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662. Excitation kinetics of chlorophyll fluorescence during light-induced greening and establishment of photosynthetic activity of barley seedlings

Creator:
Buschmann, C., Konanz, S., Zhou, M., Lenk, S., Kocsányi, L., and Barócsi, A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chlorophyll fluorescence, embedded system, induction kinetics, intelligent sensors, Kautsky effect, light adaptation, 2, and 58
Language:
Multiple languages
Description:
Excitation kinetics based on feedback regulation of chlorophyll (Chl) fluorescence of leaves measured with the chlorophyll fluorometer, FluoroMeter Modul (FMM), are presented. These kinetics showed the variation of excitation light (laser power, LP) regulated by the feedback mechanism of the FMM, an intelligent Chl fluorometer with embedded computer, which maintains the fluorescence response constant during the 300-s transient between the dark- and light-adapted state of photosynthesis. The excitation kinetics exhibited a rise of LP with different time constants and fluctuations leading to a type of steady state. The variation of excitation kinetics were demonstrated using the example of primary leaves of etiolated barley seedlings (Hordeum vulgare L. cv. Barke) during 48 h of greening in the light with gradual accumulation of Chl and development of photosynthetic activity. The excitation kinetics showed a fast rise followed by a short plateau at ca. 30 s and finally a slow constant increase up to 300 s. Only in the case of 2 h of greening in the light, the curve reached a stable steady state after 75 s followed by a slight decline. The final LP value (at 300 s of illumination) increased up to 12 h of greening and decreased with longer greening times. The active feedback mechanism of the FMM adjusted the excitation light during the measurement to the actual photosynthetic capacity of the individual leaf sample. In this way, the illumination with excessive light was avoided. The novel excitation kinetics can be used to characterize health, stress, disease, and/or product quality of plant material., C. Buschmann ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

663. Exercise-induced prostacyclin release positively correlates with VO2max in young healthy men

Creator:
Zoladz, Jerzy A., Majerczak, J., Duda, K., and Chłopicki, S.
Format:
print
Type:
article, články, model:article, and TEXT
Subject:
Biochemie. Molekulární biologie. Biofyzika, biochemie, prostaglandiny, výkon, biochemistry, prostaglandins, performance, exercise, maximal oxygen uptake, power output, 2, and 577
Language:
English
Description:
In this study we have evaluated the effect of maximal incremental cycling exercise (IE) on the systemic release of prostacyclin (PGI2), assessed as plasma 6-keto-PGF1α concentration in young healthy men. Eleven physically active - untrained men (mean ± S.D.) aged 22.7 ± 2.1 years; body mass 76.3 ± 9.1 kg; BMI 23.30 ± 2.18 kg · m-2; maximal oxygen uptake (VO2max) 46.5 ± 3.9 ml · kg-1 · min-1, performed an IE test until exhaustion. Plasma concentrations of 6-keto-PGF1α, lactate, and cytokines were measured in venous blood samples taken prior to the exercise and at the exhaustion. The net exercise-induced increase in 6-keto-PGF1α concentration, expressed as the difference between the end-exercise minus pre-exercise concentration positively correlated with VO2max (r=0.78, p=0.004) as well as with the net VO2 increase at exhaustion (r=0.81, p=0.003), but not with other respiratory, cardiac, metabolic or inflammatory parameters of the exercise (minute ventilation, heart rate, plasma lactate, IL-6 or TNF-α concentrations). The exercise-induced increase in 6-keto-PGF1α concentration was significantly higher (p=0.008) in a group of subjects (n=5) with the highest VO2max when compared to the group of subjects with the lowest VO2max, in which no increase in 6-keto-PGF1α concentration was found. In conclusion, we demonstrated, to our knowledge for the first time, that exercise-induced release of PGI2 in young healthy men correlates with VO2max, suggesting that vascular capacity to release PGI2 in response to physical exercise represents an important factor characterizing exercise tolerance. Moreover, we postulate that the impairment of exercise-induced release of PGI2 leads to the increased cardiovascular hazard of vigorous exercise., J. A. Zoladz ... [et al.]., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

664. 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

665. 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

666. 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

667. 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

668. Expression of cytochrome P450 CYP6B6 in the different developmental stages of the insect Helicoverpa armigera (Lepidoptera: Noctuidae)

Creator:
Zhang, Xuetao, Yuan, Dan, Ding, Li, Li, Pan, Li, Fen, and Liu, Xiaoning
Type:
article, články, model:article, and TEXT
Subject:
Zoologie, zoologie, entomologie, Lepidoptera, Noctuidae, Helicoverpa armigera, developmental stage, CYP6B6 expression, 2, and 59
Language:
English
Description:
In order to determine when during the development of H. armigera CYP6B6 is expressed, we measured the width of the head capsule, the length of the body and weight of the different life stages of the cotton bollworm reared under laboratory condition. The larvae took about 20 d to complete their development under these conditions, the pre-pupae about 4 d, pupae about 9 d, and the adults lived for about 9 d and the eggs took about 4 d to hatch. Knowing this it was possible to determine the pattern of cytochrome P450 CYP6B6 expression at different stages in the life cycle of H. armigera using real-time quantitative polymerase chain reaction (RT-qPCR). The CYP6B6 gene was expressed in all the developmental stages of the cotton bollworm. The results indicate that the level of expression was lower in the egg, pre-pupal, pupal and adult stages than in larvae. The level of expression of CYP6B6 decreased from the 1st to the 3rd instar larva, with the lowest level recorded in the 3rd instar larvae and then increased reaching its highest value in 6th instar larvae. A similar trend in the expression of CYP6B6 was detected using immunohistochemistry. As the results show, more efficient control of the cotton bollworm can be achieved if insecticides are applied when the larvae of H. armiger are in the 3rd instar, because at that stage the eat little food and there is a low level of detoxifying enzymes in the larvae., Xuetao Zhang ... [et al.]., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

669. 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

670. Expression quantitative trait loci analysis of the Rubisco activase gene in maize

Creator:
Sun, Q., Zhang, Y., Chen, B., Jia, B., Zhang, Z. L., Cui, M., Kan, X., Shi, H. B., Deng, D. X., and Yin, Z. T.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
kukuřice, exprese genu, výnos zrna, promotory, kvantitativní znaky, Rubisco, gene expression, grain yield, promoters, quantitative traits, maize, 2, and 581
Language:
Multiple languages
Description:
Expression quantitative trait loci (eQTL) analyses were applied in order to identify genetic factors that are relevant to the expression of a β-isoform Rubisco activase gene in maize, namely ZmRCAβ, in this study. During two years, a maize recombinant inbred line population was measured for ZmRCAβ expression levels at the grain filling stage. Based on a genetic map containing 916 molecular markers, we detected five eQTLs, namely qRCA2.1 on chromosome 2, and qRCA4.1, qRCA4.2, qRCA4.3, and qRCA4.4 on chromosome 4. These eQTLs explained the phenotypic variation ranging from 6.14% to 7.50% with the logarithm of the odd values ranging from 3.11 to 4.96. Based on the position of the eQTLs and ZmRCAβ on the chromosome, qRCA4.2 was inferred as a cis-eQTL and the remaining as a trans-eQTL, suggesting that a combination of both cis- and trans-acting elements might control ZmRCAβ expression. qRCA4.2, qRCA4.3, and qRCA4.4 were repeatedly detected during two years., Q. Sun, Y. Zhang, B. Chen, B. Jia, Z. L. Zhang, M. Cui, X. Kan, H. B. Shi, D. X. Deng, Z. T. Yin., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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