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62. Influence of temperature on the effects of artificially enhanced UV-B radiation on aquatic bryophytes under laboratory conditions
- Creator:
- Nuñez-Olivera, E., Martínez-Abaigar, J., Tomás, R., Beaucourt, N., and Arróniz-Crespo, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophylls, Fontinalis, Jungermannia, net photosynthetic rate, pheopigments, and respiration
- Language:
- Multiple languages
- Description:
- We examined, under laboratory conditions, the influence of temperature (2 °C vs. 10 °C) on the physiological responses of two aquatic bryophytes from a mountain stream to artificially enhanced UV-B radiation for 82 d. These organisms may be exposed naturally to relatively low temperatures and high levels of UV-B radiation, and this combination is believed to increase the adverse effects of UV-B radiation. In the moss Fontinalis antipyretica, UV-B-treated samples showed severe physiological damages, including significant decreases in chlorophyll (Chl) and carotenoid (Car) contents, Chl a/b and Chl/phaeopigment ratios, Chl a fluorescence parameters Fv/Fm and ΦPS2, electron transport rate (ETRmax), and growth. In the liverwort Jungermannia cordifolia, UV-B radiation hardly caused any physiological change except for growth reduction. Thus, this liverwort seemed to be more tolerant to UV-B radiation than the moss under the specific experimental conditions used, maybe partly due to the accumulation of UV-B absorbing compounds. The influence of temperature on the effects of UV-B radiation depended on the species: the higher the UV-B tolerance, the lower the influence of temperature. Also, different physiological variables showed varied responses to this influence. Particularly, the lower temperature used in our study enhanced the adverse effects of UV-B radiation on important physiological variables such as Fv/Fm, growth, and Chl/phaeopigment ratios in the UV-B-sensitive F. antipyretica, but not in the more UV-B-tolerant J. cordifolia. Thus, the adverse effects of cold and UV-B radiation were apparently additive in the moss, but this additiveness was lacking in the liverwort. The Principal Components Analyses (PCA) conducted for both species with the physiological data obtained after 36 and 82 d of culture confirmed the above results. Under natural conditions, the relatively high water temperatures in summer might facilitate the acclimation of aquatic bryophytes from mountain streams to high levels of UV-B radiation. This may be relevant to predict the consequences of concomitant global warming and increasing UV-B radiation. and E. Nuñez-Olivera ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
63. Influence of water stress and low irradiance on morphological and physiological characteristics of Picea asperata seedlings
- Creator:
- Yang, Y., Liu, Q., Han, C., Qiao, Y. Z., Yao, X. Q., and Yin, H. J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll fluorescence, growth, photosynthesis, photosystem 2, quantum yield, root/shoot raton, specific leaf area, stomatal conductance, and transpiration
- Language:
- Multiple languages
- Description:
- The combined effects of water stress (WS) and low irradiance (LI) on growth, photosynthesis, osmotic adjustment, and lipid peroxidation were studied in dragon spruce (Picea asperata Mast.) seedlings grown under two water treatments (well watered, 100 % of field capacity, and water stressed, 30 % of field capacity) and two irradiances (HI, 100 % of full sunlight and LI, 15 % of full sunlight). WS reduced growth, chlorophyll (Chl) a and b contents, net photosynthetic rate, transpiration rate, stomatal conductance, and effective quantum yield of photosystem 2 (Y) but increased free proline and malondialdehyde contents. LI increased Chl contents and decreased Y, photochemical quenching (qP), and non-photochemical quenching (qN) under both water treatments. Hence the seedlings in the understory were more sensitive to drought than to LI. and Y. Yang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
64. Interactions between photosynthetic pigments in organisms and in model systems
- Creator:
- Frąckowiak, D. and Smyk, B.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophylls, delayed luminescence, excitation energy migration, models, photoacoustic spectroscopy, photosystem 2 reaction centres, polarized radiation, and thermal deactivation
- Language:
- Multiple languages
- Description:
- The review summarizes results concerning photosynthetic systems with chlorophylls and carotenoids obtained by means of spectral methods such as polarized radiation, photoacoustic spectroscopy, delayed luminescence, thermal deactivation, and leading to construction of model systems. and D. Frąckowiak, B. Smyk.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
65. Interactive effects of sulphur dioxide and mineral nutrient supply on photosynthetic characteristics and yield in four wheat cultivars
- Creator:
- Verma, M., Agrawal, M., and Deepak, S. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- biomass, carotenoids, chlorophyll, nutrients, dioxide, and wheat
- Language:
- Multiple languages
- Description:
- Field experiments were conducted on four cultivars of wheat (Triticum aestivum L.) to examine the variability in cultivar response to sulphur dioxide (SO2) under different concentrations of mineral nutrients. Thirty-days-old plants were exposed for 8 weeks to 390±20 µg m-3 (0.15 ppm) SO2 for 4 h per day, 5 d per week. Decline in net photosynthetic rate, contents of pigments and nitrogen, biomass and grain yield of each cultivars were due to SO2 at all the nutrient concentrations studied. However, the magnitude of reduction was higher in plants grown without nutrient application. On the basis of the reductions in photosynthesis and yield, the susceptibility of wheat cultivars to SO2 was in the order of Malviya 213 > Malviya 37 > Malviya 206 > Malviya 234 at recommended dose of NPK, whereas the same without the nutrients was Malviya 206 > Malviya 234 > Malviya 213 > Malviya 37. and M. Verma, M. Agrawal, S.S. Deepak.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
66. Irradiance influences contents of photosynthetic pigments and proteins in tropical grasses and legumes
- Creator:
- Baig, M. J., Anand, A., Mandal, P. K., and Bhatt, R. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, Cenchrus, chlorophyll, Dichantium, Macroptilium, Panicum, polyacrylamide gel electrophoresis, and Stylosanthes
- Language:
- Multiple languages
- Description:
- Three tropical range grasses (Cenchrus ciliaris, Dichanthium annulatum, and Panicum antidotale) and two range legumes [Macroptilium atropurpureum (siratro) and Stylosanthes hamata (stylo)] were grown under four irradiances, i.e. 100 (I100, control), 75 (I75), 50 (I50), and 25 (I25) % of full sunlight. Accumulation of chlorophyll (Chl) b increased but that of Chl a decreased under low irradiances. The greater accumulation of Chl (a+b) in grasses (particularly in D. annulatum and P. antidotale) under shade predicted their shade adaptability. Among legumes Stylosanthes was more adaptive to the shade than Macroptilium due to its higher accumulation of Chl (a+b). Significant difference in the accumulation of carotenoids under I25 over I100 was observed in all the species, which shows the increase in quality of the fodder under limited irradiance. There was a significant decrease in soluble protein content in C. ciliaris under I75, however, no significant difference in protein content was observed under I50 and I25, which was also reflected in the SDS pattern with the reduction in content of polypeptides at I75 and following increase at I50 and I25. This was possibly due to reduction of light-induced protein at I75 and then expression of the stress-induced protein at further reduction of irradiance. Peroxidase activity in C. ciliaris increased with the decrease in irradiance and its isozyme pattern showed differences among all treatments, which indicated the role of different peroxidase isoforms at different irradiances. and M. J. Baig ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
67. Leaf anatomy and photosynthetic efficiency of Acrostichum danaeifolium after UV radiation
- Creator:
- Fonini, A. M., Barufi, J. B., Schmidt, É. C., Rodrigues, A. C., and Randi, Á. M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorofyl, karotenoidy, chlorophyll, carotenoids, mangrovníky, mladé sporofyty, fotosyntetické parametry, anatomie listů, giant leather fern, mangroves, photoresponse, young sporophyte, photosynthetic parameters, Acrostichum danaeifolium, leaf anatomy, photosynthetic efficiency, 2, and 581
- Language:
- Multiple languages
- Description:
- This paper reports effects of ultraviolet B (UVB) radiation on leaf anatomy and contents of chlorophyll and carotenoids, as well as photosynthetic parameters, in young sporophytes of Acrostichum danaeifolium Langsd. & Fisch. (Polypodiopsida, Pteridaceae) exposed to UV radiation treatments for 1 h daily for six weeks. The leaves showed large aerenchyma and present chloroplasts in both epidermises. After cultivation under PAR + UVA + UVB, leaves showed curling and malformed stomata on the abaxial face. After the UV treatment, chloroplasts in leaves were arranged against the inner wall of the epidermal cells. Transmission electron microscopy analysis showed some dilated thylakoids and plastoglobuli in chloroplasts and vesicles containing phenolic compounds in the cytoplasm. Differences were not observed between control and UV-treated plants in their contents of chlorophylls, carotenoids, and photosynthetic parameters. A. danaeifolium grown in sunny mangrove environment seems to have mechanisms preventing photosystem damage., A. M. Fonini, J. B. Barufi, É. C. Schmidt, A. C. Rodrigues, Á. M. Randi., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
68. Linear dichroism, fluorescence polarization, and path of the thermal deactivation of excited cyanobacterial (Synechococcus elongatus) photosystem 1 immobilized and oriented in polymer films
- Creator:
- Białek-Bylka, G. E., Sofrová, D., Szurkowski, J., Skwarek, R., Sopko, B., and Manikowski, H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, photoacoustic and emission spectroscopy, polarized absorption, and reaction centres
- Language:
- Multiple languages
- Description:
- Pigment-protein complexes enriched in photosystem 1 (PS1) and, for comparison, enriched in photosystem 2 (PS2) were isolated from the cyanobacterium Synechococcus elongatus Nag. f. thermalis Geitl. They were immobilized and oriented in the polyvinyl alcohol (PVA) films, and studied by linear dichroism (LD), fluorescence polarization (FP), photoacoustic spectroscopy (PAS), and polarized photoacoustic spectroscopy (PAS|| and PAS⊥). The LD signal of β-carotene in the region with maximum at 500 nm was positive in the PS1 complex. The maximum value of fluorescence polarization (FP) in the measured photosynthetic pigment region was 1.25 and was similar to higher plant values. Carotenoids exhibited different efficiencies of thermal deactivation (max. at 500 nm) in PS1 and PS2. The thermal deactivation efficiency of carotenoids in comparison with that of chlorophyll (Chl) a at its red absorbance maximum was much higher in PS1 than in PS2 complexes. Cyanobacterial complexes did not contain Chl b, interpretation of the LD, PAS, and FP results is thus easier and can be compared with PS1 and PS2 values of higher plants, especially with Chl b-less mutant values. and G. E. Białek-Bylka ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
69. mesophyll cell defective1, a mutation that disrupts leaf mesophyll differentiation in sunflower
- Creator:
- Fambrini, M., Degl'Innocenti, E., Cionini, G., Pugliesi, C., and Guidi, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, carotenoids, chlorophyll, chlorophyll fluorescence imaging, Helianthus annuus L., and leaf development
- Language:
- Multiple languages
- Description:
- Mutants with altered leaf morphology are useful as markers for the study of genetic systems and for probing the leaf differentiation process. One such mutant with deficient greening and altered development of the leaf mesophyll appeared in an inbred line of sunflower (Helianthus annuus L.). The objectives of the present study were to determine the inheritance of the mutant leaf trait and its morphological characterisation. The mutation, named mesophyll cell defective1 (mcd1), has pleiotropic effects and it is inherited as a monogenic recessive. The structure and tissue organization of mcd1 leaves are disrupted. In mcd1 leaves, the mesophyll has prominent intercellular spaces, and palisade and spongy tissues are not properly shaped. The mutant palisade cells also appear to be more vacuolated and with a reduced number of chloroplasts than the wild type leaves of equivalent developmental stage. The lamina thickness of mcd1 leaves is greatly variable and in some areas no mesophyll cells are present between the adaxial and abaxial epidermis. The leaf area of the mcd1 mutant is extremely reduced as well as the stem height. A deficient accumulation of photosynthetic pigments characterizes both cotyledons and leaves of the mutant. In mcd1 leaves, chlorophyll (Chl) fluorescence imaging evidences a spatial heterogeneity of leaf photosynthetic performance. Little black points, which correspond to photosystem II (PSII) maximum efficiency (Fv/Fm) values close to zero, characterize the mcd1 leaves. Similarly, the lightadapted quantum efficiency (ΦPSII) values show a homogeneous distribution over wild type leaf lamina, while the damaged areas in mcd1 leaves, represented by yellow zones, are prominent. In conclusion, the loss of function of the MCD1 gene in Helianthus annuus is correlated with a variegated leaf phenotype characterized by a localized destruction of mesophyll morphogenesis and defeat of PSII activity. and M. Fambrini ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
70. Modelling net photosynthetic rate of winter wheat in elevated air CO2 concentrations
- Creator:
- Harnos, N., Tuba, Z., and Szente, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- acclimation, carotenoids, chlorophyll, intercellular CO2 concentration, leaf area, net photosynthetic rate, ribulose-1,5-bisphosphate carboxylase/oxygenase capacity, temperature, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- Winter wheat plants were grown in open top chambers either at 365 µmol mol-1 (AC) or at 700 µmol mol-1 (EC) air CO2 concentrations. The photosynthetic response of flag leaves at the beginning of flowering and on four vertical leaf levels at the beginning of grain filling were measured. Net photosynthetic rates (PN) were higher at both developmental phases in plants grown at EC coupled with larger leaf area and photosynthetic pigment contents. The widely accepted Farquhar net photosynthesis model was parameterised and tested using several observed data. After parameterisation the test results corresponded satisfactorily with observed values under several environmental conditions. and N. Harnos, Z. Tuba, K. Szente.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public