Search results for "fertilization"
showing 10 items of 326 documents
Root topology and allocation patterns of Atriplex patula supplied with different nutrient concentrations
2007
To test whether sub-optimal available nutrient concentrations would result in a more herringbone root branching pattern, in lower root diameters, and in greater resource allocation to root growth than to above-ground portions, seedlings of Atriplex patula were grown under optimal (full), intermediate (1/3 full), and low (1/6 full) nutrient treatments. No significant differences were found between the full and 1/3 nutrient treatments for any of the parameters tested. Root topologies did not show conclusive responses to nutrient availability, however roots treated with 1/6 nutrient concentration showed the tendency to grow in a more herringbone pattern. Total dry weights and shoot dry weights…
Beneficial Effect of Two Culture Systems with Small Groups of Embryos on the Development and Quality of In Vitro-Produced Bovine Embryos
2014
Summary Currently, in vitro-produced embryos derived by ovum pick up (OPU) and in vitro fertilization (IVF) technologies represent approximately one-third of the embryos worldwide in cattle. Nevertheless, the culture of small groups of embryos from an individual egg donor is an issue that OPU-IVF laboratories have to face. In this work, we tested whether the development and quality of the preimplantation embryos in vitro cultured in low numbers (five embryos) could be improved by the addition of epidermal growth factor, insulin, transferrin and selenium (EGF-ITS) or by the WOW system. With this aim, immature oocytes recovered from slaughtered heifers were in vitro matured and in vitro ferti…
La responsabilità dello Stato per violazione del diritto dell'Unione europea
2014
La tesi, inerente gli sviluppi della giurisprudenza Francovich in Europa e nei singoli Stati membri dell'Unione europea, illustra, sullo sfondo del rapporto fra sovranità e responsabilità civile dello Stato, alcune specifiche questioni: se e quanto vadano ridefiniti i limiti dell’autonomia procedurale tradizionalmente riconosciuta a ciascuno degli Stati membri dell’Unione europea; se la responsabilità abbia natura contrattuale o extra-contrattuale, soggettiva o oggettiva, e se di alternativa all’illecito, in punto di fonte dell’obbligazione, possa parlarsi, ad esempio con riferimento all’ingiustificato arricchimento; quali indicazioni operative provengano da alcuni casi nazionali dei singol…
La collection historique d’échantillons de sols de l’essai patrimonial des ‘42 parcelles’ (INRAE, Versailles) : une machine à remonter le temps...
2020
Following three previous papers (van Oort et al., 2016, 2017, 2020) dealing with current soil characteristics and geochemical budgets in surface horizons, as well as the impacts of fertilization in subsurface horizons in soils of INRAE’s long term bare fallow experiment (the 42-plots trial), we now present some chronological aspects of soil evolution at the soil’s surface since 1928. For that, we analyzed several series of about 15 samples from the historical sample archive for 10 representative treatments: fertilizers with acidifying effects (ammonium sulphate, ammonium phosphate), fertilizers with dispersive effects (sodium nitrate, sylvinite, and potassium chloride), superphosphate, amen…
Effects of tributyltin(IV) chloride on fertilization ofStyela plicata(Ascidiacea: Tunicata): II. Scanning and transmission electron microscopy studies
2003
The morphological aspects of Styela plicata fertilization after treatment with tributyltin(IV) chloride are described by means of scanning and transmission electron microscopy investigations. Alterations have been shown both on female and male gametes; spermatozoa, all the egg envelopes and the mitochondria of the egg cortical cytoplasm are modified in relation to incubation time. As a consequence, the damage to gametes blocks sperm–egg interaction and fertilization does not occur. Copyright © 2003 John Wiley & Sons, Ltd.
Differential responses of bacterial and archaeal groups at high taxonomical ranks to soil management
2010
Little is known about abundances of the major bacterial taxa in agricultural soils and how they are affected by fertilization or other agricultural practices. Our aim was to determine the abundance and relative distribution of several bacterial phyla and one class, as well as the archaeal and crenarchaeal communities, and how they were affected by different fertilization regimes to examine whether specific responses of microorganisms could be identified at these high taxonomic ranks. We used real-time PCR with taxa specific primers to quantify the abundance of the Actinobacteria, Acidobacteria, Bacteriodetes, Firmicutes, Gemmatimonadetes, Verrucomicrobia, Alphaproteobacteria and Crenarchaeo…
An Analysis of the Process of Fertilization and Activation of the Egg
1957
Publisher Summary Fertilization consists fundamentally in the release of a chain of metabolic reactions by virtue of which morphogenesis is started. The result of fertilization is the activation of the egg. This can be achieved also by several agents other than the spermatozoon and it is then spoken of as “artificial activation.” This chapter discusses the structural, physiological, and chemical changes that occur in the egg at fertilization that are significant in the understanding of the mechanisms of the activation. The chapter presents the hypothesis that in the cortex of the unfertilized sea urchin egg an inhibitor–enzyme complex is present. By reacting with some substance introduced b…
Cytochrome oxidase activity in the mitochondria of unfertilized and fertilized sea urchin eggs
1959
Abstract The cytochrome oxidase activity of isolated mitochondria of unfertilized and fertilized eggs of Paracentrotus lividus has been studied. It has been found that whereas in the mitochondria of unfertilized eggs saturation is reached at a cytochrome c concentration of 3.28 × 10−5 M, in those of fertilized eggs this occurs at a concentration of 5.74 × 10−5 M. It is shown that upon fertilization an increase of about 30 per cent of the activity of cytochrome oxidase takes place and no further changes appear to occur until blastula stage.