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4052. Reduced nitrogen allocation to expanding leaf blades suppresses ribulose-1,5-bisphosphate carboxylase/oxygenase synthesis and leads to photosynthetic acclimation to elevated CO2 in rice
- Creator:
- Seneweera, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, elevated CO2, photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase, rice, and spatial nitrogen deposition
- Language:
- Multiple languages
- Description:
- Net photosynthetic rate (PN) measured at elevated CO2 concentration (Ce), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and nitrogen (N) content in rice leaves decreased significantly after exposure to long term Ce. The reduction in PN, Rubisco, and leaf N at Ce was similar for the last fully expanded leaf blade (LFELB) and expanding leaf blade (ELB). Spatial leaf N content in the ELB was highest in the zone of cell division, sharply declined as cell expansion progressed and gradually increased with cell maturation. Maximum reduction in spatial leaf N and Rubisco content was found at Ce only within cell expansion and maturation zones. The spatial leaf N content correlated well with the amount of Rubisco synthesized during leaf expansion, suggesting that N deposition into the expanding leaf blade may be the key for Rubisco synthesis and possibly photosynthetic acclimation to Ce. and S. Seneweera.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4053. Reduction of photosynthetic apparatus plays a key role in survival of the microalga Haematococcus pluvialis (Chlorophyceae) at freezing temperatures
- Creator:
- Chekanov, K., Vasilieva, S., Solovchenko, A., and Lobakova, E.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, cold stress, Haematococcys pluvialis, stress tolerance, 2, and 581
- Language:
- Multiple languages
- Description:
- The microalga Haematococcus pluvialis is a biotechnologically important microorganism producing a ketocarotenoid astaxanthin. Haematococcus exists either as metabolically active vegetative cells with a high chlorophyll content or astaxanthin-rich haematocysts (aplanospores). This microalga featuring outstanding tolerance to a wide range of adverse conditions is a highly suitable model for studies of freezing tolerance in phototrophs. The retention of H. pluvialis cell viability after freezing-thawing is ascribed to elevated antioxidant enzyme activity and high ketocarotenoid content. However, we report that only haematocysts characterized by a lower photosynthetic activity were resistant to freezing-thawing even without cryoprotectant addition. The key factors of haematocyst freezing tolerance were assumed to be a low water content, rigid cell walls, reduction of the membranous structures, photosynthesis downregulation, and low chlorophyll content. Collectively, viability of Haematoccus after freezing-thawing can be improved by forcing the transition of vegetative cells to freeze-tolerant haematocysts before freezing., K. Chekanov, S. Vasilieva, A. Solovchenko, E. Lobakova., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4054. Reflectance indices indicative of changes in water and pigment contents of peanut and wheat leaves
- Creator:
- Peñuelas, J. and Inoue, Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Arachis, leaf desiccation, normalized difference vegetation index, relative water content, structural independent pigment index, Triticum, and water index
- Language:
- Multiple languages
- Description:
- Measurements of reflectance in visible and near-infrared spectral regions were made on detached leaves of two crop species of different leaf morphology, structure, and water content (peanut and wheat) throughout progressive desiccation. Relative water content (RWC) was well correlated with water index (WI) but even better with the ratio of WI and normalized difference vegetation index. RWC was also significantly correlated with structural independent pigment index indicative of carotenoids/chlorophyll ratio. New indication is thus provided to assess leaf water content and apply simple and fast radiometric techniques for plant water stress management. and J. Peñuelas, Y. Inoue.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4055. Regulating photoprotection improves photosynthetic growth and biomass production in QC-site mutant cells of the cyanobacterium Synechocystis sp. PCC 6803
- Creator:
- Huang, J.-Y., Hung, N.-T., Lin, K.-M., Chiu, Y.-F., and Chu, H.-A.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- cytochromy, fotosyntéza, ochrana před ultrafialovým zářením, cytochromes, photosynthesis, photoprotection, cytochrome b559, photosystem II, 2, and 581
- Language:
- Multiple languages
- Description:
- We characterized the photosynthetic growth of wild-type (WT) and QC-site mutant cells of the cyanobacterium Synechocystis sp. PCC 6803 grown in a photobioreactor under medium-intensity [~70 μmol(photon) m-2 s-1] and high-intensity [~200 μmol(photon) m-2 s-1] light conditions. Photosynthetic growth rate (the exponential phase) increased about 1.1-1.2 fold for the A16FJ, S28Aβ, and V32Fβ mutant compared with WT cells under medium-intensity light and about 1.2-1.3 fold under high-intensity light. Biomass production increased about 17-20% for A16FJ and S28Aβ mutant cells as compared with WT cells under medium-intensity light and about 14-17% for A16FJ and V32Fβ mutant cells under high-intensity light. The greater photosynthetic growth rate and biomass production of these QC-site mutant cells could be attributed to the increased photosynthesis efficiency and decreased dissipation of wasteful energy from phycobilisomes in mutants vs. WT cells. Our results support that manipulation of photoprotection may improve photosynthesis and biomass production of photosynthetic organisms., J.-Y. Huang, N.-T. Hung, K.-M. Lin, Y.-F. Chiu, H.-A. Chu., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4056. Regulation mechanism of excitation energy transfer in phycobilisome-thylakoid membrane complexes
- Creator:
- Li, Ye, Zhang, Jianping, Zhao, Jingquan, and Jiang, Lijing
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- absorption spectra, allophycocyanin, betaine, DCMU, fluorescence spectra, models of energy transfer, N-ethylmaleimide, photosystems 1 and 2, and state transition
- Language:
- Multiple languages
- Description:
- Regulation mechanism of excitation energy transfer between phycobilisomes (PBS) and the photosynthetic reaction centres was studied by the state transition techniques in PBS-thylakoid membrane complexes. DCMU, betaine, and N-ethylmaleimide were applied to search for the details of energy transfer properties based on the steady fluorescence measurement and individual deconvolution spectra at state 2 or state 1. The closure of photosystem (PS) 2 did not influence on fluorescence yields of PS1, i.e., energy could not spill to PS1 from PS2. When the energy transfer pathway from PBS to PS1 was disturbed, the relative fluorescence yield of PS2 was almost the same as that of PS2 in complexes without treatment. If PBSs were fixed by betaine, the state transition process was restrained. Hence PBS may detach from PS2 and become associated to PS1 at state 2. Our results contradict the proposed "spill-over" or "PBS detachment" models and support the mobile "PBS model". and Ye Li ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4057. Regulation of photosynthesis by radiation quality in the lichen Evernia prunastri
- Creator:
- Segovia, M. and Figueroa, F. L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, photochemical quenching, photoreceptors, quantum yield, and spectrum quality
- Language:
- Multiple languages
- Description:
- In Evernia prunastri, photosynthetic gas exchange was saturated with yellow radiation (SOX) at 400 μmol m-2s-1, and then red (R), far-red (FR), or blue (B) radiations at irradiance of 15 μmol m-2s-1 were added. Because of photosynthesis saturation, any stimulation or decay in CO2 assimilation by any radiation quality could be attributed to the involvement of a non-photosynthetic photoreceptor. Thus CO2 assimilation, effective quantum yield, and photochemical quenching were enhanced when R was included, and decreased with FR. Blue radiation completely abolished CO2 fixation. Hence different spectral radiation qualities may activate non-photosynthetic photoreceptors such as phytochrome and blue photoreceptors, which are involved in regulating the photosynthetic activity in E. prunastri. and M. Segovia, F. L. Figueroa.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4058. Regulation of photosynthetic carbon metabolism by limiting irradiance in three different C4 plants
- Creator:
- Sailaja, M.V. and Rama Das, V.S.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- alanine aminotransferase, Amaranthus, aspartate aminotransferase, Eleusine, Gomphrena, malate dehydrogenase, malic enzyme, phosphoenolpymvate carboxylase, photosynthetic acclimation, and pyruvate phosphate dikinase
- Language:
- Multiple languages
- Description:
- A low irradiance mediated regulation of C4 metabolism during acclimation is reported for first time in Amaranthus hypochondriacus L., a NAD-ME dicot, Eleusine coracana (L.) Gaertn., an NAD-ME monocot, and Gomphrena globosa, a NADP-ME dicot. Significant decline in activities of key C4 enzymes were observed under limited irradiances in each of the species studied. When the plants were transferred to full natural irradiance, the enzyme activities were restored to originál State in 3-5 d, a similar time frame needed for acclimation to limiting irradiance. This identifies the decarboxylation reaction involving NAD-ME in Amaranthus and Eleusine or NADP-ME in Gomphrena as crucial sites of regulation under limiting irradiance.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4059. Regulation of photosystem 1 reaction centre formation
- Creator:
- Chaika, M.T., Abramchik, L.M., and Savchenko, G.E.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- A surprísingly high level of the CPI membrane-bound apoprotein was found through ELISA test in barley coleoptiles, cotnpared with etiolated leaves. Non-synchronous changes of the chlorophyll (Chl) a and CPI apoprotein contents were found in greening etiolated seedlings after brief preinradiation, in green leaves after continuous darkness and the second weak irradiation, and in old leaves after a period of darkness. The complexity of these fmdings gives a possibility of the CPI apoprotein formation without direct cotmection to Chl a biosynthesis. The CPI apoprotein accumulation in young etiolated leaves was stimulated by S-aminolevulinic acid.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4060. Regulation of plastid gene expression by high temperature during light Induced chloroplast development
- Creator:
- Singh, Abhay K. and Singhal, G. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- biogenesis, photosynthesis, wheat, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- Effect of high temperature on the plastid gene expression during the light induced chloroplast development in etiolated seedlings was determined by Northern hybridisation using cloned DNA fragments of wheat chloroplast genome. Based on their response to high temperature, plastid genes were grouped into three categories: (1) plastid genes whose expression was not affected by high temperature (genes for rRNA, ribosomal proteins, tRNAs, and some genes coding for putative NADH dehydrogenase); (2) plastid genes whose expression increased at high temperature (genes coding for α-subunit of RNA polymerase and some unidentified transcripts, and (3) plastid genes whose expression decreased at high temperature (genes coding for proteins involved in photosynthetic process). Loss of a number of primary transcripts originating from operons consisting of genes that code for proteins involved in the photosynthetic process was observed. The expression of all the light inducible plastid genes was inhibited suggesting that the light inducibility property was lost at high temperature. and Abhay K. Singh, G. S. Singhal.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public