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22. Centrum excelence rostlinné biologie v 19. století - ústav Julia Sachse ve Würzburgu =
- Creator:
- Volkmann, Dieter
- Type:
- article, biography, články, journal articles, model:article, and TEXT
- Subject:
- Obecná botanika, Sachs, Julius, 1832-1897, 19. století, botanika, fyziologie rostlin, botany, plant physiology, Germany, 2, and 581
- Language:
- Czech
- Description:
- V článku je zdůrazněn rozhodující význam školy moderní fyziologie rostlin založené Juliem Sachsem, který byl uveden do experimentálních metod fyziologie Janem Evangelistou Purkyněm jako jeho asistent v Praze. Dále jsou krátce charakterizováni nejdůležitější Sachsovi žáci z jeho rozhodujícího období působení na univerzitě ve Würzburgu a je zdůrazněno trvající působení Sachsových myšlenek až do současného období studia biologie rostlin., The decisive importance of the school of modern plant physiology established by Julius Sachs, who was introduced to the experimental methods of physiology by Jan Evangelista Purkyně as his assistant in Prague, is underscored in this article. The most important disciples of Julius Sachs as a professor in Würzburg are portrayed and the lasting influence of Sachs´s ideas on plant biology is described., Dieter Volkmann., and 5 il.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
23. 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
24. 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
25. 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
26. Chlorophyll a fluorescence as a tool for a study of the Potato virus Y effects on photosynthesis of nontransgenic and transgenic Pssu-ipt tobacco
- Creator:
- Spoustová, P., Synková, Helena, Valcke, R., and Čeřovská, N.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll a fluorescence imaging, cytokinins, gas-exchange parameters, ipt, photosynthesis, Potato virus Y, transgenic tobacco, 2, and 58
- Language:
- Multiple languages
- Description:
- The effect of Potato virus Y NTN (PVY) infection upon photosynthesis was analysed in transgenic Pssu-ipt tobacco overproducing endogenous cytokinins in comparison with control, nontransgenic Nicotiana tabacum plants. The course of the infection from the early to the late stage was monitored by measuring of photosynthetic gas exchange and fast chlorophyll (Chl) a fluorescence induction kinetics. Leaf photosynthesis was also analysed using Chl fluorescence imaging (Chl-FI). From the different fluorescence parameters obtained using Chl-FI, the nonphotochemical quenching (NPQ) proved to be the most useful parameter to assess the effect of PVY infection. On the other hand, Chl-FI was found to be inapplicable for any presymptomatic detection of PVY infection in tobacco. The lower accumulation of the virus was found in transgenic plants and corresponded also with the presence of visible symptoms of PVY infection. The net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) significantly decreased with the progress of the infection in both control plant types and transgenic rooted plants, while transgenic grafts were much less affected. The analysis of the Chl fluorescence transient revealed higher number of silent dissipative reaction centres, higher nonphotochemical dissipation, and significantly lower performance index, PI(abs), in the healthy transgenic grafts. Chl-FI also confirmed significantly higher NPQ in transgenic grafts., P. Spoustová ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
27. Chlorophyll content and photosystem II efficiency in soybean exposed to supplemental ultraviolet-B radiation
- Creator:
- Hu, Z., Li, H., Chen, S., and Yang, Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll content, fluorescence quenching, Glycine max, rapid light curves, ultraviolet-B radiation, 2, and 58
- Language:
- Multiple languages
- Description:
- Chlorophyll (Chl) a fluorescence parameters and rapid light curves of soybean [Glycine max (L.) Merrill] were measured by pulse amplitude modulation fluorometry. Measurements were taken during different stages of soybean growth under field conditions with 20% enhancement in ultraviolet-B (UV-B) radiation. Results showed that supplemental UV-B radiation decreased Chl contents by 5.5% (P=0.048), 8.7% (P=0.046), and 10.5% (P=0.005) in seedling, in branching-flowering, and in pod-setting stages, respectively. In the branching-flowering and pod-setting stages, maximum quantum yield of photosystem (PS) II photochemistry (Fv/Fm) decreased by 6.1% (P=0.001) and 3.0% (P=0.009), respectively. Supplemental UV-B radiation significantly decreased the effective quantum yield (Y). The photosynthetic capacity at light saturation (Pm) also decreased in both the seedling and branching-flowering stages by 28.9% (P=0.007) and 15.5% (P=0.041), respectively. However, Y and Pm showed no significant difference in the trefoil and pod-setting stages with and without the UV treatment. The light saturation parameter (E k) decreased by 21.1% (P=0.000) and 23.2% (P=0.029) in the trefoil and seedling stages, respectively. Moreover, the initial slope (α) decreased by 21.1% (P=0.001) in the branching-flowering stage. Nonphotochemical quenching (NPQ) in the seedling stage and photochemical quenching coefficient (qp) in the branching-flowering stage decreased significantly under UV-B treatments. The results of the present study suggest that supplemental UV-B radiation adversely affected Chl content and electron transport activity in PSII and consequently decreased the photosynthetic efficiency of soybean plants., Z. Hu ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
28. Chloroplast functionality assessment by flow cytometry: case study with pea plants under Paraquat stress
- Creator:
- Rodriguez, E., Azevedo, R., Costa, A., Serôdio, J., and Santos, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll fluorescence, chloroplast, flow cytometry, herbicide, Paraquat, photosynthesis, pulse-amplitude modulation fluorometry, 2, and 58
- Language:
- Multiple languages
- Description:
- a1_Photosynthesis is one of the most important processes in plant biology and in the development of new methodologies that allow a better understanding and characterization of the photosynthetic status of organisms, which is invaluable. Flow cytometry (FCM) is an excellent tool for measuring fluorescence and physical proprieties of particles but it has seldom been used in photosynthetic studies and thus the full extent of its potentialities, in this field of research, remains unknown. To determine the suitability of FCM in photosynthesis studies, pea plants were exposed to Paraquat and their status was analyzed during 24 h. FCM was used to evaluate the integrity (volume and internal complexity) and the relative fluorescence intensity (FL) of chloroplasts extracted from those plants. To elucidate which type of information the FL conveys, FL values were correlated with the minimum fluorescence level (F0), maximum fluorescence level (Fm) and maximum photochemical efficiency of PSII (Fv/Fm), obtained by using Pulse-Amplitude-Modulation (PAM) fluorometry. Results indicate that: (1) the biomarkers used to evaluate the structural integrity of the chloroplasts were more sensitive to Paraquat exposure than the ones related to fluorescence; (2) the variation of the chloroplast’s structure, as time progressed, pointed to a swelling and subsequent burst of the chloroplast which, in turn, compromised fluorescence emission; (3) FL presented a high and significant correlation with the Fv/Fm and to a lesser degree with Fm but not with F0; (4) pigment content did not reveal significant changes in response to Paraquat exposure and is in agreement with the proposed model, suggesting that the cause for fluorescence decrease is due to chloroplast disruption., a2_In sum, FCM proved to be an outstanding technique to evaluate chloroplastidal functional and structural status and therefore it should be regarded as a valuable asset in the field of photosynthetic research., E. Rodriguez ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29. Chrpy - botanická noční můra?: o jejich diverzitě, systematice a hybridizaci
- Creator:
- Petr Koutecký
- Format:
- bez média and svazek
- Type:
- article, text, články, journal articles, model:article, and TEXT
- Subject:
- Biologické vědy, biologie, botanika, pěstitelství, fyziologie rostlin, botany, biology, horticultural education, plant physiology, hybridizace rostlin, polyploidie, chrpy, Centaurea, 2, and 57/59
- Language:
- Czech
- Description:
- Článek přestavuje taxonomicky problematický rod chrpa z čeledi Asteraceae. Jsou diskutovány současné pohledy na vymezení a vnitřní členění rodu založené na molekulárních znacích. Dále je popsána problematika hybridizace, která je v rodu velmi častá, a její souvislost s polyploidií (druhy stejné ploidie se často kříží za vzniku rozsáhlých a variabilních hybridních rojů, zatímco mezi ploidiemi je silná reprodukční bariéra)., Centaurea is a taxonomically critical genus from the Asteraceae family. Current delimitation of the genus and its internal classification based on molecular data are discussed. Hybridization and polyploidy are common in Centaurea. The frequency of hybridization depends on ploidy levels of the taxa (homoploid taxa usually hybridize easily and form extensive and variable hybrid swarms, while heteroploid taxa are reproductively strongly isolated)., and Petr Koutecký.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
30. Co dali čeští botanici světu?
- Creator:
- Adam Veleba
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Botanika, botanika, botanici, flóra, Česko, 2, and 58
- Language:
- Czech
- Description:
- Two families of carnivorous plants have been described by Czech botanists: Byblidaceae Domin 1922 and Drosophyllaceae Chrtek, Slavíková and Studnička 1989. A history of the descriptions and some basic and interesting information about these families are presented. and Adam Veleba.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public