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Hieracium petrovae Vladimirov & Szeląg sp. nov. , a new diploid (2 n  = 18) species in H. sect. Pannosa Zahn, is described and illustrated from the Rhodope Mountains, South Bulgaria, and compared with related taxa. It grows in relict habitats in crevices of limestone rock together with many Balkan endemics. H. petrovae is morphologically similar to taxa from the H. pannosum , H. pilosissimum and H. heldreichii groups (collective species sensu Zahn) to some of which it is a presumed ancestral species.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 261–265.  相似文献   
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Photosynthetic activities of cadmium-treated tomato plants   总被引:20,自引:0,他引:20  
Tomato plants (Lycopersicum esculentum Mill. cv. Moneymaker) grown on nutrient medium containing cadmium exhibit reduced net photosynthesis and reduced contents of chlorophyll and accessory pigments. In chloroplasts isolated from cadmiumtreated plants photosystem II activity, as measured by 2,6-dichlorophenolindophenol photoreduction, and photosystem II + I activity (H2O → methyl viologen) were both inhibited to about 60%. When 1,5-diphenylcarbazide was used as artificial electron donor, no significant cadmium effect was observed. Photosystem I activity was not affected by cadmium. The fine structure of chloroplasts in cadmium-treated plants was degenerated, similarly to senescence response. The principal symptom of cadmium action was the occurrence of large plastoglobules and a disorganization of the lamellar structure, mainly grana stacks. Transfer of cadmium-treated plants into a medium with increased manganese level caused grana stacking and restoration of photosystem II activity.  相似文献   
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Falseryx neervelpensis sp. nov. (Booid-grade, 'Tropidophiidae') from the earliest Oligocene (MP 21) of Belgium is described on the basis of vertebrae coming from all major portions of the vertebral column. In its peculiar caudal osteology, the snake approaches the unique morphological pattern characteristic of the living Neotropical Tropidophiinae. This is the first time such a complete and informative vertebral column of a dwarf boa has been described. The genus Falseryx was absent from Western Europe in younger parts of the Oligocene, but reappeared at the end of the Early Miocene. This dispersal pattern provides additional evidence that in most phases of the Oligocene and Early Miocene Western European snake faunas were effectively isolated from possible influences from the East.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 393–406.  相似文献   
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Abstract: Radiotelemetry is a widely used method to study ecology, behavior, and physiology of different animals but has rarely been used on shrews. Small body size, wide neck and narrow skull, high mobility, and fragility of shrews cause problems for both transmitter attachment and the safety of the animals. We developed a method for nonpermanent attachment of transmitters, which allowed us to track such small mammals as the Eurasian water shrews (Neomys fodiens; n = 39, mean body mass 14.9 g), Mediterranean water shrews (Neomys anomalus; n = 32, 10.9 g), and common shrews (Sorex araneus; n = 51, 8.1 g). We used microtransmitters weighing 0.47 g, but those we applied to the larger Neomys species were heavier (0.67 g) because we fortified them with a layer of hard material to prevent damage from biting. We glued a transmitter directly to the skin on a shrew's back, with the anterior edges particularly well sealed. We tracked shrews in the wild and in outdoor enclosures. Transmitters usually dropped off together with peeled skin (on average, after 56.0 hr, n = 92 observations), but if not dropped and if the signal was not lost, mean duration of monitoring was 96.7 hours (n = 37) and in 2 cases exceeded 194 hours. Other advantages of our attachment method were 1) it was less invasive and easier to apply than implantation of transmitters into the body cavity, and 2) we could find dropped transmitters and reuse them. We give suggestions on how to minimize the risk of injury to animals by correct handling, manipulation, and gluing. In conclusion, we recommend radiotelemetry as a useful technique for studying shrew behavior in both free-living populations and experimental enclosures.  相似文献   
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