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1072. Effects of reduced irradiance on leaf morphology, photosynthetic capacity, and fruit yield in olive (Olea europaea L.)
- Creator:
- Gregoriou, K., Pontikis, K., and Vemmos, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- areal leaf mass, chlorophyll, chloroplasts, fruit yield, leaf anatomy, net photosynthetic rate, shade, stomata, and trichomes
- Language:
- Multiple languages
- Description:
- One-year-old olive trees (cv. Koroneiki) were grown in plastic containers of 50 000 cm3 under full daylight and 30, 60, and 90 % shade for two years. The effects of shade on leaf morphology and anatomy, including stomatal density and chloroplast structure, net photosynthetic rate (PN), stomatal conductance (gs), and fruit yield were studied. Shade reduced leaf thickness due to the presence of only 1-2 palisade layers and reduced the length of palisade cells and spongy parenchyma. The number of thylakoids in grana as well as in stroma increased as shade increased, while the number of plastoglobuli decreased in proportion to the reduced photosynthetically active radiation (PAR). The higher the level of shade, the lower the stomatal and trichome density, leaf mass per area (ALM), gs, and PN. Shade of 30, 60, and 90 % reduced stomatal density by 7, 16, and 27 %, respectively, while the corresponding reduction in PN was 21, 35, and 67 %. In contrast, chlorophyll a+b per fresh mass, and leaf width, length, and particularly area increased under the same shade levels (by 16, 33, and 81 % in leaf area). PN reduction was due both to a decrease in PAR and to the morphological changes in leaves. The effect of shade was more severe on fruit yield per tree (32, 67, and 84 %) than on PN indicating an effect on bud differentiation and fruit set. The olive tree adapts well to shade compared with other fruit trees by a small reduction in stomatal and trichome density, palisade parenchyma, and a significant increase in leaf area. and K. Gregoriou, K. Pontikis, S. Vemmos.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1073. Effects of rhizobia inoculation and nitrogen fertilization on photosynthetic physiology of soybean
- Creator:
- Zhou, X.-J., Liang, Y., Chen, H., Shen, S.-H., and Jing, Y.-X.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- biological nitrogen fixation, biomass, carboxylation efficiency, carotenoids, chlorophyll fluorescence, Glycine max, intercellular CO2 concentration, leaf area, stomatal conductance, and quantum yield
- Language:
- Multiple languages
- Description:
- Plant growth, contents of photosynthetic pigments, photosynthetic gas exchange, and chlorophyll (Chl) fluorescence in soybean [Glycine max (L.) Merr. cv. Heinong37] were investigated after it was inoculated with Sinorhizobium fredii USDA191 or treated with 5 mM (NH4)2SO4 (N5) and 30 mM (NH4)2SO4 (N30), respectively. In the plants following N5 fertilization, not only plant biomass, leaf area, and Chl content, but also net photosynthetic rate (PN), stomatal conductance (gs), carboxylation efficiency (CE), maximum photochemical efficiency (Fv/Fm) of photosystem 2 (PS2), and quantum yield of PS2 (ΦPS2) were markedly improved as compared with the control plants. There were also positive effects on plant growth and plant photosynthesis after rhizobia inoculation, but the effects were much less than those of N5 fertilization. For N30 plants there were no significant positive effects on plant growth and photosynthetic capacity. Plant biomass, PN, and gs were similar to those of N-limited (control) plants. ΦPS2 and photochemical quenching (qP) were obviously declined while content of carotenoids and non-photochemical quenching (qN) were significantly enhanced in N30 treated plants. This indicated that excess N supply may cause some negative effects on soybean plants. and X.-J. Zhou ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1074. Effects of root temperature on leaf gas exchange and xylem sap abscisic acid concentrations in six Cucurbitaceae species
- Creator:
- Zhang, Y. P., Qiao, Y. X., Zhang, Y. L., Zhou, Y. H., and Yu, J. Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- adaptation, CO2 assimilation, photosystem 2 photochemistry, photosynthesis, and stomatal behaviour
- Language:
- Multiple languages
- Description:
- Roots of six Cucurbitaceae species were exposed to low (14 °C), middle (24 °C), and high (34 °C) temperatures while aerial parts of plants were maintained at ambient temperatures between 23 and 33 °C. The highest dry mass (DM), photon-saturated rate of net photosynthesis (PNsat), and stomatal conductance (gs) were found at 14 °C in figleaf gourd and turban squash plants, at 24 °C in cucumber and melon plants, while bitter melon and wax gourd plants had lower DM, PNsat, and gs at 14 °C than at 24 or 34 °C. Sub-or supra-optimum root temperatures did not induce photoinhibition but induced slight changes in the quantum efficiency of photosystem 2, PS2 (ΦPS2) and photochemical quenching (qp). Meanwhile, xylem sap abscisic acid (ABA) concentration followed a contrasting change pattern to that of gs. Thus the change in PNsat was mainly due to the change in gs and roots played an important role in the regulation of stomatal behaviour by delivering increased amount of ABA to shoots at sub-or supra-optimum root temperatures. and Y. P. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1075. Effects of salinity on chlorophyll fluorescence and CO2 fixation in C4 estuarine grasses
- Creator:
- Maricle, B. R., Lee, R. W., Hellquist, C. E., Kiirats, O., and Edwards, G. E.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Distichlis spicata, gas exchange, net photosynthesis rate, salt stress, Spartina species, species differences, and stomatal conductance
- Language:
- Multiple languages
- Description:
- The effects of salinity (sea water at 0 ‰ versus 30 ‰) on gross rates of O2 evolution (JO2) and net rates of CO2 uptake (PN) were measured in the halotolerant estuarine C4 grasses Spartina patens, S. alterniflora, S. densiflora, and Distichlis spicata in controlled growth environments. Under high irradiance, salinity had no significant effect on the intercellular to ambient CO2 concentration ratio (Ci/Ca). However, during photosynthesis under limiting irradiance, the maximum quantum efficiency of CO2 fixation decreased under salinity across species, suggesting there is increased leakage of the CO2 delivered to the bundle sheath cells by the C4 pump. Growth under salinity did not affect the maximum intrinsic efficiency of photosystem 2, PS2 (FV/FM) in these species, suggesting salinity had no effect on photosynthesis by inactivation of PS2 reaction centers. Under saline conditions and high irradiance, PN was reduced by 75 % in Spartina patens and S. alterniflora, whereas salinity had no effect on PN in S. densiflora or D. spicata. This inhibition of PN in S. patens and S. alterniflora was not due to an effect on stomatal conductance since the ratio of Ci/Ca did not decrease under saline conditions. In growth with and without salt, PN was saturated at -500 µmol(quantum) m-2 s-1 while JO2 continued to increase up to full sunlight, indicating that carbon assimilation was not tightly coupled to photochemistry in these halophytic species. This increase in alternative electron flow under high irradiance might be an inherent function in these halophytes for dissipating excess energy. and B. R. Maricle ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1076. Effects of salinity on chlorophyll fluorescence and photosynthesis of barley (Hordeum vulgare L.) grown under a triple-line-source sprinkler system in the field
- Creator:
- Belkhodja, R., Morales, F., Abadía, A., Medrano, H., and Abadía, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, cultivar differences, photosystem 2 efficiency, stomatal conductance and frequency, and transpiration rate
- Language:
- Multiple languages
- Description:
- In flag leaves of four cultivars of barley (Hordeum vulgare L.) grown in the field under a triple-line-source sprinkler system, that produces a linear soil salinity gradient, a decrease in net carbon dioxide assimilation rate (PN) and stomatal conductance for water vapour (gs) was found. These changes were related to salinity tolerance at moderate salinity. With increasing salinity, PN was saturated at low irradiances and stomatal frequencies increased. A decrease in photosystem 2 (PS2) efficiency was not found in the field after dark adaptation even at high salinity. Salinity induced only small decreases in the actual PS2 efficiency at midday steady-state photosynthesis, indicating that the photosynthetic electron transport was little affected by salinity. Therefore, using PS2 efficiency estimates in attached leaves is probably not a useful tool to screen barley genotypes grown under saline conditions in the field for salinity tolerance. In contrast, excised flag leaves from high salinity plots, once in the laboratory, exhibited a decrease in the variable to maximum chlorophyll fluorescence ratio as compared to excised leaves from control plants. On the other hand, the PN rate might allow for a good discrimination between tolerant and non-tolerant cultivars. and R. Belkhodja ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1077. Effects of salinity on temperature-dependent photosynthetic parameters of a native C3 and a non-native C4 marsh grass in the Yangtze Estuary, China
- Creator:
- Ge, Z.-M., Zhang, L.-Q., Yuan, L., and Zhang, C.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, Čína, China, carboxylation efficiency, coastal wetlands, gas exchange, invasive species, marsh grass, Yangtze Estuary, 2, and 581
- Language:
- Multiple languages
- Description:
- The invasion of Spartina alterniflora along the coasts of China has allowed this C4 grass to outcompete often much of the native, salt marsh vegetation, such as Phragmites australis (C3 grass), in the Yangtze Estuary. In this study, native grass, P. australis, and non-native grass, S. alterniflora, were grown in fresh and saline water (moderate salinity of 15‰ and high salinity of 30‰) to compare the effects of salinity on photosynthetic and biochemical parameters in combination with measurement temperatures. The C4 grass, S. alterniflora, showed a greater CO2 assimilation rate than P. australis, across the tested temperatures. The net photosynthetic rate declined significantly with increasing salinity as a result of inhibited stomatal conductance together with a greater decrease in the maximum rate of electron transport (Jmax). In P. australis, salt treatments shifted the optimum temperatures for the maximum rate of carboxylation by Rubisco (Vcmax) and J max to lower temperatures. S. alterniflora showed a greater salt tolerance to moderate stress than that of the native grass, with lower sensitivity of V cmax, Jmax, and the maximum rate of phosphoenolpyruvate carboxylation. Both moderate and high stress decreased significantly stomatal conductance of S. alterniflora; high salinity reduced significantly photosynthetic efficiency and Jmax. Our findings indicated that the combination of stomatal conductance, enzyme activity, and electron transport affected the photosynthetic performance of the plants in response to salt treatments. The success of S. alterniflora could be probably attributed to its C4 photosynthetic pathway and the tolerance to moderate salinity. In this study, a modified parameterization of the photosynthetic model was suggested to support a more reasonable simulation of photosynthesis under salt stress., Z.-M. Ge, L.-Q. Zhang, L. Yuan, C. Zhang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1078. Effects of salt stress on basic processes of photosynthesis
- Creator:
- Sudhir, P. and Murthy, S. D. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carboxylases, carotenoids, chlorophyll, cyanobacteria, electron transport, eukaryotic algae, NaCl, photophosphorylation, photosynthetic rate, photosystems, phycobiliproteins, and salt tolerance
- Language:
- Multiple languages
- Description:
- Salt stress causes decrease in plant growth and productivity by disrupting physiological processes, especially photosynthesis. The accumulation of intracellular sodium ions at salt stress changes the ratio of K : Na, which seems to affect the bioenergetic processes of photosynthesis. Both multiple inhibitory effects of salt stress on photosynthesis and possible salt stress tolerance mechanisms in cyanobacteria and plants are reviewed. and P. Sudhir, S. D. S. Murthy.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1079. Effects of salt stress on growth, photosynthesis and solute accumulation in three poplar cultivars
- Creator:
- Chen, W., Zhou, D., Guo, W., Xu, H., Shi, D., and Yang, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- growth, photosynthesis, poplar, salt stress, and solute accumulation
- Language:
- Multiple languages
- Description:
- This study compared the effects of salt (NaCl) stress on growth, photosynthesis and solute accumulation in seedlings of the three poplar (Populus bonatii) cultivars Populus × BaiLin-2 (BL-2), Populus × BaiLin-3 (BL-3), and Populus × Xjiajiali (XJJL). The results showed that BL-2 and BL-3 could not survive at a salinity level of 200 mM but XJJL grew well. The effect of moderate salt stress on leaf extension of the three cultivars was only slight. At a high level of salinity, however, NaCl clearly inhibited leaf extension of BL-2 and BL-3, whereas it did not affect that of XJJL, and the net photosynthetic rate (PN) in XJJL was much higher than those of BL-2 and BL-3. The lower PN of BL-2 and BL-3 might be associated with the high concentration of Na+ and/or Cl- accumulated in the leaves, which could be toxic in photosynthesis system. In summary, the greater salt-tolerance of XJJL compared with that of BL-2 and BL-3 might be explained by the higher PN and photosynthetic area, the lower Na+/K- ratio and Cl- in the leaf, and the greater accumulation of soluble sugars and SO4 2-. and W. Chen ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1080. Effects of salt stress on low molecular antioxidants and redox state of plastoquinone and P700 in Arabidopsis thaliana (glycophyte) and Eutrema salsugineum (halophyte)
- Creator:
- Wiciarz, M., Niewiadomska, E., and Kruk, J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- chloroplasty, oxidační stres, chloroplasts, oxidative stress, fotosystémy, salinita, photosystems, salinity, 2, and 581
- Language:
- Multiple languages
- Description:
- The effects of NaCl treatment were analysed in two species of considerably different resistance. In glycophyte, the content of ascorbate decreased but lipophilic antioxidants (α-tocopherol, plastochromanol, and hydroxy-plastochromanol) increased due to 150 mM NaCl. In halophyte, 300 mM NaCl caused a significant increase in hydrophilic antioxidants (ascorbate, total glutathione) but not in the lipophilic antioxidants. The redox states of plastoquinone (PQ) and P700 were also differently modulated by salinity in both species, as illustrated by an increased oxidation of these components in glycophyte. The presented data suggest that E. salsugineum was able to avoid a harmful singlet oxygen production at PSII, which might be, at least in part, attributed to the induction of the ascorbate-glutathione cycle. Another important cue of a high salinity resistance of this species might be the ability to sustain a highly reduced states of PQ pool and P700 under stress, which however, drastically affect the NADPH yield., M. Wiciarz, E. Niewiadomska, J. Kruk., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public