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15973. Tocopherols modulate leaf vein arrangement and composition without impacting photosynthesis

Creator:
Stewart, J. J., Adams, William W., Cohu, C. M., and Demmig-Adams, Barbara
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
vitamin E, foliar vasculature, leaf venation, vein density, vitamin E deficiency, xylem, 2, and 581
Language:
Multiple languages
Description:
Growth of the tocopherol-deficient vte1 mutant and Col-0 wild type of Arabidopsis thaliana in a sunlit glasshouse revealed both similarities and differences between genotypes. Photosynthetic capacity and leaf mesophyll features did not differ between mutant and wild type. Likewise, the total volume of water conduits (tracheary elements, TEs), sugar conduits (sieve elements, SEs), and sugar-loading cells (companion and phloem parenchyma cells) on a leaf area basis were unaffected by tocopherol deficiency. However, tocopherol deficiency yielded smaller and more numerous minor veins with fewer phloem cells and smaller TEs, resulting in greater ratios of TEs to SEs. The smaller TEs in the vte1 mutant may present a decreased risk for cavitation under high evaporative demand or in response to freezing. In turn, compensation for fewer phloem cells and smaller TEs by more numerous veins may bolster resistance to cavitation at no cost to photosynthetic capacity., J. J. Stewart, W. W. Adams, C. M. Cohu, B. Demmig-Adams., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

15974. TOFA 2014: o termodynamice slitin v Brně

Creator:
Kroupa, Aleš and Ludvík Kunz
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Věda. Všeobecnosti. Základy vědy a kultury. Vědecká práce, mezinárodní konference, materiálové inženýrství, international conferences, materials engineering, Brno (Česko), Brno (Czechia), 12, and 00
Language:
Czech
Description:
Aleš Kroupa, Ludvík Kunz.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

15976. Tolerance mechanisms in Cassia alata exposed to cadmium toxicity - potential use for phytoremediation

Creator:
Silva, J. R. R., Fernandes, A. R., Silva Junior, M. L., Santos, C. R. C., and Lobato, A. K. S.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
těžké kovy, heavy metals, kadmium, fytoremediace, cadmium, phytoremediation, detoxifikace, výměna plynu, reaktivní formy kyslíku, remediace, detoxification, gas exchange, reactive oxygen species, remediation, Cassia alata, 2, and 581
Language:
Multiple languages
Description:
Cadmium is often detected in areas contaminated by heavy metals and the incidence of this element in dangerous concentrations has been increasing due to anthropogenic activities. The aim of this research was to determine Cd concentrations in tissues, quantify compounds, pigments and enzymes, and to evaluate the gas exchange. Our aim was also to identify components that can modify and contribute to tolerance of Cassia alata against Cd toxicity. We used five Cd concentrations (0, 22, 44, 88, and 132 μM) to validate our hypothesis. The Cd concentrations in tissues of C. alata plants increased significantly, compared with the control treatment, in the following graduated sequence: root > leaf > stem. Progressive enhancement in glutathione (GSH) was verified in plants treated with all Cd concentrations used, when compared with treatment without Cd. Antioxidant enzyme activities presented similar patterns with progressive enhancements, being a desirable characteristic for plants with a potential to hyperaccumulate Cd. Our results suggest that C. alata plants can be used for phytoremediation programs. Their defense mechanism is based on Cd accumulation in roots, coupled with increase in GSH and the efficient activity of antioxidant enzymes that contribute to minimize the oxidative stress and consequently improve the protection of the metabolic machinery., J. R. R. Silva, A. R. Fernandes, M. L. Silva Junior, C. R. C. Santos, A. K. S. Lobato., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

15977. Tolerance of isolated rabbit hearts to short ischemic periods is affected by increased LV mass fraction

Creator:
Marie Hlaváčová, Veronika Olejníčková, Ronzhina, M., Tibor Stračina, Oto Janoušek, Nováková, M., Petr Babula, Kolářová, J., Ivo Provazník, and Hana Paulová
Format:
print, bez média, and svazek
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, srdce, ischemie, heart, ischemia, 4-hydroxy-2-nonenal, electrogram, rabbit isolated heart, LV mass, global ischemia, 14, and 612
Language:
English
Description:
Hypertrophied hearts are known for increased risk of arrhythmias and are linked with reduced ischemic tolerance. However, still little is known about state characterized only by increased left ventricle (LV) mass fraction. Seventeen isolated rabbit hearts with various LV mass were divided into two groups according to LV weight/heart weight ratio (LVW/HW ratio), namely group H and L (with higher and lower LVW/HW ratio, respectively) and underwent three short cycles of global ischemia and reperfusion. The differences in electrogram (heart rate, QRSmax, mean number, onset and dominant form of ventricular premature beats) and in biochemical markers of myocardial injury (creatine kinase, lactate dehydrogenase - LDH) and lipid peroxidation (4-hydroxy-2-nonenal - 4-HNE) were studied. As compared to group L, hearts in group H exhibited lower tolerance to ischemia expressed as higher incidence and severity of arrhythmias in the first ischemic period as well as increase of LDH and 4-HNE after the first reperfusion. In the third cycle of ischemia-reperfusion, the preconditioning effect was observed in both electrophysiological parameters and LDH release in group H. Our results showed consistent trends when comparing changes in electrograms and biochemical markers. Moreover, 4-HNE seems to be good potential parameter of moderate membrane alteration following ischemia-reperfusion injury., M. Hlaváčová, V. Olejníčková, M. Ronzhina, T. Stračina, O. Janoušek, M. Nováková, P. Babula, J. Kolářová, I. Provazník, H. Paulová., and Obsahuje bibliografii
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

15978. Tolerance of Mitragyna parvifolia (Roxb.) Korth. seedlings to NaCl salinity

Creator:
Bidalia, A., Hanief, M., and Rao, K. S.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fluorescence chlorofylu, výměna plynu, analýza růstu, efektivita využívání vody, dlouhodobá salinita, chlorophyll fluorescence, gas exchange, growth analysis, water-use efficiency, Kadam, long-term salinity, 2, and 581
Language:
Multiple languages
Description:
Increase in salinity is predicted to affect plant growth and survival in most arid and semiarid regions worldwide. Mitragyna parvifolia (Roxb.) Korth. is an important medicinal tree species distributed throughout the semiarid regions of India; however, it is facing a threat of its extinction in its natural habitat. We examined the effects of increasing NaCl salinity on two-month-old M. parvifolia seedlings grown in an environment-controlled chamber and exposed to soils of different electrical conductivity (EC) caused by NaCl [0-5 (control), 5-10, 10-15, 15-20, and 20-25 dS m-1)] for 85 days. Seedlings transferred to soil of EC >15 dS m-¹ did not survive beyond 1 week. Increase in the Na+ concentration negatively correlated with their height and positively correlated with their water-use efficiency (WUE). However, leaf area, net photosynthetic rate (PN), stomatal conductance, and transpiration rate showed varying correlations and an overall decrease in these parameters compared with the control. At EC of 10-15 dS m-1, the seedling height was reduced by 37% and PN was lowered by 50% compared with those of the control. An increase in the Na+/K+ ratio was observed with increasing salinity. The maximum quantum efficiency of PSII significantly decreased with increasing salinity compared with the control. Our results suggest that the increase in salinity reduced the overall performance of the M. parvifolia seedlings. However, the maintenance of WUE and maximum quantum efficiency of PSII might help M. parvifolia to tolerate NaCl salinity of 15 dS m-1., A. Bidalia, M. Hanief, K. S. Rao., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

15979. Tolerance to acute ischemia in adult male and female spontaneously hypertensive rats

Creator:
Josef Bešík, Ondrej Szárszoi, Jaroslav Kuneš, Ivan Netuka, Jan Malý, František Kolář, Jan Pirk, and Bohuslav Ošťádal
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie, hypertenze, pohlavní rozdíly, physiology, hypertension, sex differences, srdeční tolerance, ischemické / reperfuzní poškození, spontánně hypertenzivní krysy, genderové rozdíly, cardiac tolerance, ischemia / reperfusion injury, spontaneously hypertensive rats, gender differences, 14, and 612
Language:
English
Description:
Clinical and experimental studies have repeatedly indicated that overloaded hearts have a higher vulnerability to ischemia/reperfusion injury. The aim of the present study was to answer the question whether the degree of tolerance to oxygen deprivation in hearts of spontaneously hypertensive rats (SHR) may be sex-dependent. For this purpose, adult SHR and their normotensive control Wistar Kyoto (WKY) rats were used. The isolated hearts were perfused according to Langendorff at constant pressure (proportionally adjusted to the blood pressure in vivo). Recovery of contractile parameters (left ventricular systolic, diastolic and developed pressure as well as the peak rate of developed pressure) was measured during reperfusion after 20 min of global no-flow ischemia in 5 min intervals. Mean arterial blood pressure was measured by direct puncture of carotid artery under light ether anesthesia in a separate group of animals. The degree of hypertension was comparable in both sexes of SHR. The recovery of contractile functions in SHR males and females was significantly lower than in WKY rats during the whole investigated period. There was no sex difference in the recovery of WKY animals; on the other hand, the recovery was significantly better in SHR females than in SHR males. It may be concluded that the hearts of female SHR are more resistant to ischemia/reperfusion injury as compared with male SHR. This fact could have important clinical implications for the treatment of cardiovascular disease in women., J. Bešík, O. Szárszoi, J. Kuneš, I. Netuka, J. Malý, F. Kolář, J. Pirk, B. Ošťádal., and Obsahuje bibliografii a bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

15980. Tolerance to waterlogging in young Euterpe oleracea plants

Creator:
Pereira, T. S., Lobato, A. K. S., Alves, G. A. R., Ferreira, R. N., Silva, O. N., Martins Filho, A. P. , Pereira, E. S., and Sampaio, L. S.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, Amazonka (řeka : oblast), Amazonas (Brazil), abiotic stress, açaí palm, ascorbate, glutathione, submergence, Euterpe oleracea, 2, and 581
Language:
Multiple languages
Description:
This study investigated whether gas exchange and the present content of antioxidant compounds can contribute to the survival of Euterpe oleracea plants in environments of frequent waterlogging. A factorial randomised, experimental design included two distinct water conditions (waterlogging and control) and five evaluation times (0, 6, 12, 18, and 24 d). Gasexchange parameters, leaf temperature, electrolyte leakage, and contents of antioxidant compounds were measured. Waterlogging did not promote significant alterations in net photosynthetic rate and transpiration, and stomatal conductance was reduced only after 18 d. Malondialdehyde and glutathione contents did not significantly change during waterlogging. Additionally, electrolyte leakage was significant only after 18 d of waterlogging. Thus, this study revealed that maintenance in gas exchange and antioxidant compounds might contribute to the survival of E. oleracea plants in environments exposed to waterlogging., T. S. Pereira, A. K. S. Lobato, G.A.R. Alves, R.N. Ferreira, O.N. Silva, A. P. Martins Filho, E.S. Pereira, L.S. Sampaio., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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