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32. Changes in chloroplast morphology of different parenchyma cells in leaves of Haberlea rhodopensis Friv. during desiccation and following rehydration

Creator:
Nagy-Déri, H., Péli, E. R., Georgieva, K., and Tuba, Z.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chloroplast, dessication tolerance, homoiochlorophyllous, mesophyll, palisade parenchyma, and spongy parenchyma
Language:
Multiple languages
Description:
The size, shape, and number of chloroplasts in the palisade and spongy parenchyma layers of Haberlea rhodopensis leaves changed significantly during desiccation and following rehydration. The chloroplasts became smaller and more rounded during desiccation, and aggregated in the middle of the cell. The size and number of chloroplasts in the palisade parenchyma cells were higher than in spongy parenchyma. The good correlation observed between the size or number of chloroplasts and the cross-sectional area of mesophyll cells, the cross-sectional width of the leaf and its water content suggested that the palisade cells were more responsive to water availability than the spongy cells. Changes in chloroplast number during desiccation and rehydration process are characteristic features for desiccation-tolerant plants (especially in homoiochlorophyllous strategy). and H. Nagy-Déri ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

33. Changes in photosynthesis, fluorescence, and nitrogen metabolism of hawthorn (Crataegus pinnatifida) in response to exogenous glutamic acid

Creator:
Yu, C., Lv, D. G. , Qin, S. J., Yang, L., Ma, H. Y., and Liu, G. C.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chlorophyll fluorescence, glutamine synthetase, leaf nitrogen content, net photosynthetic rate, nitrate reductase, soluble protein content, stomatal conductance, and transpiration rate
Language:
Multiple languages
Description:
Photosynthesis, chlorophyll (Chl) a fluorescence, and nitrogen metabolism of hawthorn (Crataegus pinnatifida Bge.), subjected to exogenous L-glutamic acid (GLA) (200 mg l-1, 400 mg l-1, and 800 mg l-1) that possibly affect secondary metabolic regulation, were measured. The results indicated that photosynthetic and fluorescence characteristics of hawthorn exhibited positive responses to the application of GLA. Different concentrations of GLA caused an increase in Chl content, net photosynthetic rate (PN) and stomatal conductance (g s) as well as transpiration rate (E), and improved the carboxylation efficiency (CE), apparent quantum yield (AQY) and maximum carboxylation velocity of Rubisco (Vcmax). Application of GLA could also enhance the maximum ratio of quantum yields of photochemical and concurrent non-photochemical processes in PSII (Fv/F0), the maximal quantum yield of PSII (Fv/Fm), the probability that an absorbed photon will move an electron into the electron transport chain beyond QA (ΦEo) as well as the performance index on absorption basis (PIABS), but decreased the intercellular CO2 concentration (Ci) and the minimal fluorescence (F0). Application of GLA also induced an increase in nitrate reductase (NR; EC 1.6.6.1) and glutamine synthetase (GS; EC 6.3.1.2) activities, and increased the soluble protein content, leaf nitrogen (N) content and N accumulation in leaves as well as the plant biomass. However, the effects were different among different concentrations of GLA, and 800 mg l-1 GLA was better. This finding suggested that application of GLA is recommended to improve the photosynthetic capacity by increasing the light energy conversion and CO2 transfer as well as the photochemical efficiency of PSII, and enhanced the nitrogen metabolism and growth and development of plants. and C. YU ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

34. 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

35. 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

36. Changes in the photosynthetic characteristics and photosystem stoichiometries in wild-type and Chl b-deficient mutant rice seedlings under various irradiances

Creator:
Yamazaki, J.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, antenna size, Cl b-deficient mutant, photosystem stoichiometry, PSII heterogeneity, and rice (Oryza sativa L.)
Language:
Multiple languages
Description:
By using a wild-type rice (Oryza sativa L. cv. Norin No. 8) and the chlorophyll (Chl) b-deficient mutant derived from Norin No. 8 (chlorina 11), the present study monitored the oxygen evolution, contents of Chl a and b, β-carotene, and lutein in leaf and the contents of cytochrome f, and the reaction centres of photosystem I (PSI) and photosystem II (PSII) in thylakoids. The oxygen evolution, maximal quantum yield of PSII (Fv/Fm) and Chl concentration remained constant in both Norin No. 8 and chlorina 11 under 5 and 2% of full sunlight for six days. On the other hand, on the thylakoid level, the PSII reaction centre of chlorina 11 was more stable even under high irradiance, while approximately 40% decrease in levels of the PSII reaction centre occurred under 2% of full sunlight for six days. However, under such conditions, by regulating the stoichiometry of active PSII and PSI centres, the light absorption balance in both rice types was adjusted between the two photosystems. The present study attempted to examine whether the light absorption balance between PSII and PSI is altered to effectively conduct photosynthesis in the wild-type and Chl b-deficient mutant rice seedlings. and J. Yamazaki.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

37. Changes of the photosynthetic behaviour in annual C3 species at late successional stage under environmental drought conditions

Creator:
Karatassiou, M. and Noitsakis, B.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, instaneous water-use efficiency, intrinsic water-use efficiency, net photosynthetic rate, stomatal conductance, and water stress
Language:
Multiple languages
Description:
Differences in structural, physiological, and biochemical features between C3 and C4 species resulted in different wateruse efficiencies and different adaptations to climate. This paper aimed at investigating, at a late successional stage, the water-use efficiency of two forage species, Dichanthium ischaemum and Dasypyrum villosum, which exhibit different growth forms (perenial, annual) and photosynthetic mechanisms (C4 and C3, respectively). The annual C3 species Avena fatua, at an early successional stage, was included in our experiments to contrast its behaviour against D. villosum. The experiment was conducted during the growing season in low-elevation grasslands of North Greece. Midday leaf water potential, net photosynthetic rate, transpiration rate and stomatal conductance were measured. Instantaneous water-use efficiency (WUE) and intrinsic water-use efficiency (WUEi) were calculated in D. ischaemum, D. villosum, and A. fatua. The results suggest that, under natural rainfall conditions, the annual C3 grass species D. villosum exhibits a similar WUE with higher values of WUEi than the perennial C4 species D. ischaemum at late stage of succession on the low elevation Mediterranean grasslands. Moreover, A. fatua at an early successional stage, exhibited different photosynthetic behaviour than D. villosum at a late successional stage. These findings indicate that the annual C3 species D. villosum under drought and at a late successional stage seems to modify the WUE obtaining values similar to those of C4 species. The extent to which the ecophysiological characteristics of D. villosum are environmentally or intrinsically determined remains to be answered. and M. Karatassiou, B. Noitsakis.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

38. Characteristics of sun- and shade-adapted populations of an endangered plant Primulina tabacum Hance

Creator:
Liang, K. M., Lin, Z. F., Ren, H., Liu, N., Zhang, Q. M., Wang, J., Wang, Z. F., and Guan, L. L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, cave microenvironment, chloroplast ultrastructure, ecophysiological trait, light adaptation, morphological structure, and Primulina tabacum Hance
Language:
Multiple languages
Description:
Primulina tabacum Hance is an endangered perennial herb distributed in calcium-rich and nitrogen-limited soil of the karst limestone areas in southern China. The morphological, ultrastructural, and physiological traits were determined for P. tabacum populations growing in three different environment conditions: twilight zone of a cave (site TZ, extremely low light intensity), at a cave entrance (site EZ, low light intensity), and in an open area (site OA, high light intensity). At site OA, P. tabacum plants were exposed to high light (635 μmol m-2 s-1 of mean daily photosynthetically active radiation) with drought stress, and expressed traits to minimize light capture and water loss. Compared to plants at sites EZ and TZ, those at site OA had thicker leaves with higher densities of stomata and pubescence, higher palisade/spongy ratio, higher light-saturated rate of net photosynthetic rate (Pmax), higher biomass, higher non-photochemical quenching coefficient (NPQ), and higher light saturation point (LSP) but fewer grana per chloroplast and less thylakoid stacking per granum. In contrast, P. tabacum growing at the cave vicinities: EZ (mean daily irradiance 59 μmol m-2 s-1) and TZ (mean daily irradiance 11 μmol m-2 s-1) showed typical shade-adapted characteristics for optimum light capture. The presence of sun- and shade-adapted characteristics indicates that P. tabacum has different strategies to cope with different environments but whether these strategies reflect genetic selection or phenological plasticity is yet to be determined. Such variability in physiological and morphological traits is important for the survival of P. tabacum in heterogeneous light conditions. and K. M. Liang ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

39. 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

40. Chill-induced inhibition of photosynthesis was alleviated by 24-epibrassinolide pretreatment in cucumber during chilling and subsequent recovery

Creator:
Hu, W. H., Wu, Y., Zeng, J. Z., He, L., and Zeng, Q. M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, antioxidant enzymes, brassinosteroids, chlorophyll fluorescence, cfhilling stress, Cucumis sativau L., photosynthesis, and reactive oxygen species
Language:
Multiple languages
Description:
To investigate whether brassinosteroids (BRs) could be used to alleviate chill-induced inhibition of photosynthesis in cucumber (Cucumis sativus L) during chilling and subsequent recovery, the effects of exogenously applied 24-epibrassinolide (EBR) on gas exchange, chlorophyll fluorescence parameters, and antioxidant enzyme activity were studied. Cucumber plants were exposed to chilling under low light (12/8°C and 100 μmol m-2 s-1 PPFD) for 3 days and then recovered under normal temperature and high irradiance (28/18°C and 600 μmol m-2 s-1 PPFD) for 6 days. Chilling significantly decreased the net photosynthetic rate (PN) and stomatal conductance (g s), and increased rate of O2 .- formation and H2O2 and malondialdehyde (MDA) content in cucumber leaves, but did not influence the optimal quantum yield of PSII (Fv/Fm). Chilling also decreased the effective quantum yield of PSII photochemistry (ΦPSII) and photochemical quenching (qP), but induced an increase in nonphotochemical quenching (NPQ), and the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). High irradiance (600 μmol m-2 s-1) further aggravated the decrease in PN, gs, ΦPSII and qP, and enhanced the increase in reactive oxygen species (ROS) generation and accumulation in the first day of recovery after chilling. However, high irradiance induced a sharp decrease in Fv/Fm and NPQ, as well as the activities of SOD and APX on the first day of recovery. EBR pretreatment significantly alleviated chill-induced inhibition of photosynthesis during chilling stress and subsequent recovery period, which was mainly due to significant increases in gs, ΦPSII, qP and NPQ. EBR pretreatment also reduced ROS generation and accumulation, and increased the activities of SOD and APX during chilling and subsequent recovery. Those results suggest that EBR pretreatment alleviates the chill reduction in photosynthesis and accelerated the recovery rate mainly by increasing of the stomatal conductance, the efficiency of utilization and dissipation of leaf absorbed light, and the activity of the ROS scavenging system during chilling and subsequent recovery period. and W. H. Hu ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public