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Wyświetlanie 1-15 z 27
Tytuł:
Wpływ zeolitów na proces hydratacji spoiw mineralnych
The influence of zeolites on hydration process of mineral binders
Autorzy:
Małolepszy, J.
Grabowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/390377.pdf
Data publikacji:
2013
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
klinoptylolit
Ca(OH)2
aktywność pucolanowa
warunki hydrotermalne
C-S-H
hydrogranat
clinoptilolite
pozzolanic activity
hydrothermal conditions
hydrogarnet
Opis:
W artykule przedstawiono wyniki badań właściwości fizycznych i chemicznych zeolitu - klinoptilolitu (Z), na podstawie których została oceniona jego przydatność do zastosowania w produkcji materiałów budowlanych. Analizowano wpływ zeolitu na proces hydratacji mieszanin z wapnem, cementem portlandzkim oraz wapnem, cementem i rozdrobnionym piaskiem. W celu identyfikacji produktów reakcji hydratacji w warunkach naturalnych, niskoprężnego naparzania (80ºC) i autoklawizacji (180ºC) posłużono się metodą XRD, DTA/TG oraz SEM. Wyniki badań wskazują, że klinoptilolit odznacza się umiarkowaną aktywnością pucolanową oraz można go z powodzeniem stosować jako dodatek pucolanowy do cementu, a także do spoiwa w produkcji betonu komórkowego.
This paper presents the results of physical and chemical properties of zeolite - clinoptilolite (Z), on the basis of which its usefulness in different terms and applications was assessed. Same pozzolan was also investigated and analyzed in term of the changes that it causes in the system pozzolan - cement – lime - sand - water with different content of ingredients. In order to identify the hydration products in the natural conditions, infusion (80ºC) and autoclaving (180°C) XRD, DTA / TG and SEM was used. The results indicate that clinoptilolite is characterized by moderate pozzolanic activity and can be successfully used as a pozzolanic additive for cement, and a binder in the production of aerated concrete.
Źródło:
Budownictwo i Architektura; 2013, 12, 3; 185-192
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and characterisation of porous, calcium enriched coatings formed on Titanium via Plasma Electrolytic Oxidation
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Powiązania:
https://bibliotekanauki.pl/articles/1179160.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
85% orthophosphoric acid H3PO4
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate tetrahydrate Ca(NO3)2∙4H2O
Opis:
The SEM and EDS study results of porous and calcium enriched coatings obtained via Plasma Electrolytic Oxidation (Micro Arc Oxidation) on the Commercial Purity Titanium Grade 2 samples, at three potentials 450 VDC, 550 VDC, 650 VDC in electrolytes containing 500 g Ca(NO3)2∙4H2O in 1000 mL H3PO4, are presented in the paper. In the same electrolyte three Titanium samples, one after other, were treated, with the PEO processing time equaling 3 minutes after each immersion. Based on SEM and EDS results, it was possible to state that all obtained coatings are porous and their calcium-to-phosphorus (Ca/P) ratio decreases with decreasing PEO voltage. In addition, it was found out that electrolyte aging results in decreasing Ca/P ratio, too.
Źródło:
World Scientific News; 2017, 83; 29-44
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SEM and EDS studies of selected porous coatings obtained on titanium by Plasma Electrolytic Oxidation
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Malorny, Winfried
Powiązania:
https://bibliotekanauki.pl/articles/1178480.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate Ca(NO3)2∙4H2O
copper nitrate Cu(NO3)2∙3H2O
magnesium nitrate Mg(NO3)2∙6H2O
Opis:
In present work, SEM and EDS results of porous and enriched in calcium, copper, magnesium and phosphorus coatings, which were obtained during 3-minute treatments of Plasma Electrolytic Oxidation PEO (Micro Arc Oxidation MAO) processes on CP Titanium Grade 2 at two potentials, i.e. 500 VDC and 650 VDC, are presented. It was found that the voltage of that process influences the chemical composition of coatings shapes obtained on titanium in electrolytes containing calcium, copper and magnesium nitrates. The pores shapes of PEO coatings formed on titanium in electrolytes containing calcium, copper and magnesium nitrates are presented, too. In addition, it was also noted that with using of higher voltage (here 650 VDC) of PEO treatments, the higher Ca/P, Cu/P and Mg/P ratios were found than those after treatments at 500 VDC.
Źródło:
World Scientific News; 2017, 70, 2; 71-85
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Powiązania:
https://bibliotekanauki.pl/articles/1178366.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate Ca(NO3)2∙4H2O
linear polarization
ramp voltage
zinc nitrate Zn(NO3)2∙6H2O
Opis:
In this work, the SEM and EDS results of porous and enriched in calcium or zinc coatings, which were obtained during 3-minute treatments using Plasma Electrolytic Oxidation (Micro Arc Oxidation) processes on CP Titanium Grade 2 at ramp potentials (linear polarization) from 0 up to 650 VDC in electrolytes containing 500 g Ca(NO3)2∙4H2O and/or 500 g Zn(NO3)2∙6H2O in 1 L H3PO4, are presented. It was found that obtained coatings have pores with different shapes and diameters. The Ca/P and Zn/P ratios by atomic concentration are the same and equal to 0.2, what may suggest hydroxyapatite-like structure (M,Ti)x(PO4)y, where M = {Ca, Zn}.
Źródło:
World Scientific News; 2017, 77, 2; 242-255
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regulation of Ca2+ release from internal stores in cardiac and skeletal muscles.
Autorzy:
Wrzosek, Antoni
Powiązania:
https://bibliotekanauki.pl/articles/1044313.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Ca2+-induced Ca2+ release
calcium channels
dihydropyridine receptor
calcium sparks
excitation-contraction coupling
ryanodine receptor
Opis:
It is widely accepted that Ca2+ is released from the sarcoplasmic reticulum by a specialized type of calcium channel, i.e., ryanodine receptor, by the process of Ca2+-induced Ca2+ release. This process is triggered mainly by dihydropyridine receptors, i.e., L-type (long lasting) calcium channels, directly or indirectly interacting with ryanodine receptor. In addition, multiple endogenous and exogenous compounds were found to modulate the activity of both types of calcium channels, ryanodine and dihydropyridine receptors. These compounds, by changing the Ca2+ transport activity of these channels, are able to influence intracellular Ca2+ homeostasis. As a result not only the overall Ca2+ concentration becomes affected but also spatial distribution of this ion in the cell. In cardiac and skeletal muscles the release of Ca2+ from internal stores is triggered by the same transport proteins, although by their specific isoforms. Concomitantly, heart and skeletal muscle specific regulatory mechanisms are different.
Źródło:
Acta Biochimica Polonica; 2000, 47, 3; 705-723
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Purification of Synthetic Gas from Fine Coal Waste Gasification as a Clean Fuel
Autorzy:
Faizal, Muhammad
Said, Muhammad
Nurisman, Enggal
Aprianti, Nabila
Powiązania:
https://bibliotekanauki.pl/articles/1838398.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
absorption
CO2 capture
Ca(OH)2
fine coal
hydration
Opis:
The presence of CO2 in the syngas is attracting more attention in terms of reducing the greenhouse gas emissions in its utilisation. The aim of this study was to purify syngas from the CO2 content of fine coal gasification. Fine coal is gasified with and without absorption using CaO, which is hydrated to Ca(OH) 2 in the modified updraft gasifier at 450–700 °C. Apart from investigating the CO2 absorption process, the gasification process also evaluates the influence of temperature in terms of its synergy with Ca(OH) 2. The best conditions for the gasification process are achieved at 700 °C. The content of CO2 was proven to be well absorbed, which is characterised by a decrease in the CO2 content and an increase in H2 in syngas. After the absorption process, the H2 content obtained increased from 42.6 mole% to 48.8 mole% of H2 at 700°C. The H2 ratio also increased after absorption to 2.57 from the previous value of 2.23. The highest absorption efficiency of CO2 by Ca(OH) 2 occurred at 700°C at 50.63%. With an increase in temperature in the gasification process with absorption, the CO2 content decreased dramatically from 16.9 mole% to 3.9%. Ca(OH) 2 has good absorption power at CO2 at high temperatures.
Źródło:
Journal of Ecological Engineering; 2021, 22, 5; 114-120
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porous PEO coatings on titanium, obtained under DC regime, enriched in magnesium, calcium, zinc, and copper
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1156239.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
plasma electrolytic oxidation (peo)
micro arc oxidation (mao)
cp titanium grade 2
calcium nitrate ca(no3)2•4h2o
magnesium nitrate mg(no3)2∙6h2o
zinc nitrate zn(no3)2∙6h2o
copper nitrate cu(no3)2∙3h2o
Opis:
In the present paper, the analysis of SEM and EDS results of porous and enriched in calcium, magnesium, zinc, copper and phosphorus coatings, obtained during 3-minute treatments performed by Plasma Electrolytic Oxidation (PEO)/Micro Arc Oxidation (MAO) processes on CP Titanium Grade 2, is presented. The PEO process was carried out at DC potentials of 500 VDC, 575 VDC, and 650 VDC in electrolytes containing 125 g Ca(NO3)2•4H2O, and 125 g Mg(NO3)2∙6H2O, and 125 g Zn(NO3)2∙6H2O, and 125 g Cu(NO3)2∙3H2O in 1 L H3PO4. It was found that obtained coatings have pores with different shapes and diameters and/or size/dimentions. The Ca/P, Mg/P, Zn/P, Cu/P, and M/P ratios (M=Ca+Mg+Zn+Cu) were equal to 0.074, 0.046, 0.056, 0.042, and 0.218, respectively. The highest value of each of these ratios was recorded for 650 VDC. It may be concluded that the obtained PEO coatings structures most likely are similar to hydroxyapatite-like structures, in which the Ca2+ may be replaced with Zn2+, Mg2+, Cu2+.
Źródło:
World Scientific News; 2018, 94, 2; 99-114
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plasma membrane Ca2+ -ATPase in excitable and nonexcitable cells.
Autorzy:
Żylińska, Ludmiła
Soszyński, Mirosław
Powiązania:
https://bibliotekanauki.pl/articles/1044284.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
calcium homeostasis
brain
erythrocytes
plasma membrane Ca2+ -ATPase
Opis:
There is a significant number of data confirming that the maintenance of calcium homeostasis in a living cell is a complex, multiregulated process. Calcium efflux from excitable cells (i.e., neurons) occurs through two main systems - an electrochemically driven Na+/Ca2+ exchanger with a low Ca2+ affinity (K0.5 = 10-15 μM), and a plasmalemmal, specific Ca2+-ATPase, with a high Ca2+ affinity (K0.5 < 0.5-1 μM), whereas in nonexcitable cells (i.e., erythrocytes) the calcium pump is the sole system responsible for the extrusion of calcium ions. The plasma membrane Ca2+-ATPase (PMCA) is a ubiquitously expressed protein, and more than 26 transcripts of four PMCA genes are distributed in a tissue specific manner. Differences in the structure and localization of PMCA variants are thought to correlate with specific regulatory properties and may have consequences for proper cellular Ca2+ signaling. The regulatory mechanisms of calcium pump activity have been studied extensively, resulting in a new view of the functioning of this important molecule in the membranes.
Źródło:
Acta Biochimica Polonica; 2000, 47, 3; 529-539
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoreceptor guanylate cyclase variants: cGMP production under control.
Autorzy:
Sokal, Izabela
Alekseev, Andrei
Palczewski, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/1043388.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
rhodopsin
photoreceptor cells
guanylate cyclase
Ca2+-binding proteins
guanylate cyclase-activating protein
retina
Opis:
Changes in the Ca2+ concentration are thought to affect many processes, including signal transduction in a vast number of biological systems. However, only in few cases the molecular mechanisms by which Ca2+ mediates its action are as well understood as in phototransduction. In dark-adapted photoreceptor cells, the equilibrium level of cGMP is maintained by two opposing activities, such as phosphodiesterase (PDE) and guanylate cyclase (GC). Upon absorption of photons, rhodopsin-G-protein-mediated activation of PDE leads to a transient decrease in [cGMP] and subsequently to lowering of [Ca2+]. In turn, lower [Ca2+] increases net production of cGMP by stimulation of GC until dark conditions are re-established. This activation of GC is mediated by Ca2+-free forms of Ca2+-binding proteins termed GC-activating proteins (GCAPs). The last decade brought the molecular identification of GCs and GCAPs in the visual system. Recent efforts have been directed toward understanding the properties of GC at the physiological and structural levels. Here, we summarize the recent progress and present a list of topics of ongoing research.
Źródło:
Acta Biochimica Polonica; 2003, 50, 4; 1075-1095
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Permian trepostome bryozoans from the Zechstein Main Dolomite (Ca2) of Western Poland and NE Germany
Autorzy:
Hara, U.
Ernst, A.
Mikołajewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2059208.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Western Poland
NE Germany
Bryozoa
Zechstein
Main Dolomite (Ca2)
taxonomy
Opis:
The trepostome bryozoan Dyscritella microstoma Ernst, 2001 is reported for the first time from the Zechstein Main Dolomite (Ca2) of Poland and Germany. This species has been previously recognized in the older fossiliferous Zechstein Lime stone (Ca1) of the North Sudetic Basin (Poland) and in the northern part of Germany. The Polish specimens derive from a few boreholes located in the Pomerania region and in the Wolsztyn High, both in the western part of Poland. The German material comes from a borehole on Rügen Island in North eastern Germany. The present paper deals with the taxonomic description of D. microstoma and its distribution in the Main Dolomite deposits.
Źródło:
Geological Quarterly; 2009, 53, 2; 249-254
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Order-disorder structural transitions in synthetic filaments of fast and slow skeletal muscle myosins under relaxing and activating conditions.
Autorzy:
Podlubnaya, Zoya
Malyshev, Sergey
Nieznański, Krzysztof
Stępkowski, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/1044221.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
method of slow skeletal muscle myosin preparation.
Ca2+-induced structural transitions
myosin filaments
fast and slow skeletal muscle myosin
Opis:
In the previous study (Podlubnaya et al., 1999, J. Struc. Biol. 127, 1-15) Ca2+-induced reversible structural transitions in synthetic filaments of pure fast skeletal and cardiac muscle myosins were observed under rigor conditions (-Ca2+/+ Ca2+). In the present work these studies have been extended to new more order-producing conditions (presence of ATP in the absence of Ca2+) aimed at arresting the relaxed structure in synthetic filaments of both fast and slow skeletal muscle myosin. Filaments were formed from column-purified myosins (rabbit fast skeletal muscle and rabbit slow skeletal semimebranosus proprius muscle). In the presence of 0.1 mM free Ca2+, 3 mM Mg2+ and 2 mM ATP (activating conditions) these filaments had a spread structure with a random arrangement of myosin heads and subfragments 2 protruding from the filament backbone. Such a structure is indistinguishable from the filament structures observed previously for fast skeletal, cardiac (see reference cited above) and smooth (Podlubnaya et al., 1999, J. Muscle Res. Cell Motil. 20, 547-554) muscle myosins in the presence of 0.1 mM free Ca2+. In the absence of Ca2+ and in the presence of ATP (relaxing conditions) the filaments of both studied myosins revealed a compact ordered structure. The fast skeletal muscle myosin filaments exhibited an axial periodicity of about 14.5 nm and which was much more pronounced than under rigor conditions in the absence of Ca2+ (see the first reference cited). The slow skeletal muscle myosin filaments differ slightly in their appearance from those of fast muscle as they exhibit mainly an axial repeat of about 43 nm while the 14.5 nm repeat is visible only in some regions. This may be a result of a slightly different structural properties of slow skeletal muscle myosin. We conclude that, like other filaments of vertebrate myosins, slow skeletal muscle myosin filaments also undergo the Ca2+-induced structural order-disorder transitions. It is very likely that all vertebrate muscle myosins possess such a property.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 1007-1017
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
LaCl3 induces genomic DNA instability and increases DNA methylation levels in wheat roots
Autorzy:
Lei, X.
Ma, K.
Zhang, F.
Powiązania:
https://bibliotekanauki.pl/articles/2117694.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
cell cycle
Ca 2+ -channel blocker
RAPD
CRED-RA
Triticum aestivum
Opis:
Accumulation of LaCl3 , a well-known Ca 2+ -channel blocker, can inhibit plant growth. However, the current understanding of its effects on gene expression is limited. In this paper, different concentrations of LaCl 3 (0, 0.5, 1.0, 1.5, 2.0 mM) were used to treat germinated wheat (Triticum aestivum L.) seeds for 24 h. The degree of root growth inhibition gradually increased with increasing LaCl 3 concentration. qRT-PCR analysis revealed that the expression of several key genes related to the cell cycle process, such as pcna, mcm2, rdr and cyclin B, were significantly down-regulated. Further analysis of genomic DNA instability using Random Amplified Polymorphic DNA (RAPD) and methylation levels by Coupled Restriction Enzyme Digestion-Random Amplification (CRED-RA) analysis indicated a significant increase in genomic DNA polymorphisms and methylation levels. The results of this study verified that the reasons why LaCl3 treatment can inhibit the growth of wheat roots are as follows: interference in the normal progression of the cell cycle, induction of genomic DNA instability and increase in DNA methylation levels.
Źródło:
Acta Biologica Cracoviensia. Series Botanica; 2021, 63, 1; 31-41
0001-5296
Pojawia się w:
Acta Biologica Cracoviensia. Series Botanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of structures in As-cast alloys from the Mg-Zn-Ca system
Badanie struktury odlewanych stopów magnezu z układu Mg-Zn-Ca
Autorzy:
Kubok, K.
Lityńska-Dobrzyńska, L.
Wojewoda-Budka, J.
Góral, A.
Dębski, A.
Powiązania:
https://bibliotekanauki.pl/articles/356353.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
magnesium alloy
Mg-Zn-Ca
Ca2Mg6Zn3
microstructure
TEM
stop magnezu
mikrostruktura
Opis:
Alloys of nominal composition Mg-3Zn-xCa (x = 0, 0.2, 0.5, 0.7, 1.0, 1.3) wt.% have been prepared by resistance melting and casting into graphite mould under argon atmosphere. All investigated alloys have revealed α(Mg) dendritic microstructures with intermetallic phases distributed in interdendritic spacing. The Mg4Zn7 has been identified as the main phase which coexists with α(Mg) in the Mg-Zn alloy. Calcium addition causes the formation of ternary Ca2Mg6Zn3 hexagonal phase, denoted also as Ca3MgxZn15-x . The increase of Mg/Zn ratio from 0.59 in Mg-3Zn-0.2Ca wt.% alloy to 2.72 in Mg-3Zn-1.3Ca wt.% alloy in this phase is connected with an increase in the lattice parameters. The microhardness of the Ca containing alloys increases up to 67 HV (for the alloy containing 1.3 wag.% Ca) compared to the 50 HV for Mg-3Zn wt.% alloy.
Stopy o składach Mg-3Zn-xCa (x = 0, 0.2, 0.5, 0.7, 1.0, 1.3) %wag. topiono w piecu oporowym w atmosferze argonu i odlano do tygla grafitowego. Wszystkie badane stopy posiadają po odlaniu mikrostrukturę dendrytyczną α -Mg, z obecnością faz międzymetalicznych w przestrzeniach międzydendrytycznych. Główna faza międzymetaliczna w stopie Mg-3Zn (referencyjnym) była faza Mg4Zn7. Dodatek Ca powoduje tworzenie się heksagonalnej fazy potrójnej Ca2Mg6Zn3, opisywanej również jako Ca3MgxZn15-x . Stosunek Mg/Zn w tej fazie zmienia się od wartości 0.59 dla stopu Mg-3Zn-0.2Ca do 2.72 dla stopu Mg-3Zn-1.3Ca, co związane jest ze zwiększaniem się parametrów komórki elementarnej. Obecność Ca w stopie powoduje wzrost mikrotwardości do 67 HV dla stopu zawierającego 1.3 wag.% Ca (w porównaniu do 50 HV dla stopu Mg-3Zn).
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 2; 329-333
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of plant heat tolerance by modification of xanthophyll cycle activity
Autorzy:
Trojak, Magdalena
Skowron, Ernest
Powiązania:
https://bibliotekanauki.pl/articles/1178460.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ascorbic acid (AsA);
calcium ions (Ca2+)
dithiothreitol (DTT)
heat stress
plant protection products (PPPs)
putrescine (Put)
xanthophyll cycle
Opis:
Plants are sessile organisms hence environmental factors such as excessive light and high air temperature lead to significant reductions of their productivity and quality of gained yield. In fact, scientific and agriculture hubs make lots of efforts to improve crop tolerance to elevated temperature, selecting more tolerant varieties. We analyzed less expensive and highly efficient method to improve resistance of well-known cultivars of crop plant by reversible modification of xanthophyll cycle. It functions as a safety valve to adjust energy transfer and protects fragile structures of photosynthetic machinery from excessive light, especially accompanied by heat or water stress. Efficiency of modified xanthophyll cycle activity was measured after pre-treatment with four, chemically different regulators, with or without light illumination. Analyses were carried out on barley (Hordeum vulgare L.) cv. Zenek treated with ascorbic acid (AsA), dithiothreitol (DTT), putrescine (Put) and calcium ions (Ca2+). To measure the scale of thermal energy dissipation we traced energy transfer absorbed by PSII with PAM chlorophyll fluorescence technique. Results showed clear correlation between AsA (activator of violaxanthin de-epoxidase) treatment and stimulation of the Φ(NPQ) at increased temperature. DTT (inhibitor of violaxanthin de-epoxidase) decreased the cycle activity at 45 °C at the same time increasing its value at 35°C, caused by interaction with other enzymes. Action of Put (hydrogen ions buffer) concerned mainly a non regulated Φ(NO) energy quenching. We noticed that application of Ca(NO3)2 (Ca2+ source for enzyme activity) reduced the Φ(NPQ) at 45 °C and stimulated it at 25 °C. Obtained results confirmed postulated possibility of creating new type of plant protection products (PPPs) able to precisely manage natural mechanisms of heat resistance.
Źródło:
World Scientific News; 2017, 70, 2; 51-70
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
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