Search results for "Polyploid"
showing 9 items of 59 documents
Impact of endopolyploidy on seed coat development and cell expansion in Medicago truncatula
2013
Growth of the seed coat is regulated by genetic interactions between maternal and filial tissues that ultimately establish seed size. However, endopolyploidy is one of the welldocumented factors controlling organ size. During seed development, the arrest of cell division at 4 DAP in the expanding seed coat is compensated for by cell elongation. Thus, the ploidy status of seed coat nuclei was assessed in order to determine if there is any correlation of endopolyploidy with cell elongation. In 10 DAP seed sections, the DAPI-integrated fluorescence, which correlates to DNA quantity, was measured in the seed coat parenchyma nuclei using the diploid embryo nuclei as internal control. Significant…
Die endokrinen dr�sen im embryo von Oncopeltus fasciatus Dallas (Insecta, Heteroptera)
1972
The differentiation of the endocrine glands in the embryo of Oncopeltus fasciatus is described. The function of these glands can be correlated with the embryonic moults. The nuclei of some tissues already become polyploid in the embryo. It is discussed whether the endomitotic growth is dependent upon the function of the endocrine glands.
Ploidy manipulation for genetic improvement in some Mediterranean fruit crops
2017
Plant breeding is focused on selection of new genotypes with improved traits. Conventional methods based on hybridization and those based on biotechnology (somatic hybridization, genetic transformation, ploidy manipulation, etc.) are used to create novel genetic variations. Biotechnology provides powerful tools for plant breeding, for instance, haploid technology allows achievement of homozygous lines from heterozygous parents in one step, which reduces significantly the time required by conventional methods. Concerning woody species, characterized by self-incompatibility, long juvenile period and high degree of heterozygosity, this technique is the only way to get homozygous lines. Haploid…
A New Polyploid Species of the Genus Tragopogon (Asteraceae, Cichorieae) from Russia
2008
ABSTRACT Tragopogon soltisiorum Mavrodiev (Asteraceae, Cichorieae, Scorzonerinae) is described as a new species. The new species is a tetraploid (2n = 24), ruderal plant with long flowering and fruiting times and differs from the vast majority of Tragopogon L. species in its ability to reproduce vegetatively from adventitious shoots. The new species is known only from southern Russia and is found in two varieties—a typical variety and a new variety latifolius Mavrodiev.
An updated catalogue of chromosome numbers in the genus Isoetes L. (Isoetaceae, Lycopodiophyta)
2010
Evolutionary site-number changes of ribosomal DNA loci during speciation: complex scenarios of ancestral and more recent polyploid events.
2015
Genes encoding ribosomal RNA are universal key constituents of eukaryotic genomes, but the number of loci varies between species. We assessed the evolutionary trends in site-number changes of rDNA loci during speciation in a lineage of the cabbage family, characterized by complex scenarios of polyploidy. Our results suggest the existence of constrictions to burst loci amplification in the 5S rDNA family in polyploids and an overall trend to further reduce their number. The 45S rDNA site change in polyploids tells a different story, implying loci amplification in most of the polyploid entities.
Nunatak survival vs. tabula rasa in the Central Pyrenees: a study on the endemic plant species Borderea pyrenaica (Dioscoreaceae)
2007
14 páginas, 4 figuras, 2 tablas.