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Wyszukujesz frazę "interspecific variation" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Ornamentation of dermal bones of Placodermi from the Lower Devonian of Morocco as a measure of biodiversity
Autorzy:
Antczak, M.
Berkowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/94702.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Arthrodira
interspecific variation
ontogeny
fishes
North Africa
zróżnicowanie międzygatunkowe
ontogeneza
ryby
Afryka Północna
Opis:
Dermal bones are formed early during growth and thus constitute an important tool in studies of ontogenetic and evolutionary changes amongst early vertebrates. Ornamentation of dermal bones of terrestrial vertebrates is often used as a taxonomic tool, for instance in Aetosauria, extant lungfishes (Dipnoi) and ray-finned fishes (Actinopterygii), for which it have been proved to be of use in differentiating specimens to species level. However, it has not been utilised to the same extent in placoderms. Several features of the ornamentation of Early Devonian placoderms from Hamar Laghdad (Morocco) were examined using both optical and scanning electron microscopy to determine whether it is possible to distinguish armoured Palaeozoic fishes. Four distinct morphotypes, based on ornamentation of dermal bones, are dif-ferentiated. These distinct types of ornamentation may be the result of either different location of dermal plates on the body or of ontogenetic (intraspecific) and/or interspecific variation.
Źródło:
Geologos; 2017, 23, 2; 65-73
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amphidiploid hybrids of Trifolium pratense L. [2n=14 and 2] with T.diffusum Ehrh. [2n=16]
Autorzy:
Strzyzewska, C
Powiązania:
https://bibliotekanauki.pl/articles/2048137.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chromosome
Trifolium diffusum
Trifolium pratense
hybrid
interspecific hybrid
plant breeding
genetic variation
Opis:
After duplicating the chromosome number by colchicine in sterile F₁ 16-chromosome hybrid T. pratense × T. diffusum some partially fertile plants with 32 chromosomes were found. Male fertility (viability of pollen grain) was from 69.3% to 86.2% (on average 81.8%), whereas female fertility estimated as seed setting after cross- and self-pollination was 21.8% and 6.9%, respectively. Male and female fertility as well as somatic chromosome number were examined in the F₂-F₄ generations. Selection for female fertility resulted in increasing seed setting in the first two generations (F₂ and F₃) and in decreasing it in F₄ generation. An average seed setting in the F₂-F₄ generations after cross-pollination amounted to 22.2%, 43.6% and 12.9%, respectively; after self-pollination it was 25.2%, 27.6% and 1.9%. In the F₂ generation all the plants had 2n=32 chromosomes. In the next generations there appeared aneuploids, among which 30-chromosome individuals were predominant.
Źródło:
Journal of Applied Genetics; 1995, 36, 2; 147-154
1234-1983
Pojawia się w:
Journal of Applied Genetics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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