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282. Response of photosynthesis of Pisum sativum to salt stress as affected by methyl jasmonate
- Creator:
- Velitchkova, M. and Fedina, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, Cl, Na, NaCl, pea, proline, relative water content, ribulose-1,5-bisphosphate carboxylase/oxygenase, and salt stress
- Language:
- Multiple languages
- Description:
- 10-5 M methyl jasmonate (JA-Me) treatment itself did not considerably change the 14CO2 fixation, parameters of room temperature chlorophyll fluorescence induction, proline content, and Na+ as well as Cl- accumulation. Salt stress (30 mM NaCl) lead to a decrease of both 14CO2 fixation and relative water content, and to an increase of proline content. Immediate nonvariable fluorescence (F0) also increased and the variable to maximal fluorescence ratio (Fv/Fm) decreased. Pretreatment with JA-Me for 3 d before salt treatment diminished the inhibitory effect of NaCl on the rate of 14CO2 fixation, protein content, and activity and content of ribulose-1,5-bisophosphate carboxylase/oxygenase. The Na+ and Cl- contents in leaves decreased in JA-Me pretreated plants. The JA-Me pretreatment prevented the increase of F0 level and restored the values of Fv/Fm. and M. Velitchkova, I. Fedina.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
283. Response of photosynthesis to short-term drought stress in rice seedlings overexpressing C4 phosphoenolpyruvate carboxylase from maize and millet
- Creator:
- Ding, Z. S., Sun, X. F., Huang, S. H., Zhou, B. Y., and Zhao, M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll, chlorophyll fluorescence, gas exchange, photoprotection, stomatal opening, 2, and 581
- Language:
- Multiple languages
- Description:
- Abiotic stresses induce phosphoenolpyruvate carboxylase (PEPC) expression in C3 plants which suggests PEPC function in plant adaptation to stresses. Here, we studied the response of photosynthesis to short-term drought stress in rice seedlings overexpressing C4 PEPC from maize and millet. The transgenic lines exhibited 1.2-5.5 fold of PEPC activities than the wild type before the treatment, while 1.5-8.5 fold after five or ten days of water deficit. Net photosynthetic rate (P N) declined less during the water stress and recovered more after rewatering in the transgenic lines. These changes were accompanied with changes in the stomatal conductance (g s). The lower decrease in P N and g s resulted in significantly higher intrinsic water use efficiency in the transgenic rice lines after ten days of water withdrawal. There were no significant differences between the wild type and transgenic lines in maximum photochemical efficiency of PSII and photochemical quenching. The nonphotochemical quenching and the quantum efficiency of PSII maintained both higher in transgenic lines than those in the wild type during drought stress. This indicated that the transgenic lines could dissipate more excess energy to heat to protect PSII. Our result suggested that the increased PEPC activities in rice could alleviate the decrease of photosynthesis during short-term drought stress., Z. S. Ding, X. F. Sun, S. H. Huang, B. Y. Zhou, M. Zhao., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
284. Response of photosystem II performance and antioxidant enzyme activities in stay-green wheat to cytokinin
- Creator:
- Yang, D. Q., Luo, Y. L., Dong, W. H., Yin, Y. P., Li, Y., and Wang, Z. L.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- růstový hormon, pšenice, growth hormone, wheat, chlorofylová fluorescence, výměna plynu, JIP test, index výkonnosti, peroxidáza, cytokininy, chlorophyll fluorescence, gas exchange, performance index, peroxidase, cytokinin, 2, and 581
- Language:
- Multiple languages
- Description:
- WN6 (a stay-green wheat cultivar) and JM20 (control) were used to evaluate the effects of exogenous cytokinin on photosynthetic capacity and antioxidant enzymes activities in flag leaves. Results showed that WN6 reached the higher grain mass, which was mainly due to the higher photosynthetic rate resulting from the higher maximal quantum yield of PSII photochemistry (ΦPSII) and probability that a trapped exaction transfers an electron into the electron transport chain beyond QA (Ψo), and lower relative variable fluorescence intensity at the J-step (Vj). Exogenous 6-benzylaminopurine (6-BA) enhanced antioxidant enzymes activities and decreased malondialdehyde (MDA) content. Enhanced Ψo and electron transport rate (ETR), and decreased Vj contributed to improved photosynthetic rate in the 6-BA treatment. In addition, exogenous 6-BA significantly increased endogenous zeatin (Zt) content, which was significantly and positively correlated with the antioxidant enzyme activity and ΦPSII, implying that higher Zt content was responsible for the improved antioxidant status and photosynthetic performance., D. Q. Yang, Y. L. Luo, W. H. Dong, Y. P. Yin, Y. Li, Z. L. Wang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
285. Response of spinach leaves (Spinacia oleracea L.) to ozone measured by gas exchange, chlorophyll a fluorescence, antioxidant systems, and lipid peroxidation
- Creator:
- Calatayud, A., Iglesias, D. J., Talón, M., and Barreno, E.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- antioxidant enzymes, ascorbate, chlorophyll fluorescence, intracelullar CO2 concentration, malondialdehyde, photosynthetic rate, quantum efficiency of photosystem 2, quenching, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Spinach (Spinacia oleracea L. cv. Clermont) leaves grown in open-top chambers and exposed to three different concentrations of ozone were measured for gas exchange, chlorophyll a fluorescence, antioxidant systems, and lipid peroxidation at the end of growing season. High O3 concentration reduced Fv/Fm, indicating that the efficiency in the energy conversion of photosystem 2 (PS2) was altered. The rate of non-cyclic electron transport rate and the capacity to reduce the quinone pool were also affected. The development of non-photochemical quenching was not high enough to decrease the photon excess in the PS2. The limitation of photosynthetic activity was probably correlated with stomata closure and with an increase in intercellular CO2 concentration. Under oxidative stress, superoxide dismutase (SOD) activity was stimulated in parallel with lipid peroxidation. We did not find any differences in the ascorbate (AsA) pool and ascorbate peroxidase (APX) or glutathione reductase (GR) activities between air qualities. Small, but similar responses were observed in spinach leaves exposed to ambient ozone concentration. and A. Calatayud ...[et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
286. Response of two tomato cultivars to field-applied proline under irrigation with saline water: growth, chlorophyll fluorescence and nutritional aspects
- Creator:
- Kahlaoui, B., Hachicha, M., Rejeb, S., Rejeb, M. N., Hanchi, B., and Misle, E.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, rajčata, photosynthesis, tomatoes, Tunisko, Rio Grande (Mexický záliv : řeka : oblast), Tunisia, Rio Grande River Valley (Colo.-Mexico and Tex.), chlorophyll fluorescence, foliar pulverization, proline, salt tolerance, salinity, Solanum lycopersicum, 2, and 581
- Language:
- Multiple languages
- Description:
- The response of tomato (Solanum lycopersicum L.) to abiotic stress has been widely investigated. Recent physiological studies focus on the use of osmoprotectants to ameliorate stress damage, but experiments at a field level are scarce. Two tomato cultivars were used for an experiment with saline water (6.57 dS m-1) and subsurface drip irrigation (SDI) in a silty clay soil. Rio Grande is a salinity-tolerant cultivar, while Heinz-2274 is the salt-sensitive cultivar. Exogenous application of proline was done by foliar spray at two concentrations (10 and 20 mg L-1) during the flowering stage. Control plants were treated with saline water without proline. Proline at the lower concentration (10 mg L-1) increased dry mass of different plant organs (leaves, stems, and roots) and it improved various chlorophyll a fluorescence parameters compared with controls. Regarding mineral nutrition, K+ and P were higher in different organs, while low accumulation of Na+ occurred. However, Mg2+ was very high in all tissues of Rio Grande at the higher concentration of proline applied. Thus, the foliar spray of proline at 10 mg L-1 increased the tolerance of both cultivars. The growth of aboveground biomass of Heinz-2274 was enhanced by 63.5%, while Rio Grande improved only by 38.9%., B. Kahlaoui, M. Hachicha, S. Rejeb, M. N. Rejeb, B. Hanchi, E. Misle., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
287. Responses of dominant desert species Artemisia ordosica and Salix psammophila to water stress
- Creator:
- Xiao, C. W., Zhou, G. S., Zhang, X. S., Zhao, J. Z., and Wu, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- biomass allocaton, chlorophyll fluorescence, gas exchange, morphology, specific leaf area, stomatal conductance, water supply, water use efficiency, and transpiration rate
- Language:
- Multiple languages
- Description:
- Morphology, biomass accumulation and allocation, gas exchange, and chlorophyll fluorescence were compared for one-year-old seedlings of Salix psammophila and Artemisia ordosica, two dominant desert species, in response to two water supplies (equivalent to 315.0 mm for present precipitation in growing season and to 157.5 mm for future decreasing precipitation) during 105 d. For both species, photochemical efficiency of photosystem 2 (Fv/Fm), net photosynthetic rate, transpiration rate, stomatal conductance, biomass accumulation in different organs, tree height, number of leaves, and leaf area were reduced in response to the decrease in water supply. For both species, instantaneous water use efficiency was not affected by the water deficit. However, diurnal patterns of gas exchange and biomass allocation were affected in different ways for the two species, with notably a decrease in specific leaf area and an increase in root : shoot ratio for S. psammophila only. Overall, S. psammophila was more responsive to the decreasing precipitation than A. ordosica. and C. W. Xiao ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
288. Responses of leaf photosynthesis, pigments and chlorophyll fluorescence within canopy position in a boreal grass (Phalaris arundinacea L.) to elevated temperature and CO2 under varying water regimes
- Creator:
- Ge, Z.-M., Zhou, X., Kellomäki, S., Wang, K.-Y., Peltola, H., and Martikainen, P. J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll fluorescence, CO2, layer position, photosynthesis, pigment, temperature, and water deficite
- Language:
- Multiple languages
- Description:
- The effects of elevated growth temperature (ambient + 3.5°C) and CO2 (700 μmol mol-1) on leaf photosynthesis, pigments and chlorophyll fluorescence of a boreal perennial grass (Phalaris arundinacea L.) under different water regimes (well watered to water shortage) were investigated. Layer-specific measurements were conducted on the top (younger leaf) and low (older leaf) canopy positions of the plants after anthesis. During the early development stages, elevated temperature enhanced the maximum rate of photosynthesis (Pmax) of the top layer leaves and the aboveground biomass, which resulted in earlier senescence and lower photosynthesis and biomass at the later periods. At the stage of plant maturity, the content of chlorophyll (Chl), leaf nitrogen (NL), and light response of effective photochemical efficiency (ΦPSII) and electron transport rate (ETR) was significantly lower under elevated temperature than ambient temperature in leaves at both layers. CO2 enrichment enhanced the photosynthesis but led to a decline of NL and Chl content, as well as lower fluorescence parameters of ΦPSII and ETR in leaves at both layers. In addition, the down-regulation by CO2 elevation was significant at the low canopy position. Regardless of climate treatment, the water shortage had a strongly negative effect on the photosynthesis, biomass growth, and fluorescence parameters, particularly in the leaves from the low canopy position. Elevated temperature exacerbated the impact of water shortage, while CO2 enrichment slightly alleviated the drought-induced adverse effects on P max. We suggest that the light response of ΦPSII and ETR, being more sensitive to leaf-age classes, reflect the photosynthetic responses to climatic treatments and drought stress better than the fluorescence parameters under dark adaptation. and Z.-M. Ge ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
289. Responses of nine bryophyte and one lichen species from different microhabitats to elevated UV-B radiation
- Creator:
- Csintalan, Z., Tuba, Z., Takács, Z., and Laitat, E.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, induction, desiccation tolerance, and fluorescence emission spectrum
- Language:
- Multiple languages
- Description:
- Chlorophyll fluorescence parameters (Fv/Fm, RFd) of nine bryophyte and one lichen species were investigated after prolonged exposure to elevated UV-B radiation. The majority of the investigated bryophytes showed a prompt or inducible tolerance to increase UV-B irradiation. Among the investigated species high degree of UV-tolerance coincides with strong desiccation tolerance. and Z. Csintalan ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
290. Responses of the Antarctic microalga Koliella antarctica (Trebouxiophyceae, Chlorophyta) to cadmium contamination
- Creator:
- La Rocca, N., Andreoli, C., Giacometti, G. M., Rascio, N., and Moro, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Antarctica, cadmium, chlorophyll fluorescence, Koliella antarctica, pollution effects, PSII activity, and ultrastructure
- Language:
- Multiple languages
- Description:
- Ultrastructural and physiological effects of exposure to 1 ppm and 5 ppm of cadmium (Cd) on cultured cells of Koliella antarctica, a green microalga from Antarctica, were investigated. The amount of Cd in the alga rose with the increase of the metal concentration in the growth medium and most Cd remained outside the cells, bound to the components of the cell walls. The increase of Cd in the microalga was concomitant with the decrease of other elements, mainly calcium (Ca). Exposure to 1 ppm Cd slowed culture growth by inhibiting cell division and also caused the development of some misshapen cells with chloroplast showing disordered thylakoids. However, this concentration did not substantially affect the chlorophyll (Chl) content or photosystem (PS) activity. At 5 ppm, Cd cell growth suddenly stopped and some cells lysed. After a week of Cd contamination, the cells were enlarged and severely damaged. The chloroplasts showed great ultrastructural alterations and a reduced Chl content. Cd exposure negatively affected PSII, whose activity was almost completely lost after four days. and N. La Rocca ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public