Number of results to display per page
Search Results
112. A long-lasting photorespiration in CO2-free air, measured as the postirradiation CO2 burst, indicates mobilization of storage photosynthates
- Creator:
- Xiong, Fusheng, Gao, Yuzhu, and Song, Ping
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- DCMU, iodoacetic acid, N-ethylmaleimide, photoinhibition, Pi, and Triticum
- Language:
- Multiple languages
- Description:
- In CO2-free air, the CO2 postirradiation burst (PIB) in wheat leaves was measured with an IRGA in an open gas exchange system to ascertain its potential role in alleviating photoinhibition of photorespiratory carbon oxidation (PCO) under a CO2 deficiency. A pre-photosynthesized leaf having been transferred into CO2-free air exhibited a typical CO2 PIB following darkening which could last, with a rate substantially higher than that of dark respiration, over a long time period (at least more than 2 h) of continuously alternate irradiation (2 min)-dark (2 min)-light transitions. The rate and the time of PIB maintenance, although unaffected by the exogenous dark respiration inhibitor iodoacetic acid, were stimulated largely by increasing irradiance and O2 level, and suppressed by DCMU and N-ethyl-maleimide (NEM). They also showed a large photosynthates-loading dependence. In a darkened leaf, the irradiation-induced PIB in the CO2-free air was clearly revealed and it was characterized by an initial net uptake of respiratory CO2. The light-induced PIB was accelerated by increasing irradiance, and delayed by prolonging the period of darkening the leaves. Hence, the origin of carbon needed for a long-term CO2 evolution in the CO2-free air might not only be derived directly from the pool of intermediates in the Calvin cycle, but it might also arise indirectly from a remotely fixed reserve of photosynthates in the leaf via a PCO-mediated, yet to be further clarified, mobilization process. Such mobilization of photosynthates probably exerted an important role in coordination of photochemical reactions and carbon assimilation during photosynthesis in C3 plants under the photoinhibitory conditions. and Fusheng Xiong, Yuzhu Gao, Ping Song.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
113. A long-term response of chlorophyll fluorescence induction to one-shot application of cyanazine on barley plants and its relation to crop yield
- Creator:
- Matoušková, M., Nauš, J., and Flašarová, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Bladex 50 SC, caryopsis mass, grain number and mass in spike, herbicide, Hordeum vulgare, leaf age, plant dry mass, and plant topography
- Language:
- Multiple languages
- Description:
- Field-grown plants of spring barley (Hordeum vulgare L. cv. Akcent) in the growth phase 30 DC (beginning of stem extension) were exposed to a one-shot application of a commercial product containing cyanazine (Bladex 50 SC) in two doses, C30 and C60 (30 and 60 mg m-2). The reaction of the plant photosynthetic system was followed non-destructively using chlorophyll fluorescence induction (the O-J-I-P transient) within three weeks after the application in the fifth developed leaf and three further gradually appearing leaves. An immediate response of plants to the application of cyanazine and a regeneration of plants from cyanazine action were detected. The biological (plant dry mass) and crop yield production (the number and mass of grains in a spike) were analyzed in time of full ripeness. The crop yield was lowered by the herbicide effect to the same level for the two doses used. and M. Matoušková, J. Nauš, M. Flašarová.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
114. 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
115. A mathematical model for describing light-response curves in Nicotiana tabacum L.
- Creator:
- Chen, Z. Y., Peng, Z. S., Yang, J., Chen, W. Y., and Ou-Yang, Z. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, light-response curves, light saturation point, maximum net photosynthetic rate, modified exponential model, net photosynthetic rate, and Nicotiniana tabacum L.
- Language:
- Multiple languages
- Description:
- A modified exponential model was used to describe light-response curves of Nicotiana tabacum L. The accuracies of an exponential model, a nonrectangular hyperbola model, a rectangular hyperbola model, a modified rectangular hyperbola model and the modified exponential model were evaluated by Mean square error (MSE) and Mean absolute error (MAE). The tests MSE and MAE of the modified exponential model were the lowest among the five models. The light saturation point (LSP) obtained by the exponential model, the nonrectangular hyperbola model and the rectangular hyperbola model were much lower than the measured values, and the maximum net photosynthetic rates (Pmax) calculated from these models, were greater than the measured values. Pmax at LSP of 1,077 μmol m-2 s-1 calculated by the modified exponential model was 12.34 μmol(CO2) m-2 s-1, which was more accurate than the values obtained from the modified rectangular hyperbola model. The results show that the modified exponential model is superior to other models for describing light-response curves. and Z. Y. Chen ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
116. 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
117. A microscope for two-dimensional measurements of in vivo chlorophyll fluorescence kinetics using pulsed measuring radiation, continuous actinic radiation, and saturating flashes
- Creator:
- Küpper, H., Šetlík, I., Trtílek, M., and Nedbal, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Ectocarpus, Elodea, fluorescence imaging, fluorescence quenching analysis, Hibiscus, photosynthetic heterogeneity, photosystem 2, Scenedesmus, and topography of fluorescence induction
- Language:
- Multiple languages
- Description:
- Transients of chlorophyll fluorescence in photosynthetic objects are often measured using short pulses of exciting radiation, which has recently been employed to capture kinetic images of fluorescence at the macroscopic level. Here we describe an instrument introducing this principle to recording of two dimensional fluorescence transients in microscopic objects. A modified fluorescence microscope is equipped with a CCD camera intensified by a micro-channel plate image amplifier. The microscopic field is irradiated simultaneously by three types of radiation: actinic radiation, saturating flashes, and pulsed measuring radiation. The measuring pulses are generated by a light-emitting diode and their duration is between 10 to 250 µs. The detection of fluorescence images (300×400 pixels, 8 bit) has a maximum time resolution of 40 ms and is gated in synchrony with the exciting pulses. This allows measuring on a background of a continuous actinic radiation up to irradiance that can elicit the maximal fluorescence yield (FM). On the other hand, the integral irradiance of the objects by the measuring radiation is very low, e.g., 0.08 µmol m-2 s-1 at 0.05 µm spatial resolution and 0.006 µmol m-2 s-1 at 4 µm spatial resolution. This allows a reliable recording of F0 even in very short time intervals (e.g., 5×80 ms). The software yields fluorescence kinetic curves for objects in user-selected areas as well as complete false-colour maps of the essential fluorescence kinetics parameters (FM, FO, FV, FV/FM, etc.) showing a two-dimensional distribution of their values. Several examples demonstrate that records of fluorescence kinetics can be obtained with a reasonable signal-to-noise ratio with all standard microscope objectives and with object sizes reaching from segments of leaf tissue to individual algal cells or chloroplasts. and H. Küpper ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
118. 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
119. A new approach to distinguishing photosynthetic types of plants. A case study in Northeast China Transect (NECT) platform
- Creator:
- Tang, H. P. and Zhang, X. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- C3, C4, discriminant analysis method, intercellular CO2 concentration, leaf and atmosphere temperature, net photosynthetic rate, stomatal condductance, transpiration rate, and water use efficiency
- Language:
- Multiple languages
- Description:
- Discriminant analysis is an important method in multivariable statistic analysis to show what type an individual should belong to. Based on actual field photosynthetic value set obtained from our research platform, North East China Transect (NECT), a new approach, developed from the concept and principle of discriminant analysts, was proposed to distinguish C3 and C4 plants. Indices related to plant photosynthetic capacity measured by an LCA4 photosynthesis system were selected to build the discriminant model which is based on four related parameters: net photosynthetic rate, transpiration rate, stomatal conductance, and difference in temperature between leaf surface and atmosphere. Compared with other approaches, the present one is fast, straightforward, and efficient. and H. P. Tang, X. S. Zhang.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
120. A new model for relationship between irradiance and the rate of photosynthesis in Oryza sativa
- Creator:
- Ye, Z.-P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- apparent quantum yield, compensation irradiance, intrinsic quantum yield, and saturation irradiance
- Language:
- Multiple languages
- Description:
- The calculated maximum net photosynthetic rate (PN) at saturation irradiance (I m) of 1 314.13 µmol m-2 s-1 was 25.49 µmol(CO2) m-2 s-1, and intrinsic quantum yield at zero irradiance was 0.103. The results fitted by nonrectangular hyperbolic model, rectangular hyperbolic method, binomial regression method, and the new model were compared. The maximum PN values calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were higher than the measured values, and the I m calculated by nonrectangular hyperbolic model and rectangular hyperbolic model were less than measured values. Results fitted by new model showed that the response curve of PN to I was nonlinear at low I for Oryza sativa, PN increased nonlinearly with I below saturation value. Above this value, PN decreased nonlinearly with I.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public