Radish (Raphanus sativus L.) and carrot (Daucus carota L.), plants with underground storage organs grown in the field, were exposed to either ambient (UVA) or 20 % UV-B (UVE) enhanced solar radiation till their root yield stage. In radish, UVE produced a significant increase in shoot and root fresh mass (FM), increase in the contents of chlorophyll, carotenoids, flavonoids, and total proteins per unit FM, Hill reaction rate, and root yield. In contrast, carrot responded negatively to UVE showing a loss in the above parameters. and S. M. J. Nithia, N. Shanthi, G. Kulandaivelu.
Zkoumáním, pozorováním a přemýšlením o Měsíci trávili lidé čas odpradávna. Přestože první člověk se po našem souputníkovi prošel již téměř před padesáti lety, naše chápání tohoto prostého prostředí je stále v počátcích a nedostatek experimentálních dat často doháníme počítačovými modely. Článek pojednává o našich představách o nabíjení měsíčního povrchu a také prachových zrnek na něm a nad ním., Watching and thinking about the Moon has been a popular subject for mankind for a long time. Despite the fact that the first human footprint on the lunar surface is more than fifty years old, our understanding of this rather simple environment is still poor and a lack of experimental data is often supported with computer models. The presented contribution deals with numerical simulations of charging of the lunar surface as well as with charging of dust grains attached to or levitating above the charged surface., Jiří Pavlů, Zdeněk Němeček, Jana Šafránková., and Obsahuje bibliografii
Tolerance of Festuca rupicola Heuff., Botriochloa ischaemum (L.) Keng., and Salvia nemorosa L. to co-occurring drought, high air temperature and high irradiance were investigated in stands representing different degree of degradation. Air and leaf temperatures were higher for the stands in the advanced degradation stage. The net photosynthetic rate was not significantly lower and WUE was depressed in the degraded stands as compared to the intact stands. Carbon fixation type seems to have outstanding importance in the outcome of degradation processes in semiarid temperate grasslands.
Two contrasting sea buckthorn (Hippophae rhamnoides L.) populations from the low (LA) and high (HA) altitudinal regions were employed to evaluate the plant physiological responses to solar UV-A radiation and near-ambient UV-B radiation (UV-B+A) under the sheltered frames with different solar ultraviolet radiation transmittance. LA-population was more responsive to solar UV-A. Some modification caused by UV-A only existed in LA-population, such as significant reduction of leaf size, relative water content, and chlorophyll (Chl) b content as well as δ13C elevation, coupled with larger increase of contents of total carotenoids (Cars). This higher responsiveness might be an effective pre-acclimation strategy adapting for concomitant solar UV-B stress. Near-ambient UV-B+A radiation caused significant reduction of leaf size and Chl content as well as slight down-regulation of photosystem 2 activity that paralleled with higher heat dissipation, while photosynthetic rate was modestly but significantly increased. The higher photosynthesis under near-ambient UV-B+A radiation could be related to pronounced increase of leaf thickness and effective physiological modification, like the increase of leaf protective pigments (Cars and UV-absorbing compound), constant high photochemical capacity, and improved water economy. and Y. Q. Yang, Y. Yao.
Pomphorhynchus omarsegundoi sp. n. from Gymnotus carapo Linnaeus from the Paraná River basin in Argentina is described in this paper. The new species is characterised by having a small body; a non-spirally twisted long neck forming an inconspicuous asymmetrical bulb more developed dorsally than ventrally; a proboscis almost cylindrical, with 11 to 12 longitudinal rows of 5 to 7 (usually 6) hooks each; presence of an apical organ; a mean neck/body ratio of about 1/8; and a post-equatorial male reproductive system, occupying 35-42% of total length. The new species can be easily distinguished from the other four South American pomphorhynchid species by the inconspicuous asymmetrical bulb and the lower number of hooks per row. Pomphorhynchus omarsegundoi is the second acanthocephalan recorded from G. carapo in the Paraná River basin.
The paper deals with a brief description of the basic methods of reconstruction of the object in optics providing that we know the properties of the optical system forming image of the object and the image. There are presented general iterative methods, analytical methods and numerical methods based on sampling of the image process. and V práci je uveden stručný přehled základních metod rekonstrukce předmětu zobrazeného danou optickou soustavou, a to za předpokladu, že známe vlastnosti optické soustavy a známe obraz předmětu touto optickou soustavou vytvořený. Jsou zde uvedeny obecné iterační metody i metody analytické a metody numerické, založené na diskretizaci vyšetřovaného procesu.