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1942. Photosysytem 2 activities of hyper-accumulator dicranopteris dichotoma Bernh from a light rare earth elements mine
- Creator:
- Wang, L. F., Ji, H. B., Bai, K. Z., Li, L. B., and Kuang, T. Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- β-carotene, chlorophyll fluorescence, photosynthetic electron transport, photosystem 2, and thylakoid membrane
- Language:
- Multiple languages
- Description:
- The distribution of rare earth elements (REEs) in the fern Dicranopteris dichotoma Bernh plants from a light rare earth elements mine (LRM) and a non-mining (NM) area in Longnan county of Jiangxi province, China were investigated by means of inductively coupled plasma-mass spectrometry, transmission electron microscopy, and energy-dispersive X-ray microanalysis. The photosynthetic characteristics of D. dichotoma were studied by chlorophyll (Chl) a fluorescence kinetics. Contents of REEs in the lamina and the root of D. dichotoma were higher than those in soils, and were mainly distributed in lamina. A part of them was found in the chloroplast. By comparing with D. dichotoma from NM area, the efficiency of photosystem 2 photochemistry and electron transport rate were significantly enhanced in lamina of the plant from LRM because most of REEs deposits were distributed along cell wall, in vacuole, and in chloroplast. High contents of REEs in lamina did not decrease the photosynthetic activities in LRM plants of D. dichotoma. Besides, D. dichotoma could change its β-carotene content to avoid the damaging effect of high REEs content. and L. F. Wang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1943. Photothermal spectra of thylakoids isolated from cucumber cotyledons at various stages of greening
- Creator:
- Waloszek, A., Więckowski, S., Planner, A., Boguta, A., and Frąckowiak, D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Cucumis sativus, laser-induced optoacoustic spectra, and photoacoustic steady state spectra
- Language:
- Multiple languages
- Description:
- The character of interaction between carotenoids (Cars) and chlorophylls (Chls) in thylakoids isolated from cucumber cotyledons at three stages of greening (3, 6, and 24 h of irradiation with 120 µmol m-2 s-1) was studied. The shapes of the steady state photoacoustic spectra were changed with the change in time of greening and with the frequency of radiation modulation. The shapes show that changes not only in the contents of various pigments but also in pigment interactions with surrounding occur and that processes of thermal deactivation characterised by different kinetics take place. Slow processes of thermal deactivation are in most cases due to deactivation of triplet states. Long living triplet states are very often engaged in photochemical reactions that can destroy the tissue. Analysis of the time-resolved photothermal spectra shows that at later stage of greening, the chlorophyll (Chl) molecules are better shielded against photo-destruction because Cars more efficiently quench their triplet states. The yield of formation of the pigment triplet states measured by the time resolved photothermal method, always at the same energy absorbed by pigment mixture, declined during sample greening. The decay time of the slow component of pigment thermal deactivation, due predominantly to deactivation of the triplet state of Chl, decreases with the increase of time of greening from 6.2 µs for the 3-h sample to 1.5 µs for the 24 h sample. The energy taken by Cars from Chls is dissipated into heat, therefore the steady state and quick thermal deactivation values increased during the greening process. The Cars/Chls ratio in the thylakoids decreased during greening approximately 2 fold. Hence at a later phase of greening the Cars can quench the triplet states of Chls more efficiently than at an earlier phase of greening. and A. Waloszek ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1944. Phycobilisome from Anabaena variabilis Kütz. and its model conjugates
- Creator:
- Zhao, Jiquan, Zhao, Jingquan, Zhang, Jingmin, and Jiang, Lijin
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- allophycocyanin, dithiothreitol, energy transfer, N-succinimidyl-3-(2-pyridyldithio)propionate, phycocyanin, phycoerythrocyanin, and rod-core complex (αβ)6PCLRC27 (αβ)3APCLC8.9
- Language:
- Multiple languages
- Description:
- The model conjugates phycocyanin-allophycocyanin (C-PC-APC) and phycoerythrocyanin-phycocyanin-allophycocyanin (PEC-C-PC-APC) were synthesized by using a heterobifunctional coupling reagent N-succinimidyl-3-(2-pyridyldithio)propionate. The rod-core complex (αβ)6 PCLRC 27(αβ)3 APCLC 8.9 and phycobilisomes were separated from Anabaena variabilis. Energy transfer features for the conjugates and the complexes were compared. The absorption and fluorescence emission spectra indicated that the linker-peptides mediate interaction of phycobiliproteins and prompt energy transfer. The energy transfer in the conjugates was detected by fluorescence emission spectra and confirmed by the addition of dithiothreitol. The conjugates may be used as models for studying the energy transfer mechanism in phycobilisomes. and Jiquan Zhao ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1945. Physio-anatomical responses of tobacco under caffeine stress
- Creator:
- Alkhatib, R., Alkhatib, B., Al-Eitan, L., Abdo, N., Tadros, M., and Bsoul, E.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chloroplasty, chloroplasts, photosynthetic rate, stomatal conductance, 2, and 581
- Language:
- Multiple languages
- Description:
- Caffeine, a purine alkaloid, is reported to act both as an inducer or inhibitor to plant growth in various species. The aim of this study was to examine the effect of exogenous caffeine on tobacco (Nicotiana tabacum) plants, a plant that does not naturally synthesise caffeine. A hydroponic experiment was carried out in a growth chamber for 14 d using Hoagland’s solution supplemented with 0 (control), 25, 50, 100, 1,000; and 5,000 μM caffeine. None of the investigated caffeine concentrations significantly decreased the net photosynthetic rate except the highest concentrations of 1,000 and 5,000 μM. Light microscopy of thick-sectioned roots showed that 1,000 μM and 5,000 μM caffeine-treated plants possessed deformed epidermal cells, reduced number of cortical cells, and deformed vascular tissues with cells exhibiting thickened xylem walls as compared with control plants. Moreover, transmission electron micrographs of roots revealed that mitochondria and the plasma membrane were affected., R. Alkhatib, B. Alkhatib, L. Al-Eitan, N. Abdo, M. Tadros, E. Bsoul., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1946. Physiological and biochemical responses of roadside trees grown under different urban environmental conditions in Seoul
- Creator:
- You, H. N., Woo, S. Y., and Park, C. R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, urban forest, urban air pollution, antioxidant, pigments, transpiration, 2, and 581
- Language:
- Multiple languages
- Description:
- The present study revealed that Ginkgo biloba and Platanus occidentalis, the most abundant roadside trees in Seoul, grown under polluted environmental conditions, displayed lower contents of total chlorophyll (Chl), carotenoids (Car), and ascorbic acid (AsA) compared to the trees grown under clean conditions. The reduction in Chl, Car, and AsA contents was 59, 53, and 50%, respectively, in G. biloba, contrary to 26, 23, and 24%, respectively, in P. occidentalis. Furthermore, relative ion leakage and leaf temperature was higher in the trees grown under polluted conditions than in those grown under clean conditions. The increase in relative ion leakage and leaf temperature was 58 and 3% for G. biloba and 17 and 4% for P. occidentalis, respectively. Our results, therefore, highlighted the negative impact of urban environmental pollution on the physiological and biochemical parameters in roadside trees., H. N. You, S. Y. Woo, C. R. Park., and Seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1947. Physiological and biochemical responses of Theobroma cacao L. genotypes to flooding
- Creator:
- Bertolde, F. Z., Almeida, A.-A. F., Pirovani, C. P., Gomes, F. P., Ahnert, D., Baligar, V. C., and Valle, R. R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, 2, and 58
- Language:
- Multiple languages
- Description:
- Flooding is common in lowlands and areas with high rainfall or excessive irrigation. A major effect of flooding is the deprivation of O2 in the root zone, which affects several biochemical and morphophysiological plant processes. The objective of this study was to elucidate biochemical and physiological characteristics associated with tolerance to O2 deficiency in two clonal cacao genotypes. The experiment was conducted in a greenhouse with two contrasting clones differing in flood tolerance: TSA-792 (tolerant) and TSH-774 (susceptible). Leaf gas exchange, chlorophyll (Chl) fluorescence, chemical composition and oxidative stress were assessed during 40 d for control and flooded plants. Flooding induced a decrease in net photosynthesis, stomatal conductance and transpiration of both genotypes. In flood conditions, the flood-susceptible clone showed changes in chlorophyll fluorescence, reductions in chlorophyll content and increased activity of peroxidase and polyphenol oxidase. Flooding also caused changes in macro- and micronutrients, total soluble sugars and starch concentrations in different plant organs of both genotypes. Response curves for the relationship between photosynthetically active radiation (PAR) and net photosynthetic rate (PN) for flooded plants were similar for both genotypes. In flood conditions, the flood-susceptible clone exhibited (1) nonstomatal limitations to photosynthesis since decreased in maximum potential quantum yield of PSII (Fv/Fm) values indicated possible damage to the PSII light-harvesting complex; (2) oxidative stress; (3) increased leaf chlorosis; and (4) a reduction in root carbohydrate levels. These stresses resulted in death of several plants after 30 d of flooding., F. Z. Bertolde ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1948. Physiological and biochemical responses of two tree species in urban areas to different air pollution levels
- Creator:
- Baek, S. G. and Woo, S. Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, antioxidant enzyme, chlorophyll content, chloroplasts, photosynthetic rate, and plastoglobuli
- Language:
- Multiple languages
- Description:
- We investigated the physiological and biochemical differences in Pterocarpus indicus and Erythrina orientalis grown in four sites at different pollution levels in the Philippines: Makati, Pasig and Quezon (high pollution levels; HP) located in Metro Manila, and La Mesa Watershed (a non-polluted area; NP). Among these four areas, HP sites had higher net photosynthetic rates (PN) than NP sites, except for Makati. Among HP sites, Makati and Quezon had the lowest PN for P. indicus and E. orientalis, respectively. Chlorophyll (Chl) contents were significantly lower in HP than in NP sites. Trees in Makati had the lowest Chl contents among HP sites, and P. indicus had higher Chl contents than did E. orientalis. In addition, the chloroplasts in HP trees had small starch grains with numerous dark, large plastoglobuli. Furthermore, antioxidant enzymes, indicative of the defense mechanism, showed a significantly higher activity in HP than in NP trees. and S. G. Baek, S. Y. Woo.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1949. Physiological and biochemical responses to saline-alkaline stress in two halophytic grass species with different photosynthetic pathways
- Creator:
- Guo, C. Y., Wang, X. Z., Chen, L., Ma, L. N., and Wang, R. Z.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- trávy, photosynthesis, grasses, Čína, China, ATP content, gas exchange, membrane permeability, Na2CO3 stress, salinity, Puccinellia tenuiflora, Chloris virgata, proline, 2, and 581
- Language:
- Multiple languages
- Description:
- We examined the physiological and biochemical responses of two halophytic grasses with different photosynthetic pathways, Puccinellia tenuiflora (C3) and Chloris virgata (C4), to saline-alkaline stresses. Plants were grown at different Na2CO3 concentrations (from 0 to 200 mM). Low Na2CO3 (< 12.5 mM) enhanced seed germination and plant growth, whereas high Na2CO3 concentrations (> 100 mM) reduced seed germination by 45% in P. tenuiflora and by 30% in C. virgata. Compared to C. virgata, P. tenuiflora showed lower net photosynthesis, stomatal conductance, intercellular CO2 concentration, and water-use efficiency under the same treatment. C. virgata exhibited also relatively higher ATP content, K+ concentration, and the K+/Na+ ratio under the stress treatments implying that salt tolerance may be the main mechanism for salt resistance in this species. Our results demonstrated that the C. virgata was relatively more resistant to saline-alkaline stress than the co-occurring P. tenuiflora; both two species adapt to their native saline-alkaline habitat by different physiological mechanisms., C. Y. Guo, X. Z. Wang, L. Chen, L. N. Ma, R. Z. Wang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1950. Physiological and morphological leaf trait variations in two Apennine plant species in response to different altitudes
- Creator:
- Gratani, L., Catoni, R., Pirone, G., Frattaroli, A. R., and Varone, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, gas exchange, leaf mass per unit of leaf area, mountain species, plasticity index, 2, and 58
- Language:
- Multiple languages
- Description:
- Morphological and physiological traits of Crepis pygmaea L. subsp. pygmaea and Isatis apennina Ten. ex Grande growing at different altitudes in the Gran Sasso Massif (Abruzzo, Italy) were analyzed. The two populations of C. pygmaea and I. apennina growing at the highest altitude (Cp2 and Ip2 at 2,310 m a.s.l. and 2,350 m a.s.l., respectively) had a lower leaf mass area (LMA) than the two populations growing at the lowest altitude (Cp1 and Ip1 at 2,250 m a.s.l. and 2,310 m a.s.l., respectively). Leaf tissue density (LTD) had the same LMA trend, decreasing 23 and 10% in C. pygmaea and I. apennina, respectively, from the highest to the lowest altitude. C. pygmaea and I. apennina had the highest photosynthetic rates (PN) in July decreasing on an average 17 and 30%, respectively, in August and 50 and 38%, respectively, in September. Leaf respiration (R) in Ip1 and Ip2 had the same trend as Cp1 and Cp2, showing the highest rates in September. Global warming could drive C. pygmaea and I. apennina toward higher altitudes in the Gran Sasso Massif. Nevertheless, C. pygmaea with the higher plasticity index (PI) both at physiological and at morphological levels (0.50 and 0.35, respectively) might have a competitive advantage over I. apennina over the long term., L. Gratani ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public