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252. Role of alternative oxidase pathway in protection against drought-induced photoinhibition in pepper leaves

Creator:
Hu, W. H., Yan, X. H., He, Y., and Ye, X. L.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, photoinhibition, alternative oxidase pathway, Capsicum annuum L, chlorophyll fluorescence, drought, 2, and 581
Language:
Multiple languages
Description:
The aim of this study was to assess the impact of the mitochondrial alternative oxidase (AOX) pathway on energy metabolism in chloroplasts, and evaluate the importance of the AOX in alleviating drought-induced photoinhibition in pepper (Capsicum annuum L.). Inhibition of AOX pathway decreased photosynthesis and increased thermal energy dissipation in plants under normal conditions. It indicated that AOX pathway could influence chloroplast energy metabolism. Drought reduced carbon assimilation. Photoinhibition was caused by excess of absorbed light energy in spite of the increase of thermal energy dissipation and cyclic electron flow around PSI (CEF-PSI). Upregulation of AOX pathway in leaves experiencing drought would play a critical role in protection against photoinhibition by optimization of carbon assimilation and PSII function, which would avoid over-reduction of photosynthetic electron transport chain. However, inhibition of AOX pathway could be compensated by increasing the thermal energy dissipation and CEF-PSI under drought stress, and the compensation of CEF-PSI was especially significant., W. H. Hu, X. H. Yan, Y. He, X. L. Ye., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

253. Role of cyanide-resistant respiration during light-induced attraction of predators to herbivore-infested leaves

Creator:
Feng, H. Q., Sun, K., Wei, Y., Wang, R. F., Jia, L. Y., Zhang, J. P., and Li, Y.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, cyanide-resistant respiration, herbivore attack, light, predatory mites, 2, and 581
Language:
Multiple languages
Description:
The present work showed that spider mite-infested leaves placed in the light were more attractive to predatory mites than the infested leaves placed in the dark; furthermore, an increase in the light intensity enhanced this attractiveness. However, the increase of the light intensity did not change the attractiveness of the uninfested leaves to predatory mites. The capacity of cyanide-resistant respiration and the photosynthetic rates of both the infested and uninfested leaves increased with increasing light intensities, whereas the photosystem (PS) II chlorophyll (Chl) fluorescence decreased. The increase of the capacity of cyanide-resistant respiration in the infested leaves was more dramatic than that in the uninfested leaves, whereas the values of photosynthetic rates and Chl fluorescence were lower in the infested leaves than those in the uninfested leaves. Treatment of the infested and uninfested leaves with 1 mM salicylhydroxamic acid (SHAM, an inhibitor of cyanide-resistant respiration) decreased photosynthetic rates and caused further reductions in PSII fluorescence, especially under a higher light intensity. In contrast, the effects of SHAM on PSII fluorescence parameters and photosynthetic rates of the infested leaves were more dramatic than on those of the uninfested leaves. The treatment with SHAM did not significantly change the attractiveness of the infested or uninfested leaves to the predatory mites under all of the light intensities tested. These results indicated that cyanide-resistant respiration was not directly associated with the light-induced attraction of predators to plants, but it could play a role in the protection of photosynthesis. Such role might become relatively more important when photosynthesis is impaired by herbivores infestation. and H. Q. Feng ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

254. Root-zone CO2 and root-zone temperature effects on photosynthesis and nitrogen metabolism of aeroponically grown lettuce (Lactuca sativa L.) in the tropics

Creator:
He, J., Qin, L., and Lee, S. K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, elevated root-zone CO2 concentration, root-zone temperature, Rubisco, total reduced N., 2, and 581
Language:
Multiple languages
Description:
Effects of elevated root-zone (RZ) CO2 concentration (RZ [CO2]) and RZ temperature (RZT) on photosynthesis, productivity, nitrate (NO3-), total reduced nitrogen (TRN), total leaf soluble and Rubisco proteins were studied in aeroponically grown lettuce plants in a tropical greenhouse. Three weeks after transplanting, four different RZ [CO2] concentrations (ambient, 360 ppm, and elevated concentrations of 2,000; 10,000; and 50,000 ppm) were imposed on plants at 20°C-RZT or ambient(A)-RZT (24-38°C). Elevated RZ [CO2] resulted in significantly higher light-saturated net photosynthetic rate, but lower light-saturated stomatal conductance. Higher elevated RZ [CO2] also protected plants from both chronic and dynamic photoinhibition (measured by chlorophyll fluorescence Fv/Fm ratio) and reduced leaf water loss. Under each RZ [CO2], all these variables were significantly higher in 20°C-RZT plants than in A-RZT plants. All plants accumulated more biomass at elevated RZ [CO2] than at ambient RZ [CO2]. Greater increases of biomass in roots than in shoots were manifested by lower shoot/root ratios at elevated RZ [CO2]. Although the total biomass was higher at 20°C-RZT, the increase in biomass under elevated RZ [CO2] was greater at A-RZT. Shoot NO3- and TRN concentrations, total leaf soluble and Rubisco protein concentrations were higher in all elevated RZ [CO2] plants than in plants under ambient RZ [CO2] at both RZTs. Under each RZ [CO2], total leaf soluble and Rubisco protein concentrations were significantly higher at 20°C-RZT than at A-RZT. Our results demonstrated that increased P Nmax and productivity under elevated [CO2] was partially due to the alleviation of midday water loss, both dynamic and chronic photoinhibition as well as higher turnover of Calvin cycle with higher Rubisco proteins. and J. He, L. Qin, S. K. Lee.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

255. Salinity response pattern and isolation of catalase gene from halophyte plant Aeluropus littoralis

Creator:
Modarresi, M., Nematzadeh, G. A., and Moradian, F.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, bioinformatic analysis, catalase activity, gene isolation, 2, and 581
Language:
Multiple languages
Description:
The role of the antioxidant defense system in salt tolerance of Aeluropus littoralis has not been yet reported; therefore in the present study, the changes of catalase (CAT) activity in this halophyte plant was investigated and CAT gene was isolated. The leaves of treated and control plants were harvested at various times, starting 1 day prior to initiating treatment, then periodically at 72-h intervals for 21 days. The data collected showed that CAT activity increased significantly with time in plants treated with 200, 400, and 600 mM NaCl when compared with the control plants. Maximum enzyme activity was observed between the 6th and 12th day at all NaCl concentrations. CAT gene was isolated and cloned via pTZ57R/T cloning vector in Escherichia coli. CAT gene encoded 494 amino acids and had also high homology of 90, 87, 86, and 86% with CAT genes from Zea mays, Oryza sativa, Triticum aestivum, and Hordeum vulgare, respectively. and M. Modarresi, G. A. Nematzadeh, F. Moradian.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

256. Seasonal and interannual variations of ecosystem photosynthetic features in an alpine dwarf shrubland on the Qinghai-Tibetan Plateau, China

Creator:
Li, H. Q., Zhang, F. W., Li, Y. N., Cao, G. M., Zhao, L., and Zhao, X. Q.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, fenologie, photosynthesis, phenology, Čína západní, Tibet (Čína), China, Western, ecosystem photosynthetic parameters, eddy covariance technique, leaf area index, rectangular hyperbolic light response, 2, and 581
Language:
Multiple languages
Description:
Ecosystem photosynthetic characteristics are of utmost importance for the estimation of regional carbon budget, but such characteristics are not well understood in alpine regions. We collected CO2 flux data measured by eddy covariance technique over an alpine dwarf shrubland on the Qinghai-Tibetan Plateau during years 2003-2010; and we quantified the temporal patterns of ecosystem apparent quantum yield (a), saturated photosynthetic rate (Pmax), and ecosystem dark respiration (RDe). Results showed that the strong seasonality of a and RDe was driven mainly by air temperature (Ta), whereas that of Pmax was much more determined by leaf area index rather than abiotic factors. Diurnal thermal fluctuation inhibited significantly the daytime photosynthetic capacity. Stepwise regression revealed that the seasonal deviations of a, Pmax, and RDe were significantly controlled by Ta. The annual a was regulated mainly by annual growing season Ta, which indicated that the response of ecosystem a was instant. The annual variations of Pmax correlated positively with soil temperature 5 cm below ground (Ts) of the annual nongrowing season and those of RDe related negatively with the annual nongrowing season precipitation. We suggested that a lagged response regulated the annual Pmax and the annual RDe. Annual deviations of a and RDe were both significantly controlled by annual Ts, and those of Pmax were marginally determined by annual PPFD. Thus, the future warming scenario, especially significant for nongrowing seasonal warming in the Qinghai-Tibetan Plateau, would favor ecosystem photosynthetic capacity in the alpine dwarf shrubland., H. Q. Li, F. W. Zhang, Y. N. LI, G. M. Cao, L. Zhao, X. Q. Zhao., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

257. Seasonal variation in photosynthesis performance of cassava at two different growth stages under irrigated and rain-fed conditions in a tropical savanna climate

Creator:
Vongcharoen, K., Santanoo, S., Banterng, P., Jogloy, S., Vorasoot, N., and Theerakulpisut, P.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, canopy, leaf gas exchange, light-response curve, Manihot esculenta, 2, and 581
Language:
Multiple languages
Description:
Seasonal variations in photosynthesis of cassava cv. Rayong 9 (RY9) under irrigated and rain-fed conditions were evaluated at the age of three and six months after planting (MAP). Photosynthetic light-response (PN/I) curves revealed that cassava leaves attained the highest maximum net photosynthetic rates (PNmax) in the rainy season, followed by the hot one, while the lowest PNmax was found in the cool season. Photosynthetic potential of the 3-month-old plants was mostly higher than that of the 6-month-old plants, and the seasonal variation in photosynthetic capacity was also more apparent in the younger plants. PN/I curves were used to predict daily net photosynthetic rate (PN) for each season based on daily average solar radiation data. The predicted PN were considerably lower than the PNmax values. This indicated that solar radiation is a limiting factor for photosynthesis, particularly in the rainy season. The data provided basic information for breeding cassava genotypes with enhanced photosynthesis during the period of unfavorable environment. Furthermore, the data are potentially useful in modeling photosynthesis and crop growth as affected by environmental factors., K. Vongcharoen, S. Santanoo, P. Banterng, S. Jogloy, N. Vorasoot, P. Theerakulpisut., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

258. Selenium improves photosynthesis and protects photosystem II in pear (Pyrus bretschneideri), grape (Vitis vinifera), and peach (Prunus persica)

Creator:
Feng, T., Chen, S. S., Gao, D. Q., Liu, G. Q., Bai, H. X., Li, A., Peng, L. X., and Ren, Z. Y.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, foliar feeding, fruit tree, gas exchange, intercellular CO2 concentration, 2, and 581
Language:
Multiple languages
Description:
The effects of selenium on photosynthesis and Chl fluorescence in pear, grape, and peach were analyzed. The foliar spray of amino acid-chelated selenium solution was performed soon after fruit setting, totally six times, with an interval of ten days. After seven days from the last spray, the leaves in the middle of shoots were examined. Foliar spray of selenium increased the net photosynthetic rate in pear, grape, and peach. In contrast, the treatment decreased stomatal conductance, transpiration rate, and substomatal CO2 concentration in all the three species. The selenium treatment improved the maximum quantum yield of PSII, effective quantum yield of PSII, and photochemical quenching in all three species. Conversely, the selenium treatment reduced nonphotochemical quenching in all three species. We suggested that selenium can improve photosynthesis and protect PSII in fruit crops., T. Feng, S. S. Chen, D. Q. Gao, G. Q. Liu, H. X. Bai, A. Li, L. X. Peng, Z. Y. Ren., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

259. Sequence of physiological responses in groundnut (Arachis hypogaea L.) subjected to soil moisture deficit

Creator:
Jeyaramraja, P. R. and Thushara, S. S.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, drought susceptibility, drought tolerance, net photosynthesis, peanut, physiological mechanism, water-use efficiency, 2, and 581
Language:
Multiple languages
Description:
Responses of drought-tolerant (DT) and drought-susceptible (DS) pot-grown groundnut (Arachis hypogaea L.) varieties to changes in leaf relative water content (RWC) were studied. Water stress (WS) was imposed on 30-day-old plants for 2 weeks. Leaf RWC decreased significantly under WS conditions with simultaneous decrease in net photosynthetic rate (PN) and stomatal conductance (gs). Even though no significant difference was observed between DT and DS varieties with regard to RWC, DT varieties were able to maintain significantly higher PN than DS varieties. Higher values of water use efficiency (WUE) were also observed in DT varieties during WS conditions. The decline in PN due to WS could be attributed to both reduction in g s (i.e. stomatal limitation) and to reduction in chlorophyll content (Chl). No significant difference in leaf area index (LAI) was found between DT and DS types and LAI was not reduced by WS. Significant differences were found among the studied groundnut varieties, but not between DT and DS types, in terms of root, aboveground, and total dry mass. These growth parameters significantly decreased under WS conditions. Based on the results, a sequence of physiological responses in groundnut crop subjected to WS was postulated. and P. R. Jeyaramraja, S. S. Thushara.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

260. Severe water deficit-induced ethylene production decreases photosynthesis and photochemical efficiency in flag leaves of wheat

Creator:
Yang, W., Yin, Y., Jiang, W., Peng, D., Yang, D., Cui, Y., and Wang, Z.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, ethylen, pšenice, photosynthesis, ethylene, wheat, 1-aminocyclopropane-1-carboxylic acid, chlorophyll fluorescence, net photosynthetic rate, severe water deficit, Triticum aestivum L., 2, and 581
Language:
Multiple languages
Description:
Wheat (Triticum aestivum L.) cv. Jimai22 was used to evaluate the effect of ethylene evolution rate (EER) and 1-aminocyclopropane-1-carboxylic acid (ACC) and their relations with photosynthesis and photochemical efficiency in plants well-watered (WW) and under a severe water deficit (SWD). SWD caused a noticeable reduction in the grain mass. The marked increases in both EER and the ACC concentration were observed under SWD; it was reversed effectively by exogenous spermidine (Spd) or amino-ethoxyvinylglycine (AVG). Thermal images indicated that SWD increased obviously the temperature of flag leaves, mainly due to the decrease in transpiration rate under SWD. Exogenous Spd or AVG decreased to some extent the temperature of the flag leaves. The strong decline in photosynthetic rate (PN) and stomatal conductance as well as the photodamage of PSII were also observed under SWD after 14 and 21 days after anthesis (DAA). Intercellular CO2 concentration was reduced at 7 DAA, but slightly increased at 14 and 21 DAA under SWD, indicating that the decreased PN at 7 DAA might result from stomatal limitations, while the decline after 14 and 21 DAA might be attributed to nonstomatal limitations. Correlation analysis suggested that EER and ACC showed negative relations to photosynthesis and photochemical efficiency. Data obtained suggested that the effects of SWD were mediated predominantly by the increase in EER and ACC concentration, which greatly decreased the leaf photosynthesis and photochemical efficiency, and, therefore, reduced the grain mass. Application of Spd or AVG reduced the EER and ACC, and thus positively influenced photosynthesis and photochemical efficiency under SWD., W. Yang, Y. Yin, W. Jiang, D. Peng, D. Yang, Y. Cui, Z. Wang., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public