Research and development of interferometric systems for coordinate and multiaxis measuring are the goal of a common collaborative project involving the Institute of Scientific Instruments, Czech Academy of Sciences and Meopta - optika, s.r.o. The common effort is oriented to applications with the highest demands for precision in the dimensional metrology and nanometrology. The concept of the system represents a modular family of components configurable for various arrangements especially for coordinate measurements in nanotechnology and measurement of topography of surfaces. Meopta - optika, s.r.o. contributes to the project through development of new technology of production of optical components. We present here compact interferometric units designed for measurement by reflection from flat mirror. and Výzkum a vývoj interferometrických odměřovacích systémů pro souřadnicové a víceosé odměřování je náplní společného projektu, v němž spolupracují Ústav přístrojové techniky, Akademie věd České republiky, v.v.i. a podnik Meopta - optika, s.r.o. Společné snažení směřuje k aplikacím s nejvyššími nároky na přesnost v dimenzionální metrologii a nanometrologii. Zvolená koncepce systému představuje modulární rodinu komponent konfigurovatelnou pro různá uspořádání, zvláště pro víceosá měření v nanotechnologiích a měřeních topografie povrchů. Meopta - optika, s.r.o. přispívá především vývojem nové technologie výroby optických prvků rovinné optiky. Zde prezentujeme kompaktní interferometrické jednotky navržené pro interferometrické měření odrazem od rovinného zrcadla.
Source-sink manipulation could regulate the net photosynthetic rate (PN) of winter wheat after anthesis, however, the direction and magnitude of the regulation varied with time after anthesis. The PN was significantly increased by source reduction at the initial time of grain filling, but sink reduction had little influence on the PN, which suggested that the sink (spike) limitation did not occur at this time. Source-sink relation markedly affected PN during rapid grain filling. The PN was increased by source reduction and decreased by sink reduction significantly, which indicated that PN was closely associated with the change of source or sink size. The effect of source-sink manipulation on PN had some relationship with the occurrence of plant senescence at the time of late grain filling. Source reduction accelerated the senescence and dropped the PN, meanwhile, sink reduction delayed the senescence and promoted the PN. A direct relation between the effect of source-sink manipulation on PN and stomatal limitation was not found. Removing one quarter of leaves (RQ) had little influence on spike development after anthesis. In this case there was enough compensation in source production through photosynthesis. Removing one half of leaves (RH) made grain mass per spike and mass of grains lowered, especially the grain mass in the top and base positions of spike declined markedly. The source supply was grain-limiting. Removing one quarter of spikelets (RS) was beneficial to grain-setting in the remaining spikelets, leading to the increase of grain mass. Thus promoting the source supply of photosynthates after anthesis is of major importance for grain to set and to develop. and Zhenlin Wang ... [et al.].
Photosynthetic capacities of green leaves (GL) and green flower petals (GFP) of different ages of the CAM plant Dendrobium cv. Burana Jade were studied through chlorophyll (Chl) content, Chl fluorescence characteristic Fv/Fm, maximal photosynthetic O2 evolution rates (P max), and CAM acidities [dawn/dusk fluctuations in titratable acidity (TA)]. All these photosynthetic parameters were higher in GL than in GFP. Among the different ages of GFP, the young GFP had significant higher readings of all photosynthetic parameters than the oldest GFP, indicating that reduced photosynthesis occurred in the senesced GFP. The source-to-sink relationship between GL and GFP was also studied by comparing the diurnal changes in contents of total soluble and insoluble sugars and TA between the fully irradiated (FI) control (with both irradiated GL and GFP) and GL-darkened plants (covering all GL with aluminium foils, leaving only the GFP exposed to radiation). CAM acidities were much lower in GL darkened with aluminium foils compared to those of FI-GL while there were no differences in CAM acidities of their GFP. The contents of total soluble and insoluble sugars and the CAM acidities of GL towards the end of the day were lower in GL-darkened plants compared to that of FI-plants. Hence CAM acidities of GL depended on their saccharide contents. However, diurnal changes of TA in GFP were similar in all GFP regardless of their ages, with or without GL photosynthetic sources. Thus CAM acidities of GFP are independent of GL saccharides. However, lower saccharide content in GFP (especially the oldest GFP) of GL-darkened plants implies that GFP function as sinks and depend on saccharides exported from GL for its development and growth. and J. He, W. L. Woon.
In this paper, photosynthetic characteristics of green leaves (GL) and green pseudobulbs (GPSB) of C3 orchid Oncidium Golden Wish were first studied. Light saturation for photosynthesis and maximum photosynthetic rates (Pmax) were significantly higher in GL than in GPSB. The results of the optimal PSII quantum yield (Fv/Fm ratio), electron transport rate (ETR), the effective photochemical quantum yield (ΔF/Fm') and nonphotochemical quenching (NPQ) of Chl fluorescence revealed that GPSB had lower light utilization than that of GL. Significantly higher photosynthetic pigments were found in GL than in GPSB. Alteration of source/sink ratio had no impact on all photosynthetic parameters for both GL and GPSB after a short term of 3 days or even a long term of 2 weeks of treatments although there were significant decreases in GL carbohydrate concentration of GL-darkened plants by the end of the day. However, decreases of all photosynthetic parameters of GL were observed in GL-darkened plants after 4 weeks of treatment compared to those of fully illuminated (FI) and GPSB-darkened plants. These results indicate that the level of carbohydrates in GL plays an important role in regulating their photosynthesis. Due to their lower photosynthetic capacities, GPSB function mainly as sinks. Darkening GPSB up to 2 weeks did not affect their own Pmax and the Pmax of GL and thus, did not result in significant decreases of total carbohydrate concentration of GPSB. As GPSB store a large amount of carbohydrates, it could also act as a source when the level of carbohydrates decreased. Thus, GL could depend on GPSB carbohydrates to regulate their photosynthesis when their source capacity was removed. However, 4 weeks after treatments, photosynthetic capacities of GL were significantly lower in GL- and GPSB-darkened plants than in FI plants, which could be due to the lower total soluble and insoluble sugar concentrations of both GL and GPSB in these plants. and J. He, B. H. G. Tan, L. Qin.
Od vyhlášení první chráněné krajinné oblasti (CHKO) v České republice v loňském roce uplynulo 60 let, od formulování prvního uceleného návrhu na zřízení soustavy velkoplošných chráněných území dokonce 100 let. V září 2014 byla vyhlášena nová CHKO Kokořínsko - Máchův kraj, přesněji řečeno dosavadní CHKO Kokořínsko byla rozšířena o přírodovědecky pozoruhodné Dokesko. V současnosti probíhá vyhlašování CHKO Brdy. Je tedy na místě si položit otázku, zda poté bude soustava CHKO v ČR již úplná., Sixty years passed in 2014 since the announcement of the first landscape park in the Czech Republic and a hundred years since the formulation of the first integrated plan to set up a system of large-scale landscape parks. In September 2014 a new Kokořínsko-Mácha country landscape park was announced, or to be more precise the former Kokořínsko landscape park was expanded to include the Doksy district, which is of interest from a natural-sciences viewpoint. At present the preparations for the Brdy landscape park are nearing completion. This article presents these two landscape parks and discusses whether or not the landscape park system in the Czech Republic will now be complete., and Pavel Pešout.
Příspěvek přináší aktuální informace o jedné z nejmladších žákovských přírodovědných soutěží - Fyzikálním DUETu. Tato soutěž dvojic je založena na experimentování jako prostředku k rozvíjení tvůrčích schopností ve fyzice. and Jitka Strouhalová [et al.].