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412. Promotion of 5-aminolevulinic acid treatment on leaf photosynthesis is related with increase of antioxidant enzyme activity in watermelon seedlings grown under shade condition
- Creator:
- Sun, Y.-P., Zhang, Z.-P., and Wang, L.-J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- 5-aminolevulinic acid, antioxidant enzymes, chlorophyll fluorescence, JIP test, low light stress, photosynthesis, and watermelon
- Language:
- Multiple languages
- Description:
- Watermelon [Citrullus lanatus (Thunb.) Mansfeld] is a photophilic plant, whose net photosynthetic rate was significantly decreased when seedlings were grown under low light condition. However, treatment with 100 mg kg-1 5-aminolevulinic acid (ALA) could significantly restore the photosynthetic ability under the environmental stress. The parameters of leaf gas exchange, chlorophyll modulated fluorescence and fast induction fluorescence of the ALA-treated plants were higher than that of the control. Additionally, ALA treatment increased the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). Nevertheless, the treatment of diethyldithiocarbamate (DDC), an inhibitor of SOD activity, dramatically depressed photosynthesis of watermelon leaves, while ALA could reverse the inhibition of DDC. Therefore, it can be deduced that ALA promotion on photosynthesis of watermelon leaves under low light stress is attributed to its promotion on antioxidant enzyme activities, and the increased activities of the enzymes, which are mainly located near the reaction centers of PSI, can scavenge superoxide anions, leading to an increase of apparent electron transport rate and an alleviation of photosynthetic photoinhibition under the stressed environment. and Y.-P. Sun, Z.-P. Zhang, L.-J. Wang.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
413. Prospects of photosynthetic research for increasing agricultural productivity, with emphasis on the tropical C4 Amaranthus and the cassava C3-C4 crops
- Creator:
- El-Sharkawy, M. A.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- photosynthesis, agricultural sustainability, breeding, C3, C4, C3-C4 species, canopy, climate change, crop modeling, environmental stress, enzyme, food security, genetic engineering, grain, leaf Kranz anatomy, photorespiration, photosynthetic pathway, protein, starch, storage-root, water, yield, 2, and 581
- Language:
- Multiple languages
- Description:
- Productivity of most improved major food crops showed stagnation in the past decades. As human population is projected to reach 9-10 billion by the end of the 21st century, agricultural productivity must be increased to ensure their demands. Photosynthetic capacity is the basic process underlying primary biological productivity in green plants and enhancing it might lead to increasing potential of the crop yields. Several approaches may improve the photosynthetic capacity, including integrated systems management, in order to close wide gaps between actual farmer’s and the optimum obtainable yield. Conventional and molecular genetic improvement to increase leaf net photosynthesis (P N) are viable approaches, which have been recently shown in few crops. Bioengineering the more efficient CC4 into C3 system is another ambitious approach that is currently being applied to the C3 rice crop. Two under-researched, yet old important crops native to the tropic Americas (i.e., the CC4 amaranths and the C3-CC4 intermediate cassava), have shown high potential P N, high productivity, high water use efficiency, and tolerance to heat and drought stresses. These physiological traits make them suitable for future agricultural systems, particularly in a globally warming climate. Work on crop canopy photosynthesis included that on flowering genes, which control formation and decline of the canopy photosynthetic activity, have contributed to the climate change research effort. The plant breeders need to select for higher P N to enhance the yield and crop tolerance to environmental stresses. The plant science instructors, and researchers, for various reasons, need to focus more on tropical species and to use the research, highlighted here, as an example of how to increase their yields., M. A. El-Sharkawy., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
414. Protection of winter rape photosystem 2 by 24-epibrassinolide under cadmium stress
- Creator:
- Janeczko, A., Kościelniak, J., Pilipowicz, M., Szarek-Łukaszewska, G., and Skoczowski, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll fluorescence induction, photosynthesis, and winter rape
- Language:
- Multiple languages
- Description:
- Seedlings of winter rape were cultured in vitro on media containing 24-epibrassinolide, EBR (100 nM) and cadmium (300 µM). After 14 d of growth, fast fluorescence kinetics of chlorophyll (Chl) a and contents of photosynthetic pigments and Cd in cotyledons were measured. Cd was strongly accumulated but its content in cotyledons was 14.7 % smaller in the presence of EBR. Neither Cd nor EBR influenced the contents of Chl a and b and carotenoids. Cd lowered the specific energy fluxes per excited cross section (CS) of cotyledon. The number of active reaction centres (RC) of photosystem 2 (RC/CS) decreased by about 21.0 % and the transport of photosynthetic electrons (ET0/CS) by about 17.1 %. Simultaneously, under the influence of Cd, the activity of O2 evolving centres (OEC) diminished by about 19.5 % and energy dissipation (DI0/CS) increased by about 14.6 %. In the cotyledons of seedlings grown on media without Cd, EBR induced only a small increase in the activity of most photochemical reactions per CS. However, EBR strongly affected seedlings cultured with cadmium. Specific energy fluxes TR0/CS and ET0/CS of the cotyledons of plants Cd+EBR media were about 10.9 and 20.9 % higher, respectively, than values obtained for plants grown with Cd only. EBR also limited the increase of DI0/CS induced by Cd and simultaneously protected the complex of OEC against a decrease of activity. Hence EBR reduces the toxic effect of Cd on photochemical processes by diminishing the damage of photochemical RCs and OECs as well as maintaining efficient photosynthetic electron transport. and A. Janeczko ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
415. Proteomic study reveals photosynthesis as downstream of both MAP kinase and cAMP signaling pathways in Chlamydomonas reinhardtii
- Creator:
- Lee, C., Rhee, J.-K., Kim, D. G., and Choi, Y.-E.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, gene regulation, mass spectrometry, two-dimensional gel electrophoresis, 2, and 581
- Language:
- Multiple languages
- Description:
- Previously, our data indicated that both cAMP and MAP kinase signaling play important roles in microalgal physiology as well as in lipid or carotenoid biosynthesis. In order to understand downstream genes of these signaling pathways, we employed proteomics approach. Both signal pathways were first altered with specific signaling inhibitors or modulators. Treatment of specific inhibitors changed microalgal size and increased lipid contents. With the microalgal cells after treatments of specific signaling inhibitor or modulators, we performed the proteomics analysis to identify downstream genes responsible for these phenotypes. Interestingly, multiple photosynthesis genes were identified, particularly proteins associated with PSII. Our data suggested that MAP kinase and cAMP signaling affect the photosynthesis, thereby leading to microalgal lipid or carotenoid biosynthesis., C. Lee, J.-K. Rhee, D. G. Kim, Y.-E. Choi., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
416. 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
417. PsbP-induced protein conformational changes around Cl- ions in the water oxidizing center of photosystem II
- Creator:
- Kondo, J. and Noguchi, T.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, Mn4CaO5 cluster, oxygen evolution, 2, and 581
- Language:
- Multiple languages
- Description:
- PsbP is an extrinsic protein of PSII having a function of Ca2+ and Cl- retention in the water-oxidizing center (WOC). In order to understand the mechanism how PsbP regulates the Cl- binding in WOC, we examined the effect of PsbP depletion on the protein structures around the Cl- sites using Fourier transform infrared (FTIR) spectroscopy. Light-induced FTIR difference spectra upon the S1-S2 transition were obtained using Cl--bound and NO3--substituted PSII membranes in the presence and absence of PsbP. A clear difference in the amide I band changes by PsbP depletion was observed between Cl--bound and NO3--substituted PSII samples, indicating that PsbP binding perturbed the protein conformations around the Cl-ion(s) in WOC. It is suggested that PsbP stabilizes the Cl- binding by regulating the dissociation constant of Cl- and/or an energy barrier of Cl- dissociation through protein conformational changes around the Cl- ion(s)., J. Kondo, T. Noguchi., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
418. PSII photochemistry responses to drought stress in autochthonous and modern sweet cherry cultivars
- Creator:
- Mihaljević, I., Viljevac Vuletić, M., Tomaš, V., Horvat, D., Zdunić, Z., and Vuković, D.
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- chlorophyll a fluorescence, chlorophyll content, malondialdehyde, photosynthesis, sweet cherry, and water content
- Language:
- Multiple languages
- Description:
- In this study, the JIP test was used to assess the drought tolerance of two sweet cherry cultivars (Prunus avium L.) (modern and autochthonous). Plants were exposed to progressive drought by withholding water and their fast (< 1 s) chlorophyll fluorescence kinetics was evaluated. JIP test analysis showed that drought stress caused a greater decrease in performance indices (PIABS and PItotal) in a modern cultivar, as compared to an autochthonous one. Our results suggest that limited reoxidation of primary quinone electron acceptor (QA), higher amount of secondary quinone electron acceptor (QB-) nonreducing reaction centres, or inhibition of the electron transport between QA and QB, decreased more seriously the photosynthetic performance of the modern cultivar. Further, higher positive L- and K-bands observed for the modern cultivar also suggest lower energetic connectivity between PSII units and increased inhibition of oxygen-evolving complex over autochthonous cultivar. Our results suggest that the autochthonous cultivar Crveni hrušt had better photosynthetic performance under drought conditions, compared to the modern cultivar New Star.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
419. Quality of supplementary LED lighting effects on growth and photosynthesis of two different Lactuca recombinant inbred lines (RILs) grown in a tropical greenhouse
- Creator:
- Choong, T. W., He, J., Qin, L., and Lee, S. K.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- pigmenty, světelné diody, fotosyntéza, pigments, light emitting diodes, photosynthesis, electron transport rate, leaf expansion, light- and CO2-saturated net photosynthetic rate, photochemical and nonphotochemical quenching, stomatal density, 2, and 581
- Language:
- Multiple languages
- Description:
- LED lamps with various combinations of red (R) and blue (B) wavelengths were used to supplement sunlight for the growth of a heat-resistant (HR) and heat-sensitive (HS) recombinant inbred lines (RIL) of lettuce. The RB-LED ratios were 100R:0B (0B), 92R:8B (8B), 84R:16B (16B), and 76R:24B (24B) with an equal PPFD of 100 μmol m-2 s-1. The greatest leaf expansion rates were observed at 8B for both genotypes. All HR-RILs had similar values of growth parameters and specific leaf area (SLA). However, higher values of growth parameters were observed in HS-RIL with 0B, 8B, and 16B than that under 24B and sunlight. Furthermore, HS-RIL had higher SLA under 0B compared to other conditions. Photosynthetic light-use efficiency and maximal oxygen evolution rate were the lowest under 8B for both genotypes. The quality of LED lighting, if provided, seemed to implicate genotype dependence, probably as a result of their different sensitivities to heat stress., T. W. Choong, J. He, L. Qin, S. K. Lee., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
420. Quantifying the measurement errors in a portable open gas-exchange system and their effects on the parameterization of Farquhar et al. model for C3 leaves
- Creator:
- Wang, Q., Fleisher, D. H., Timlin, D., Reddy, V. R., and Chun, J. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, open gas-exchange system, measurement errors, parameterization, leaf model, photosynthesis, transpiration, 2, and 58
- Language:
- Multiple languages
- Description:
- A portable open gas-exchange system (Li-6400, Li-Cor, Inc., Lincoln, NE, USA) has been widely used for the measurement of net gas exchanges and calibration/parameterization of leaf models. Measurement errors due to diffusive leakage rates of water vapor (LW) and CO2 (LC) between inside and outside of the leaf chamber, and the inward dark transpiration rate (DW) and dark respiration rate (DC) released from the leaf under the gasket, can be significant. Rigorous model-based approaches were developed for estimating leakage coefficients of water vapor (KW) and CO2 (KC) and correcting for the combination of these errors. Models were based on mass balance equations and the Dusty Gas Model for a ternary gas mixture of water vapor, CO2, and dry air. Experiments were conducted using two Li-6400 systems with potato and soybean leaves. Results indicated that models were reliable for estimating KW and KC, and the values varied with instrument, chamber size, gasket condition, and leaf structure. A thermally killed leaf should be used for this determination. Measurement error effects on parameterization of the Farquhar et al. (1980) model as determined by PN/C i curves were substantial and each parameter had its own sensitivity to measurement errors. Results also indicated that all four error sources should be accounted for when correcting measurements., Q. Wang ... [et al.]., and Obsahuje bibliografii a dodatky
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public