In the culminating and late middle ages funny scenes, the so called drôleries, appear in the borders of illuminated manuscripts. Th eir problems are not explained completely; they seem to contain hidden spiritual meanings. Besides singing birds, which are symbols of the unearthly sphere, fi gures appear most oft en who were taken as negative in middle-ages – owls, apes, beasts of prey, dragons, and clowns. Th e fi gures of antique mythology were perceived as negative too; the cults connected with them were perceived as demoniacism by the Christian society. Drôleries are usually placed in borders which are decorated with an acanth. Th e acanth in time became a symbol of victory over death. It can be also interpreted as Christ´s crown of thorns. In this way the spirit of medieval symbolism indicated that negative forces are driven to the margin and defeated by Christ´s victim.
Extreme conditions, such as drought, high temperature, and solar irradiance intensity, are major factors limiting growth and productivity of grapevines. In a field experiment, kaolin particle film application on grapevine leaves was examined during two different summer conditions (in 2012 and 2013) with the aim to evaluate benefits of this practice against stressful conditions hindering photochemical processes. We used chlorophyll a fluorescence to investigate attached leaves. Two months after the application, during the hottest midday, the kaolin-treated plants showed by the JIP test significantly higher quantum yield of PSII photochemistry, flux ratios, maximum trapped excitation flux of PSI, absorption flux, electron transport flux, maximum trapped energy flux per cross section, and performance index than plants under control conditions in the warmer year. On the contrary, the treated plants showed a lower initial slope of relative variable fluorescence and a decrease in the absorption and electron transport per cross section. The JIP test showed higher efficiency of PSII in the plants treated with kaolin mainly in 2013 (higher temperature and drought). Our results supported the hypothesis that the accumulation of active PSII reaction centres was associated with decreased susceptibility to photoinhibition in the kaolin-treated plants and with more efficient photochemical quenching. Grapevines in the Douro Region seems to profit from the kaolin application., L.-T. Dinis, H. Ferreira, G. Pinto, S. Bernardo, C. M. Correia, J. Moutinho-Pereira., and Obsahuje seznam literatury
The contribution deals with the Tractatus de ordine stellarum fixarum (Prague, National Library, XXVI A 3, c. 1405, fol. 1r–48r). Chosen parts of this text containing ancient star myths are edited here, translated into Czech and compared with Hyginus’ treatise De astronomia for the first time.