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71.
72.
In situ Observations of Stomatal Movements 总被引:8,自引:0,他引:8
Kappen, L., Andresen, G. and L?sch, R. 1987. In situ observationsof stomatal movements.J. exp. Bot. 38: 126141. A device is described by which stomatal movements in situ canbe observed and recorded continuously in light and in darkness.It is mounted in a conditioned CO2 exchange measuring chamberso that stomatal movements can be observed whilst CO2 exchange(photosynthesis and respiration) of the same leaf is measured.Advantages and limitations are discussed. By this method itwas shown that stomata of Vicia faba although responding inthe same direction to environmental stimuli exhibited a widerange of pore widths. Responses to changes of air humidity andof CO2 content were clearly evident when the leaves were exposedto light. Before stomata closed due to decreasing water vapourpressure differences between leaf and air they showed a markedwidening of the pore. An inverse response occurred when watervapour pressure deficit decreased. In darkness stomata did notrespond to such changes. Key words: Stomata, leaf gas exchange, microscopic observation 相似文献
73.
NORBERT WILBERT 《The Journal of eukaryotic microbiology》1972,19(4):590-592
The ciliate Marituja pelagica Gajewskaja, 1928 was described originally from Lake Baikal. Recently this organism was found in the plankton of a eutrophic pond in the area of Bonn. Studies of structure of living ciliates and of silver-stained preparations aided in the solution of hitherto existing taxonomic problems with regard to M. pelagica and led to its placement in the suborder Peniculina. 相似文献
74.
CLIFFORD RAY JOHNSON WILLIAM G. VOIGT E. NORBERT SMITH 《Zoological Journal of the Linnean Society》1978,62(2):179-188
Grouped data for head and body mean-preferred temperature were 31.° C (range 28.9° -35.9° C) and 32.0° C (range 29.9° -35.6° C) respectively, and the differences were not significant. Grouped data for measn-voluntary maxima for the head and body were 34.4° C (range 31.4° -38.1° C) and 33.7° C (range 31.5° -38.5° C) respectively. A comparison of thermal preferenda and varying sized individuals of Alligator mississipiensis showed a direct relationship between size and preferred temperature. The most effective method of reducing head and body temperature was that of seeking shade; water would be effective, but in this study enough water for complete submersion was not available in the experimental enclosures. Gaping was observed several times during the study but had little effect on head temperature. Heating and cooling experiments conducted in constant temperatute water-baths demonstrated that a 49.9 kg alligator heated in 36.5% of the time it required to cool. The alligator shows a greater alteration in heating and cooling time than any other reptile studied. 相似文献
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76.
ANN‐CHRISTIN HONNEN FRANK HAILER NORBERT KENNTNER IVAN LITERÁK LENKA DUBSKÁ FRANK E. ZACHOS 《Biological journal of the Linnean Society. Linnean Society of London》2010,99(4):727-737
We analysed 123 white‐tailed sea eagles (Haliaeetus albicilla) from (primarily central) Europe with respect to variability and differentiation based on 499 bp of the mitochondrial control region and genotypes at seven unlinked nuclear microsatellites. Variability was high (overall expected heterozygosity, haplotype and nucleotide diversity being 0.70, 0.764 and 0.00698, respectively) and both marker systems showed a subdivision into two main genetic clusters (microsatellites) or haplogroups (mtDNA). In line with earlier analyses focusing on populations from northern and eastern Europe, as well as from Asia, we found a high level of admixture in Europe and no signs of a bottleneck – despite a severe decline of white‐tailed sea eagle populations during the 20th century. Europe is thus a global stronghold for this species not only with respect to the number of breeding pairs but also regarding the proportion of species‐wide genetic diversity. Our dense sampling revealed a possibly clinal variation within central Europe from north‐west to south‐east that was reflected by the distribution of mtDNA haplotypes as well as the two microsatellite‐based clusters. This population differentiation in central Europe probably originated from a geographically structured postglacial colonization and was later enhanced by recent demographic fluctuations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 727–737. 相似文献
77.
SIMONA BONELLI MAGDALENA WITEK SARA CANTERINO MARCIN SIELEZNIEW ANNA STANKIEWICZ‐FIEDUREK ANDRÁS TARTALLY EMILIO BALLETTO KARSTEN SCHŐNROGGE 《Ecological Entomology》2011,36(2):135-143
1. In 2002 Microdon myrmicae, a social parasite of Myrmica ants, was taxonomically separated from Microdon mutabilis. The original study in the U.K. found Microdon myrmicae to be specific to one ant species, Myrmica scabrinodis, yet it became apparent that the range of Microdon myrmicae includes at least the western Palaearctic. 2. Current knowledge of the European distributions of both Microdon myrmicae and Microdon mutabilis in Europe is reviewed. Also, in detailed studies of two Polish populations, Microdon myrmicae was found to survive equally well with two Myrmica ant species. We examine, however, the possibility that this reflects the presence of two separate Microdon species, each connected to one species of Myrmica. 3. Forty populations of Microdon myrmicae and 37 populations of Microdon mutabilis are currently known in Europe. All the populations in central and southern Europe that were visited after the separation of the two species were identified as Microdon myrmicae, while Microdon mutabilis’ recognised range is now restricted to the British Isles and Scandinavia. Myrmica scabrinodis was found to host Microdon myrmicae in 26 out of 31 populations investigated. Four other Myrmica species were identified to the host Microdon myrmicae: Myrmica gallienii (eight populations), Myrmica rubra (four), Myrmica vandeli (one), and Myrmica sabuleti (one). Microdon myrmicae occurs in waterlogged grassland habitats, mainly of the ‘Molinietum’ type, resulting in a patchy distribution relative to its host ants. 4. In two populations Myrmica scabrinodis and Myrmica gallienii are both abundant and rear Microdon myrmicae in equal proportions. Microdon myrmicae pupae from Myrmica gallienii nests were heavier and the anterior respiratory organs were of significantly different shape. In contrast, the comparisons of Microdon myrmicae pupae among all other populations showed no significant differences, suggesting only one species throughout the European range. 相似文献
78.
79.
Many individuals with mental illnesses are troubled by self-stigma and the subsequent processes that accompany this stigma: low self-esteem and self-efficacy. “Why try” is the overarching phenomenon of interest here, encompassing self-stigma, mediating processes, and their effect on goal-related behavior. In this paper, the literature that explains “why try” is reviewed, with special focus on social psychological models. Self-stigma comprises three steps: awareness of the stereotype, agreement with it, and applying it to one’s self. As a result of these processes, people suffer reduced self-esteem and self-efficacy. People are dissuaded from pursuing the kind of opportunities that are fundamental to achieving life goals because of diminished self-esteem and self-efficacy. People may also avoid accessing and using evidence-based practices that help achieve these goals. The effects of self-stigma and the “why try” effect can be diminished by services that promote consumer empowerment. 相似文献
80.
J. C. HESSON F. RETTICH E. MERDIĆ G. VIGNJEVIĆ Ö. ÖSTMAN M. SCHÄFER F. SCHAFFNER R. FOUSSADIER G. BESNARD J. MEDLOCK E.‐J. SCHOLTE J. O. LUNDSTRÖM 《Medical and veterinary entomology》2014,28(2):179-186
Two species of arbovirus vector, Culex torrentium and Culex pipiens (Diptera: Culicidae), occur in several European countries, but difficulties in their accurate identification and discrimination have hampered both detailed and large‐scale distribution and abundance studies. Using a molecular identification method, we identified to species 2559 larvae of Cx. pipiens/torrentium collected from 138 sites in 13 European countries ranging from Scandinavia to the Mediterranean coast. In addition, samples of 1712 males of Cx. pipiens/torrentium collected at several sites in the Czech Republic were identified to species based on the morphology of their hypopygia. We found that the two species occur together in large areas of Europe, and that Cx. torrentium dominates in northern Europe and Cx. pipiens dominates south of the Alps. The transition in dominance occurs in central Europe, where both species are roughly equally common. There was a strong correlation between the length of the growing season at different sites and occurrences of the two species. As the growing season increases, the proportion and detection of Cx. torrentium decrease, whereas those of Cx. pipiens increase. The present findings have important consequences for the interpretation of the results of studies on major enzootic and link‐vectors of mosquito‐borne bird‐associated viruses (i.e. Sindbis, West Nile and Usutu viruses), especially in central Europe and Scandinavia. 相似文献