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553. Mesophyll conductance variations in response to diurnal environmental factors in Myrcia paivae and Minquartia guianensis in Central Amazonia

Creator:
Nascimento, H. C. S. and Marenco, R. A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, Amazonka (řeka : oblast), Amazon River Valley, chloroplast carbon dioxide concentration, electron transport rate, maximum carboxylation velocity of Rubisco, stomatal conductance, 2, and 581
Language:
Multiple languages
Description:
Mesophyll conductance (gm) is essential to determine accurate physiological parameters used to model photosynthesis in forest ecosystems. This study aimed to determine the effects of time of day on photosynthetic parameters, and to assess the effect of using either intercellular CO2 concentration (Ci) or chloroplast CO2 concentration (Cc), on maximum carboxylation velocity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), Vcmax. We used Amazonian saplings of Myrcia paivae and Minquartia guianensis. Photosynthetic parameters were measured using an infrared gas analyzer (IRGA); gm was determined using both gas exchange and chlorophyll (Chl) a fluorescence and gas-exchange data alone. Leaf thickness (LT) and specific leaf area (SLA) were also measured. Air temperature, relative humidity or understory light did not correlate with gm and on average daily IRGA-fluorometer-determined gm was 0.04 mol(CO2) m-2 s-1 for M. paivae and 0.05 mol(CO2) m-2 s-1 for M. guianensis. Stomatal conductance (gs), gm, electron transport rate (JF), and light-saturated net photosynthetic rate (PNmax) were lower in the afternoon than in the morning. However, no effect of time of day was observed on Vcmax. LT and SLA did not affect any of the examined parameters. IRGA-determined g m was almost the double of the value obtained using the IRGA-fluorescence method. Vcmax values determined using Cc were about 25% higher than those obtained using Ci, which highlighted the importance of using Cc in Vcmax calculation. Decline in PNmax at the end of the afternoon reflected variations in gs and gm rather than changes in Vcmax. Diurnal variation in gm appeared to be associated more with endogenous than with atmospheric factors. and H. C. S. Nascimento, R. A. Marenco.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

555. Metody studia vodních bakterií pomocí fluorescenční mikroskopie

Creator:
Karel Šimek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Biologické vědy, vodní mikroorganismy, bakterie, fluorescenční mikroskopie, prvoci, aquatic microorganisms, bacteria, fluorescence microscopy, Protozoa, vodní bakterie, aquatic bacteria, 2, and 57/59
Language:
Czech
Description:
Při studiu interakcí bakterií a prvoků se používají zejména metody fluorescenční mikroskopie v kombinaci se značenými bakteriemi, nebo i vysoce specifické fluorescenčně značené RNA-sondy (fluorescence in situ hydridizace), které umožňují i přesnou taxonomickou identifikaci druhů bakterií, pohlcovaných prvoky. Můžeme tak studovat nejenom rychlost, ale i selektivitu eliminace bakterií heterotrofními a mixotrofními bičíkovci a nálevníky v různých přírodních vodách., Trophic interaction between bacteria and protozoa is mainly studied by means of fluorescence microscopy exploiting various fluorescence labelling of bacteria, including highly specific RNA-probes for fluorescence in situ hybridization, which allows precise identification of bacterial species grazed by protozoa. By combining these approaches we can examine not only the total rate of protozoan bacterivory, but also the grazing selectivity of heterotrophic and mixotrophic flagellates and ciliates feeding on bacteria in a broad array of aquatic ecosystems., Karel Šimek., and autor: Redakce a Karel Šimek
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

556. Mikroorganismy kvasného průmyslu a mykologie

Creator:
Josef Ryšavý
Publisher:
[nakladatel není známý],
Format:
print, text, regular print, bez média, svazek, and 108 stran : ilustrace
Type:
text, volume, přednášky, model:monograph, and TEXT
Subject:
Mikrobiologie, kvasný průmysl, kvašení, kvasná chemie, mikroorganizmy, bakterie, kvasinky, houby nižší, mykologie, 663, 579.67, 2, 579, and UB02
Language:
Czech
Description:
dle přednášek J. Ryšavého and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

557. Mikroskopičtí korýši západokarpatských pramenišť

Creator:
Zhai, Marie, Hřívová, Dana, and Výravský, David
Format:
bez média and svazek
Type:
article, text, články, journal articles, model:article, and TEXT
Subject:
Biologické vědy, biologie, korýši, lasturnatky, vodní bezobratlí, biology, Crustacea, Ostracoda, aquatic invertebrates, Západní Karpaty (pohoří : oblast), Western Carpathian Mountains Region, plazivky, Harpacticoida, 2, and 57/59
Language:
Czech
Description:
V návaznosti na výzkum botaniků a malakozoologů se na unikátních prameništních mokřadech Západních Karpat rozběhlo v posledních letech také intenzivní studium vodních bezobratlých zaměřených rovněž na skupiny mikroskopických korýšů - lasturnatek (Ostracoda) a plazivek (Harpacticoida). Podařilo se nám objasnit jejich distribuci na prameništích, nalézt 8 nových druhů pro Českou a Slovenskou republiku a rozšířit znalosti o jejich ekologii., In connection with research by botanists and malacozoologists at unique spring areas in Western Carpathian marshland, intensive study has taken place over the last few years into water invertebrates and groups of microscopic crustaceans - ostracodes (Ostracoda) and Harpacticoida. We have succeeded in clarifying their distribution in the spring areas, finding eight new species for the Czech and Slovak Republics and expanding knowledge of their ecology., and Marie Zhai, Dana Hřívová, David Výravský.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

559. Miniature excitatory synaptic ion currents in the earthworm Lumbricus terrestris body wall muscles

Creator:
Volkov, E. M., Nurullin, L. F., Nikolsky, E., and Vyskočil, F.
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Biochemie. Molekulární biologie. Biofyzika, biochemie, acetylcholin, ionty, svalové buňky, žížaly, biochemistry, acetylcholine, ions, muscle cells, earthworms, 2, and 577
Language:
English
Description:
The miniature excitatory postsynaptic currents (MEPCs) of the muscle cells of the earthworm Lumbricus terrestris were recorded by glass microelectrodes. In a single synaptic zone, three types of MEPC were recorded: a fast single-exponential type that decayed with τ=0.9 ms, a slow single-exponential with τ=9.2 ms and a two-exponential MEPC with τ = 1.3 and 8.5 ms, respectively. The muscle cells of earthworms contain populations of yet-unidentified ionic channels that might be different from the common nicotinic and muscarinic groups of acetylcholine receptors, since these MEPCs are not sensitive to d-tubocurarine, atropine, benzohexonium or proserine. Alternatively, besides ACh receptors, the membrane may contain receptors for an other yet-unidentified excitatory transmitter., E. M. Volkov, L. F. Nurullin, E. Nikolsky, F. Vyskočil., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

560. Modelling photosynthesis in shallow algal production ponds

Creator:
Ritchie, R. J. and Larkum, A. W. D.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, algal production ponds, Chlorella, Dunaliella, electron transport rate, light saturation curves, Phaeodactylum, photoinhibition, photosynthesis, photosynthesis vs. depth, primary productivity, pulse amplitude modulation fluorometry, 2, and 58
Language:
Multiple languages
Description:
a1_Shallow ponds with rapidly photosynthesising cyanobacteria or eukaryotic algae are used for growing biotechnology feedstock and have been proposed for biofuel production but a credible model to predict the productivity of a column of phytoplankton in such ponds is lacking. Oxygen electrodes and Pulse Amplitude Modulation (PAM) fluorometer technology were used to measure gross photosynthesis (PG) vs. irradiance (E) curves (PG vs. E curves) in Chlorella (chlorophyta), Dunaliella salina (chlorophyta) and Phaeodactylum (bacillariophyta). PG vs. E curves were fitted to the waiting-in-line function [PG = (PGmax × E/Eopt) × exp(1 — E/Eopt)]. Attenuation of incident light with depth could then be used to model PG vs. E curves to describe PG vs. depth in pond cultures of uniformly distributed planktonic algae. Respiratory data (by O2-electrode) allowed net photosynthesis (PN) of algal ponds to be modelled with depth. Photoinhibition of photosynthesis at the pond surface reduced PN of the water column. Calculated optimum depths for the algal ponds were: Phaeodactylum, 63 mm; Dunaliella, 71 mm and Chlorella, 87 mm. Irradiance at this depth is ≈ 5 to 10 μmol m-2 s-1 photosynthetic photon flux density (PPFD). This knowledge can then be used to optimise the pond depth. The total net P N [μmol(O2) m-2 s-1] were: Chlorella, ≈ 12.6 ± 0.76; Dunaliella, ≈ 6.5 ± 0.41; Phaeodactylum ≈ 6.1 ± 0.35. Snell’s and Fresnel’s laws were used to correct irradiance for reflection and refraction and thus estimate the time course of PN over the course of a day taking into account respiration during the day and at night. The optimum PN of a pond adjusted to be of optimal depth (0.1-0.5 m) should be approximately constant because increasing the cell density will proportionally reduce the optimum depth of the pond and vice versa., a2_Net photosynthesis for an optimised pond located at the tropic of Cancer would be [in t(C) ha-1 y-1]: Chlorella, ≈ 14.1 ± 0.66; Dunaliella, ≈ 5.48 ± 0.39; Phaeodactylum, ≈ 6.58 ± 0.42 but such calculations do not take weather, such as cloud cover, and temperature, into account., R. J. Ritchie, A. W. D. Larkum., and Obsahuje bibliografii a dodatky
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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