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2. 24-epibrassinolide and/or putrescine trigger physiological and biochemical responses for the salt stress mitigation in Cucumis sativus L.
- Creator:
- Fariduddin, Q., Mir, B. A., Yusuf, M., and Ahmad, Altaf
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, brassinosteroids, Cucumis sativus, polyamines, salt stress, 2, and 581
- Language:
- Multiple languages
- Description:
- Brassinosteroids (BRs) and polyamines, well-established growth regulators, play a key role in abiotic stress response in plants. In the present study, we examined the role of 24-epibrassinolide (EBL, an active BR) and/or putrescine (Put) in the salt-induced stress in cucumber. The 15-d-old plants were exposed to 100 mM NaCl and they were subsequently treated by exogenous EBL and/or Put. The salt stress reduced significantly plant growth and gas-exchange parameters, and increased proline content and electrolyte leakage in the leaves. Toxic effects induced by salt stress were completely overcome by the combination of EBL and Put. EBL and/or Put treatments improved the growth parameters of the NaCl-treated plants, such as shoot length, root length, fresh and dry mass. Our data also indicated that applications of EBL and Put upregulated the activities of the antioxidant enzymes, such as catalase, peroxidase, and superoxide dismutase under salt stress., Q. Fariduddin, B. A. Mir, M. Yusuf, A. Ahmad., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. 24-epibrassinolide improves cucumber photosynthesis under hypoxia by increasing CO2 assimilation and photosystem II efficiency
- Creator:
- Ma, Y. H. and Guo, S. R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, brassinosteroids, chlorophyll content, CO2-response curve, light energy allocation, light-response curve, 2, and 581
- Language:
- Multiple languages
- Description:
- Seedlings of the hypoxia-sensitive cucumber cultivar were hydroponically grown under hypoxia for 7 d in the presence or absence of 24-epibrassinolide (EBR, 2.1 nM). Hypoxia significantly inhibited growth, while EBR partially counteracted this inhibition. Leaf net photosynthetic rate (PN), stomatal conductance, transpiration rate, and water-use efficiency declined greatly, while the stomatal limitation value increased significantly. The maximum net photosynthetic rate was strongly reduced by hypoxia, indicating that stomatal limitation was not the only cause of the PN decrease. EBR markedly diminished the harmful effects of hypoxia on PN as well as on stomata openness. It also greatly stimulated CO2 fixation by the way of increasing the carboxylation capacity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), ribulose-1,5-bisphosphate regeneration, Rubisco activity, and the protection of Rubisco large subunit from degradation. Our data indicated that photosystem (PS) II was damaged by hypoxia, while EBR had the protective effect. EBR further increased nonphotochemical quenching that could reduce photodamage of the PSII reaction center. The proportion of absorbed light energy allocated for photochemical reaction (P) was reduced, while both nonphotochemical reaction dissipation of light energy and imbalanced partitioning of excitation energy between PSI and PSII increased. EBR increased P and alleviated this imbalance. The results suggest that both stomatal and nonstomatal factors limited the photosynthesis of cucumber seedlings under hypoxia. EBR alleviated the growth inhibition by improving CO2 asimilation and protecting leaves against PSII damage., Y. H. Ma, S. R. Guo., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. A comparison of chlorophyll fluorescence transient measurements, using Handy PEA and FluorPen fluorometers
- Creator:
- Padhi, B., Chauhan, G., Kandoi, D., Stirbet, A., Tripathy, Baishnab C., and Govindjee, G.
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- huseníček rolní, Arabidopsis thaliana, blue and red excitation light, fluorescence imaging, OJIP transient, 2, and 581
- Language:
- Multiple languages
- Description:
- We provide here a general introduction on chlorophyll (Chl) a fluorescence, then we present our measurements on fast (< 1 s) induction curves (the so-called OJIP transients) on dark-adapted intact leaves of Arabidopsis thaliana, under five different light intensities [in the range of ~ 500 to ~ 3,000 µmol(photons) m‒2 s‒1] using two different instruments: Handy PEA (Hansatech Instruments, UK; excitation light, 650 nm) and FluorPen (model FP-110; Photon Systems Instruments, The Czech Republic; excitation light, 470 nm). We then discuss the observed differences in the OJIP curves, as well as in Fo (F20μs, F50μs, or the extrapolated Ft→0), FP (the peak), and the ratios FP/Fo, and Fv (= FP ‒ Fo)/FP in terms of differences in excitation light intensity and absorptance (or absorbance) of the excitation light by the leaves, and other factors, as well as the data available in the literature. We suggest that such measurements be accompanied, in the future, by parallel measurements on Chl a fluorescence imaging, an area pioneered by Hartmut K. Lichtenthaler., B. Padhi, G. Chauhan, D. Kandoi, A. Stirbet, B. C. Tripathy, G. Govindjee., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. A comparison of seasonal foliar chlorophyll change among ecotypes and cultivars of Andropogon gerardii (Poaceae) by using nondestructive and destructive methods
- Creator:
- Caudle, K. L., Johnson, L. C., Baer, S. G., and Maricle, B. R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, sucha, travní porosty, populace (biologie), pigmenty, rostliny prérií, photosynthesis, grasslands, population (biology), pigments, prairies plants, drouhgt, prairie, precipitation gradient, sand bluestem, tallgrass prairie, Andropogon gerardii, 2, and 581
- Language:
- Multiple languages
- Description:
- Leaf chlorophyll (Chl) concentration can be an indicator of plant health, including photosynthetic potential and nutrient status. In some cases, this measure can indicate the degree to which plants are water-stressed. Traditional methods of measuring Chl concentration have involved a destructive sampling technique: extraction and spectrophotometric analysis. A compatible nondestructive method to measure leaf Chl concentration exists and applies transmittance spectroscopy to plants with a Minolta SPAD-502 meter. These techniques were evaluated by comparing leaf Chl concentration in big bluestem (Andropogon gerardii). Leaves were sampled from plants representing three ecotypes (originating from Central Kansas, Eastern Kansas, and Illinois, USA) and two cultivars of A. gerardii growing in Hays, Kansas, USA. Leaf Chl concentration was measured using nondestructive and destructive techniques. We documented a saturating relationship between destructively measured leaf Chl concentration and SPAD index resulting from a decelerating change in SPAD index as Chl concentration increased. The comparison of A. gerardii ecotypes and cultivars demonstrated highest Chl concentration in the ecotype and cultivar from areas with historically low precipitation, Central Kansas and A. gerardii var. hallii, respectively. A high ratio of Chl a to Chl b is an index of drought adaptation and was also manifested in A. gerardii from drier regions. Thus, drought-adapted ecotypes and cultivars might be able to maintain high photosynthetic productivity and protect photosystem II during dry periods. Conversely, the ecotypes and cultivar originating from areas with higher precipitation had lower leaf Chl and a lower Chl a/b ratio., K. L. Caudle, L. C. Johnson, S. G. Baer, B. R. Maricle., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. A marine phytoplankton Prymnesium parvum upregulates the component proteins of photosystem II under iron stress
- Creator:
- Rahman, M. M., Rahman, M. A., Maki, T., Nishiuchi, T., Asano, T., and Hasegawa, H.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, fytoplankton, železo, photosynthesis, phytoplankton, iron, Japonsko, Hirošima (Japonsko), Japan, mořský fytoplankton, Fe limitation, growth rate, protein expression, Prymnesium parvum, marine phytoplankton, Fukuyama Bay, 2, and 581
- Language:
- Multiple languages
- Description:
- Iron is an essential limiting factor for primary production in many marine systems. The present study investigated differential regulation of protein expression in marine phytoplankton Prymnesium parvum under low Fe concentration. The phytoplankton was grown in f/2 culture medium in artificial seawater with low (0.0025 μM) and high (0.05 μM) Fe concentrations. Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption-ionization-time of flight-mass spectrometer analysis were performed for protein identification and characterization. The growth of the alga declined substantially under the low Fe compared to the high Fe concentration. Under low Fe conditions, P. parvum upregulated 10 proteins including chloroplastic ATP synthase subunit b, D2 protein of PSII, D1 protein of PSII reaction centre, and light harvesting complex II protein, most of which are associated with photosynthetic activities in PSII. The results suggest that the marine alga P. parvum altered the biosynthesis of several photosynthetic proteins in order to cope with low Fe conditions., M. M. Rahman, M. A. Rahman, T. Maki, T. Nishiuchi, T. Asano, H. Hasegawa., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. A method of a bicolor fast-Fourier pulse-amplitude modulation chlorophyll fluorometry
- Creator:
- Lysenko, V., Lazár, D., and Varduny, T.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorofyl, chlorophyll, multi-color PAM, chromatic adaptation, greenhouse lighting, dual-wavelength PAM, 2, and 581
- Language:
- Multiple languages
- Description:
- A simple method of a bicolor (multicolor), fast-Fourier, PAM chlorophyll fluorometry has been developed to obtain fluorescence induction curves. Quantum yields of PSII photochemistry were determined with blue and red simultaneously applied pulsed measuring lights for three subsequent 20-min periods of dark-, light-adaptation under actinic light and dark recovery. Measuring lights were cross-combined with blue and red actinic lights and saturation pulses. Coefficients of chromatic divergence were calculated as a ratio of the quantum yields obtained by red measuring light to that obtained by blue measuring light. Adaptation of Ficus benjamina and Hordeum vulgare leaves under blue (but not red) actinic light resulted in the sufficient increase of chromatic divergence. In addition, fraction of active, non(photo)inhibited, PSII centers was shown to be dependent on the color of measuring light. Thus, color of the light sources should be considered when reporting results of parameters evaluated from fluorescence induction curves., V. Lysenko, D. Lazár, T. Varduny., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. A modified nonrectangular hyperbola equation for photosynthetic light-response curves of leaves with different nitrogen status
- Creator:
- Xu, J. Z., Yu, Y. M., Peng, S. Z., Yang, S. H., and Liao, L. X.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, leaf nitrogen, modified nonrectangular hyperbola equation, Oryza sativa, photosynthetic light-response curve, SPAD, 2, and 581
- Language:
- Multiple languages
- Description:
- Chlorophyll index and leaf nitrogen status (SPAD value) was incorporated into the nonrectangular hyperbola (NRH) equation for photosynthetic light-response (PLR) curve to establish a modified NRH equation to overcome the parameter variation. Ten PLR curves measured on rice leaves with different SPAD values were collected from pot experiments with different nitrogen (N) dosages. The coefficients of initial slope of the PLR curve and the maximum net photosynthetic rate in NRH equation increased linearly with the increase of leaf SPAD. The modified NRH equation was established by multiplying a linear SPAD-based adjustment factor with the NRH equation. It was sufficient in describing the PLR curves with unified coefficients for rice leaf with different SPAD values. SPAD value, as the indicator of leaf N status, could be used for modification of NRH equation to overcome the shortcoming of large coefficient variations between individual leaves with different N status. The performance of the SPAD-modified NRH equation should be further validated by data collected from different kinds of plants growing under different environments., J. Z. Xu, Y. M. Yu, S. Z. Peng, S. H. Yang, L. X. Liao., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9. A novel method for the estimation of soybean chlorophyll content using a smartphone and image analysis
- Creator:
- Rigon, J. P. G., Capuani, S., Fernandes, D. M., and Guimarães, T. M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorofyl, karotenoidy, chlorophyll, carotenoids, mathematical models, fotosyntetické pigmenty, přenosná zařízení, quinoa, sezam, sójové boby, ricinový olej, tmavě zelený barevný index, vegetační index, smart phone camera, color model, photosynthetic pigments, portable equipment, sesame, soybean, castor oil, pod formation stage, Surinam cherry, dark green color index, vegetation index, 2, and 581
- Language:
- Multiple languages
- Description:
- The development of smartphones, specifically their cameras, and imaging technologies has enabled their use as sensors/measurement tools. Here we aimed to evaluate the applicability of a fast and noninvasive method for the estimation of total chlorophyll (Chl), Chl a, Chl b, and carotenoids (Car) content of soybean plants using a smartphone camera. Single leaf disc images were obtained using a smartphone camera. Subsequently, for the same leaf discs, a Chl meter was used to obtain the relative index of Chl and the photosynthetic pigments were then determined using a classic method. The RGB, HSB and CIELab color models were extracted from the smartphone images and correlated to Chl values obtained using a Chl meter and by a standard laboratory protocol. The smartphone camera was sensitive enough to capture successfully a broad range of Chl and Car contents seen in soybean leaves. Although there was a variation between color models, some of the proposed regressions (e.g., the S and b index from HSB and Lab color models and NRI [RGB model]) were very close to the Chl meter values. Based on our findings, smartphones can be used for rapid and accurate estimation of soybean and Car contents in soybean leaves., J. P. G. Rigon, S. Capuani, D. M. Fernandes, T. M. Guimarães., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
10. A portable reflectance-absorptance-transmittance meter for photosynthetic work on vascular plant leaves
- Creator:
- Ritchie, R. J. and Runcie, J. W.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, absorptance, electron transport rate, integrating sphere, leaf absorptance factor, PAM fluorometry, reflectance, 2, and 581
- Language:
- Multiple languages
- Description:
- PAM (pulse amplitude modulation) fluorometers can be used to estimate the electron transport rate (ETR) [μmol(e-) m-2 s-1] from photosynthetic yield determinations, provided the absorptance (Abtλ) of the photoorganism is known. The standard assumed value used for absorptance is 0.84 (leaf absorptance factor, AbtF). We described a reflectance-absorptancetransmittance (RAT) meter for routine experimental measurements of the actual absorptance of leaves. The RAT uses a red-green-blue (RGB) LED diode light source to measure absorptances at wavelengths suitable for use with PAM fluorometers and infrared gas analysers. Results using the RAT were compared to Abtλ spectra using a Taylor integrating sphere on bird’s nest fern (Asplenium nidus), banana, Doryanthes excelsa, Kalanchoe daigremontiana, and sugarcane. Parallel venation had no significant effect upon Abt465 in banana, Doryanthes, a Dendrobium orchid, pineapple, and sugarcane, but there was a slight difference in the case of the fern A. nidus. The average Abt465 (approximately 0.96) and Abt625 (approximately 0.89) were approximately 14% and 6% higher than the standard value (AbtF = 0.84). The PAR-range Abt400-700 was only approximately 5% higher than the standard value (approximately 0.88) based on averaged absorptance from the blue, green, and red light data and from where the RGB-diode was used as a ‘white’ light source. In some species, absorptances at blue and red wavelengths are quite different (e.g. water lily). Reflectance measurements of leaves using the RAT would also be useful for remote sensing studies., R. J. Ritchie, J. W. Runcie., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
11. A sunny day at the beach: ecophysiological assessment of the photosynthetic adaptability of coastal dune perennial herbs by chlorophyll fluorescence parameters
- Creator:
- Bermúdez, R. and Retuerto, R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, Eryngium maritimum, Euphorbia paralias, light curve, Matthiola sinuata, nonphotochemical quenching, Pancratium maritimum, photochemical quenching, quantum yield of photosystem II, 2, and 581
- Language:
- Multiple languages
- Description:
- Light is critical in determining plant structure and functioning in dune ecosystems, which are characterised by high incident and reflected radiation. Light variations demand great plasticity of the photosynthetic apparatus. This study assessed the phenotypic plasticity of foredune species by analysing their light response and dark recovery curves measured under field conditions. We also addressed the question how coexisting species, structurally distinct, differed in their photochemical efficiency in response to short-term changes in light. Finally, we examined how the varying intensity of stressors operating along a dune gradient affected responses to light. The species differed in light use strategies but showed similar patterns of the dark recovery. Species differences in photochemistry varied seasonally, with species being winter specialists, summer specialist or generalists. Some aspects of their photochemistry varied significantly along the gradient. Unexpectedly, other traits did not vary as predicted. For example, changes in light efficiency of plants along the gradient were not consistent with assumed directional changes in the severity of stressors. The different light use strategies observed in coexisting species did not conform to the prediction that stressors constrain the range of possible functional designs in harsh environments. However, the species followed very similar patterns of post-illumination recovery, which suggests that evolutionary pressures might be acting to maintain similar recovery mechanisms. Our results indicated that dune gradients might be nondirectional, which determines unpredictable patterns of variation in leaf traits along the dune gradient. Seasonal differences in the relative performance may allow species to coexist where otherwise one species would exclude the other., R. Bermúdez, R. Retuerto., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
12. Acclimation and photoprotection of young gametophytes of Acrostichum danaeifolium to UV-B stress
- Creator:
- Randi, A. M., Freitas, M. C. A., Rodrigues, A. C., Maraschin, M., and Torres, M. A.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, karotenoidy, chlorofyl, photosynthesis, carotenoids, chlorophyll, gametophyte development, phenolic compounds, ultrastructure, ultraviolet-B radiation, Acrostichum danaeifolium, 2, and 581
- Language:
- Multiple languages
- Description:
- The effect of ultraviolet B radiation (UV-B) on cellular ultrastructure, chlorophyll (Chl), carotenoids, and total phenolics of Acrostichum danaeifolium gametophytes was analyzed. The control group of spores was germinated under standard conditions, while the test group of spores was germinated with additional UV-B for 30 min every day for 34 d. The cell characteristics were preserved in gametophytes irradiated with UV-B, but the number of starch grains increased in the chloroplasts and the more developed grana organization in contrast to the chloroplasts of the control group. Chl a content decreased, while Chl b content increased in the gametophytes cultivated with UV-B for 34 d. Contents of lutein and zeaxanthin decreased and trans-β-carotene concentration was enhanced in the gametophytes irradiated with UV-B. The content of total phenolic compounds increased in the gametophytes cultivated with UV-B. Therefore our data suggest that the gametophytes of A. danaeifolium, a fern endemic to the mangrove biome, were sensitive to enhancement of UV-B radiation at the beginning of their development and they exhibited alterations in their ultrastructure, pigment contents, and protective mechanisms of the photosynthetic apparatus, when exposed to this radiation., A. M. Randi, M. C. A. Freitas, A. C. Rodrigues, M. Maraschin, M. A. Torres., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
13. Accumulation of photosynthetic pigments in Larix decidua Mill. and Picea abies (L.) Karst. cotyledons treated with 5-aminolevulinic acid under different irradiation
- Creator:
- Maximová, N. and Slováková, Ľudmila.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll biosynthesis, D1 protein, light-harvesting complex, protochlorophyllide, 2, and 581
- Language:
- Multiple languages
- Description:
- European larch (Larix decidua Mill.) and Norway spruce [Picea abies (L.) Karst.] synthesize chlorophyll (Chl) in darkness. This paper compares Chl accumulation in 14-d-old dark-grown seedlings of L. decidua and P. abies after shortterm (24 h) feeding with 5-aminolevulinic acid (ALA). We used two ALA concentrations (1 and 10 mM) fed to cotyledons of both species in darkness and in continuous light. The dark-grown seedlings of L. decidua accumulated Chl only in trace amounts and the seedlings remained etiolated. In contrast, P. abies seedlings grown in darkness were green and had significantly higher Chl content. After ALA feeding, higher protochlorophyllide (Pchlide) content was observed in L. decidua than in P. abies cotyledons incubated in darkness. Although short-term ALA feeding stimulated the synthesis of Pchlide, Chl content did not change significantly in cotyledons incubated in darkness. The Chl accumulation in cotyledons fed with ALA was similar to the rate of Chl accumulation in the controls. Higher Chl accumulation was reported in control samples after illumination: 86.9% in L. decidua cotyledons and 46.4% in P. abies cotyledons. The Chl content decreased and bleaching occurred in cotyledons incubated with ALA in light due to photooxidation. Analyses of Chlbinding proteins (D1 and LHCIIb) by Western blotting proved differences between Chl biosynthesis in L. decidua and P. abies seedlings in the dark and in the light. No remarkable increase was found in protein accumulation (D1 and LHCIIb) after ALA application. Our results showed interspecific difference in Chl synthesis between two gymnosperms. Shortterm ALA feeding did not stimulate Chl synthesis, thus ALA synthesis was not the rate-limiting step in Chl synthesis in the dark., N. Maximová, Ľ. Slováková., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14. Adaptation strategies of two leaf cohorts of Prosopis juliflora produced in spring and monsoon
- Creator:
- Shirke, P. A., Pathre, U. V., and Sane, P. V.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- asimilace uhlíku, carbon assimilation, carboxylation efficiency, dark respiration rate, quantum efficiency, tree photosynthesis, water-use efficiency, 2, and 581
- Language:
- Multiple languages
- Description:
- Prosopis juliflora is an invasive leguminous tree species growing profusely under wide environmental conditions. Primary objective of this study was to investigate adaptation strategies evolved to deal with wide environmental conditions during different seasons. P. juliflora adapts through a production of leaves in two seasons, namely, the spring (the first cohort) and monsoon (the second cohort) with differing but optimal physiological characteristics for growth in respective seasons. Our studies show that the first cohort of leaves exhibit maximum carbon fixation under moderate temperatures and a wide range of PPFD. However, these leaves are sensitive to high leaf-to-air-vapor pressure deficit (VPD) occurring at high temperatures in summer resulting in senescence. While the second cohort of leaves produced during monsoon showed maximum carbon fixation at high irradiance and temperatures with low VPD, it is sensitive to low temperatures causing senescence in winter., P. A. Shirke, U. V. Pathre, P. V. Sane., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
15. Adaptive photosynthetic and physiological responses to drought and rewatering in triploid Populus populations
- Creator:
- Liao, T., Wang, Y., Xu, C. P., Li, Y., and Kang, X. Y.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- topol, populace (biologie), poplar, population (biology), chlorofylová fluorescence, výměna plynu, malondialdehyd, stomatální omezení, deficit vody, sucho, chlorophyll fluorescence, gas exchange, malondialdehyde, stomatal limitation, water deficit, drought, 2, and 581
- Language:
- Multiple languages
- Description:
- Cuttings of Populus cathayana Rehd, originating from three triploid and one diploid populations with the same parents but different gamete origins, were used to examine physiological responses to drought stress and rewatering by exposure to three progressive water regimes. Progressive drought stress significantly decreased the leaf relative water content (RWC), photosynthesis, and chlorophyll fluorescence parameters, and increased the relative electrolyte leakage, malondialdehyde (MDA), free proline (Pro), and antioxidant enzymes, such as superoxide dismutase, peroxidase, and catalase, in the four populations evaluated. However, compared to the diploid population, triploid populations showed lower relative electrolyte leakage and MDA, higher RWC and Pro content, and more efficient photosynthesis and antioxidant systems under the same water regime. Our data indicated that triploid populations possessed more efficient protective mechanisms than that of diploid population with gradually increasing drought stress. Moreover, some triploid genotypes were less tolerant to water stress than that of diploids due to large intrapopulation overlap., T. Liao, Y. Wang, C. P. Xu, Y. Li, X. Y. Kang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16. Alkali tolerance in rice (Oryza sativa L.): growth, photosynthesis, nitrogen metabolism, and ion homeostasis
- Creator:
- Wang, H., Lin, X., Cao, S., and Wu, Z.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- rýže, photosynthesis, rice, Čína, China, citrate, gas exchange, gene expression regulation, germination rate, malate, Na+/K+ ratio, survival rate, Oryza sativa, 2, and 581
- Language:
- Multiple languages
- Description:
- Alkali stress is an important agricultural problem that affects plant metabolism, specifically root physiology. In this study, using two rice cultivars differing in alkali resistance, we investigated the physiological and molecular responses of rice plants to alkali stress. Compared to the alkali-sensitive cultivar (SC), the alkali-tolerant cultivar (TC) maintained higher photosynthesis and root system activity under alkali stress. Correspondingly, the Na+ content in its shoots was much lower, and the contents of mineral ions (e.g., K+, NO3-, and H2PO4-) in its roots was higher than those of the SC. These data showed that the metabolic regulation of roots might play a central role in rice alkali tolerance. Gene expression differences between the cultivars were much greater in roots than in shoots. In roots, 46.5% (20 of 43) of selected genes indicated over fivefold expression differences between cultivars under alkali stress. The TC had higher root system activity that might protect shoots from Na+ injury and maintain normal metabolic processes. During adaptation of TC to alkali stress, OsSOS1 (salt overly sensitive protein 1) may mediate Na+ exclusion from shoots or roots. Under alkali stress, SC could accumulate Na+ up to toxic concentrations due to relatively low expression of OsSOS1 in shoots. It possibly harmed chloroplasts and influenced photorespiration processes, thus reducing NH4+ production from photorespiration. Under alkali stress, TC was able to maintain normal nitrogen metabolism, which might be important for resisting alkali stress., H. Wang, X. Lin, S. Cao, Z. Wu., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
17. Allakhverdiev S. I., Rubin A. B., Shuvalov V. A. (ed.): Contemporary Problems of Photosynthesis (Современные проблемы фотосинтеза)
- Creator:
- Papageorgiou, George C.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, 2, and 581
- Language:
- Multiple languages
- Description:
- [autor recenze] George C. Papageorgiou.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18. Ameliorating effects of three kinds of antioxidants to ozone-polluted painted nettle (Coleus blumei Benth.)
- Creator:
- Zhang, L., Jia, L. L., Sui, J. X., Wen, M. X., and Chen, Y. J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fluorescence chlorofylu a, výměna plynu, kinetin, Na-askorbát, spermidin, chlorophyll a fluorescence, gas exchange, Na-ascorbate, spermidine, 2, and 581
- Language:
- Multiple languages
- Description:
- Ground concentration of ozone (O3) causes serious threat to plants. In order to protect sensitive plants from O3 pollution, many kinds of antioxidants were assessed in previous studies. In this study, effects of O3 fumigation (a single spike of 120 ± 20 nmol mol-1 for four hours) on an ornamental species (Coleus blumei) was examined in open-top chambers. Before the O3 treatment, plants were sprayed respectively either with a solution of three different antioxidants [Na-ascorbate (NaAsA), kinetin (KIN), and spermidine (Spd)] or with distilled water to compare their protective effects to plants. Our results revealed that O3 fumigation impaired the plasma membrane, decreased chlorophyll (Chl) content, inhibited photosynthesis, induced photoinhibition and photodamage, and caused visible injury. Spraying with KIN, NaAsA or Spd ameliorated the decrease of the Chl content and photosynthetic capability, the impairment of membrane, and visible injury under O3 fumigation. The plants treated with KIN showed the best ability to mitigate the injury caused by O3., L. Zhang, L. L. Jia, J. X. Sui, M. X. Wen, Y. J. Chen., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
19. Ameliorative role of salicylic acid and spermidine in the presence of excess salt in Lycopersicon esculentum
- Creator:
- Fariduddin, Q., Khan, T. A., Yusuf, M., Aafaqee, S. T., and Khalil, R. R. A. E.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- abiotické faktory, antioxidanty, fotosyntéza, abiotic factors, antioxidants, photosynthesis, prolin, kyselina salicylová, spermidin, rajče jedlé, proline, salicylic acid, spermidine, Lycopersicon esculentum, 2, and 581
- Language:
- Multiple languages
- Description:
- Salicylic acid (SA) and polyamines (PA) are widely used to overcome various abiotic stresses including salt (NaCl) stress in plants. In the present investigation, co-application efficacies of SA and PA on the salt stress (200 mM NaCl) were evaluated in Lycopersicon esculentum. After transplantation, at 10-d stage, seedlings were exposed to NaCl through soil and then allowed to grow till 30-d stage. At 31-d stage of growth, plants were sprayed with double distilled water (control) or spermidine (1.0 mM) and/or SA (10-5 M). The salt stress significantly reduced the growth, gas-exchange parameters, but increased antioxidant enzymes and proline content in the leaves. Moreover, the loss caused by salt stress was successfully restored by the following treatment of spermidine and SA., Q. Fariduddin, T. A. Khan, M. Yusuf, S. T. Aafaqee, R. R. A. E. Khalil., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
20. An improved method for the simultaneous determination of photosynthetic O2 evolution and CO2 consumption in Rhizophora mucronata leaves
- Creator:
- Ulqodry, T. Z., Nose, A., and Zheng, S.-H.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, carbon dioxide consumption, oxygen evolution, photosynthetic performance, 2, and 581
- Language:
- Multiple languages
- Description:
- The photosynthetic gas-exchange has been assessed traditionally either as O2 evolution or CO2 consumption. In this study, we used a liquid-phase O2 electrode combined with CO2 optodes to examine simultaneously photosynthesis in intact leaves of mangrove Rhizophora mucronata. We verified suitable conditions for leaf photosynthetic rates by assessing pH levels and NaHCO3 concentrations and compared these to the gas-exchange method at various PAR levels. The photosynthetic rate in response to pH exhibited a similar pattern both for O2 evolution and CO2 consumption, and higher rates were associated with intermediate pH compared with low and high pH values. The net photosynthetic quotient (PQ) of R. mucronata leaves ranged from 1.04-1.28. The PQ values, which were never lesser than 1, suggested that photorespiration did not occur in R. mucronata leaves under aqueous conditions. The similar maximum photosynthetic rates suggested that all measurements had a high capacity to adjust the photosynthetic apparatus under a light saturation condition. The simultaneous measurements of O2 evolution and CO2 consumption using the Clark oxygen electrode polarographic sensor with the CO2 optode sensor provided a simple, stable, and precise measurement of PQ under aqueous and saturated light conditions., T. Z. Ulqodry, A. Nose, S.-H. Zheng., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public