共查询到20条相似文献,搜索用时 46 毫秒
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Annelise Koch 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1963,33(8):352-354
Zusammenfassung Die vorläufigen Ergebnisse über aussichtsreiche Klone aus Kreuzungsnachkommenschaften mit der Sorte Valentine wurden mitgeteilt, weil bei ihnen hochgradige Widerstandsfähigkeit gegenBotrytis mit anderen wertvollen Eigenschaften wie Frühzeitigkeit, Mehltauresistenz, hohem Ertrag und guten Fruchtqualitätseigenschaften verbunden ist. 相似文献
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Four lines of Ephestia kühniella each homozygous for one of three different allozyme alleles at the Est-2 locus and two alleles at the Adh locus were crossed in order to study the extent of somatic, reproductive and adaptive heterosis in F1 hybrids in comparison with the mean performance of the simultaneously reared inbred parent lines. With regard to adult weight and wing length (somatic heterosis) hybrids exhibit maximally 20% (males 10%) and 9% heterosis, respectively. As concerns the production of eggs and hatched larvae (reproductive heterosis) hybrids exceed the parental mean by 90% and 200%. Adaptive heterosis is realized by a shorter development period of the hybrids (maximally by 30%) as well as by significant lower variance of all metrical characters studied. In the F2 the degree of heterosis diminishes. There is neither an excess of heterozygotes among the segregating allozyme genotypes nor superior performance of the heterozygotes concerning any one of the traits studied. Therefore, it is concluded that the pronounced heterosis in F1 is not a single-gene-heterosis operating at the Est-2 and the Adh-locus. 相似文献
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The Adélie penguin, Pygoscelis adeliae, an important component of the Antarctic marine ecosystem, is closely associated with sea ice. Using data collected by Japanese Antarctic Research Expeditions since the 1960s, we examined trends in breeding populations of this species around Lützow-Holm Bay. Ten colonies ranging in size from 10 to 2,500 individuals were counted along the Soya Coast. Populations fluctuated synchronously, and overall increased at most colonies, except for two: one located deep inside the bay and another where human disturbance was substantial. Populations tended to increase during, or after, periods of sparse sea ice in summer, a condition that occurred once every decade. An increase in population size also occurred 5 years after a winter of extensive sea ice and after a winter of especially reduced sea ice. 相似文献
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Weale R 《Spatial Vision》2008,21(3-5):363-377
Two-dimensional views of three-dimensional space are based on conventions. Renaissance perspectival drawing invented by Brunelleschi is one of them. It caused difficulties to fifteenth and sixteenth century and later artists, although readily taken up by those understanding mathematics. Raphael was amongst those who did not seem to have understood some of its elements: this is illustrated in the first section. The second addresses the question of whether a squint may manifest in an artist's work. Giorgione's ocular anomaly was well documented by several of his self-portraits, and reference is made to some of his paintings with a special analysis of The Tempest. The final section deals with chromatic stereoscopy, with particular reference to the work of Dürer. His apparently anomalous spatial sense is tentatively explained with the suggestion that he may have suffered from a defect of colour vision (protanomaly). 相似文献
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The extent and biomass of the Gracilaria beds in the Lüderitz Bay area, Namibia were surveyed in winter and summer. The beds covered most of the suitable sediments
available (grain size 106–212 μm) and did not occur in water shallower than 1 m or deeper than 11 m. Total surface area, most
of which occurred in the Bay system, changed very little from winter to summer but biomass increased by 3.5 fold. In winter,
total Gracilaria biomass was 200 t and 650 t and in summer, 150 t and 2850 t respectively in the Lagoon and Bay. Maximum biomass occurred
at 3–4 m in the Lagoon and 5–6 m in the Bay in both winter and summer. Gracilaria beach cast data from 1987 to 1991 for the area were analysed for seasonality and, depending on the specific site, correlated
with swell, southerly wind velocity and sea temperature. Beach cast in the Lagoon system is a more continuous process than
in the Bay, where beach casts at most sites follow an annual pattern. Wind driven currents and chop were the most important
causative parameters of beach cast in the Lagoon whereas the depth at which the plants were growing and swell were more important
in the Bay system. The two systems viz. Lagoon and Bay are independent of one another with very little or no exchange of Gracilaria between them. This was evidenced by the similar percentage each contributes to the total beach cast and the similar pattern
of beach cast from year to year. The decrease in total beach cast from 1989 to the end of the study period was attributed
to a trend towards increasing swell height and low sea temperatures in 1991. 相似文献
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Oŀŀo Knapp 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1940,12(8):193-199
Ohne Zusammenfassung 相似文献
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Albert Boerger 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1939,11(9):265-277
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Stefan Vogel 《Plant Systematics and Evolution》1958,104(4-5):491-530
Ohne ZusammenfassungMeinem hochverehrten Lehrer Herrn Professor Dr. WilhelmTroll zum 60. Geburtstage dargereicht. 相似文献
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Hermann Kuckuck Martin Schmidt 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1948,19(5-6):129-135
Ohne Zusammenfassung 相似文献
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Dr. Heribert Peter 《Cell and tissue research》1960,52(3):401-407
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Ebeling hat im Jahre 1925 über Differenzierung und Follikelbildung in Schilddrüsenkulturen 18–19 Tage alter Hühnerembryonen berichtet. Diese Versuche wurden mit den Schilddrüsen erwachsener Hähne nachgeprüft. Dabei zeigte es sich, daß unter den von Ebeling angegebenen Bedingungen keine morphologische Differenzierung eintritt. Die von ihm beobachteten und fälschlich als neu entstanden bezeichneten Follikel sind Reste der Mutterstücke, d.h. des ursprünglich ausgepflanzten voll ausdifferenzierten Schilddrüsenfragmentes. 相似文献