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1092. Effects of supplementary potassium nitrate on growth and gas-exchange characteristics of salt-stressed citrus seedlings
- Creator:
- Khoshbakht, D., Ghorbani, A., Baninasab, B., Naseri, L. A., and Mirzaei, M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, dusík, citrusy, photosynthesis, nitrogen, citruses, chlorophyll fluorescence, mineral nutrition, net gas exchange, rootstocks, salinity, salt stress, potassium nitrate, 2, and 581
- Language:
- Multiple languages
- Description:
- We investigated the effects of supplementary KNO3 and NaCl on one-year-old, potted Valencia orange (Citrus sinensis) scions grafted on Iranian mandarin Bakraii [Citrus reticulate × Citrus limetta] (Valencia/Bakraii) and Carrizo citrange [C. sinensis × Poncirus trifoliata] (Valencia/Carrizo) rootstocks. After watering plants for 60 days with 50 mM NaCl, the lowest reduction in dry mass, stomatal conductance, and chlorophyll (Chl) content was found in Valencia/Bakraii. Bakraii accumulated more Cl- and Na+ in roots and transferred less to Valencia leaves compared with Carrizo rootstock. Moreover, higher net photosynthetic rate was found in Valencia/Bakraii than those on Carrizo rootstock. NaCl caused a decrease in the maximal efficiency of PSII photochemistry (Fv/Fm) and effective quantum yield (ΦPSII) but elevated coefficient of nonphotochemical quenching. Salinity reduced Ca2+, Mg2+, and total N contents, and increased Na+/K+ ratio in leaves and roots of both grafting combinations. Salinity increased K+ and proline content in leaves and decreased K+ concentrations in roots of both grafting combinations. In salinized plants, nitrate supplementation (10 mM KNO3) reduced leaf abscission, Cl-, Na+, Na+/K+, and Ca2+ concentrations in leaves and roots of both combinations. K+ and N concentrations and proline increased in leaves of the nitrate-supplemented salinized plants. Supplementary nitrate increased leaf number and area, stem elongation, Chl content, Fv/Fm, and ΦPSII and stimulated photosynthetic activity. Thus, nitrate ameliorated the deleterious effects of NaCl stress and stimulated the plant metabolism and growth. It can be used as a vital treatment under such condition., D. Khoshbakht, A. Ghorbani, B. Baninasab, L. A. Naseri, M. Mirzaei., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1093. Effects of temperature and irradiance on quantum yield of PSII photochemistry and xanthophyll cycle in a tropical and a temperate species
- Creator:
- Dongsansuk, A., Lütz, Cornelius, and Neuner, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Allium ursinum, β-carotene, freezing stress, heat, ice nucleation, lutein, Musa sp., photosynthetic pigments, 2, and 58
- Language:
- Multiple languages
- Description:
- a1_The effect of a wide range of temperatures (-15 and 60°C) in darkness or under strong irradiation [1,600 μmol(photon) m-2 s-1] on quantum yield of photosystem II photochemistry and xanthophyll cycle pigments was investigated in a tropical fruit crop (Musa sp.) and a temperate spring flowering plant (Allium ursinum L.). In darkness within the nonlethal thermal window of A. ursinum (from -6.7 to 47.7°C; 54.5 K) and of Musa sp. (from -2.2°C to 49.5°C; 51.7 K) maximal quantum yield of PSII photochemistry (Fv/Fm) was fairly unaffected by temperature over more than 40 K. At low temperature Fv/Fm started to drop with ice nucleation but significantly only with initial frost injuries (temperature at 10% frost damage; LT10). The critical high temperature threshold for PSII (Tc) was 43.8°C in A. ursinum and 44.7°C in Musa sp. Under strong irradiation, exposure to temperatures exceeding the growth ones but being still nonlethal caused photoinhibition in both species. Severity of photoinhibition increased with increasing distance to the growth temperature range. ΔF/Fm′ revealed distinctly different optimum temperature ranges: 27-36°C for Musa sp. and 18-27°C for A. ursinum exceeding maximum growth temperature by 2-7 K. In both species only at temperatures > 30°C zeaxanthin increased and violaxanthin decreased significantly. At nonlethal low temperature relative amounts of xanthophylls remained unchanged. At temperatures > 40°C β-carotene increased significantly in both species. In Musa sp. lutein and neoxanthin were significantly increased at 45°C, in A. ursinum lutein remained unchanged, neoxanthin levels decreased in the supraoptimal temperature range. In darkness, Fv/Fm was highly temperature-insensitive in both species., a2_Under strong irradiation, whenever growth temperature was exceeded, photoinhibition occurred with xanthophylls being changed only under supraoptimal temperature conditions as an antiradical defence mechanism., A. Dongsansuk, C. Lütz, and G. Neuner., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1094. Effects of temperature and nitrogen application on photosynthetic characteristics and the absorption and distribution of carbon and nitrogen in apple plants
- Creator:
- Zhang, H.H., Liu, H.F., Li, Z., Ding, H.F., Xue, Z.X., Zhao, F.Y., Yu, S.L., and Yu, K.
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, gas exchange, Malus sieversii, temperature stress, and tracing technology
- Language:
- Multiple languages
- Description:
- Low temperature has negative effects on apple photosynthesis by inhibiting the accumulations of photosynthates and nitrogen. The interactive effects of low temperature and nitrogen application on photosynthetic parameters and the absorption and distribution of carbon and nitrogen in different organs were assessed to investigate if nitrogen application can relieve the low-temperature stress on gas exchange and the accumulations of carbon and nitrogen inside the apple plants. No matter under normal or low-temperature conditions, nitrogen application both improved the photosynthetic parameters including net photosynthetic rate, intercellular CO2 concentration, and quantum yield of regulated energy dissipation of PSII as well as the absorption of carbon and nitrogen in roots, stems, and leaves. Thus, we conclude that nitrogen application can relieve the effects of low-temperature stress on photosynthesis and is of benefit for the accumulations of carbon and nitrogen in multiple organs of apple seedlings.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1095. Effects of temperature on energy-dependent fluorescence quenching in chloroplasts
- Creator:
- Krause, G. H.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Energy-dependent quenching of chlorophyll fluorescence and its reversion in intact isolated spinách chloroplasts were recorded at temperatures between 0 and 20 ®C. A temperature-dependence of Ihe quenching formation (and of quenching relaxation) corresponding to Qio values between 2 and 3 was found. Long-term cold acclimation of the plants resulted in a decrease of die fluorescence dechne half-time. The finál steady-state extent of quenching (q^) was not influenced by temperature shifts or cold acclimation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1096. Effects of thallus temperature and hydration on photosynthetic parameters of Cetraria islandica from contrasting habitats
- Creator:
- Hájek, J., Barták, M., and Gloser, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, Cladonia rangiferina, high and low attitude, high and low temperature, iceland moss, irradiance response curves, lichens, Pseudevernia furfuracea, and shade acclimation
- Language:
- Multiple languages
- Description:
- Two methods of induced in vivo chlorophyll (Chl) fluorescence were used to investigate the effects of varying thallus temperature and hydration on the performance of photosynthetic apparatus of a foliar lichen Cetraria islandica: slow Chl fluorescence induction kinetic with the analysis of quenching mechanisms, and rapid irradiance response curves of photosynthesis derived from quantum yield of photochemical reactions of photosystem 2 (Φ2) recorded at increasing irradiances. We compared responses of photosynthetic apparatus in populations of C. islandica growing in lower altitude (LAP: 1 350 m a.s.l.) and in higher altitude (HAP: 2 000 m a.s.l.). At each altitude, the samples were collected both in fully irradiated sites (HI) and in shade (LI). Temperature optimum of photosynthetic processes was the same for LAP and HAP thalli of LI populations (18 °C), while it was significantly lower for HI HAP (14 °C). Gradual dehydration of fully hydrated thalli led to initial increase (up to 20 % of water saturation deficit, WSD) in FV/FM and Φ2, no change at 20-50 % WSD, and a dramatic decrease of the parameters within 50-80 % of WSD. LI HAP of C. islandica was the best adapted population to low temperature having higher rates of photochemical processes of photosynthesis than HI HAP within temperature range of -5 to +5 °C. The differences between populations were apparent also in Chl content and thallus morphology. and J. Hájek, M. Barták, J. Gloser.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1097. Effects of the applícation of cement kiln exhausts on leaf biochemistry in certain legume crops
- Creator:
- Saralabai, V.C. and Vivekanandan, M.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- ascorbic acid, enzymes, growth characters, N-compounds, photosynthetic rate, photosystem 2, saccharides, stomatal resistance, superoxide dismutase, and transpiration rate
- Language:
- Multiple languages
- Description:
- Application of the electrostatic precipitator (ESP) dust to soil and leaves of Cajanus cajan, Vigna mungo, Vigna radiata, Vigna catjung and Glycina max increased biomass, chloroplast pigments, Chemical constituents and enzyme activities of leaves, besides crop productivity evidently indicating that the dust acted as a fertilizer. The net photosynthetic rate, photosystem 2 activity and rate of transpiration were not altered in špite of the dust forming a thin uniform coating ověř the leaf surface. The contents of intermediary N-compounds like allantoin, allantoic acid and total ureides of the leaves, which might serve as an indirect evidence of symbiotic N2-fixation, were higher in the treated plants. There were increments in free proline, soluble proteins, total nitrogen, nitrates, nitrites, soluble sugars and phenols in the treated plants. The concentrations of ffee amino acids, soluble starch, total sucrose and water soluble SH compounds of the leaves of the control and treated plants did not show any significant difference. The activity of superoxide dismutase was significantly higher which possibly indicated its role in alleviation of H2O2 and Oj toxicity. Enzymes like nitráte reductase, nitrite reductase, glutamine S3mthetase, acid and alkaline phosphatases, carbonic anhydrase, catalase, glutathione reductase and ascorbate peroxidase also functioned normally. In the treated plants, the concentration of ascorbic acid was significantly higher in the roots and nodules indicating the possible role of ascorbic acid in stress alleviation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1098. Effects of the interaction between ozone and carbon dioxide on gas exchange, ascorbic acid content, and visible leaf symptoms in rice leaves
- Creator:
- Imai, K. and Kobori, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dark respiration, net photosynthesis, Oryza sativa, photochemical oxidant, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Tropospheric ozone (O3) decreases photosynthesis, growth, and yield of crop plants, while elevated carbon dioxide (CO2) has the opposite effect. The net photosynthetic rate (PN), dark respiration rate (RD), and ascorbic acid content of rice leaves were examined under combinations of O3 (0, 0.1, or 0.3 cm3 m-3, expressed as O0, O0.1, O0.3, respectively) and CO2 (400 or 800 cm3 m-3, expressed as C400 or C800, respectively). The PN declined immediately after O3 fumigation, and was larger under O0.3 than under O0.1. When C800 was combined with the O3, PN was unaffected by O0.1 and there was an approximately 20 % decrease when the rice leaves were exposed to O0.3 for 3 h. The depression of stomatal conductance (g s) observed under O0.1 was accelerated by C800, and that under O0.3 did not change because the decline under O0.3 was too large. Excluding the stomatal effect, the mesophyll PN was suppressed only by O0.3, but was substantially ameliorated when C800 was combined. Ozone fumigation boosted the RD value, whereas C800 suppressed it. An appreciable reduction of ascorbic acid occurred when the leaves were fumigated with O0.3, but the reduction was partially ameliorated by C800. The degree of visible leaf symptoms coincided with the effect of the interaction between O3 and CO2 on PN. The amelioration of O3 injury by elevated CO2 was largely attributed to the restriction of O3 intake by the leaves with stomatal closure, and partly to the maintenance of the scavenge system for reactive oxygen species that entered the leaf mesophyll, as well as the promotion of the PN. and K. Imai, K. Kobori.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1099. Effects of the interaction between ozone and carbon dioxide on gas exchange, photosystem II and antioxidants in rice leaves
- Creator:
- Kobayakawa, H. and Imai, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, ascorbic acid, chlorophyll II fluorescence, elevated CO2, glutathione, net photosynthesis, Oryza sativa, ozone, quantum efficiency, respiration, and stomatal conductance
- Language:
- Multiple languages
- Description:
- To understand the interactive effects of O3 and CO2 on rice leaves; gas exchange, chlorophyll (Chl) fluorescence, ascorbic acid and glutathione were examined under acute (5 h), combined exposures of O3 (0, 0.1, or 0.3 cm3 m-3, expressed as O0, O0.1, or O0.3, respectively), and CO2 (400 or 800 cm3 m-3, expressed as C400 or C800, respectively) in natural-light gas-exposure chambers. The net photosynthetic rate (PN), maximum (Fv/Fm) and operating (Fq'/Fm') quantum efficiencies of photosystem II (PSII) in young (8th) leaves decreased during O3 exposure. However, these were ameliorated by C800 and fully recovered within 3 d in clean air (O0 + C400) except for the O0.3 + C400 plants. The maximum PSII efficiency at 1,500 μmol m-2 s-1 PPFD (Fv'/Fm') for the O0.3 + C400 plants decreased for all measurement times, likely because leaves with severely inhibited PN also had a severely damaged PSII. The PN of the flag (16th) leaves at heading decreased under O3 exposure, but the decline was smaller and the recovery was faster than that of the 8th leaves. The Fq'/Fm' of the flag leaves in the O0.3 + C400 and O0.3 + C800 plants decreased just after gas exposure, but the Fv/Fm was not affected. These effects indicate that elevated CO2 interactively ameliorated the inhibition of photosynthesis induced by O3 exposure. However, changes in antioxidant levels did not explain the above interaction. and H. Kobayakawa, K. Imai.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1100. Effects of the interaction between vapor-pressure deficit and salinity on growth and photosynthesis of Cucumis sativus seedlings under different CO2 concentrations
- Creator:
- Shibuya, T., Kano, K., Endo, R., and Kitaya, Y.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- vlhkost vzduchu, humidity, poptávka po odpařování, výměna plynu, analýza růstu, reakce na stres, vodní potenciál, evaporative demand, gas exchange, growth analysis, stress response, water potential, 2, and 581
- Language:
- Multiple languages
- Description:
- We studied growth and photosynthesis of cucumber (Cucumis sativus) seedlings under two vapor-pressure deficit levels (VPD; 0.4 and 3.0 kPa), two salinity levels (0 mM and 34 mM NaCl), and two CO2 concentrations ([CO2]; 400 and 1,000 μmol mol-1). Relative growth rate (RGR) decreased with increasing VPD, but the causal factor differed between salinity levels and CO2 concentrations. Under ambient [CO2], RGR decreased with increasing VPD at low salinity mainly due to decreased leaf area ratio (LAR), and decreased net assimilation rate (NAR) at high salinity. The decrease in intercellular [CO2] (Ci) with decreasing stomatal conductance caused by high VPD did not significantly limit net photosynthetic rate (PN) at low salinity, but PN was potentially limited by Ci at high salinity. At high [CO2], high VPD reduced LAR, but did not affect NAR. This is because the decrease in Ci occurred where slope of PN-Ci curve was almost flat., T. Shibuya, K. Kano, R. Endo, Y. Kitaya., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public