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11. Estimation of photorespiration rate by simultaneous measurements of CO2, gas exchange rate, and chlorophyll fluorescence quenching in the C3 plant Vigna radiata (L.) Wilczek and the C4 plant Amaranthus mongostanus L.

Creator:
Yoshimura, Y., Kubota, F., and Hirao, K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
electron transport rate, photosynthesis, photosystem 2, mungbean, and quantum yield
Language:
Multiple languages
Description:
So far the photorespiration rate (RP) in a leaf has been determined as the difference between the net photosynthetic rates (PN) measured in 21 % O2 air (PN21%) and 3 % O2 air (PN3%). In the C3 plant Vigna radiata and the C4 plant Amaranthus mongostanus L., PN and chlorophyll fluorescence quenching in leaves were monitored simultaneously. RP of leaves in situ was estimated as termed RPE from the electron transport rates through photosystem 2 (PS2), and compared with RPO (PN3% - PN21%). In V. radiata RPO was 11.9 µmol(CO2) m-2 s-1 and the ratio of RPO to PN21% was 42.2 %, whereas the ratio of RPE to PN21% was 25.7 %. This suggests that RPO may be over-estimated for the real RP in normal air. In A. mongostanus, PN was almost not changed with a decrease in O2 concentration from 21 to 3 %, whereas the quantum yield of PS2 was evidently affected by the change in O2 concentration. This fact shows the presence of photorespiration in this C4 species, where RPE was equivalent to 3.8 % of PN21%. and Y. Yoshimura, F. Kubota, K. Hirao.
Rights:
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12. Heliotropic leaf movement of Sophora alopecuroides L: an efficient strategy to optimise photochemical performance

Creator:
Zhu, C. G., Chen, Y. N., Li, W. H., Chen, X. L., and He, G. Z.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, Vnitřní Mongolsko (Čína), Inner Mongolia (China), jerlín, Ejina basin, electron transport rate, energy dissipation, leaf tilt angle, nonphotochemical quenching, petiole angle, quantum yield, trichome, Sophora alopecuroides L., 2, and 581
Language:
Multiple languages
Description:
We studied the survival adaptation strategy of Sophora alopecuroides L. to habitat conditions in an arid desert riparian ecosystem. We examined the responses of heliotropic leaf movement to light conditions and their effects on plant photochemical performance. S. alopecuroides leaves did not show any observable nyctinastic movement but they presented sensitive diaheliotropic and paraheliotropic leaf movement in the forenoon and at midday. Solar radiation was a major factor inducing leaf movement, in addition, air temperature and vapour pressure deficit could also influence the heliotropic leaf movement in the afternoon. Both diaheliotropic leaf movement in the forenoon and paraheliotropic leaf movement at midday could help maintain higher photochemical efficiency and capability of light utilisation than fixed leaves. Paraheliotropic leaf movement at midday helped plants maintain a potentially higher photosynthetic capability and relieve a risk of photoinhibition. Our findings indicated the effective adaptation strategy of S. alopecuroides to high light, high temperature, and dry conditions in arid regions. This strategy can optimise the leaf energy balance and photochemical performance and ensure photosystem II function., C. G. Zhu, Y. N. Chen, W. H. Li, X. L. Chen, G. Z. He., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

13. Improving photosynthetic performance and some fruit quality traits in mango trees by shading

Creator:
Jutamanee, K. and Onnom, S.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
chlorofyl, teplota, stín, chlorophyll, temperature, shade, kvalita ovoce, fluorescence chlorofylu, nadměrné ozařování, fotoinhibice, rychlost přenosu elektronů, mango, ozáření, fruit quality, chlorophyll fluorescence, excessive irradiation, net photosynthetic rate, photoinhibition, electron transport rate, irradiation, nonphotochemical quenching, peel color, photochemical quenching coefficient, 2, and 581
Language:
Multiple languages
Description:
Excess solar radiation under hot climate can lead to decline in photosynthetic activity with detrimental effects on growth and yield. The aim of this study was to evaluate the use of a transparent plastic roof as shading for diurnal changes in photosynthetic gas exchange, chlorophyll fluorescence, fruit set and quality of mango (Mangifera indica L.) cv. 'Nam Dok Mai' growth in the field conditions. Fully expanded leaves were examined either shaded by the plastic roof or sunlit under natural conditions. Leaf temperature and leaf-to-air vapour pressure deficit of the shaded leaves measured on the clear day were lowered compared to those of the sunlit leaves. It resulted in increased stomatal conductance and photosynthetic rates of the shaded leaves compared to those of the sunlit leaves, especially from the morning to midday. Furthermore, the reversible decrease of the maximal quantum yield of PSII was more pronounced in the sunlit leaves than that in the shaded ones. Shading increased the total fruit number; the shaded fruits developed better external color than that of the sun-exposed fruits. Our results indicated that shading could maintain the high photosynthetic activity by reducing stomatal limitations for carbon supply and was effective in alleviating the photoinhibitory damage to PSII during bright and clear days with excessive radiation. Finally, shading could increase the number of fruits and improve mango peel color., K. Jutamanee, S. Onnom., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

14. Lead-induced toxicity and interference in chlorophyll fluorescence in Talinum triangulare grown hydroponically

Creator:
Kumar, A. and Prasad, Majeti Narasimha Vara
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
photosynthesis, Indie, India, ceylon spinach, chlorophyll fluorescence, electron transport rate, photosystems, lead, 2, and 581
Language:
Multiple languages
Description:
We investigated the lead (Pb) effect on chlorophyll (Chl) fluorescence and photosynthetic electron transport system in Talinum triangulare (Jacq.) Willd. Plants were exposed to different concentrations of Pb(NO3)2 (i.e. 0, 0.25, 0.5, 0.75, 1.0, and 1.25 mM) for seven days in hydroponic experiments. Pb-treated leaves exhibited a relative decrease in Chl fluorescence induction curve, which resulted in the decrease of maximal fluorescence yield, maximal quantum yield, and effective quantum yield of PSII, while nonphotochemical quenching, quantum yield of regulated and nonregulated energy dissipation of PSII significantly increased during Pb stress. Furthermore, Pb concentrations also caused a decrease in maximal P700 change, photochemical quantum yield, nonphotochemical quantum yield, and ETR of PSI. We suggested that the changes in these parameters were a manifestation of Pb interference in the electron transport chain in both PSII and PSI. The sensitivity of PSII was greater than that of PSI in T. triangulare leaves., A. Kumar, M. N. V. Prasad., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

15. Mesophyll conductance variations in response to diurnal environmental factors in Myrcia paivae and Minquartia guianensis in Central Amazonia

Creator:
Nascimento, H. C. S. and Marenco, R. A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, Amazonka (řeka : oblast), Amazon River Valley, chloroplast carbon dioxide concentration, electron transport rate, maximum carboxylation velocity of Rubisco, stomatal conductance, 2, and 581
Language:
Multiple languages
Description:
Mesophyll conductance (gm) is essential to determine accurate physiological parameters used to model photosynthesis in forest ecosystems. This study aimed to determine the effects of time of day on photosynthetic parameters, and to assess the effect of using either intercellular CO2 concentration (Ci) or chloroplast CO2 concentration (Cc), on maximum carboxylation velocity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), Vcmax. We used Amazonian saplings of Myrcia paivae and Minquartia guianensis. Photosynthetic parameters were measured using an infrared gas analyzer (IRGA); gm was determined using both gas exchange and chlorophyll (Chl) a fluorescence and gas-exchange data alone. Leaf thickness (LT) and specific leaf area (SLA) were also measured. Air temperature, relative humidity or understory light did not correlate with gm and on average daily IRGA-fluorometer-determined gm was 0.04 mol(CO2) m-2 s-1 for M. paivae and 0.05 mol(CO2) m-2 s-1 for M. guianensis. Stomatal conductance (gs), gm, electron transport rate (JF), and light-saturated net photosynthetic rate (PNmax) were lower in the afternoon than in the morning. However, no effect of time of day was observed on Vcmax. LT and SLA did not affect any of the examined parameters. IRGA-determined g m was almost the double of the value obtained using the IRGA-fluorescence method. Vcmax values determined using Cc were about 25% higher than those obtained using Ci, which highlighted the importance of using Cc in Vcmax calculation. Decline in PNmax at the end of the afternoon reflected variations in gs and gm rather than changes in Vcmax. Diurnal variation in gm appeared to be associated more with endogenous than with atmospheric factors. and H. C. S. Nascimento, R. A. Marenco.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

16. Modelling photosynthesis in shallow algal production ponds

Creator:
Ritchie, R. J. and Larkum, A. W. D.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, algal production ponds, Chlorella, Dunaliella, electron transport rate, light saturation curves, Phaeodactylum, photoinhibition, photosynthesis, photosynthesis vs. depth, primary productivity, pulse amplitude modulation fluorometry, 2, and 58
Language:
Multiple languages
Description:
a1_Shallow ponds with rapidly photosynthesising cyanobacteria or eukaryotic algae are used for growing biotechnology feedstock and have been proposed for biofuel production but a credible model to predict the productivity of a column of phytoplankton in such ponds is lacking. Oxygen electrodes and Pulse Amplitude Modulation (PAM) fluorometer technology were used to measure gross photosynthesis (PG) vs. irradiance (E) curves (PG vs. E curves) in Chlorella (chlorophyta), Dunaliella salina (chlorophyta) and Phaeodactylum (bacillariophyta). PG vs. E curves were fitted to the waiting-in-line function [PG = (PGmax × E/Eopt) × exp(1 — E/Eopt)]. Attenuation of incident light with depth could then be used to model PG vs. E curves to describe PG vs. depth in pond cultures of uniformly distributed planktonic algae. Respiratory data (by O2-electrode) allowed net photosynthesis (PN) of algal ponds to be modelled with depth. Photoinhibition of photosynthesis at the pond surface reduced PN of the water column. Calculated optimum depths for the algal ponds were: Phaeodactylum, 63 mm; Dunaliella, 71 mm and Chlorella, 87 mm. Irradiance at this depth is ≈ 5 to 10 μmol m-2 s-1 photosynthetic photon flux density (PPFD). This knowledge can then be used to optimise the pond depth. The total net P N [μmol(O2) m-2 s-1] were: Chlorella, ≈ 12.6 ± 0.76; Dunaliella, ≈ 6.5 ± 0.41; Phaeodactylum ≈ 6.1 ± 0.35. Snell’s and Fresnel’s laws were used to correct irradiance for reflection and refraction and thus estimate the time course of PN over the course of a day taking into account respiration during the day and at night. The optimum PN of a pond adjusted to be of optimal depth (0.1-0.5 m) should be approximately constant because increasing the cell density will proportionally reduce the optimum depth of the pond and vice versa., a2_Net photosynthesis for an optimised pond located at the tropic of Cancer would be [in t(C) ha-1 y-1]: Chlorella, ≈ 14.1 ± 0.66; Dunaliella, ≈ 5.48 ± 0.39; Phaeodactylum, ≈ 6.58 ± 0.42 but such calculations do not take weather, such as cloud cover, and temperature, into account., R. J. Ritchie, A. W. D. Larkum., and Obsahuje bibliografii a dodatky
Rights:
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17. Photoadaptation in the green alga Spongiochloris sp. A three-fluorometer study

Creator:
Koblížek, M., Ciscato, M., Komenda, J., Kopecký, J., Šiffel, P., and Masojídek, J.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll fluorescence, photochemical yield, non-photochemical quenching, connectivity, and electron transport rate
Language:
Multiple languages
Description:
The dark-adapted cells of the green alga Spongiochloris sp. were exposed to "white light" of 1000 µmol(photon) m-2 s-1 for 2 h and then dark adapted for 1.5 h. Changes of photochemical activities during photoadaptation were followed by measurement of chlorophyll (Chl) fluorescence kinetics, 77 K emission spectra, photosynthetic oxygen evolution, and pigment composition. We observed a build-up of slowly-relaxing non-photochemical quenching which led to a decrease of the Fv/Fm parameter and the connectivity. In contrast to the depression of Fv/Fm (35 %) and the rise of non-photochemical quenching (∼ 1.6), we observed an increase in effective absorption cross-section (20 %), Hill reaction (30 %), photosynthetic oxygen evolution (80 %), and electron transport rate estimated from the Chl fluorescence analysis (80 %). We showed an inconsistency in the presently used interpretation schemes, and ascribe the discrepancy between the increase of effective absorption cross-section and the photosynthetic activities on one side and the effective non-photochemical quenching on the other side to the build-up of a quenching mechanism which dissipates energy in closed reaction centres. Such a type of quenching changes the ratio between thermal dissipation and fluorescence without any effect on photochemical yield. In this case the Fv/Fm ratio cannot be used as a measure of the maximum photochemical yield of PS2. and M. Koblížek ... [et al.].
Rights:
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18. Photorespiration rate in spinach leaves under moderate NaCl stress

Creator:
di Martino, C., Delfine, S., Alvino, A., and Loreto, F.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
amino acids, carboxylation rate, electron transport rate, oxygenation rate, photosynthetic rate, and Spinacia oleracea
Language:
Multiple languages
Description:
We analyzed the effect of NaCl stress on photorespiration of spinach leaves by calculating the rate of carboxylation/oxygenation of ribulose-1,5-bisphosphate carboxylase/oxygenase, and by measuring the content of amino acids produced through photorespiration. After 20 d of NaCl stress the carboxylation rate was reduced while the oxygenation rate was not affected. The contents of serine, glycine, and alanine increased relevantly. The amount of glutamine also increased after 20 d but the amount of glutamate did not. Hence photorespiration may be stimulated under moderate NaCl stress. A relevant electron transport rate was observed under CO2-free air, which may indicate refixation of photorespiratory CO2. When NaCl accumulation proceeded for more than 20 d, photosynthesis was reduced and the content of photo-respiratory amino acids started to decrease, but the oxygenation rate did not change. and C. di Martino ... [et al.].
Rights:
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19. Photosynthesis and yield traits in different soybean lines in response to salt stress

Creator:
He, Y., Chen, Y., Yu, C. L., Lu, K. X., Jiang, Q. S., Fu, J. L., Wang, G. M., and Jiang, D. A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
chlorofyl, chlorophyll, fluorescence chlorofylu, nefotochemické zhášení, fotochemické zhášení, stomatální vodivost, chlorophyll fluorescence, cyclic electron flow, electron transport rate, nonphotochemical quenching, photochemical quenching, stomatal conductance, 2, and 581
Language:
Multiple languages
Description:
To evaluate utility of different salt-tolerant lines, three soybean lines with different resistance to salt were planted in the field under control and salt-stress conditions for two years. The results showed that net photosynthetic rate (PN) was significantly different among lines at the anthesis stage and decreased on average by 13.6-34.1% under conditions of salt stress. The stomatal conductance was a primary limiting factor for the reduction of PN under salt stress. Meanwhile, the grain yield (GY) decreased on average by 14.0-35.3% among lines under salt stress. The salt-tolerant lines S111-9 and S113-6 showed higher PN and GY under salt stress in comparison with the salt-sensitive cultivar Melrose. Regression analysis indicated that there was extremely significantly positive correlation between GY and PN under field conditions. Therefore, PN might be used as a physiological index for field resistance of soybean to salt stress., Y. He, Y. Chen, C. L. Yu, K. X. Lu, Q. S. Jiang, J. L. Fu, G. M. Wang, D. A. Jiang., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

20. Photosynthesis, chlorophyll fluorescence, and antioxidant enzyme responses of invasive weed Mikania micrantha to Bemisia tabaci infestation

Creator:
Zhang, L. L. and Wen, D. Z.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
carotenoids, catalase, chlorophyll fluorescence, electron transport rate, glutathione, photochemical quenching, photosystem 2 efficiency, proline, and superoxide dismutase
Language:
Multiple languages
Description:
In a glasshouse, Bemisia tabaci infestation largely reduced response of photosynthesis to irradiance and CO2 concentration of Mikania micrantha compared with the non-infested control (C) ones. The maximum irradiance-saturated photosynthetic rate (Pmax) and saturation irradiance (SI) of the infested M. micrantha were only 21.3 % and 6.5 % of the C-plants, respectively. B. tabaci infestation led to the reduction of contents of chlorophyll and carotenoids in M. micrantha, which was accompanied with the decrease of actual photosystem 2 (PS2) efficiency (ΦPS2), efficiency of excitation energy capture by open PS2 reaction centres (Fv'/Fm'), electron transport rate (ETR), and photochemical quenching (qP). Moreover, superoxide dismutase and catalase activities significantly decreased while proline and glutathione contents significantly increased in infested M. micrantha. Hence B. tabaci infestation not only induced direct damage of photosynthetic apparatus but also altered the antioxidant enzymes activities in M. micrantha, which might as consequences accelerate senescence of this weed. and L. L. Zhang, D. Z. Wen.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public