Two wheat {Triticum aestivum L.) cultivars, Trakia (drought-sensitive, DS) and Slavianka 196 (drought-tolerant, DT), were subjected to water stress induced by polyethyleneglycol (PEG) 6000; 15 % PEG for 6 h (mild stress); 25 % PEG for 6 h and 15 % PEG for 24 h (severe stress). Exposure of plants to water stress led to a noticeable decrease in both the initial slope of net photosynthetic rate to intercellular CO2 concentration {Pfilc^ curves and the maximum P-^. Ribulose 1,5-bisphosphate carboxylase (RuBPC) activity was almost unchanged under mild stress while under severe stress it was reduced by about 26-27 %. The ratio of variable to maximal chlorophyll fluorescence did not change which implied that there was little effect of examined stress conditions on the photosystem 2 electron transport. The relative magnitude of stomatal and nonstomatal factors in limitation of photosynthesis depended on stress severity.
In juvenile trees growing at the rainforest understory, light is the most limiting factor for growth. It has been assumed that stomata quickly respond to light irrespective of the physical conditions prevailing before leaf illumination. Nevertheless, so far this issue has not been addressed for saplings of Amazonian tree species. The aim of this study was to determine how stomatal conductance (gs) and photosynthetic parameters of Amazonian saplings respond to diurnal variation in the physical environment and to rainfall seasonality. Light-saturated net photosynthetic rate (PNmax) and gs at light saturation (gsmax) were measured in the dry (August) and rainy (January) season of 2008 in saplings of 10 Amazonian tree species (Minquartia guianensis, Myrcia paivae, Protium apiculatum, Guatteria olivacea, Unonopsis duckei, Rinorea guianensis, Dicypellium manausense, Eschweilera bracteosa, Gustavia elliptica, and Tapura amazonica). At the forest understory, variables of the physical environment were measured. Rainfall seasonality did not affect PNmax and gsmax, nor was the effect of species on PNmax and gsmax significant (p>0.05). The gs and PNmax increased as the forest understory became brighter and warmer; as a result, PNmax and gsmax were higher at midday than early in the morning or in the afternoon. However, contrary to expectations, neither changes in air vapor pressure deficit nor air CO2 concentration at the forest understory affected stomatal opening. More investigation is needed to elucidate the role of environmental factors in modulating stomatal movements in juvenile trees growing beneath the dense canopy of tropical rainforests., R. A. Marenco, H. C. S. Nascimento, N. S. Magalhães., and Obsahuje bibliografii
Spiders are generalist predators that contribute to the control of pests in agroecosystems. Land use management determines habitats including refuges for hibernation and aestivation. The availability of shelters on the ground can be crucial for maintaining populations of spider within crops. We studied the effect of the number of stones on the surface of the soil on the spider community in selected olive groves in Trás-os-Montes (northeastern Portugal). The number of stones significantly influenced the overall diversity of spiders, abundance of immature individuals and abundance of ground hunters. Agricultural management practices aimed at the conservation of soil microhabitats such as hedgerows, stonewalls and stones on the ground should be promoted in order to maintain or increase the number of shelters for potential natural enemies of pests., Jacinto Benhadi-Marín, José A. Pereira, José A. Barrientos, José P. Sousa, Sónia A.P. Santos., and Obsahuje bibliografii
Článek zkoumá transformaci komunistické identity ve východním bloku po roce 1956, přičemž poukazuje jak na okamžiky jejího úpadku, tak na pokusy znovu tuto identitu vytvořit. Věnuje se tomu, jak se komunistická identita přetvářela a proměňovala mimo nejvyšší kruhy stranického vedení, mezi řadovými členy strany. Po dvacátém sjezdu sovětských komunistů a následujících událostech roku 1956 čelil pocit sounáležitosti komunistických stran a společnosti vážné výzvě, kterou představovaly obrozené národní, etnické, konfesní či náboženské identity. Renesance těchto partikulárních identit v roce 1956 těžce narušila zastřešující utopický příběh komunistické budoucnosti. Na druhou stranu však víra v komunistické panství oslabena nebyla. Tato studie nabízí tezi, že se objevila jakási náhražková utopie schopná sjednotit partikulární identity v sourodý významový celek, jenž se opíral o představu strany coby lokálního a národního aktéra. Autor popisuje tuto změnu jako posun od programatické utopie k procesuální utopii, která podle něj spočívala na prostorově decentralizovaných a časově fragmentovaných příbězích. and Pavel Kolář.
The paper analyses the fact that the Czech communist party (KSČM) can rely on substantial and stable (occasi- onally even rising) electoral support. The phenomenon has been discussed extensively in academic as well as social and political discourses. On the basis of available empirical data, sociological analyses and statistical information, the paper categorizes some basic socio-political conditions and predispositions which may help explain the fact that the political party once considered to be the anti-system heir of the non-democratic regime is now one of the most stable elements of Czech politics., Daniel Kunštát., and Obsahuje seznam literatury
20. dubna 2005 tomu bude deset let, co byly vyzdviženy ostatky Marie a Pierra Curieových z hrobu v Sceaux u Paříže a slavnostně uloženy pod Panthéonem. Marie Curie se tak stala první ženou, která byla takto poctěna. O pohnutém životě této neobyčejně nadané vědkyně bylo napsáno mnohé a její příběh se dočkal i hojného uměleckého ztvárnění. Mezi jedno z nejúspěšnějších děl patří bezesporu divadelní hra Jeana-Noela Fenwicka "Pierre et Marie", kterou u nás uvádí Divadlo Radka Brzobohatého v překladu Alexandra Jerie pod názvem "...nebylo by libo Nobela?" and Andrea Cejnarová.