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2532. Exogenous Ca2+ alleviates waterlogging-caused damages to pepper
- Creator:
- Yang, B. Z., Liu, Z. B., Zhou, S. D., Ou, L. J., Dai, X. Z., Ma, Y. Q., Zhang, Z. Q., Chen, W. C., Li, X. F., Liang, C. L., Yang, S., and Zou, X. X.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- vápník, biomasa, karotenoidy, pšenice, calcium, biomass, carotenoids, wheat, Capsicum annuum, waterlogging, CaCl2, kalmodulin, výměna plynu, respiratory, calmodulin, gas exchange, 2, and 581
- Language:
- Multiple languages
- Description:
- Ca2+ has been considered as a necessary ion for alleviation of stress-induced damages in plants. We investigated effects of exogenous Ca2+ on waterlogging-induced damage to pepper and its underlying mechanisms. Pepper seedlings under stress were treated by spraying of 10 mM CaCl2. Applying exogenous Ca2+ increased the biomass of pepper leaves and roots, improved photosynthetic characteristics, membrane permeability, root activity, osmotic substance contents, antioxidant enzyme and alcohol dehydrogenase activities, while it reduced lactate dehydrogenase activity. It maintained hydroxide radical contents and activities of malate dehydrogenase and succinate dehydrogenase relatively high. Our results suggested that applying exogenous Ca2+ could regulate osmotic substance contents, antioxidant system activity, root respiration, and metabolism, and subsequently alleviate waterlogging-induced damages to pepper plants., B. Z. Yang, Z. B. Liu, S. D. Zhou, L. J. Ou, X. Z. Dai, Y. Q. Ma, Z. Q. Zhang, W. C. Chen, X. F. Li, C. L. Liang, S. Yang, X. X. Zou., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2533. Exogenous glycine betaine modulates ascorbate peroxidase and catalase activities and prevent lipid peroxidation in mild water-stressed Carapa guianensis plants
- Creator:
- Cruz, F. J. R., Castro, G. L. S., Silva Júnior, D. D., Festucci-Buselli, R. A., and Pinheiro, H. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, antioxidant enzymes, drought, gas exchange, malondialdehyde, oxidative stress, 2, and 58
- Language:
- Multiple languages
- Description:
- The hypothesis that application of exogenous glycine betaine (GBEX) may attenuate the effects of mild water deficit in leaf gas exchange and lipid peroxidation in Carapa guianensis was examined. For this reason, 110-d old plants were sprayed with 0, 25, and 50 mM GBEX and then subjected to two watering regimes. In the first, irrigation was continuously performed to maintain the soil near to field capacity (watered plants). In the second, irrigation was withheld and water deficit resulted from progressive evapotranspiration (water-stressed plants). Treatment comparisons were assessed when predawn leaflet water potential (Ψpd) of stressed plants reached -1.28 ± 0.34 MPa. Regardless of the watering regime, significant (P<0.05) increases in foliar glycine betaine (GBLeaf) concentration were observed in response to increasing GBEX; however, such increases were more expressive in stressed plants. The net photosynthetic rate, stomatal conductance to water vapor, and intercellular to ambient CO2 concentration ratio were significantly lower in water-stressed plants independently of GBEX concentration sprayed on leaves. The application of 25 and 50 mM GBEX caused significant (P<0.05) increases in ascorbate peroxidase (APX) activity in stressed plants, while significant (P<0.05) increases in catalase activity was observed just in the stressed plants treated with 50 mM GBEX. Malondialdehyde concentrations did not differ between watered and stressed plants regardless of GBEX concentration. In conclusion, C. guianensis was able to incorporate GBEX through their leaves and the resulting increases in GBLeaf attenuated lipid peroxidation in stressed plants through positive modulation of APX and CAT activities., F. J. R. Cruz ...[et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2534. Exogenous hexoses cause quantitative changes of pigment and glycerolipid composition in filamentous cyanobacteria
- Creator:
- Mykhaylenko, N. F., Syvash, O. O., Tupik, N. D., and Zolotareva, O. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll, glucose, mannose, monogalactosyldiacylglycerol, phosphatidylglycerol, Nostoc linckia, Spirulina platensis, and sugars
- Language:
- Multiple languages
- Description:
- Cyanobacteria Spirulina platensis and Nostoc linckia were grown in the presence of 5 mM and 50 mM glucose or 5 mM mannose, non-metabolisable glucose analogue that effectively triggers the repression of photosynthesis. Glucose evoked active cyanobacterial growth but chlorophyll (Chl) content decreased to some extent and porphyrins were excreted. The content of monogalactosyldiacylglycerol decreased in glucose-grown cyanobacteria and that of phosphatidylglycerol increased substantially. Mannose inhibited cyanobacteria growth as well as Chl synthesis, however, phosphatidylglycerol contents were higher than in respective control samples. In cyanobacterial cells glucose may not only inhibit photosynthetic processes, but also cause structural transformations of membranes which may be necessary for the activity of respiratory electron transport chain components under heterotrophic conditions. and N. F. Mykhaylenko ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2535. Exogenous melatonin improves growth and photosynthetic capacity of cucumber under salinity-induced stress
- Creator:
- Wang, L. Y., Liu, J. L., Sun, Y., and Wang, W. X.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, antioxidant enzymes, chlorophyll fluorescence, gas exchange, growth analysis, melatonin, salt tolerance, 2, and 581
- Language:
- Multiple languages
- Description:
- Melatonin mediates many physiological processes in animals and plants. To examine the potential roles of melatonin in salinity tolerance, we investigated the effects of exogenous melatonin on growth and antioxidant system in cucumber under 200 mM NaCl stress conditions. The results showed that the melatonin-treated plants significantly increased growth mass and antioxidant protection. Under salinity stress, the addition of melatonin effectively alleviated the decrease in the net photosynthetic rate, the maximum quantum efficiency of PSII, and the total chlorophyll content. Our data also suggested that melatonin and the resistance of plants exhibited a concentration effect. The application of 50-150 μM melatonin significantly improved the photosynthetic capacity. Additionally, the pretreatment with melatonin reduced the oxidative damage under salinity stress by scavenging directly H2O2 or enhancing activity of antioxidant enzymes (including superoxide dismutase, peroxidase, catalase, ascorbate peroxidase) and concentrations of antioxidants (ascorbic acid and glutathione). Therefore, the melatonin-treated plants could effectively enhance their salinity tolerance., L. Y. Wang, J. L. Liu, W. X. Wang, Y. Sun., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2536. Experimental and simulated light responses of photosynthesis in leaves of three tree species under different soil water conditions
- Creator:
- Lang, Y., Wang, M., Zhang, G. C., and Zhao, Q. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, drought-resistant tree species, light-response model, photoinhibition, photosynthetic rate, quantum yield, relative soil water content, 2, and 581
- Language:
- Multiple languages
- Description:
- Water deficit is one of the major limiting factors in vegetation recovery and restoration in loess, hilly-gully regions of China. The light responses of photosynthesis in leaves of two-year old Prunus sibirica L., Hippophae rhamnoides L., and Pinus tabulaeformis Carr. under various soil water contents were studied using the CIRAS-2 portable photosynthesis system. Light-response curves and photosynthetic parameters were analyzed and fitted using the rectangular hyperbola model, the exponential model, the nonrectangular hyperbola model, and the modified rectangular hyperbola model. Under high light, photosynthetic rate (PN) and stomatal conductance (gs) were steady and photoinhibition was not significant, when the relative soil water content (RWC) varied from 56.3-80.9%, 47.9-82.9%, and 33.4-92.6% for P. sibirica, H. rhamnoides, and P. tabulaeformis, respectively. The light-response curves of PN, the light compensation point (LCP), and the dark respiration rate (RD) were well fitted using the above four models. The nonrectangular hyperbola was the best model in fitting the data; the modified rectangular hyperbola model was the second, and the rectangular hyperbola model was the poorest one. When RWC was higher or lower than the optimal range, the obvious photoinhibition and significant decrease in PN with increasing photosynthetic photon flux density (PPFD) were observed in all three species under high light. The light saturation point (LSP) and apparent quantum yield also decreased significantly, when the upper limit of PPFD was 200 μmol m-2 s-1. Under these circumstances, only the modified rectangular hyperbola model was able to fit well the curves of the light response, LCP, LSP, RD, and light-saturated PN. and Y. Lang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2537. Experimental and theoretical study on high temperature induced changes in chlorophyll a fluorescence oscillations in barley leaves upon 2 % CO2
- Creator:
- Lazár, D., Kaňa , R., Klinkovský, T., and Nauš, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Hordeum vulgare, model, NADPH, and 1,5-bisphosphate carboxylase, oxygenase and its activase
- Language:
- Multiple languages
- Description:
- Oscillations in many of photosynthetic quantities with a period of about 1 min can be routinely measured with higher plant leaves after perturbation of the steady state by sudden change in gas phase. Among all hypotheses suggested so far to explain the oscillations, an effect of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activation status to control the oscillations is highly probable, at least upon high temperature (HT) treatment when in vivo RuBPCO activity controlled by RuBPCO activase (RuBPCO-A) decreases. Therefore, we measured the oscillations in fluorescence signal coming from barley leaves (Hordeum vulgare L. cv. Akcent) after their exposure for various time intervals to different HTs in darkness. We also evaluated steady state fluorescence and CO2 exchange parameters to have an insight to functions of electron transport chain within thylakoid membrane and Calvin cycle before initiation of the oscillations. The changes in period of the oscillations induced by moderate HT (up to 43 °C) best correlated with changes in non-photochemical fluorescence quenching (qN) that in turn correlated with changes in gross photosynthetic rate (PG) and rate of RuBPCO activation (kact). Therefore, we suggest that changes in period of the oscillations caused by moderate HT are mainly controlled by RuBPCO activation status. For more severe HT (45 °C), the oscillations disappeared which was probably caused by an insufficient formation of NADPH by electron transport chain within thylakoid membrane as judged from a decrease in photochemical fluorescence quenching (qP). Suggestions made on the basis of experimental data were verified by theoretical simulations of the oscillations based on a model of Calvin cycle and by means of a control analysis of the model. and D. Lazár ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2538. Exposed red leaves display adaptive adjustments in chlorophyll and photosystem ratios compatible with the shade imposed by anthocyanin accumulation
- Creator:
- Zeliou, K., Kyzeridou, A., and Petropoulou, Y.
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- fluorescence emission spectra, foliar anthocyanins, photosystem ratio, and shade-acclimation syndrome
- Language:
- Multiple languages
- Description:
- Foliar anthocyanins shape a peculiar shade in a red leaf's interior leading to uneven energy distribution between the two photosystems. Accordingly, a readjustment of PSII/PSI stoichiometry could restore excitation balance. To test this hypothesis, 77 K fluorescence emission spectra of thylakoids from green and red leaves of seven species with different pigment profiles were compared. The ratio of F686/F736 served as an indication of the PSII/PSI functional ratio. To avoid possible species-dependent differences in the measured parameters, plants showing intra-individual, intra-species, or intra-leaf variation in the expression of the anthocyanic character were used. Red leaves or red leaf areas displayed higher PSII/PSI ratio, irrespectively of species and anthocyanin accumulation pattern. PSII/PSI ratio declined in parallel with anthocyanin decrease. In five species, red leaves displayed also a lower Chl a/b ratio. We conclude that red leaves growing in full sunlight develop adaptive adjustments in their chlorophyll and photosystem ratios, compatible with the shade-acclimation syndrome.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2539. Expression of genes encoding key components of chlororespiration and cyclic electron transfer in soybean under different light qualities
- Creator:
- Sun, X., Chen, X. F., Du, J. B., and Yang, W. Y.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- obecná botanika, fotosyntéza, stín, general botany, photosynthesis, shade, chlorophyll fluorescence, NAD(P)H dehydrogenase, 2, and 581
- Language:
- Multiple languages
- Description:
- Our present work showed that the expression of genes encoding PTOX (terminal oxidase of chlororespiration) and PGR5 (one essential component of cyclic electron transfer) were stimulated by red and blue light, but the stimulation under red light was soon reversed by subsequent far-red light. The expression levels of PTOX and PGR5 under simulated light quality conditions in line with maize-soybean relay strip intercropping (SRI) were obviously lower than those under simulated soybean monocropping (SM), since the lower red:far-red ratio under SRI. Measurements on photosynthetic and chlorophyll fluorescence parameters suggested a decline of assimilatory power supply and a lower nonphotochemical quenching under SRI as compared to SM. In this case, weaker PGR-dependent cyclic electron transfer and chlororespiration under SRI, suggested by lower expression levels of PGR5 and PTOX, could be considered as means of reducing excitation energy dissipation to allocate more power toward CO2 assimilation., X. Sun, X. F. Chen, J. B. Du, W. Y. Yang., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2540. Expression of the large isoform of ribulose-1,5-bisphosphate carboxylase/oxygenase activase gene driven by rbcS promoter in Oryza sativa enhances the photosynthetic capacity
- Creator:
- Wu, H. R., Ding, Z. S., Li, L. B., Jing, Y. X., and Kuang, T. Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carboxylation efficiency, chlorophyll fluorescence, net photosynthetic rate, photosystem 2, and transgenic rice
- Language:
- Multiple languages
- Description:
- In order to investigate the effect of large isoform of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO) activase (RuBPCO-A) on photosynthesis, cDNA of the enzyme (rca) was transferred to rice cultivars (Oryza sativa f. japonica cv. Nipponbare) under the control of RuBPCO small subunit gene promoter (rbcS) via Agrobacterium tumefaciens-mediated transformation. Transgenic rice plants were identified by polymerase chain reaction (PCR) and Southern and Western blot analyses. Net photosynthetic rate (PN ) values of the T1 transgenic lines 34 (T34) and 40 (T40) were 45.26 and 46.32 % higher than that of the control plants, respectively. At the same time, their carboxylation efficiency and RuBPCO initial activity, quantum yield of electron transport in photosystem 2 (ΦPS2), and steady state photochemical fluorescence quenching (qP) increased. In addition, heading time of the transgenic rice was advanced. Thus increasing the amount of large isoform of RuBPCO-A in the transgenic rice might have a stimulatory effect on both photosynthesis and plant growth. and H. R. Wu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public