The photosynthetic pigments and photochemical efficiency of photosystem 2 (PS2) were studied in four constitutive species (Achillea millefolium L., Festuca pseudovina Hack. ex Wiesb., Potentilla arenaria Borkh., and Thymus degenianus Lyka) of a semiarid grassland in South-eastern Hungary. Every species displayed typical sun-adapted traits and substantial plasticity in the composition and functioning of the photosynthetic apparatus. The contents of chlorophylls (Chls) and carotenoids (Cars) on a dry matter basis declined from May to July, however, the amount of total Cars on a Chl basis increased. This increase was the largest in Potentilla (48 %) and the smallest in Achillea (14 %). The pool of xanthophylls (VAZ) was between 25 % and 45 % of the total Car content and was larger in July than in May. The content of β-carotene increased by July, but lutein content did not change significantly. The Chl fluorescence ratio Fv/Fm was reduced by 3-10 % at noon, reflecting the down-regulation of PS2 in the period of high irradiance and high temperature. The occurrence of minimal values of ΔF/Fm' showed close correlation to the de-epoxidation rate of violaxanthin. Hence in natural habitats these species developed a considerable capacity to dissipate excess excitation energy in the summer period in their photosynthetic apparatus through the xanthophyll cycle pool and a related photoprotective mechanism, when the photochemical utilization of photon energy was down-regulated. and S. Veres ... [et al.]
The photosynthetic pigments of twigs in five tree and shrub species possessing chlorenchyma under a well developed, stomata-less, and highly photon absorptive periderm were analysed and compared to those of the corresponding canopy leaves. We asked whether the unavoidable shade acclimation of corticular chlorenchyma results in photosynthetic pigment complements typically found in shade leaves. As expected, chlorophyll (Chl) a/b ratios in twigs were consistently low. However, carotenoid (Car) analysis did not confirm the initial hypothesis, since twigs generally contained increased Chl-based pool sizes of the xanthophyll cycle components. The contents of photo-selective neoxanthin and lutein were high as well. Yet, β-carotene content was extraordinarily low. In addition, twigs retained high pre-dawn ratios of the deepoxidized antheraxanthin and zeaxanthin, although environmental conditions were not pre-disposing for such a state. The unexpected Car composition allows the conclusion that other micro-environmental conditions within twigs (hypoxia, increased red to blue photon ratios, and extremely high CO2 concentrations) are more important than shade in shaping the Car profiles. and E. Levizou, Y. Petropoulou, Y. Manetas.
The following caryophyllidean tapeworms were found in freshwater fishes from Japan (species reported from Japan for the first time marked with an asterisk): family Caryophyllaeidae: Paracaryophyllaeus gotoi (Motomura, 1927) from Misgurnus anguillicaudatus (Cantor); Archigetes sieboldi Leuckart, 1878 from Pseudorasbora parva (Temminck et Schlegel) and Sarcocheilichthys variegatus microoculus Mori (new hosts); family Lytocestidae: *Caryophyllaeides ergensi Scholz, 1990 from Tribolodon hakuensis (Günther), T. ezoe Okada et Ikeda, Hemibarbus barbus (Temminck et Schlegel) and Chaenogobius sp. (new hosts); Khawia japonensis (Yamaguti, 1934) from Cyprinus carpio Linnaeus; K. sinensis Hsü, 1935 from H. barbus (new host) and C. carpio; *K. parva (Zmeev, 1936) from Carassius auratus langsdorfii Valenciennes in Cuvier et Valenciennes and Carassius sp. (new hosts); and *Atractolytocestus sagittatus (Kulakovskaya et Akhmerov, 1962) from C. carpio; family Capingentidae: *Breviscolex orientalis Kulakovskaya, 1962 from H. barbus (new host); and Caryophyllidea gen. sp. (probably Breviscolex orientalis) from C. carpio. The validity of C. ergensi, originally described from Leuciscus leuciscus baicalensis from Mongolia, is confirmed on the basis of an evaluation of extensive material from Japan. Atractolytocestus sagittatus (syn. Markevitschia sagittata) is tentatively considered a valid species, differing from the only congener, A. huronensis Anthony, 1958, in its considerably greater number of testes.
Parasitological examination of two ornate Nile monitors Varanus ornatus (Daudin, 1803) imported from Benin revealed the presence of a new species of Caryospora. Oocysts of Caryospora varaniornati sp. n. are spherical to slightly subspherical, 12.0 (11-12.5) × 11.5 (11-12) µm, without a micropyle and oocyst residuum, and occasionally possessing one small polar granule. Sporocysts are broadly ellipsoidal, 8.8 (8.5-9.5) × 6.7 (6.5-7) µm; a lentil-like Stieda body is present, ca. 0.5 × 1 µm; substieda body not visible. Experimental infection of a closely related host, Varanus niloticus (L.), did not lead to the oocyst excretion despite the fact that one of the experimentally inoculated monitors was immunosuppressed by dexamethasone. Histological examination did not reveal stages of coccidian development. Therefore, it is possible that C. varaniornati is strictly host specific.
The study deals with the journal Religion und Priester, which was published between 1782 and 1784 in Prague and Vienna. At first, the author tries to summarize some basic facts on the journal, correcting some errors concerning its publishing and authorship. The core of the study consists in the analysis of its criticism of priestly celibacy. Religion und Priester discussed this problem repeatedly, using various strategies of argumentation based on history, philosophy of human nature and political thought., Vít Pěček., and Obsahuje bibliografické odkazy