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52. Changes in chloroplast ultrastructure in leaves of drought-stressed maize inbred lines

Creator:
Shao, R. X., Xin, L. F., Zheng, H. F., Li, L. L., Ran, W. L., Mao, J., and Yang, Q. H.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, biomass, chlorophyll, maize, membrane peroxidation, water content, 2, and 581
Language:
Multiple languages
Description:
Chloroplasts are commonly the site of the earliest abiotic injury visible in plant ultrastructure. In this study, six inbred lines of maize (Zea mays L.) were used to analyze changes in the ultrastructure of chloroplasts and related physiological parameters under conditions of drought stress simulated by 20% polyethylene glycol 6000 (-0.6 MPa) for two days. Chloroplasts of three maize lines proved to be more sensitive. They showed changes in the ultrastructure in response to drought, including damage of thylakoid membranes, an increase in the number and size of plastoglobuli, swelling of thylakoid membranes both stromal and granal, disorganization of the thylakoid membrane system, an obvious increase in the intrathylakoid space, and a decrease in the length-to-width ratio and area of chloroplasts. In addition, the contents of malondialdehyde increased markedly in the sensitive lines. Contrary to the sensitive lines, stable structures and shapes of chloroplasts were observed in the drought-resistant lines; it could be considered as an advantage contributing to drought tolerance in the plants. In addition, the drought index of leaf fresh mass (LMDI) in the drought-sensitive lines was ≤ 0.5, which was also associated with a lower content of leaf chlorophyll. In contrast, drought tolerance coincided with lesser growth reduction, and higher LMDI and leaf chlorophyll content., R. X. Shao, L. F. Xin, H. F. Zheng, L. L. Li, W. L. Ran, J. Mao, Q. H. Yang., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

53. Changes in photosynthesis, pigment composition and glutathione contents in two Antarctic lichens during a light stress and recovery

Creator:
Balarinová, K., Barták, Miloš, Hazdrová, J., Hájek, Josef, and Jílková, J.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, karotenoidy, lišejníky, photosynthesis, carotenoids, lichenes, Antarktida, Antarctica, chlorophyll fluorescence, performance index, thallus, light stress, 2, and 581
Language:
Multiple languages
Description:
Over last decades, several studies have been focused on short-term high light stress in lichens under laboratory conditions. Such studies reported a strong photoinhibition of photosynthesis accompanied by a partial photodestruction of PSII, involvement of photoprotective mechanisms, and resynthetic processes into gradual recovery. In our paper, we applied medium [800 μmol(photon) m-2 s-1] light stress to induce negative changes in PSII funcioning as well as pigment and glutathione (GSH) content in two Antarctic fruticose lichen species. Chlorophyll (Chl) fluorescence parameters, such as potential and effective quantum yield of photosynthetic processes and fast transients (OJIP) recorded during high light exposition and recovery, revealed that Usnea antarctica was less susceptible to photoinhibition than U. aurantiaco-atra. This might be supported by a more pronounced high light-induced reduction in Chl a and b contents in U. aurantiaco-atra compared with U. antarctica. In both experimental species, total GSH showed an initial increase during the first 30-40 min of high light treatment followed by a decrease (60 min) and an increase during dark recovery. Full GSH recovery, however, was not finished in U. aurantiaco-atra even after 5 h indicating lower capacity of photoprotective mechanisms in the species. OJIP curves showed high light-induced decrease in both species, however, the recovery of the OJIPs shape to pre-photoinhibitory values was faster and more apparent in U. antarctica than in U. aurantiaco-atra. The results are discussed in terms of sensitivity of the two species to photoinhibition and their photosynthetic performance in natural environment., K. Balarinová, M. Barták, J. Hazdrová, J. Hájek, J. Jílková., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

54. Changes in photosynthetic activity in five common hybrids of oil palm (Elaeis guineensis Jacq.) seedlings under water deficit

Creator:
Suresh, K., Nagamani, C., Kantha, D. L., and Kumar, M. K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, drought, Elaeis guineensis Jacq., gas exchange, stomatal conductance, water deficit, 2, and 58
Language:
Multiple languages
Description:
The leaf water potential, gas-exchange parameters and chlorophyll fluorescence were evaluated in five common oil palm (Elaeis guineensis Jacq.) tenera hybrids 913X1988, 1425X2277, 748X1988, 7418X1988, and 690X1988 under water deficit with an aim to identify hybrids which can cope up better under such conditions and understand possible differences among hybrids in relation to the physiological mechanisms triggered by water deficit. Our findings indicate oil palm hybrids 913X1988, 1425X2277, and 7418X1988 maintained higher leaf water potentials than the other hybrids. Hybrids 7418X1988 and 1425X2277 recorded lower stomatal conductance after water deficit, which resulted in higher intrinsic water-use efficiency. The excess light energy produced due to decreased photosynthesis in 7418X1988 and 690X1988 hybrids under water deficit was dissipated as heat by higher nonphotochemical quenching. The maximum efficiency of photosystem II was not affected, even after withholding water for 24 days, suggesting an increased efficiency of photoprotection mechanisms in all these oil palm hybrids., K. Suresh ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

55. Changes in plant growth and photosynthetic performance of Zizania latifolia exposed to different phosphorus concentrations under hydroponic condition

Creator:
Yan, N., Zhang, Y.-L., Xue, H.-M., Zhang, X.-H., Wang, Z.-D., Shi, L.-Y., and Guo, D.-P.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, chlorophyll a fluorescence, growth characteristics, phosphorus availability, 2, and 581
Language:
Multiple languages
Description:
The effects of phosphate concentration on plant growth and photosynthetic performance were examined in leaves of Zizania latifolia. Plants were grown for four weeks in a solution containing 0, 0.16, 0.64, and 2.56 mM orthophosphate. The results showed that the highest net photosynthetic rate (P N) was achieved at 0.64 mM orthophosphate, which corresponded to the maximum content of organic phosphorus in leaves. Low phosphorus (low-P) content in the culture solution inhibited plant growth, affecting plant height, leaf length, leaf number, tiller number, and fresh mass of leaf, sheath, culm, root, and total plant. In addition, we observed that low-P (0.16 mM) did not hinder the growth of roots but increased the root:shoot ratio, and significantly decreased the chlorophyll content, P N, stomatal conductance, and transpiration rate, but increased the intercellular CO2 concentration. Additionally, low-P significantly decreased the maximum carboxylation rate of Rubisco, the maximum rate of ribulose-1,5-bisphosphate regeneration, the effective quantum yield of PSII photochemistry, photochemical quenching coefficient, and electron transport rate, but increased the nonphotochemical quenching. However, the maximal quantum yield of PSII photochemistry was not significantly affected by low-P. High phosphorus (2.56 mM) caused only a slight decrease in gas-exchange parameters. Therefore, the decrease in growth of P-deficient Z. latifolia plants could be attributed to the lowered photosynthetic rate., N. Yan, Y.-L. Zhang, H.-M. Xue, X.-H. Zhang, Z.-D. Wang, L.-Y. Shi, D.-P. Guo., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

56. Changes in stomatal characteristics and photochemical efficiency during leaf development in six species of Sorbus

Creator:
Čaňová, I., Ďurkovič, J., Hladká, D., and Lukáčik, Ivan
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, phenological stages, photochemical efficiency, Sorbus chamaemespilus, 2, and 58
Language:
Multiple languages
Description:
Measurements of Sorbus stomata size and density, maximal photochemical efficiency of photosystem II (Fv/Fm), variable-to-initial fluorescence ratio (Fv/F0) and potential electron acceptor capacity (‘area’) were performed during leaf development in four parental diploid species, S. aria, S. aucuparia, S. chamaemespilus, S. torminalis, and two hybrid species, S. hazslinszkyana and S. intermedia. In fully expanded mature leaves, stomata lengths and densities were significantly larger in the shrub S. chamaemespilus than in the five tree species. The best performance of both the Fv/Fm and the Fv/F0 ratio was recorded in S. intermedia, whereas S. chamaemespilus had the highest value of ‘area’. From a physiological point of view, the results of this study showed that the photosystem II reaction centers remained intact functionally through all phenological stages of leaf expansion for all examined species of Sorbus., I. Čaňová ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

57. Changes in thermic limits and acclimation assessment for an alpine plant by chlorophyll fluorescence analysis: Fv/Fmvs. Rfd

Creator:
Perera-Castro, A. V., Brito, P., and González-Rodríguez, A. M.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
horko, vysoká hora, Národní park Teide, teplotní odolnost, index vitality, freezing acclimation, heat, high mountain, Teide National Park, temperature resistance, vitality index, 2, and 581
Language:
Multiple languages
Description:
A comparison between maximum quantum yield of PSII photochemistry (Fv/Fm) and chlorophyll fluorescence decrease ratio (Rfd) for low and high temperature resistance was assessed in a seasonal study of the acclimation in Pterocephalus lasiospermus. Analyzing the regression adjustment of both parameters and the lethal temperatures (LT50), Rfd resulted in being a more sensitive indicator for low and high temperature treatments, since the thermic resistance estimated with Rfd parameter was never higher than those estimated with Fv/Fm. Furthermore, the use of Fv/Fm led to an overestimation of the acclimation phenomena, with 6ºC of a maximum difference between both parameters. Using Rfd as the indicator parameter, P. lasiospermus acclimated to low temperatures but it kept on being a sensitive species (the lowest LT50 values only achieved -9.9 ± 0.3ºC). However, no heat acclimation was observed (LT50 around 43.5ºC). Thus, according to Rfd evaluation of the thermic threshold, this species could be in risk of damage at low temperatures in this alpine ecosystem., A. V. Perera-Castro, P. Brito, A. M. González-Rodríguez., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

58. Changes in winter snow depth affects photosynthesis and physiological characteristics of biological soil crusts in the Tengger Desert

Creator:
Hui, R., Zhao, R. M., Liu, L. C., Li, Y. X., Yang, H. T., Wang, Y. L., Xie, M., and Wang, X. Q.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, biological soil crusts, chlorophyll fluorescence, photosynthetic pigments, soluble sugar, water availability, 2, and 581
Language:
Multiple languages
Description:
Water availability is a major limiting factor in desert ecosystems. However, a winter snowfall role in the growth of biological soil crusts is still less investigated. Here, four snow treatments were designed to evaluate the effects of snow depth on photosynthesis and physiological characteristics of biological soil crusts. Results showed that snow strongly affected the chlorophyll fluorescence properties. The increased snow depth led to increased contents of photosynthetic pigments and soluble proteins. However, all biological soil crusts also exhibited a decline in malondialdehyde and soluble sugar contents as snow increased. Results demonstrated that different biological soil crusts exhibited different responses to snow depth treatment due to differences in their morphological characteristics and microhabitat. In addition, interspecies differentiation in response to snow depth treatment might affect the survival of some biological soil crusts. Further, this influence might lead to changes in the structural composition and functional communities of biological soil crusts., R. Hui, R. M. Zhao, L. C. Liu, Y. X. Li, H. T. Yang, Y. L. Wang, M. Xie, X. Q. Wang., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

59. Characterization of different isoforms of the light-harvesting chlorophyll a/b complexes of photosystem II in bamboo

Creator:
Jiang, Z. H., Peng, Z. H., Gao, Z. M., Liu, C., and Yang, C. H.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, bamboo, isoform, light-harvesting complexes, 2, and 58
Language:
Multiple languages
Description:
The major light-harvesting chlorophyll (Chl) a/b complexes of photosystem II (LHCIIb) play important roles in energy balance of thylakoid membrane. They harvest solar energy, transfer the energy to the reaction center under normal light condition and dissipate excess excitation energy under strong light condition. Many bamboo species could grow very fast even under extremely changing light conditions. In order to explain whether LHCIIb in bamboo contributes to this specific characteristic, the spectroscopic features, the capacity of forming homotrimers and structural stabilities of different isoforms (Lhcb1-3) were investigated. The apoproteins of the three isoforms of LHCIIb in bamboo are overexpressed in vitro and successfully refolded with thylakoid pigments. The sequences of Lhcb1 and Lhcb2 are similar and they are capable of forming homotrimer, while Lhcb3 lacks 10 residues in the N terminus and can not form the homotrimeric structure. The pigment stoichiometries, spectroscopic characteristics, thermo- and photostabilities of different reconstituted Lhcbs reveal that Lhcb3 differs strongly from Lhcb1 and Lhcb2. Lhcb3 possesses the lowest Qy transition energy and the highest thermostability. Lhcb2 is the most stable monomer under strong illumination among all the isoforms. These results suggest that in spite of small differences, different Lhcb isoforms in bamboo possess similar characteristics as those in other higher plants., Z. H. Jiang ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

60. Characterization of isolated photosystem I from Halomicronema hongdechloris, a chlorophyll f-producing cyanobacterium

Creator:
Li, Y., Vella, N., and Chen, M.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
sinice, Cyanophyta, far-red light photoacclimation, oxygenic photosynthesis, red-shifted chlorophyll, 2, and 581
Language:
Multiple languages
Description:
Halomicronema hongdechloris is a chlorophyll (Chl) f-producing cyanobacterium. Chl f biosynthesis is induced under far-red light, extending its photosynthetically active radiation range to 760 nm. In this study, PSI complexes were isolated and purified from H. hongdechloris, grown under white light (WL) and far-red light (FR), by a combination of density gradient ultracentrifugation and chromatographic separation. WL-PSI showed similar pigment composition as that of Synechocystis 6803, using Chl a in the reaction center. Both Chl a and f were detected in the FR-PSI, although Chl f was a minor component (~8% of total Chl). The FR-PSI showed a maximal fluorescence emission peak of 750 nm at 77 K, which is red-shifted ~20 nm compared to the 730 nm recorded from the WL-PSI. The absorption peaks of P700 for WLPSI and FR-PSI were 699 nm and 702 nm, respectively. The function of Chl f in FR-PSI is discussed., Y. Li, N. Vella, M. Chen., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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