Sorbus eximia Kovanda, a hybridogenous species that originated from the parental combination S. torminalis and S. aria s.l., is thought to be an apomictic species, which includes diploid and tetraploid individuals. The present study confirmed the existence of only triploid individuals. A new tentatively apomictic triploid (2n = 3x = 51) species from the S. latifolia group: S. barrandienica P. Vít, M. Lepší et P. Lepší is described based on a revision of S. eximia. This species is assumed to have originated from a cross between S. danubialis or S. aria s.l. and S. torminalis. A wide palette of biosystematic techniques, including molecular (nuclear microsatellite markers) and karyological analyses (chromosome counts, DAPI flow cytometry) as well as multivariate morphometric and elliptic Fourier analyses, were used to assess the variation in this species and justify its independent taxonomic status. Allopatric occurrences of both species were recorded east of the town of Beroun in the Český kras, central Bohemia (Bohemian Karst). A distribution map of the two species is provided. Sorbus eximia occurs at four localities (the total number of adults and juveniles is 100 and 200, respectively) in basiphilous thermophilous oak forests (Quercion pubescenti-petraeae), mesic oak forests (Melampyro nemorosi-Carpinetum), woody margins of dry grasslands (Festucion valesiacae) and pine plantations. Sorbus barrandienica has so far been recorded at 10 localities (ca 50 adults). Recent field studies failed to verify two of these localities. It is mainly found growing on the summits of hills, usually in thermophilous open forests (Primulo veris-Carpinetum, Melampyro nemorosi-Carpinetum, Quercion pubescenti-petraeae) and woody margins of dry grassland. Its populations exhibit minimal genetic variation and are phenotypically homogeneous and well separated from other Bohemian hybridogenous Sorbus species. The epitype of S. eximia is designated here, and a photograph of the specimen is included. Photographs of the type specimens and in situ individuals, and line drawings of both species are presented.
Changes in the temperature dependence of the maximum carboxylation capacity (VCmax) of Rubisco during thermal acclimation of PN remain controversial. I tested for acclimation of the temperature dependence of VCmax in quinoa, wheat, and alfalfa. Plants were grown with day/night temperatures of 12/6, 20/14, and 28/22°C. Responses of PN to substomatal CO2 (Ci) and CO2 at Rubisco (Cc) were measured at leaf temperatures of 10-30°C. VCmax was determined from the initial slope of the PNvs. Ci or Cc curve. Slopes of linear regressions of 1/VCmaxvs. 1/T [K] provided estimates the activation energy. In wheat and alfalfa the increases in activation energy with growth temperature calculated using Ci did not always occur when using Cc, indicating the importance of mesophyll conductance when estimating the activation energy. However, in quinoa, the mean activation energy approximately doubled between the lowest and highest growth temperatures, whether based on Ci or Cc., J. A. Bunce., and Obsahuje bibliografii
The thermal photoacoustic signal (279 Hz) and the chlorophyll (Chl) fluorescence of radish cotyledons (Raphanus sativus L.) were measured simultaneously. The signals were recorded during a photosynthetic induction with actinic radiation of different quantum fluence rates [20, 200, and 1200 µmol(PAR-quantum) m-2 s-1]. The rise of these signals upon irradiation saturating photosynthesis was followed in the steady state of the induction and during the subsequent dark-recovery (i.e., in dark periods of 1, 5, 15, and 45 min after the induction). From these values various parameters (e.g., quantum yield, photochemical loss, different types of quenching coefficients) were calculated. The results show that heat dissipation detected by photoacoustic measurements is neither low, constant, nor always parallel to Chl fluorescence. Therefore, the thermal signal should always be measured in order to fully understand the way leaves convert energy taken up by PAR absorption. This helps in the interpretation of photosynthesis under different natural and anthropogenic conditions (stress and damage effects).
The aim of this paper is to show the complex thermal analyses used to design of aircraft electronic control unit. Control Power Supply for Jet (CPSJ). The goal is to examine thermal conditions of power and control electronics components. With respect to aircraft application a computational fluid dynamics (CFD) method is used for heat transfer coefficient determination. This method is compared to analytic solution based on Petuchov equation of Nusselt number. The temperature conditions inside the CPSI unit are presented as results. and Obsahuje seznam literatury
The thermal resistance is one of the important behaviors of the construction and thermal insulating materials. This study describes foamed material made from fluidized bed ash (FBA) in combination with natural smectite having a filler function. The foaming effect was insured by addition of metallic aluminum to the FBA/smectite mixture. Highly calcareous FBA containing calcium oxide creates during slaking processes an alkali reaction and with aluminum develops foaming agent - hydrogen. Study of thermal resistance was a part of experiments directed on heat insulating materials and article presents test results of this life gardening material. Specific attention was focused on differences between the results of chemical analyses and the crystal phases identified by X-ray diffractions. The paper presents hypothesis of chained alumina-silicates acting as bonding agent confirmed by infra-red spectroscopy and assuring together with calcium sulfates high thermal resistance even under condition of direct flame attack., Tomáš Hanzlíček and Ivana Perná., and Obsahuje bibliografii
The relative size of the pool of electrons accumulated in stroma reductants during actinic irradiation, which can be donated to P700+ via the intersystem chain, was estimated after short-term exposure of intact Zea mays leaves to elevated temperatures. When the temperature increased from 25 to 50 °C by 5 °C steps, the relative size of the stroma electron pool went through a maximum at around 30 °C, and decreased gradually thereafter. and Ming-Xian Jin, Hualing Mi.
The aim of this study was to ascertain whether repeated local cooling induces the same or different adaptational responses as repeated whole body cooling. Repeated cooling of the legs (immersion into 12 °C water up to the knees for 30 min, 20 times during 4 weeks = local cold adaptation – LCA) attenuated the initial increase in heart rate and blood pressure currently observed in control subjects immersed in cold water up to the knees. After LCA the initial skin temperature decrease tended to be lower, indicating reduced vasoconstriction. Heart rate and systolic blood pressure appeared to be generally lower during rest and during the time course of cooling in LCA humans, when compared to controls. All these changes seem to indicate attenuation of the sympathetic tone. In contrast, the sustained skin temperature in different areas of the body (finger, palm, forearm, thigh, chest) appeared to be generally lower in LCA subjects than in controls (except for temperatures on the forehead). Plasma levels of catecholamines (measured 20 and 40 min after the onset of cooling) were also not influenced by local cold adaptation. Locally cold adapted subjects, when exposed to whole body cold water immersion test, showed no change in the threshold temperature for induction of cold thermogenesis. This indicates that the hypothermic type of cold adaptation, typically occurring after systemic cold adaptation, does not appear after local cold adaptation of the intensity used. It is concluded that in humans the cold adaptation due to repeated local cooling of legs induces different physiological changes than systemic cold adaptation.
Thermoluminescence (TL) in green plants arises from charge recombination of charged molecules in the reaction centre (RC) of photosystem 2 (PS2) in chloroplasts. The TL technique is used for detection of alterations in the architecture of PS2 RCs. The donor side 'S-states' and the acceptor side quinone molecules (QA and QB) are involved the charge recombination processes of PS2. High temperature (70-75 °C) glow peaks are also used to detect non-photosynthetic peroxidation processes in thylakoid membranes. The TL peaks with their characteristic charge recombination can be utilised for the study of chloroplast development, ageing, chemical, biotic, and abiotic stress induced alterations in the PS2 RC and for the study of the primary photochemical events of photosynthesis. The technique has been used successfully in the characterisation of transgenic plants in the study of genetically engineered organisms. and A. N. Misra ... [et al.].
The thermoluminescence (TL) emission of photosynthesising materials originates from the recombination of charge pairs created by a previous excitation. Using a recently described TL set-up the effect of chilling stress on TL bands occurring at positive temperatures (AG, B, and HTL) was investigated in intact leaves. The far-red irradiation of leaves at low, but non-freezing temperatures induced a TL band peaking at around 40-45 °C (AG band), together with a B band peaking between 20 and 35 °C. Low temperature stress first caused a downshift and a temporary increase in the AG band after 4 h at 0 °C in the light, then a decrease in the AG and B TL bands after 1 d at 0 °C in the light. This decrease was less pronounced in cold-tolerant genotypes and in those grown at acclimating temperatures. Furthermore, an additional band appeared above 80 °C after severe cold stress. This band indicates the presence of lipid peroxides. Thus TL is a useful technique for studying the effects of low temperature stress. and T. Janda, G. Szalai, E. Páldi.
Metabolic rate and body temperature (Tb) reduction during torpor can provide significant energy savings for bats during inclement weather and food scarcity. However, torpor use may slow down biochemical processes including fetal and juvenile development and sperm production. Sex-differences in the timing of reproductive activity of bats in the temperate climate zone should result in differences of the thermoregulation behaviour by males and females during summer. To test this hypothesis, we studied thermoregulation of freeranging, tree-dwelling gleaning bats (Myotis bechsteinii) and trawling bats (M. daubentonii) during different reproductive periods. Gleaners and trawlers are able to forage on prey which is sitting on vegetation and the ground (gleaning) or which is slowly moving over water bodies (trawling). This prey is characterized by lower ambient temperature (Ta) dependent abundance than flying prey. We used temperature-sensitive radio transmitters to measure skin temperature (Tsk). Temperature telemetry over 144 census days revealed a significant effect of reproductive period and sex on Tsk. Pre-spermatogenic males exhibited a significantly greater Tsk reduction than females in early pregnancy. Males at the beginning of sperm production and in main spermatogenesis exhibited much more frequent and deeper temperature reductions than females in late pregnancy and in lactation. Lactating females maintained the highest Tsk of all bats. Post-lactating females reduced Tsk to the same extent or even more than males in advanced spermatogenesis. Our findings indicate that the thermoregulation of gleaning and trawling temperate bats is likely to be much less influenced by environmental conditions than that of aerial hawking bat species. We suggest that both sexes of Bechstein’s bats and Daubenton’s bats primarily adapt their thermoregulation in response to current reproductive activity.