to study embryo and endosperm development. Eight out of nine pistils from the intraspecific and nine out of 13 from the interspecific crosses enlarged to form apparently normal schizocarps. Histological analyses revealed normal development of embryo and endosperm. The breeding barriers between the two species are incomplete, making feasible the obtainment of interspecific hybrids by conventional techniques.  相似文献   

Temperature responses of nitrogen processes cannot be inferred from carbon turnover in a boreal Norway spruce forest     

Anke M. Herrmann  Elsa Coucheney 《植物养料与土壤学杂志》2019,182(6):934-944

Cold season processes contribute substantially to annual carbon (C) and nitrogen (N) budgets in boreal forest ecosystems, but little is known about how decomposition processes are affected at temperatures prevalent during wintertime. The aim of this study was to evaluate temperature responses of soil C and N processes and to test the hypothesis that there is a switch towards decomposing N‐rich material when soil temperatures drop to near 0°C. In the laboratory, soils from a boreal forest long‐term nutrient fertilization experiment were exposed to different temperatures varying from +2 to +15°C, and C mineralization, gross as well as net N mineralization/immobilization were estimated. Carbon mineralization declined exponentially as temperature decreased, whereas the response of N processes to temperature varied, with some indication that soil C and N processes are decoupled at low temperatures. We could only partially confirm that the decoupling between C and N processes at low temperature was due to a switch to N‐rich material, i.e., a change in the material undergoing decomposition. Overall, our results clearly showed that temperature responses of N processes cannot be inferred from C processes in boreal forest ecosystems, and that there is a need to improve our understanding of the relationship between the two across the range of temperatures experienced throughout the year. In particular, further research is required to establish and evaluate appropriate proxies for modelling the relationship of C and N processes at temperatures close to the freezing point.  相似文献   

Genetic variation in susceptibility to pine wilt disease of maritime pine (<Emphasis Type="Italic">Pinus pinaster</Emphasis> Aiton) half-sib families     

Isabel Carrasquinho  Ana Lisboa  Maria L. Inácio  Elsa Gonçalves 《Annals of Forest Science》2018,75(3):85

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Influence of Pygoscelis Penguin Colonies on Cu and Pb Concentrations in Soils on the Ardley Peninsula,Maritime Antarctica     

Alessandra Perfetti-Bolaño  Lucila Moreno  Roberto Urrutia  Alberto Araneda  Ricardo Barra 《Water, air, and soil pollution》2018,229(12):390

Penguins can bioaccumulate metals, a portion of which can be deposited in the environment through organic remains such as excrement, carcasses, and eggshells. In order to determine Cu and Pb concentrations and their relationship to soil, organic matter and grain size were determined in 27 samples collected in zones without penguins, penguin transit zones, and Adelie (Pygoscelis adeliae), Chinstrap (P. antarctica), and Gentoo penguin (P. papua) colonies on the Ardley Peninsula, Maritime Antarctica. An atomic absorption spectrophotometry analysis was carried out, organic matter was determined by loss on ignition, and grain size was measured with a laser diffraction particle size analyzer. The principal component analysis shows a relationship between the variables Cu, Pb, and grain size and areas with penguin presence. Cu concentrations in soils varied among areas (χ², 15.707; p =?0.0004), with higher concentrations in transit zones and penguin colonies (142.63 and 140.79 mg/kg, respectively) than in zones without penguins (83.33 mg/kg). Pb concentrations in soils also varied among areas (χ², 6.5029; p =?0.0387), and were higher in transit zones (5.92 mg/kg) than in the penguin colonies (4.45 mg/kg). Grain size differed significantly among areas (χ², 13.506; p =?0.0012), with higher values in transit zones (avg. 37.38 μm) than in penguin colonies (avg. 26.93 μm) and zones without penguins (avg. 20.72 μm). Organic matter did not differ significantly among the studied zones (χ², 2.0882; p =?0.3520). There is a positive correlation between Cu-Pb (Rho, 0.5532; p =?0.0028), Cu-grain size (Rho, 0.4756; p =?0.0130) and Pb-grain size (Rho, 0.4879; p =?0.0098). The presence of penguins increases Cu concentrations in Antarctic soils due to its bioaccumulation and elimination through excrement; however, the presence of penguins has a minor influence on Pb concentration in soil, probably because this metal is stored efficiently in bones, feathers, and eggshells.  相似文献   

Traumatic skull fractures in dogs and cats: A comparative analysis of neurological and computed tomographic features     

Pablo Amengual-Batle  Roberto José-López  Alexane Durand  Michal Czopowicz  Elsa Beltran  Julien Guevar  Kali Lazzerini  Steven De Decker  Karen Muñana  Peter Early  Christopher Mariani  Natasha Olby  Nicholas Petrovitch  Rodrigo Gutierrez-Quintana 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(5):1975-1985

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Selection of indigenous lactic acid bacteria to reinforce the intestinal microbiota of newly hatched chicken – relevance of in vitro and ex vivo methods for strains characterization     

Jaime D. Babot  Eloy Argañaraz-Martínez  Lucila Saavedra  María C. Apella  Adriana Perez Chaia 《Research in veterinary science》2014

Based on the natural benefits of the indigenous microbiota, lactic acid bacteria (LAB) from poultry origin were isolated from hens and broilers intestine, and their probiotic potential was further studied. The tolerance to digestion, adhesion, capture of a mannose-binding lectin, absence of virulent factors and antibiotic resistances were studied. Different in vitro and ex vivo assays were performed to select tolerant and adherent strains because standardized protocols have not been defined. Fourteen strains highly tolerant to gastrointestinal digestion were genetically identified. Hydrophobic surfaces were not required for the bacterial adhesion and only nine strains adhered ex vivo to the intestinal mucosa. Three strains captured a lectin of the same specificity of Type-1 fimbriae. Virulence factors were absent but some strains evidenced multiple antibiotic resistances. These results provide bases for a future standardization of methods for the selection of probiotic strains intended to reinforce the microbiota of newly hatched chickens.  相似文献   

Cytological mechanism of 2n pollen formation and unilateral sexual polyploidization in Lolium     

C. A. Sala  E. L. Camadro  M. T. Salaberry  A. O. Mendiburu 《Euphytica》1989,43(1-2):1-6

Summary Plants of Lolium perenne, L. multiflorum and L. hybridum (331, 51 and 18, respectively) were screened for 2n pollen production. The screening was based on the size differences that are expected to be found between n and 2n pollen of a plant. It was found that 28 plants of perennial ryegrass-belonging to 13 cultivars-produced produced pollen grains of heterogenous size (big and small). The estimated frequency of big pollen grain production was higher than 10% in ten out of 28 plants and in three of them it reached a value of 100%. Eight plants obtained from two 4x × 2x crosses, in which the male parent had been previously identified as producing pollen grains of heterogenous size, was tetraploid. The cytological mechanism of big pollen grain formation observed in three plants consists in the lack of spindle formation and, consequently, of chromosome migration in anaphase II. From these breeding and cytological results, it was concluded that the big pollen grains observed were viable 2n pollen grains. The nuclei of the 2n pollen grains produced by this mechanism are genetically equivalent to those formed by the restitution of the second meiotic division. The value of these gametophytes in a breeding program of Lolium is discussed.  相似文献   

First report of the citrus leafhopper <Emphasis Type="Italic">Penthimiola bella</Emphasis> (Stål) (Hemiptera,Cicadellidae) in Europe     

Vera?ZinaEmail author  Elsa?Borges?da?Silva  José?Alberto?Quartau  José?Carlos?Franco 《Phytoparasitica》2013,41(5):521-527

The presence of the citrus leafhopper, Penthimiola bella (Stål) (Hemiptera, Cicadellidae), was detected in citrus orchards in Portugal. This is the first report of this cicadellid in Europe. A survey was carried out in 30 citrus orchards in Algarve, in southern Portugal, based on both the beating method and visual observation of shoots, between July and December 2012. P. bella was detected in a total of 19 orchards distributed throughout the region. The occurrence of reproducing populations of P. bella and its dispersion over a relatively large area of at least 70 km in length within Algarve suggests that this species established and has been expanding its distribution in the region for several years since its arrival. The possible pathway of introduction and its pest status are discussed.  相似文献   

Grassland responses to global environmental changes suppressed by elevated CO2   总被引：1，自引：0，他引：1  

Shaw MR  Zavaleta ES  Chiariello NR  Cleland EE  Mooney HA  Field CB 《Science (New York, N.Y.)》2002,298(5600):1987-1990

Simulated global changes, including warming, increased precipitation, and nitrogen deposition, alone and in concert, increased net primary production (NPP) in the third year of ecosystem-scale manipulations in a California annual grassland. Elevated carbon dioxide also increased NPP, but only as a single-factor treatment. Across all multifactor manipulations, elevated carbon dioxide suppressed root allocation, decreasing the positive effects of increased temperature, precipitation, and nitrogen deposition on NPP. The NPP responses to interacting global changes differed greatly from simple combinations of single-factor responses. These findings indicate the importance of a multifactor experimental approach to understanding ecosystem responses to global change.  相似文献   

Community ecology. All that makes fungus gardens grow     

Youngsteadt E 《Science (New York, N.Y.)》2008,320(5879):1006-1007

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