Evaluation of androgenic competence through anther culture in common eggplant and related species     

Pablo Salas  Jaime Prohens  José M. Seguí-Simarro 《Euphytica》2011,182(2):261-274

Anther culture is a convenient technique to obtain androgenic haploid and doubled haploid (DH) plants. In common eggplant (Solanum melongena), this technique has been used to develop DH pure lines for producing uniform F1 hybrid seed of some commercial varieties. However, a comprehensive study of the variation of this useful trait among different materials of common eggplant and related species is still lacking. In this work, we studied the androgenic response of 12 accessions of common eggplant and related materials from the primary (eggplant complex) and secondary genepools. We cultured anthers of all the accessions under the same experimental conditions, and studied their competence to produce calli, embryos and plants, as well as the quality and origin of the embryos produced. In our conditions, anthers of 11 out of the 12 accessions produced somatic calli, whereas only 5 also produced microspore-derived embryos, with variable results in terms of embryo quality and of frequency of embryo induction and plant germination. Embryos of responding accessions were initially haploid, and reached the DH status, verified with SSR markers, after a defined period of culture. In addition to other aspects common to many androgenesis-responsive species, our results allowed us to extract conclusions particular to common eggplant and relatives, including the difficulty for finding sources of androgenic competence out of S. melongena, the reduced impact of calli in the production of non-DH individuals, and the need to avoid the occurrence of severe anatomical and functional problems in the apex of most embryos, which seriously reduces their germinative success.  相似文献   

Reference evapotranspiration estimation without local climatic data   总被引：1，自引：0，他引：1  

Pau Mart��  Pablo Gonz��lez-Altozano  Mar��a Gasque 《Irrigation Science》2011,29(6):479-495

The Penman–Monteith equation for reference evapotranspiration (ET_o) estimation cannot be applied in many situations, because climatic records are totally or partially not available or reliable. In these cases, empirical equations that rely on few climatic variables are necessary. Nevertheless, the uncertainty associated with empirical model estimations is often high. Thus, the improvement of methods relying on few climatic inputs as well as the development of emergency estimation tools that demand no local climatic records turns into a task of great relevance. The present study describes different approaches based on multiple linear regression, simple regression and artificial neural networks (ANNs) to deal with ET_o estimation exclusively from exogenous records from secondary stations. This cross-station approach is based on a continental characterization of the study region, which enables the selection and hierarchization of the most suitable ancillary data supplier stations. This procedure is compared with different traditional and cross-station approaches, including methodologies that also consider local temperature inputs. The proposed methods are also evaluated as gap infilling procedures and compared with a simple methodology, the window averaging. The artificial neural network and the multiple linear regression approaches present very similar performance accuracies, considerably higher than simple regression and traditional temperature-based approaches. The proposed input combinations allow similar performance accuracies as ANN models relying on exogenous ET_o records and local temperature measurements. The cross-station multiple linear regression procedure is recommended due to its higher simplicity.  相似文献   

Spain's Ramón y Cajal Program     

Axness C  Tornero P  Ricote J  Algueró M 《Science (New York, N.Y.)》2003,300(5616):52-53

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Structure of a thiol monolayer-protected gold nanoparticle at 1.1 A resolution     

Jadzinsky PD  Calero G  Ackerson CJ  Bushnell DA  Kornberg RD 《Science (New York, N.Y.)》2007,318(5849):430-433

Structural information on nanometer-sized gold particles has been limited, due in part to the problem of preparing homogeneous material. Here we report the crystallization and x-ray structure determination of a p-mercaptobenzoic acid (p-MBA)-protected gold nanoparticle, which comprises 102 gold atoms and 44 p-MBAs. The central gold atoms are packed in a Marks decahedron, surrounded by additional layers of gold atoms in unanticipated geometries. The p-MBAs interact not only with the gold but also with one another, forming a rigid surface layer. The particles are chiral, with the two enantiomers alternating in the crystal lattice. The discrete nature of the particle may be explained by the closing of a 58-electron shell.  相似文献   

A selective activity-dependent requirement for dynamin 1 in synaptic vesicle endocytosis     

Ferguson SM  Brasnjo G  Hayashi M  Wölfel M  Collesi C  Giovedi S  Raimondi A  Gong LW  Ariel P  Paradise S  O'toole E  Flavell R  Cremona O  Miesenböck G  Ryan TA  De Camilli P 《Science (New York, N.Y.)》2007,316(5824):570-574

Dynamin 1 is a neuron-specific guanosine triphosphatase thought to be critically required for the fission reaction of synaptic vesicle endocytosis. Unexpectedly, mice lacking dynamin 1 were able to form functional synapses, even though their postnatal viability was limited. However, during spontaneous network activity, branched, tubular plasma membrane invaginations accumulated, capped by clathrin-coated pits, in synapses of dynamin 1-knockout mice. Synaptic vesicle endocytosis was severely impaired during strong exogenous stimulation but resumed efficiently when the stimulus was terminated. Thus, dynamin 1-independent mechanisms can support limited synaptic vesicle endocytosis, but dynamin 1 is needed during high levels of neuronal activity.  相似文献   

Competencies: a cure for pre-med curriculum     

Anderson WA  Amasino RM  Ares M  Banerjee U  Bartel B  Corces VG  Drennan CL  Elgin SC  Epstein IR  Fanning E  Guillette LJ  Handelsman J  Hatfull GF  Hoy RR  Kelley D  Leinwand LA  Losick R  Lu Y  Lynn DG  Neuhauser C  O'Dowd DK  Olivera T  Pevzner P  Richards-Kortum RR  Rine J  Sah RL  Strobel SA  Walker GC  Walt DR  Warner IM  Wessler S  Willard HF  Zare RN 《Science (New York, N.Y.)》2011,334(6057):760-761

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Fluorescence detection of aluminum in arbuscular mycorrhizal fungal structures and glomalin using confocal laser scanning microscopy     

Paula Aguilera  Fernando Borie  Alex Seguel  Pablo Cornejo 《Soil biology & biochemistry》2011,43(12):2427-2431

Arbuscular mycorrhizal spores and glomalin-related soil protein (GRSP) isolated from acid soils were analyzed using confocal laser scanning microscopy (CLSM) for Al detection. Mycorrhizal structures of Glomus intraradices produced under in vitro conditions as well as spores and GRSP from neutral and Cu-polluted soils were used as contrasting criteria. Spores and GRSP from soils with 7 and 70% Al saturation showed autofluorescence which increased especially at the highest soil Al level and when Al³⁺ solution was added. G.intraradices spores showed fluorescence only when exogenous Al³⁺ was added. On the contrary, spores and GRSP from neutral and Cu-polluted soils showed little or no significant fluorescence. This fluorescence shown by fungal structures and GRSP when subjected to high Al (of endogenous or exogenous origin) suggest a high capacity for Al immobilization, which could be an effective way to reduce Al activity and phytotoxicity in acid soils.  相似文献   

Mycorrhiza induced resistance in potato plantlets challenged by Phytophthora infestans     

Adrien Gallou  Hernán Patricio Lucero Mosquera  Sylvie Cranenbrouck  Juan Pablo Suárez  Stéphane Declerck 《Physiological and Molecular Plant Pathology》2011,76(1):20-26

Biological control of soil-borne pathogens by arbuscular mycorrhizal (AM) fungi has been repeatedly demonstrated. However, their role in the control of above-ground hemibiotrophic pathogens is less conclusive. Here, we investigated in vitro the impact of an AM fungus on Phytophthora infestans in potato plants. The leaf infection index was decreased in mycorrhizal potato plants. Real-Time Quantitative PCR revealed the induction of two pathogenesis related genes (PR1 and PR2) in the leaves of mycorrhizal plants shortly after infection with P. infestans. These results suggested a systemic resistance in mycorrhizal plants, related to the priming of the two PR genes in potato.  相似文献   

Populations of inshore serranids across the Canarian Archipelago: Relationships with human pressure and implications for conservation     

Fernando Tuya  Pablo Sanchez-Jerez 《Biological conservation》2006,128(1):13-24

We investigated spatio-temporal variability in the abundances and biomasses of four species of inshore serranids (the dusky grouper Ephinephelus marginatus, the island grouper Mycteroperca fusca, the painted comber Serranus scriba, and the blacktail comber S. atricauda) throughout the Canarian Archipelago (central-east Atlantic Ocean) with underwater visual transects. By means of a multiscaled sampling design spanning three orders of magnitude of spatial variability (from 10 s of meters among replicated 100 m² transects to 100 s of kilometres among islands) and four sampling periods, we related differences in the distributions of serranids to differences in the degree of human pressure, such as fishing intensity and human population. Differences in human pressure among islands provide the most parsimonious explanation for many of the consistent inter-island differences in the abundance and biomass of the analyzed species. Larger-bodied serranids (E. marginatus and M. fusca) are more vulnerable than the smaller species (S. scriba and S. atricauda). In fact, the larger, more vulnerable species have been almost completely extirpated from the most intensely fished islands. Our results show that the larger groupers have been overexploited throughout the Canary Islands, and highlight the urgent need for stringent management measures and better control of littoral reef fish resources.  相似文献   

Effect of the addition of sewage sludge as a fertilizer on a sandy vineyard soil     

Bravo-Martín-Consuegra  Sandra  García-Navarro  Francisco Jesús  Amorós-Ortíz-Villajos  José Ángel  Pérez-de-los-Reyes  Caridad  Higueras  Pablo L. 《Journal of Soils and Sediments》2016,16(4):1360-1365

Purpose

The application of sludge from wastewater in agriculture has increased in recent years, and it is therefore important to assess the effect that such treatment has on both the soil and the plant. The aim of the study described here was to ascertain whether there is a variation in the properties of the soil and to determine if this addition has an impact on the plant.

Materials and methods

The area of investigation was close to the municipality of Villarrubia de los Ojos (Ciudad Real). In this work, six samples were taken from the surface horizon in the studied plot at a depth of 35 cm. A further three samples were taken: (i) a surface horizon of a soil close to the area under investigation but without treatment (control sample), (ii) a sample of sludge from the wastewater treatment plant and (iii) a sample of the mixture used by farmers as fertilizer. Laboratory tests were conducted in accordance with the SCS-USDA (1972) guidelines. Trace element samples were analysed by X-ray fluorescence spectrophotometry (Philips PW 2404).

Results and discussion

The parcel of land studied is dominated by a sandy texture (88.3 % sand), and a decrease in pH was observed in areas in which the mixture (manure + sludge) was added (pH?=?8.0) compared to areas in which fertilizer was not applied (pH?=?8.5). It was observed that the addition of the compound led to an increase in the electrical conductivity of the soil. The trace elements can be organized into two groups based on the results obtained in this study. One group contains the trace elements that were only present in the rows that were treated with the fertilizer. The other group of trace elements was mobilized throughout the whole plot.

Conclusions

The application of sewage sludge on agricultural soils can be very useful as an organic amendment because it produces an increase in soil organic matter. However, sewage sludge must be applied with caution due to the changes in soil chemical properties (for example, pH and E.C.). The use of this type of waste for prolonged periods of time can cause problems of contamination in the soil.

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