Search

Start Over Coverage 247-253

2. Photosynthesis of Hedera canariensis var. azorica variegated leaves as affected by ozone

Creator:
Soldatini, G. F., Nali, C., Guidi, L., and Lorenzini, G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll, fluorescence, ivy, net photosynthetic rate, stomatal conductance, and transpiration
Language:
Multiple languages
Description:
A differential response to long-term ozone exposures (50 and 100 mm3 m-3) was observed in the green and white areas of variegated leaves of Hedera canariensis var. azorica L. In green tissue the photosynthetic activity was depressed via a stomatal mechanism, and in white regions no effect was observed. Chlorophyll fluorescence parameters remained unchanged in green portions, whereas in the white ones Fm and Fv/Fm significantly diminished following ozone fumigation. and G. F. Soldatini ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Prošetření archivních holografických mřížek

Creator:
Miler, Miroslav, Skalský, Miroslav, and Třísková, Marta
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
difractive gratings, holografic gratings, difractive efficiency, scalar gratings, relief gratings, retrodifraction, modulation depth, relief depth, difrakční mřížky, holografické mřížky, difrakční účinnost, skalární mřížky, reliéfní mřížky, retrodifrakce, hloubka modulace, and hloubka reliéfu
Language:
Czech
Description:
Seven archival holographic gratings produced thirty or more years ago are tested using diffraction of the HeNe laser light. Results of measurements are compared with theoretical shape of the diffraction efficiency of the scalar gratings with a weak sinusoidal modulation, either without taking into consideration angles of incidence and diffraction, or with their including. The results should be improved by including angles, but it became direct opposite. Subsequent research of reasons should lead to harmonization of the theory with measurements. and Sedm archivních holografických mřížek, vyrobených před třiceti a více lety, je podrobeno zkoumání za využití difrakce světla HeNe laseru. Výsledky měření jsou porovnány s teoretickými průběhy difrakční účinnosti skalárních mřížek se slabou sinusovou modulací, buď bez zohlednění úhlů dopadu a difrakce, nebo s jejich započtením. Započtení úhlů mělo výsledky zlepšit, ale stal se opak. Následné zkoumání příčin by mělo vést k harmonizaci měření s teorií.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Specificity factor of Rubisco: estimation in intact leaves by carboxylation at different CO2/O2 ratios

Creator:
Viil, J., Ivanova, H., and Pärnik, T.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, carboxylation, 14CO2, intact leaves, Rubisco, specificity factor, 2, and 58
Language:
Multiple languages
Description:
The specificity factor of Rubisco (S f) was estimated in intact leaves from the carboxylation of ribulose-1,5-bisphosphate (RuBP) at various CO2/O2 ratios. As oxygenation is calculated by the difference of the 14CO2 uptake by RuBP in the absence and presence of oxygen, it is important to choose the optimum CO2/O2 ratios. At high CO2 concentration (1,000 cm3 m-3 and higher) oxygenation consumes less than 50% RuBP but the difference of concentrations of CO2 at cell walls (Cw) and at the carboxylation centers (Cc) is 2-5% and the influence of mesophyll resistance (rmd) is of minor importance. To accumulate large endogenous pool of RuBP, the leaves were preilluminated in the CO2- and O2-free gas environments for 8 to 10 s. Thereafter the light was switched off and the leaves were flushed with the gas containing different concentrations of 14CO2 and O2. The specificity factor of Rubisco was calculated from the amount of the tracer taken up under different 14CO2/O2 ratios by the exhaustion of the RuBP pool. Application of 14CO2 allowed us to discriminate between the CO2 uptake and the concurrent respiratory CO2 release which proceeded at the expense of unlabelled intermediates., J. Viil, H. Ivanova, T. Pärnik., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public