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1332. O plži, který se raději dusí, než by ztrácel tělní vodu
- Creator:
- Vladimír Košťál, Jan Rozsypal, and Pavel Pech
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, zoologie, měkkýši, životní prostředí, ekologie, molluscs, environment, ecology, 2, and 59
- Language:
- Czech
- Description:
- Ovsenka skalní (Chondrina avenacea) je plicnatý plž, který žije celoročně na holých vápencových skalách, kde dochází k drastickým denním i sezonním změnám ozáření, teploty, vlhkosti a také dostupnosti potravy. V článku popisujeme fyziologické a biochemické adaptivní mechanismy, které umožňují ovsenkám přežít na jejich extrémním stanovišti., Chondrina avenacea is a pulmonate snail dwelling on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. In this paper, we describe the physiological and biochemical adaptive mechanisms that allow the snails to survive in their extreme microhabitat., Vladimír Košťál, Jan Rozsypal, Pavel Pech., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1333. O pohlavním rozmnožování a jeho paradoxech. 1
- Creator:
- Jan Toman
- Format:
- bez média and svazek
- Type:
- article, text, články, journal articles, model:article, and TEXT
- Subject:
- Biologické vědy, biologie, pohlavní rozmnožování, jaderní, evoluční teorie, biology, sexual reproduction, Eukaryota, evolutionary theories, ekologická teorie, 2, and 57/59
- Language:
- Czech
- Description:
- Pohlavní rozmnožování je jednou z největších evolučních záhad. Mezi eukaryotickými organismy je široce rozšířené navzdory zásadním nevýhodám. V prvním díle článku se autor zaměřuje na úvod do tohoto paradoxu a prezentuje dříve navržená vysvětlení z okruhu genetických a ekologických teorií pohlavního rozmnožování. Připravuje si tak půdu pro obecnější vysvětlení vyplývající z teorie zamrzlé plasticity v druhém díle seriálu., Sexual reproduction is one of the major evolutionary enigmas. It is widely distributed among eukaryotic organisms despite its essential disadvantages. In the first part of his article the author focuses on the introduction to this paradox and a presentation of the earlier explanations postulated by the genetic and ecological theories of sexual reproduction. He thus sets the stage for a more general explanation arising from the frozen plasticity theory in the second part., and Jan Toman.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1334. O pohlavním rozmnožování a jeho paradoxech. 2
- Creator:
- Jan Toman
- Format:
- print, bez média, and svazek
- Type:
- article, text, články, journal articles, model:article, and TEXT
- Subject:
- Biologické vědy, pohlavní rozmnožování, jaderní, evoluce (biologie), sexual reproduction, Eukaryota, evolution (biology), teorie zamrzlé plasticity, 2, and 57/59
- Language:
- Czech
- Description:
- Pohlavní rozmnožování je jednou z největších evolučních záhad. Mezi eukaryotickými organismy je široce rozšířené navzdory zásadním nevýhodám. V druhém díle článku se autor zaměřuje na vysvětlení tohoto paradoxu ze strany teorie zamrzlé plasticity, které shrnuje řadu výhod pohlavních druhů postulovaných dřívějšími teoriemi a vysvětluje je prostřednictvím evolučního zamrzání. To je vlastní pohlavním druhům a spočívá v dlouhodobém udržování vysokého genetického polymorfismu umožňujícího rychlé a vratné reakce na selekční tlaky prostředí na úkor schopnosti se nevratně přizpůsobit změněným podmínkám., Sexual reproduction is one of the major evolutionary enigmas. It is widely distributed among eukaryotic organisms despite its essential disadvantages. In the second part of his article, the author focuses on the explanation of this paradox according to the “frozen plasticity theory”, which connects several advantages of sexual organisms postulated by earlier theories and explicates them by evolutionary freezing. This phenomenon applies to sexual species and is based on long-term maintenance of high genetic polymorphism, which facilitate fast and reversible reactions to selective pressures of the environment at the expense of the ability to irreversibly adapt to changed conditions., and Jan Toman.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1335. O původu a hybridizaci polyploidních pýrů - na stopě netušených předků
- Creator:
- Václav Mahelka
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Botanika, flóra, pýr, trávy, travní porosty, 2, and 58
- Language:
- Czech
- Description:
- The Wheat (Triticum aestivum) – Intermediate Wheatgrass (Thinopyrum intermedium) – Couch Grass (Elymus repens) species complex is a potential case of gene flow between crop and wild relatives in the Central European area. Understanding the genomic constitutions and evolutionary histories of both polyploid Wheatgrasses and the assessment of frequency of their hybrid formation are basic prerequisities for understanding the gene flow within the whole species complex. and Václav Mahelka.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1336. O státní organisaci výzkumnictví v oboru biotechnologie živočišné a některých jeho úkolech
- Creator:
- Just, Jaroslav
- Publisher:
- Nákladem ministerstva zemědělství republiky Československé
- Format:
- print, bez média, svazek, and 24 stran, 12 vyobrazení : ilustrace.
- Type:
- model:monograph and TEXT
- Subject:
- Zemědělství. Pedologie. Agrotechnika. Agroekologie, Biotechnologie. Genetické inženýrství, zemědělský výzkum, biotechnologie, hospodářská zvířata, výzkumné ústavy, agricultural research, biotechnology, livestock, research institutes, Československo, Czechoslovakia, 631:001.891, 60, (047.31), 24, 2, and 631
- Language:
- Czech
- Description:
- Jaroslav Just.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1337. Obhospodařování luk Krkonošského národního parku
- Creator:
- Skálová, Hana and František Krahulec
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Životní prostředí a jeho ochrana, louky, ekologie, Krkonošský národní park (Česko), Krkonoše (Česko a Polsko : pohoří), 2, and 502
- Language:
- Czech
- Description:
- Abandonment of semi-natural grasslands in the Krkonoše Mountains National Park has resulted in substantial changes in their structure and species composition. Alternative management strategies to maintain species diversity have been tested since the 1990s. These include different combinations of mowing, fertilization, grazing and mulching. and Hana Skálová, František Krahulec.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1338. Observations on sporulation of Eimeria bovis (Apicomplexa: Eimeriidae) from the European bison Bison bonasus: effect of temperature and potassium dichromate solution
- Creator:
- Pyziel, Anna M and Demiaszkiewicz, Aleksander W
- Format:
- electronic, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- kokcidie, coccidia, experimental development of oocysts, wisent, Bialowieza Primeval Forest, 2, and 59
- Language:
- English
- Description:
- The present study was designed to determine the influence of temperature and the addition of potassium dichromate solution (K2Cr2O7) on the efficiency of sporulation of Eimeria bovis (Zublin, 1908), a coccidian species most commonly diagnosed in European bison Bison bonasus (Linnaeus). Sporulation under conventional conditions (2.5% dichromate solution, 23 °C) was completed on the fourth day of incubation (control), whereas the oocyst development took two days more at the temperature of 18 °C, and two days less at 28 °C. Additionally, experimental sporulation of E. bovis at the temperature of 23 °C in the environment of sterilised tap water (without any preservation) took 9 days more compared to control. Finally, oocyst development took 16 weeks when the faces were stored in the refrigerator (3-5 °C) without any special additives. Overall, our results indicate that K2Cr2O7, besides the temperature, plays a crucial role in the process of sporulation of oocysts under laboratory conditions, as the longest delay in sporogony was observed when the faeces were stored without any other additives in the temperature of the refrigerator., Anna M. Pyziel, Aleksander W. Demiaszkiewicz., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1339. Occurrence of arrhenotoky and thelytoky in a parasitic wasp Venturia canescens (Hymenoptera: Ichneumonidae): effect of endosymbionts or existence of two distinct reproductive modes?
- Creator:
- Foray, Vincent, Henri, Helene, Martinez, Sonia, Gibert, Patricia, and Desouhant, Emmanuel
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, zoologie, entomologie, Hymenoptera, Ichneumonidae, Venturia canescens, reproductive parasite, thelytokous parthenogenesis, sex evolution, 2, and 59
- Language:
- English
- Description:
- Endosymbiotic organisms are known to manipulate the reproductive biology of their hosts. Incomplete prevalence of endosymbiont inducing thelytokous parthenogenesis results in the coexistence of sexual and asexual individuals, and could account for the maintenance of sexual reproduction in certain populations or species. In the parasitoid Venturia canescens, arrhenotokous ("sexual") and thelytokous ("asexual") individuals occur sympatrically. We aimed to determine whether endosymbionts are implicated in the thelytoky of V. canescens. After screening females of the two reproductive modes for several reproductive parasites: bacteria (Wolbachia, Rickettsia, Bacteroidetes, Spiroplasma, Arsenophonus) and Microsporidia, we concluded that thelytoky in V. canescens is not induced by any of these parasites and confirmed its suitability as a biological model for solving the evolutionary enigma of the maintenance of sexual reproduction., Vincent Foray ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1340. Occurrence of Harmonia axyridis (Coleoptera: Coccinellidae) in field crops
- Creator:
- Vandereycken, Axel, Brostaux, Yves, Joie, Emilie, Haubruge, Eric, and Verheggen, Francois J.
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, zoologie, entomologie, Coleoptera, Coccinellidae, Harmonia axyridis, habitat, crops, agroecosystems, ladybird, exotic species, 2, and 59
- Language:
- English
- Description:
- The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. This study focuses on the occurrence of this exotic species and its seasonal abundance in various field crops. The abundance of adults, larvae and pupae of H. axyridis was evaluated over a three-year period, from 2009 to 2011, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. From May to September, 48 1-m² quadrats were visually inspected in each of the fields sampled on several farms every seven days. H. axyridis colonized and reproduced in all of the four crops studied, with the largest numbers recorded in corn and broad bean crops. Larvae and adults of H. axyridis were recorded mainly in corn and to a much less extent in wheat and potato crops. From 2009 to 2011, the mean weekly abundance of H. ayxridis remained constant except in corn crops, where the recorded densities of all the immature stages and adults were higher in 2011 than in 2009. The population dynamics of aphids and H. axyridis are well described by a symmetric logistic function (S-shape) of cumulative population size. H. axyridis was not always recorded where aphids were abundant, e.g. aphids were abundant on wheat where no H. axyridis were recorded. H. axyridis start reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of the same and other species of ladybird and other aphidophagous species. H. axyridis is often considered to be bivoltine but it only completes one generation per year in field crops. The second generation generally develops late in the season in other habitats., Axel Vandereycken ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public