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1032. 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
1033. 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
1034. 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
1035. 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
1036. 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
1037. Effects of various mixed salt-alkaline stresses on growth, photosynthesis, and photosynthetic pigment concentrations of Medicago ruthenica seedlings
- Creator:
- Yang, J. Y., Zheng, W., Tian, Y., Wu, Y., and Zhou, D. W.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, mixed salt-alkali stress, Medicago ruthenica, relative growth rate, root activity, photosynthesis, photosynthetic pigments, and water content
- Language:
- Multiple languages
- Description:
- Soil salinization and alkalinization frequently co-occur in naturally saline and alkaline soils. To understand the characteristics of mixed salt-alkali stress and adaptive response of Medicago ruthenica seedlings to salt-alkali stress, water content of shoots, growth and photosynthetic characteristics of seedlings under 30 salt-alkaline combinations (salinity 24-120 mM and pH 7.03-10.32) with mixed salts (NaCl, Na2SO4, NaHCO3, and Na2CO3) were examined. The indices were significantly affected by both salinity and pH. The interactive effects between salt and alkali stresses were significant, except for photosynthetic pigments. Water content of shoots, relative growth rates of shoots and roots and pigment concentrations showed decreasing trends with increasing salinity and alkalinity. The root activity under high alkalinity and salinity treatments gradually decreased, but was stimulated by the combined effects of low alkalinity and salinity. The survival rate decreased with increased salinity, except at pH 7.03-7.26 when all plants survived. Net photosynthetic rate, stomatal conductance and intercellular CO2 concentration decreased with increased salinity and pH. M. ruthenica tolerated the stress of high salt concentration when alkali concentration was low, and the synergistic effects of high alkali and high salt concentrations lead to the death of some or all seedlings. M. ruthenica appeared to be salt-alkali tolerant. Reducing the salt concentration or pH based on the salt components in the soil may be helpful to abate damage from mixed salt-alkaline stress. and J. Y. Yang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1038. Effects of water deficit and selenium on common buckwheat (Fagopyrum esculentum Moench.) plants
- Creator:
- Tadina, N., Germ, M., Kreft, I., Breznik, B., and Gaberščik, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- photochemical efficiency, photosystem 2, root, seed number and yield, shoot, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Two cultivars of common buckwheat (Fagopyrum esculentum), Pyra and Siva, were exposed to three treatments: water deficit (WD), foliar spraying by selenium (as Na2SeO4) (Se), and the combination of both. In WD-plants the stomatal conductance (gs) was significantly lower, while WD+Se-plants of Siva had significantly higher gs. None of the treatments resulted in significant differences of potential photochemical efficiency of photosystem 2 (PS2). A significantly higher actual photochemical efficiency of PS2 was obtained in Siva WD-plants and in Pyra Se-and WD-plants which was possibly due to improvement of plant water management during treatment. A significant interaction was observed between the effects of WD and Se on respiratory potential in Pyra. WD, Se, and the WD+Se combination resulted in shorter Pyra and Siva plants, with a reduced number of nodes. WD slightly negatively affected the yield per plant. The yield was highest in plants exposed to Se only. In Siva the number of seeds was triple while the average seed mass remained unchanged. and N. Tadina ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1039. Effects of water deficit on photosynthetic rate and osmotic adjustment in tetraploid wheats
- Creator:
- Rekika, D., Nachit, M. M., Araus, J. L., and Monneveux, P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- drought tolerance, durum wheat, intercellular CO2 concentration, leaf water status, Triticum, water stress, and wild emmer wheat
- Language:
- Multiple languages
- Description:
- Osmotic adjustment, accumulation of soluble saccharides, and photosynthetic gas exchange were studied in five durum wheat (Triticum turgidum L. var. durum) and one wild emmer wheat (Triticum turgidum L. var. dicoccoïdes) cultivars of contrasting drought tolerance and yield stability. Soil water contents (SWC) were 100, 31, 20, and 12 % of maximum capillary capacity. Under mild water stress (SWC 31 to 20 %), osmotic adjustment capacity and high accumulation of saccharides were found in cv. Cham1, a high yielding and drought tolerant cultivar, and in var. dicoccoïdes, while lowest values were noted in the durum wheat landraces Oued-Zenati and Jennah-Khotifa. Under more severe water stress (SWC 12 %), the cv. Cham1 maintained higher net photosynthetic rate (PN) than other genotypes. The observed changes in the ratio intercellular/ambient CO2 concentration (ci/ca) indicated that under mild and severe water stress, the decrease in PN was mainly due to stomatal and non-stomatal factors, respectively. and D. Rekika ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1040. Effects of water stress and fertilization on leaf gas exchange and photosynthetic light-response curves of Bothriochloa ischaemum L
- Creator:
- Xu, W. Z., Deng, X. P., and Xu, B. C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, diurnal variation, nitrogen, phosphorus, photosynthetic capacity, soil water deficit, 2, and 581
- Language:
- Multiple languages
- Description:
- Bothriochloa ischaemum L. is an important species in many temperate regions, but information about the interactive effects of water stress and fertilization on its photosynthetic characteristics was inadequate. A pot experiment was conducted to investigate the effects of three water [80% (HW), 40% (MW), and 20% (LW) of field capacity (FC)] and four fertilization regimes [nitrogen (N), phosphorus (P), nitrogen with phosphorus (NP), and no fertilization] on leaf photosynthesis. Leaf gas exchange and photosynthetic light-response curves were measured at the flowering phase of B. ischaemum. Water stress decreased not only the leaf gas-exchange parameters, such as net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E), and water-use efficiency (WUE) of B. ischaemum, but also downregulated PN-photosynthetically active radiation (PAR) curve parameters, such as light-saturated net photosynthetic rate (PNmax), apparent quantum efficiency (AQE), and light compensation point (LCP). Fertilization (N, P, and NP) enhanced the daily mean PN values and PNmax under the HW regime. Addition of N (either alone or with P) improved the photosynthetic capacity of B. ischaemum under the MW and LW regimes by increasing PN, PNmax, and AQE and reducing dark respiration rate and LCP, but the addition of P alone did not significantly improve the photosynthetic performance. Decline in PN under each fertilization regime occurred during the day and it was caused mainly by nonstomatal limitation. Our results indicated that water was the primary limiting factor for photosynthesis in B. ischaemum, and that appropriate levels of N fertilization improved its potential photosynthetic capacity under water-deficit conditions. and W. Z. Xu, X. P. Deng, B. C. Xu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public