Page 3575 of 3815 Results 35741 - 35750 of 38146
Id/Author/Year/TitleOrder by:  Year  Id  Author  Title
1073
John V. (1996): UTM- Grid mapping and distribution patterns of lichens in Turkey, Proceed. IV. Plant Life Southwest Asia, 440-453

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3453
Fahselt D. (1993): UV absorbance by thallus extracts of umbilicate lichens, Lichenologist, 25(4): 415-422

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36379
Lorenz C., Bianchi E., Alberini A., Poggiali G., Benesperi R., Papini A. & Brucato J.R. (2024): UV photo-degradation of the secondary lichen substance parietin: A multi-spectroscopic analysis in astrobiology perspective, Life Sciences in Space Research, 41: 191–201

The cortical anthraquinone yellow-orange pigment parietin is a secondary lichen substance providing UVshielding properties that is produced by several lichen species. In our work, the secondary metabolite has been extracted from air-dried thalli of Xanthoria parietina. The aims of this study were to characterize parietin absorbance through UV–VIS spectrophotometry and with IR spectroscopy and to evaluate its photodegradability under UV radiation through in situ reflectance IR spectroscopy … URL EN Read more... 

8943
McEvoy M., Nybakken L., Solhaug K.A. & Gauslaa Y. (2006): UV triggers the synthesis of the widely distributed secondary lichen compound usnic acid, Mycological Progress, 5: 221–229

Synthesis of the cortical dibenzofuran derivative usnic acid and the medullary depsidone salazinic acid was studied in Xanthoparmelia stenophylla thalli. Natural levels of ultraviolet radiation clearly induced the re-synthesis of usnic acid. The resynthesis was boosted by the addition of ribitol, the carbohydrate delivered from the Trebouxia photobiont to the mycobiont. We also studied the extractability of nine extracellular lichen compounds in three species X. stenophylla, Hypogymnia tubulosa, … EN Read more... 

33146
Pedišius V. (2021): UV-B absorbing and bioactive secondary compounds in lichens Xanthoria elegans and Xanthoria parietina: A review, Czech Polar Reports, 10(2) [2020]: 252–262

Secondary metabolites are the bioactive compounds of plants which are synthesized during primary metabolism, have no role in the development process but are needed for defense and other special purposes. These secondary metabolites, such as flavonoids, terpenes, alkaloids, anthraquinones and carotenoids, are found in Xanthoria genus lichens. These lichens are known as lichenized fungi in the family Teloschistaceae, which grows on rock and produce bioactive compounds. A lot of secondary compounds … URL EN Read more... 

6205
Nybakken L. & Julkunen-Tiitto R. (2006): UV-B induces usnic acid in reindeer lichens, Lichenologist, 38(5): 477-485

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9657
Buffoni Hall R.S., Bornman J.F. & Björn L.O. (2002): UV-induced changes in pigment content and light penetration in the fruticose lichen Cladonia arbuscula ssp. mitis, Journal of Photochemistry and Photobiology B: Biology, 66: 13-20

Abstract: The response of the lichen, Cladonia arbuscula (Wallr.) Flot. ssp. mitis (Sandst.) Ruoss to enhanced UV-B (280-315 nm) radiation was investigated with respect to: (a) changes in phenolic content; (b) differential pigment accumulation under visible and UV radiation with increasing distance from thallus apices; and (c) the internal distribution of UV-B radiation within the thallus measured with quartz optical fibres. In a short-term experiment, lichens were exposed for 7 days in a growth … EN Read more... 

24009
Nguyen K.-H., Chollet-Krugler M., Gouault N. & Tomasi S. (2013): UV-protectant metabolites from lichens and their symbiotic partners, Natural Product Reports, 30: 1490-1508

Lichens are structurally complex symbiotic organisms that are exposed to a wide variety of external conditions (extreme temperatures, desiccation, UV radiation, etc.). These poikilohydric organisms have developed various mechanisms of photoprotection, such as light scattering, radiation screening, thermal dissipation, activation of antioxidant defense and macromolecules and membrane repair. These unique organisms produce a vast array of compounds, with more than 1000 secondary metabolites known. … EN Read more... 

34665
Shelyakin M., Malyshev R., Silina I., Zakhozhiy I. & Golovko T. (2022): UV‑B induced changes in respiration and antioxidant enzyme aktivity in the foliose lichen Peltigera aphthosa (L.) Willd., Acta Physiologiae Plantarum, 44: 116 [13 p.]

Lichens are phototrophic organisms tolerant to adverse environmental conditions. However, the mechanisms underlying their stress tolerance are not fully understood. For photosynthetic organisms depending on solar radiation, UV-B radiation (280–320 nm) acts as a stress factor. We studied the pro-/antioxidant and respiratory metabolism of Peltigera aphthosa to identify adaptive responses of lichen to a physiological dose of UV-B radiation (14 kJ day− 1 for 10 days). A browning of the upper … URL EN Read more... 

3511
Domin K. (1924): Úvahy a studie o regionáním členění Čech s hlediska geobotanického, Spisy PřF Karlovy Univ., Praha, 9: 1-33

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