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1462. Influence of enhanced concentration of carbon dioxide and moderate drought on fluorescence induction in white clover (Trifolium repens L.)
- Creator:
- Pol, M., Gołębiowska, D., and Miklewska, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- 2-factor interactions and vitality coefficient
- Language:
- Multiple languages
- Description:
- In a 5-months' experiment with white clover grown in two CO2 atmospheres (AC = 350 and EC = 700 cm3 m-3) and two humidities (-0.2 and -0.8 MPa), changes in fluorescence induction parameters were investigated. Changes induced by EC did not coincide with those induced by moderate drought. Long-term EC significantly increased stationary fluorescence Fs and decreased the vitality coefficient Rfd. Moderate drought significantly shortened the fluorescence half-time and decreased the area above the induction curve Sc and the Fv/Fm ratio. and M. Pol, D. Gołębiowska, J. Miklewska.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1463. Influence of enhanced temperature on photosynthesis, photooxidative damage, and antioxidant strategies in Ceratonia siliqua L. seedlings subjected to water deficit and rewatering
- Creator:
- Osório, M. L., Osório, J., Vieira, A. C., Gonçalves, S., and Romano, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, antioxidative protection, carob tree, energy partioning, lipid peroxidation, and proline
- Language:
- Multiple languages
- Description:
- Predicted future climatic changes for the Mediterranean region give additional importance to the study of photooxidative stress in local economic species subjected to combined drought and high-temperature conditions. Under this context, the impact of these stresses on photosynthesis, energy partitioning, and membrane lipids, as well as the potential ability to attenuate oxidative damage, were investigated in Ceratonia siliqua L. Two thermal regimes (LT: 25/18°C; HT: 32/21°C) and three soil water conditions (control, water stress, and rewetting) were considered. HT exacerbated the adverse effects of water shortage on photosynthetic rates (PN) and PSII function. The decrease in PN was 33% at LT whereas at HT it was 84%. In spite of this, the electron transport rate (ETR) was not affected, which points to an increased allocation of reductants to sinks other than CO2 assimilation. Under LT conditions, water stress had no significant effects on yield of PSII photochemistry (ΦPSII) and yields of regulated (ΦNPQ) and nonregulated (ΦNO) energy dissipation. Conversely, drought induced a significant decrease of ΦPSII and a concomitant increase of ΦNO in HT plants, thereby favouring the overproduction of reactive oxygen species (ROS). Moreover, signs of lipid peroxidation damage were detected in HT plants, in which drought caused an increase of 40% in malondialdehyde (MDA) content. Concurrently, a marked increase in proline content was observed, while the activities of catalase (CAT) and ascorbate peroxidase (APX) were unaffected. Despite the generation of a moderate oxidative stress response, C. siliqua revealed a great capability for photosynthetic recovery 36 h after rewatering, which suggests that the species can cope with predicted climate change. and M. L. Osório ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1464. Influence of etherel and gibberellic acid on carbon metabolism, growth, and essential oil accumulation in spearmint (Mentha spicata)
- Creator:
- Singh, Preety, Srivastava, N. K., Mishra, A., and Sharma, S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- amino acids, chlorophyll, 14CO2- and 14C-sucrose incorporation, organic acids, primary photosynthetic metabolites, stem, stomatal conductance, sugars, and transpiration rate
- Language:
- Multiple languages
- Description:
- Changes in growth parameters and 14CO2 and [U-14C]-sucrose incorporation into the primary metabolic pools and essential oil were investigated in leaves and stems of M. spicata treated with etherel and gibberellic acid (GA). Compared to the control, GA and etherel treatments induced significant phenotypic changes and a decrease in chlorophyll content, CO2 exchange rate, and stomatal conductance. Treatment with etherel led to increased total incorporation of 14CO2 into the leaves wheras total incorporation from 14C sucrose was decreased. When 14CO2 was fed, the incorporation into the ethanol soluble fraction, sugars, organic acids, and essential oil was significantly higher in etherel treated leaves than in the control. However, [U-14C]-sucrose feeding led to decreased label incorporation in the ethanol-soluble fraction, sugars, organic acids, and essential oils compared to the control. When 14CO2 was fed to GA treated leaves, label incorporation in ethanol-insoluble fraction, sugars, and oils was significantly higher than in the control. In contrast, when [U-14C]-sucrose was fed the incorporation in the ethanol soluble fraction, sugars, organic acids, and oil was significantly lower than in the control. Hence the hormone treatment induces a differential utilization of precursors for oil biosynthesis and accumulation and differences in partitioning of label between leaf and stem. Etherel and GA influence the partitioning of primary photosynthetic metabolites and thus modify plant growth and essential oil accumulation. and Preety Singh ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1465. Influence of exogenous 5-aminolevulinic acid on chlorophyll synthesis and related gene expression in oilseed rape de-etiolated cotyledons under water-deficit stress
- Creator:
- Liu, D., Kong, D. D., Fu, X. K., Ali, B., Xu, L., and Zhou, W. J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, water stress, uroporphyrinogen decarboxylase, protochlorophyllide, rapeseed, transcript, 2, and 581
- Language:
- Multiple languages
- Description:
- 5-aminolevulinic acid (ALA) is an essential precursor for the biosynthesis of tetrapyrrols such as heme and chlorophyll (Chl). Previous studies have focused mainly on promotive effects of exogenous ALA on plant growth, while regulatory mechanisms affecting Chl biosynthesis have been only partially discussed. In the present study, the ameliorative role of exogenous ALA was investigated on Chl and endogenous ALA biosynthesis in six-day-old etiolated oilseed rape (Brassica napus L.) cotyledons during the de-etiolation stage. We showed that exogenously applied ALA of a low dosage enhanced Chl and ALA accumulation in cotyledons, while 600 µM ALA treatment inhibited the accumulation of Chl and ALA severely. However, the gene expression levels of glutamyl-tRNA reductase (HEMA) and glutamate-1-semialdehyde aminotransferase (GSA) were not affected under either low or high ALA concentrations. Furthermore, water deficit induced by polyethylene glycol 6000 (PEG) suppressed the Chl and ALA accumulation in cotyledons, while the inhibition was partially alleviated in the cotyledons pretreated with ALA. The decrease in Chl biosynthesis induced by PEG stress was assumed to be related to downregulation of HEMA and Mg-chelatase ChlH (ChlH), and upregulation of ferrochelatase (FC) genes. Moreover, exogenously applied ALA did not show any effect on the expression of Chl synthesis-related genes under the PEG treatment. These results showed a difference in suppressing ALA synthesis due to the high concentration of ALA and PEG. Exogenously applied ALA did not affect the expression of HEMA and GSA, thus exogenous ALA regulated Chl synthesis not via the regulation of transcriptional level in ALA biosynthesis. However, the inhibition in Chl and endogenous ALA accumulation by the PEG treatment may be attributed to downregulation of HEMA and ChlH, and upregulation of FC., D. Liu, D. D. Kong, X. K. Fu, B. Ali, L. Xu, W. J. Zhou., and Seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1466. Influence of exogenously applied 6-benzylaininopunne on the structure of chloroplasts and arrangement of their membranes
- Creator:
- Wilhelmová, N. and Kutík, J.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- carotenoids, thylakoid stacking, starch inclusions, proteins, Nicotiana tabacum\ plastoglobuli, electron microscopy, digitonin fractionation, cytokinin, and chlorophyll
- Language:
- Multiple languages
- Description:
- The influence of a cytokinin, 6-benzylaminopurine (BAP), on chloroplast structure was studied using biochemical methods and electron microscopy. The average degree of thylakoid stacking was determined by digitonin fractionation and differential centrifugation of chloroplasts from tobacco plantlets after treatment with different concentrations of BAP in agar medium during cultivation in viíro. An elevated concentration of BAP in the medium induced an increase in grana stacking. This was in accordance with the lowering of the chlorophyll a/b ratio in these chloroplasts. The relative amoímt of proteins and carotenoids increased in both stromal and (to a lesser extent) granal chloroplast thylakoid fractions with the BAP concentration. The electron microscopic studies revealed nearly the same volume density of thylakoid membranes within chloroplasts of BAP treated plantlets and control ones. In the BAP treated plantlets the chloroplasts were smaller and had a profound accumulation of starch inclusions and a more flattened shape than the chloroplasts of control plantlets. The volume density of plastoglobuli in chloroplasts did not decrease under the influence of BAP,
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1467. Influence of foliar application of polyamines on growth, gas-exchange characteristics, and chlorophyll fluorescence in Bakraii citrus under saline conditions
- Creator:
- Khoshbakht, D., Asghari, M. R., and Haghighi, M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- abiotické faktory, biomasa, citrusy, oxidační stres, abiotic factors, biomass, citruses, oxidative stress, efektivita fotosystému II, photosystem II efficiency, 2, and 581
- Language:
- Multiple languages
- Description:
- The effects of polyamines (PAs) on salt stress in Bakraii (Citrus reticulata × Citrus limetta) seedlings were studied. Foliar treatments by putrescine (Put), spermidine (Spd), and spermine (Spm) (0, 0.5, and 1 mM) were applied during the salinity period (0 and 75 mM of NaCl). PA-treated seedlings showed a lower content of Na+ and Cl- in leaves. Application of PAs increased net photosynthetic rate in salt-stressed plants and it contributed to the enhanced growth parameters. PAs application considerably induced growth improvement in Bakraii seedlings which was found to be associated with reduced electrolyte leakage, increased relative water content, chlorophyll fluorescence parameters, activities of key antioxidant enzymes, as well as increased photosynthetic pigment concentration under saline regime. These results showed the promising use of PAs, especially of Spd and Spm, for reducing the negative effects of salinity stress and improving the growth of citrus seedlings., D. Khoshbakht, M. R. Asghari, M. Haghighi., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1468. Influence of foliar-applied salicylic acid on growth, gas-exchange characteristics, and chlorophyll fluorescence in citrus under saline conditions
- Creator:
- Khoshbakht, D. and Asgharei, M. R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, abscisic acid, electrical conductivity, leaf area, photosystem II, physiological parameters, 2, and 581
- Language:
- Multiple languages
- Description:
- Salicylic acid (SA) is a common, plant-produced signal molecule that is responsible for inducing tolerance to a number of biotic and abiotic stresses. Our experiment was therefore conducted to test whether the application of SA at various concentrations (0, 0.10, 0.50, and 1.00 mM) as a foliar spray would protect citrus seedlings (Valencia orange/Bakraii) subjected to salt stress (0, 25, 50, and 75 mM NaCl). Growth parameters, leaf chlorophyll (Chl) content, relative water content (RWC), maximal quantum yield of PSII photochemistry (Fv/Fm), and gas-exchange variables were negatively affected by salinity. In addition, leaf electrolyte leakage (EL) and proline content increased by salinity treatments. Application of SA increased net photosynthetic rate and proline content in salt stressed plants and may have contributed to the enhanced growth parameters. SA treated plants had greater Chl content and RWC compared with untreated plants when exposed to salt stress. Fv/Fm ratio and stomatal conductance were also significantly higher in SA treated plants under saline stress conditions. SA application reduced EL compared to untreated plants, indicating possible protection of integrity of the cellular membrane. It appeared that the best ameliorative remedies of SA were obtained when Valencia orange/Bakraii seedlings were sprayed by 0.50 and 1.00 mM solutions. Overall, the adverse effects of salt stress could be alleviated by exogenous application of SA., D. Khoshbakht, M. R. Asgharei., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1469. Influence of foliar-applied triacontanol on growth, gas exchange characteristics, and chlorophyll fluorescence at different growth stages in wheat under saline conditions
- Creator:
- Perveen, S., Shahbaz, M., and Ashraf, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll, salt stress, 2, and 581
- Language:
- Multiple languages
- Description:
- A greenhouse experiment was conducted to examine the effect of foliar application of triacontanol (TRIA) on two cultivars (cv. S-24 and MH-97) of wheat (Triticum aestivum L.) at different growth stages. Plants were grown in full strength Hoagland’s nutrient solution under salt stress (150 mM NaCl) or control (0 mM NaCl) conditions. Three TRIA concentrations (0, 10, and 20 μM) were sprayed over leaves at three different growth stages, i.e. vegetative (V), boot (B), and vegetative + boot (VB) stages (two sprays on same plants, i.e., the first at 30-d-old plants and the second 78-d-old plants). Salt stress decreased significantly growth, net photosynthetic rate (PN), transpiration rate (E), chlorophyll contents (Chl a and b), and electron transport rate (ETR), while membrane permeability increased in both wheat cultivars. Stomatal conductance (gs) decreased only in salt-sensitive cv. MH-97 under saline conditions. Foliar application of TRIA at different growth stages enhanced significantly the growth, PN, gs, Chl a and b contents, and ETR, while membrane permeability was reduced in both cultivars under salt stress. Of various growth stages, foliar-applied TRIA was comparatively more effective when it was applied at V and VB stages. Overall, 10 μM TRIA concentration was the most efficient in reducing negative effects of salinity stress in both wheat cultivars. The cv. S-24 showed the better growth and ETR, while cv. MH-97 exhibited higher nonphotochemical quenching. and S. Perveen, M. Shahbaz, M. Ashraf.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1470. Influence of gibberellic acid on 14CO2 metabolism, growth, and production of alkaloids in Catharanthus roseus
- Creator:
- Srivastava, N. K. and Srivastava, A. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- amino acids, chlorophyll, 14CO2 photoassimilate partitioning, leaf, organic acids, root, stem, and sugars
- Language:
- Multiple languages
- Description:
- Changes in growth parameters, carbon assimilation efficiency, and utilization of 14CO2 assimilate into alkaloids in plant parts were investigated at whole plant level by treatment of Catharanthus roseus with gibberellic acid (GA). Application of GA (1 000 g m-3) resulted in changes in leaf morphology, increase in stem elongation, leaf and internode length, plant height, and decrease in biomass content. Phenotypic changes were accompanied by decrease in contents of chlorophylls and in photosynthetic capacity. GA application resulted in higher % of total alkaloids accumulated in leaf, stem, and root. GA treatment produced negative phenotypic response in total biomass production but positive response in content of total alkaloids in leaf, stem, and roots. 14C assimilate partitioning revealed that 14C distribution in leaf, stem, and root of treated plants was higher than in untreated and variations were observed in contents of metabolites as sugars, amino acids, and organic acids. Capacity to utilize current fixed 14C derived assimilates for alkaloid production was high in leaves but low in roots of treated plants despite higher content of 14C metabolites such as sugars, amino acids, and organic acids. In spite of higher availability of metabolites, their utilization into alkaloid production is low in GA-treated roots. and N. K. Srivastava, A. K. Srivastava.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public