Search

In addition to bituminous binders (bituminous emulsion, foamed bitumen), hydraulic binders are applied in cold recycling technologies to increase the strength of a final structural layer as well as to increase its resistance to water and frost impacts. This paper deals with the use of energy by-products from fluidized bed coal combustion and mineral waste and their modification into reactive material with the potential of replacing commonly used hydraulic binders. The increase in the reactive potential takes place through a high-speed milling process where the mechanical-chemical activation of the material takes place. This process is associated with the refinement of the material, a higher proportion of micro and nanoparticles, an increased surface area, opening of particles, etc. The material treated exhibits binding properties, and it can be used as an active filler that allows for the partial or complete substitution of hydraulic binders. The experimental part is focused on the application of alternative binders to cold recycling mixtures and their assessment according to valid technical regulations, i.e., an assessment of their indirect tensile strength and water susceptibility as well as compressive strength and resistance to the effects of water and frost.

Vaccinium oxycoccos s.l. is a complex of diploid and polyploid plants. The taxonomic relationship between the cytotypes is uncertain, with conflicting treatments in recent revisions. To clarify this situation, we investigated the relationships among ploidy, morphology, and genetic diversity in this group. We collected samples from a 1000 km transect in eastern Canada. We used flow cytometry to determine DNA ploidy, completed a morphometric analysis of flowering stems, and assessed genetic diversity using AFLPs. Diploids only occurred growing in mixed populations with tetraploids. There were statistically significant morphological differences between ploidies; however, tetraploid variation encompasses the diploid range for most characters. AFLP data demonstrate that the tetraploids have undergone genetic divergence since their formation, obscuring whether they are autoor allo-polyploids. Our results agree with previous work using isozymes, which revealed genetic divergence of diploids and tetraploids in North America; and morphometry, which demonstrated clear distinctions between diploids and tetraploids in Europe. We found that diploids and tetraploids co-occur much more frequently than previously recognized, which may explain the conflicting treatment of this group by North American taxonomists. We recommend recognizing diploids and tetraploids as distinct species. The distribution of the two species in North America suggests two hypotheses regarding the successful establishment of the tetraploid: the tetraploids' success is due to their capacity to exploit novel habitats outside the range of the diploid; or the tetraploid has in fact already out-competed the diploid in large areas of its former range, limiting the diploid to the far north. While we cannot rule out ongoing gene flow between diploids and tetraploids, it is likely a rare phenomenon in this group. Keywords: AFLP, cranberry, flow cytometry, morphometrics, polyploidy, Vaccinium oxycoccos. Vaccinium oxycoccos s.l. est un complexe de plantes diploides et polyploides. La relation taxonomique entre les cytotypes est incertaine, les revisions recentes presentant des traitements contradictoires. Afin de clarifier cette situation, les auteurs ont examine les relations entre la ploidie, la morphologie et la diversite genetique au sein de ce groupe. Ils ont recoltes des echantillons a partir d'un transect de 1000 km dans l'est du Canada. Ils ont utilise la cytometrie en flux pour determiner la ploidie de l'ADN, complete une analyse morphometrique des hampes floriferes et evalue la diversite genetique par AFLP. Les individus diploides n'etaient presents qu'en populations melangees aux individus tetraploides. Les differences morphologiques entre les ploidies etaient statistiquement differentes; cependant, la variation de la population tetraploide recoupe l'etendue de la plupart des caracteres de la population diploide. Les donnees en AFLP demontrent que les individus tetraploides ont diverge genetiquement depuis leur formation, dissimulant ainsi s'ils sont auto- ou allo-polyploides. Les resultats des auteurs concordent avec ceux issus de travaux precedents realises a l'aide d'isozymes, qui avaient revele une divergence genetique des individus diploides et tetraploides en Amerique du Nord, ainsi qu'avec la morphometrie, qui avait demontre des distinctions claires entre les individus diploides et les tetraploides en Europe. Ils ont trouve que les individus diploides et tetraploides cohabitent de maniere plus frequente qu'initialement reconnue, ce qui peut expliquer le traitement contradictoire de ce groupe par les taxonomistes en Amerique du Nord. Les auteurs recommandent de reconnaetre les diploides et les tetraploides comme especes distinctes. La distribution des deux especes en Amerique du Nord suggere que deux hypotheses relativement a l'etablissement fructueux de la population tetraploide pourraient etre proposees : le succes des individus tetraploides est du a leur capacite d'exploiter de nouveaux habitats a l'exterieur de la marge de la population diploide; ou la population tetraploide a, dans les faits, deja surclasse la population diploide dans de larges zones de son etendue initiale, limitant la population diploide au grand nord. Alors qu'on ne peut exclure un flux genique entre les populations diploide et tetraploide, ce phenomene est probablement rare a l'interieur ce groupe. [Traduit par la Redaction] Mots-cles : AFLP, canneberge, cytometrie en flux, morphometrie, polyploidie, Vaccinium oxycoccos., Introduction Vaccinium oxycoccos L., the small cranberry, is a trailing, evergreen vine of peatlands, most commonly growing partially buried by living Sphagnum shoots in bogs, fens, and muskeg (Vander Kloet [...]

Background and Aims Reproductive isolation and local establishment are necessary for plant speciation. Polyploidy, the possession of more than two complete chromosome sets, creates a strong postzygotic reproductive barrier between diploid and tetraploid cytotypes. However, this barrier weakens between polyploids (e.g. tetraploids and hexaploids). Reproductive isolation may be enhanced by cytotype morphological and environmental differentiation. Moreover, morphological adaptations to local conditions contribute to plant establishment. However, the relative contributions of ploidy level and the environment to morphology have generally been neglected. Thus, the extent of morphological variation driven by ploidy level and the environment was modelled for diploid, tetraploid and hexaploid cytotypes of Campanula rotundifolia agg. Cytotype distribution was updated, and morphological and environmental differentiation was tested in the presence and absence of natural contact zones. Methods Cytotype distribution was assessed from 231 localities in Central Europe, including 48 localities with known chromosome counts, using flow cytometry. Differentiation in environmental niche and morphology was tested for cytotype pairs using discriminant analyses. A structural equation model was used to explore the synergies between cytotype, environment and morphology. Key Results Tremendous discrepancies were revealed between the reported and detected cytotype distribution. Neither mixed-ploidy populations nor interploidy hybrids were detected in the contact zones. Diploids had the broadest environmental niche, while hexaploids had the smallest and specialized niche. Hexaploids and spatially isolated cytotype pairs differed morphologically, including allopatric tetraploids. While leaf and shoot morphology were influenced by environmental conditions and polyploidy, flower morphology depended exclusively on the cytotype. Conclusions Reproductive isolation mechanisms vary between cytotypes. While diploids and polyploids are isolated postzygotically, the environmental niche shift is essential between higher polyploids. The impact of polyploidy and the environment on plant morphology implies the adaptive potential of polyploids, while the exclusive relationship between flower morphology and cytotype highlights the role of polyploidy in reproductive isolation. [ABSTRACT FROM AUTHOR]