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2. 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
3. Application of spectrally resolved fluorescence induction to study light-induced nonphotochemical quenching in algae
- Creator:
- Kaňa, Radek
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- ochrana před ultrafialovým zářením, fotosyntéza, photoprotection, photosynthesis, fluorescence parameters, light-harvesting complex, photosystem II, 2, and 581
- Language:
- Multiple languages
- Description:
- The light-induced nonphotochemical quenching (NPQ) can safely dissipate excess of absorbed light to heat. Here we describe an application of spectrally resolved fluorescence induction (SRFI) method for studying spectral variability of NPQ. The approach allows detection of spectrally-resolved nonphotochemical quenching (NPQλ) representing NPQ dependency on fluorescence emission wavelength in the whole spectral range of fluorescence emission. The experimental approach is briefly described and NPQλ is studied for the cryptophyte alga Rhodomonas salina and for green alga Chlorella sp. We confirm presence of NPQλ only in membrane-bound antennae (chlorophyll a/c antennae) and not in phycobiliproteins in lumen in cryptophyte and show that NPQλ is inhibited in the whole spectral range by NPQ inhibitors in Chlorella sp. We discuss variability in the quenching in the particular spectral ranges and applicability of the NPQλ parameter to study quenching locus in vivo., R. Kaňa., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Chloroplast and photosystems: Impact of cadmium and iron deficiency
- Creator:
- Bashir, H., Qureshi, M. I., Ibrahim, M. M., and Iqbal, M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, grana, light-harvesting complex, stroma, thylakoids, 2, and 581
- Language:
- Multiple languages
- Description:
- Chloroplasts utilize photons from solar radiation to synthesize energy-rich molecules of ATPs and NADPHs, which are further used in active cellular processes. Multiprotein complexes (MPCs), including photosystems (PSII and PSI), and the cellular architecture responsible for generation of the proton motive force and the subsequent photophosphorylation, mediate the task of ATP and NADPH synthesis. Both photosystems and other multiprotein assemblies are embedded in thylakoid membranes. Advances in techniques used to study structural biology, biophysics, and comparative genomics and proteomics have enabled us to gain insights of structure, function, and localization of each individual component of the photosynthetic apparatus. An efficient coordination among MPCs is essential for normal functioning of photosynthesis, but there are various stressors that might directly or indirectly interact with photosynthetic components and processes. Cadmium is one of the toxic heavy metals that interact with photosynthetic components and damage photosystems and other MPCs in thylakoids. In plants, iron deficiency shows similar symptoms as those caused by Cd. Our article provides a general overview of chloroplast structure and a critical account of Cd-induced changes in photosystems and other MPCs in thylakoids, and suggests the possible mechanisms involved in mediating these changes. The connection between Cd-induced Fe deficiency and the elevated Cd toxicity under the Fe-deficient condition was also discussed., H. Bashir, M. I. Qureshi, M. M. Ibrahim, M. Iqbal., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Contrasting changes of photosystem 2 efficiency in Arabidopsis xanthophyll mutants at room or low temperature under high irradiance stress
- Creator:
- Peng, Chang-Lian and Gilmore, A. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- antheraxanthin, β-carotene, chlorophyll, fluorescence, light-harvesting complex, lutein, neoxanthin, violaxanthin, and zeaxanthin
- Language:
- Multiple languages
- Description:
- We compared the responses of wild type (WT) and three mutants including npq1 (lutein-replete and violaxanthin deepoxidase-deficient), lut2 (lutein-deficient), and lut2-npq1 (double mutant) to high irradiance (HI, 2 000 μmol m-2 s-1) at both low (LT, 5 °C) and room (25 °C) temperature. Xanthophyll-dependent energy dissipation was highest in the WT, followed by the lut2, npq1, and npq1-lut2. At 25 °C the relative stress tolerance expressed by Fv/Fm was consistent with the energy dissipation capacity for the first 2 h of treatment. After 3-4 h, the Fv/Fm levels in lut2 and npq1 converged. Under combined LT and HI the relative tolerance sequence was in contrast to the energy dissipation capacity being WT > npq1> lut2 > lut2-npq1. There were little or no significant change in the contents of xanthophylls and carotenes or the chlorophyll (Chl) a/b ratio in any of the materials. Thus lutein (L) substitution possibly alters the conformation/organisation of L binding proteins to enhance damage susceptibility under HI at LT. The enhanced vulnerability is not compensated for the energy dissipation capacity in the lut2 background at LT. and Chang-Lian Peng, A. M. Gilmore.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. Induction of cyclic electron flow around photosystem 1 and state transition are correlated with salt tolerance in soybean
- Creator:
- Lu, K. X., Yang, Y., He, Y., and Jiang, D. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence induction, DBMIB, DCMU, electron flow inhibitors, light-harvesting complex, maximum photochemical efficiency, NaCl, phosphorylation, species differences, and Western blot
- Language:
- Multiple languages
- Description:
- We investigated the role of cyclic electron flow around photosystem 1 (CEF1) and state transition (ST) in two soybean cultivars that differed in salt tolerance. The CEF1 and maximum photochemical efficiency (Fv/Fm) were determined under control and NaCl (50 mM) stress and the NaCl-induced light-harvesting complex 2 (LHC2) phosphorylation in vitro was analysed in light and dark. NaCl induced the increase of CEF1 more greatly in wild soybean Glycine cyrtoloba (cv. ACC547) than in cultivated soybean Glycine max (cv. Melrose). The Fv/Fm was reduced less in G. cyrtoloba than in G. max after 10-d NaCl stress. In G. cyrtoloba, the increase of CEF1 was associated with enhancement of LHC2 phosphorylation in thylakoid membrane under both dark and light. However, in G. max the NaCl treatment decreased the LHC2 phosphorylation. Treatment with photosynthetic electron flow inhibitors (DCMU, DBMIB) inhibited LHC2 phosphorylation more in G. max than in G. cyrtoloba. Thus the NaCl-induced up-regulation in CEF1 and ST might contribute to salt resistance of G. cyrtoloba. and K. X. Lu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. Proton concentration in the thylakoid membranes can regulate energy distribution between the two photosystems
- Creator:
- Tongra, T., Bharti, S., and Jajoo, A.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, špenát, photosynthesis, light-harvesting complex, luminal pH, nonphotochemical quenching, oxygen consumption, oxygen evolution, spinach, 2, and 581
- Language:
- Multiple languages
- Description:
- The aim of our study was to investigate the role of protons in regulating energy distribution between the two photosystems in the thylakoid membranes. Low pH-induced changes were monitored in the presence of a proton blocker, N,N′-dicyclohexylcarbodiimide (DCCD). When thylakoid membranes were suspended in a low-pH reaction mixture and incubated with DCCD, then a decrease in the fluorescence intensity of photosystem II (PSII) was observed, while no change in the intensity of photosystem I (PSI) fluorescence occurred according to the measured fluorescence emission spectra at 77 K. Since low pH induced distribution of energy from PSII to PSI was inhibited in the presence of DCCD, we concluded that pH/proton concentration of the thylakoid membranes plays an important role in regulating the distribution of the absorbed excitation energy between both photosystems., T. Tongra, S. Bharti, A. Jajoo., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
8. Soybean leaf nitrogen, chlorophyll content, and chlorophyll a/b ratio
- Creator:
- Fritschi, F. B. and Ray, J. D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- areal leaf mass, canopy, Glycine max, leaf insertion, light-harvesting complex, photosystem 2, and SPAD
- Language:
- Multiple languages
- Description:
- The objective of this study was to assess genotypic variation in soybean chlorophyll (Chl) content and composition, and to test if these data could be used as a rapid screening method to predict genotypic variation in leaf tissue N content. Chl contents and composition were examined among 833 soybean (Glycine max L. Merr.) accessions and related to SPAD meter readings and leaf N content. In the initial year of the study (2002), the relationship between leaf Chl and leaf N contents (r 2 = 0.043) was not sufficiently close for Chl to be useful as a predictive tool for leaf N content. Therefore, leaf N content was not determined in 2004 but samples were again collected for determination of Chl content and composition. In 2002, the soybean accessions separated into two distinct groups according to leaf Chl a/b ratios, with the majority of a mean ratio of 3.79. However, approximately 7 % (60) of the genotypes could be readily assigned to a group with a mean Chl a/b ratio of 2.67. Chl a/b analyses in 2004 confirmed the results obtained in 2002 and of 202 genotypes, all but 6 fell into the same group as in 2002. and F. B. Fritschi, J. D. Ray.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
9. The effect of additional red irradiation on the photosynthetic apparatus of Pisum sativum
- Creator:
- Topchiy, N. M., Sytnik, S. K., Syvash, O. O., and Zolotareva, O. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll, light-emitting diodes, light-harvesting complex, non-photochemical quenching, photosystem 2, Pisum sativum, photochemical quenching, and spectral composition of radiation
- Language:
- Multiple languages
- Description:
- Pisum sativum (L.) plants were grown under "white" luminescent lamps, W [45 µ mol(quantum) m-2 s-1] or under the same irradiation supplemented with narrow spectrum red light-emitting diodes (LEDs), RE [λmax = 660 nm, Δλ = 20 nm, 40 µmol(quantum) m-2 s-1]. Significant differences in the chlorophyll (Chl) a fluorescence parameters, degree of State 1-State 2 transition, and the pigment-protein contents were found in plants grown under differing spectral composition. Addition of red LEDs to the "white light" resulted in higher effective quantum yield of photosystem 2 (PS2), i.e. F'v/F'm, linear electron transport (ϕPS2), photochemical quenching (qP), and lower non-photochemical quenching (qN as well as NPQ). The RE plants were characterised by higher degree State 1-State 2 transition, i.e. they were more effective in radiant energy utilisation. Judging from the data of "green" electrophoresis of Chl containing pigment-protein complexes of plants grown under various irradiation qualities, the percentage of Chl in photosystem 2 (PS2) reaction centre complexes in RE plants was higher and there was no difference in the total Chl bound with Chl-proteins of light-harvesting complexes (LHC2). Because the ratio between oligomeric and monomeric LHC2 forms was higher in RE plants, we suggest higher LHC2 stability in these ones. and N. M. Topchyi ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
10. The polarized photoacoustic spectra of Rhodobacter sphaeroides cells embedded in polymer and strongly irradiated by polarized radiation
- Creator:
- Goc, J. and Klecha, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- absorption, bacteriochlorophyll, carotenoids, chromophore, light-harvesting complex, purple photosynthetic bacteria, and thermal deactivation
- Language:
- Multiple languages
- Description:
- The cells of purple photosynthetic bacterium Rhodobacter sphaeroides embedded in stretched polymer films were irradiated by strong polarized "white light" with an electric vector parallel to the direction of film stretching. The polarized absorption and photoacoustic spectra before and after strong irradiation were measured. Measurements of absorbance showed no confident anisotropy before and after strong irradiation. In contradiction, the photoacoustic method showed after strong irradiation some changes in anisotropy of thermal deactivation due to the perturbation of the fate of excitations. The increase in yield of thermal deactivation, higher in a region of light-harvesting complex 2, can be explained by the irreversible changes in the conformation of the complexes due to strong irradiance reported up to now predominantly for thylakoid antenna complexes. and J. Goc, K. Klecha.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public