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251. Sekundární metabolity lišejníků a jejich význam pro taxonomii

Creator:
Malíček, Jiří
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Botanika, lišejníky, metabolity, systematická botanika, 2, and 58
Language:
Czech
Description:
Lichens are characterized by the production of a large amount of secondary metabolites. Most of them are specific to these organisms. Lichenologists commonly use the metabolites to distinguish between phenotypically similar taxa. To achieve this aim, they use a plethora of detection methods, including spot reactions, chromatography, and microcrystalization tests. and Jiří Malíček.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

253. Šíření rostlin říčními koridory - co se dozvíme ze studia DNA

Creator:
Tomáš Fér
Format:
print
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Botanika, botanika, fyziologie rostlin, pěstitelství, molekulární biologie, genetika, životní prostředí, ekologie, botany, plant physiology, horticultural education, molecular biology, genetics, environment, ecology, Polabí (Česko), 2, and 58
Language:
Czech
Description:
Molekulární metody umožnily studovat šíření rostlin v povodí Labe. Druhy šířené vodou (zevar, stulík) migrují především jednosměrně podél řek. Bylo prokázáno i šíření mezi říčními systémy, častější je u druhů šířících se také větrem (rákos, orobinec). Klonální šíření mezi populacemi není u těchto studovaných druhů rostlin tak běžné, jak se dosud předpokládalo., Molecular approaches have allowed for the study of plant dispersal in the catchment area of the River Elbe. Plants dispersed by water (Bur-reed, Pond Lily) migrated mainly unidirectionally along streams. Dispersal among river systems was also detected and is more common among plants with wind dispersal (Common Reed, Cattail). Clonal dispersal does not seem to be as common in the studied species as previously suggested., and Tomáš Fér.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

255. Současná česká botanika v rovníkových Andách

Creator:
Petr Sklenář
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Botanika, botanika, flóra, Andy (pohoří), 2, and 58
Language:
Czech
Description:
Czech botanists have participated in research into the taxonomy, diversity and ecology of plants in the equatorial high Andes since the mid 90s. The results include a description of new species of vascular plants and lichens, a contribution to generic flora, one monography and publication of several dozen original papers. and Petr Sklenář.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

257. 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

260. Study of the senescence process in primary leaves of sunflower (Helianthus annuus L.) plants under two different light intensities

Creator:
De la Mata, L., Cabello, P., De la Haba, P., and Agüera, E.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, antioxidant enzymes, ascorbate peroxidase, catalase, glutamate dehydrogenase, glutamine synthetase, hexose, nitrite reductase, irradiance, nitrate reductase, plant, reactive oxygen species, senescence, sunflower, superoxide dismutase, 2, and 58
Language:
Multiple languages
Description:
a1_Different parameters that vary during leaf development may be affected by light intensity. To study the influence of different light intensities on primary leaf senescence, sunflower (Helianthus annuus L.) plants were grown for 50 days under two photon flux density (PFD) conditions, namely high irradiance (HI) at 350 μmol(photon) m-2 s-1 and low irradiance (LI) at 125 μmol(photon) m-2 s-1. Plants grown under HI exhibited greater specific leaf mass referred to dry mass, leaf area and soluble protein at the beginning of the leaf development. This might have resulted from the increased CO2 fixation rate observed in HI plants, during early development of primary leaves. Chlorophyll a and b contents in HI plants were lower than in LI plants in young leaves. By contrast, the carotenoid content was significantly higher in HI plants. Glucose concentration increased with the leaf age in both treatments (HI and LI), while the starch content decreased sharply in HI plants, but only slightly in LI plants. Glucose contents were higher in HI plants than in LI plants; the differences were statistically significant (p<0.05) mainly at the beginning of the leaf senescence. On the other hand, starch contents were higher in HI plants than in LI plants, throughout the whole leaf development period. Nitrate reductase (NR) activity decreased with leaf ageing in both treatments. However, the NR activation state was higher during early leaf development and decreased more markedly in senescent leaves in plants grown under HI. GS activity also decreased during sunflower leaf ageing under both PFD conditions, but HI plants showed higher GS activities than LI plants. Aminating and deaminating activities of glutamate dehydrogenase (GDH) peaked at 50 days (senescent leaves). GDH deaminating activity increased 5-fold during the leaf development in HI plants, but only 2-fold in LI plants., a2_ The plants grown under HI exhibited considerable oxidative stress in vivo during the leaf senescence, as revealed by the substantial H2O2 accumulation and the sharply decrease in the antioxidant enzymes, catalase and ascorbate peroxidase, in comparison with LI plants. Probably, systemic signals triggered by a high PFD caused early senescence and diminished oxidative protection in primary leaves of sunflower plants as a result., L. De la Mata ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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