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1

The role of organic acids in the short- long-term aluminium tolerance in maize seedlings (Zea mays L.)

100%
Chaffai R., Marzouk B.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 4
Aluminum (Al) affects numerous physiological processes in plants. However, Al tolerance mechanisms mediated by increased synthesis of organic acids (OAs) have been outlined recently. In this study, we examined the role of OAs in the short (1–8 h) and long-term (4 days) Al tolerance in maize seedlings. Exposure to Al stress for 4 days results in a rapid inhibition of root growth. Al induced morphological changes in the maize roots, especially at a higher solution of Al concentration (1,000 µM Al). The increase in Al accumulation in roots, including strongly elevated levels of Al accumulated in root cell walls suggests that Al tolerance in maize is mediated in part by higher accumulation of Al in the roots. The enhanced citrate exudation, which was only observed at 1,000 µM Al may lead to detoxification of Al by formation of OA–Al complexes in the root apoplast. This mechanism has been suggested to play a significant role in Al resistance response in maize. The short-term responses underlying internal detoxification via OA-chelators were also investigated. Succinate, malate, citrate and total root OA contents decreased markedly, 2 h after the Al exposure. At 4 and 8 h time points, OA contents increased or remained unchanged, except for that of malate which decreased. The level of OAs in shoots, on the other hand, showed alterations that were less pronounced in response to Al. Specifically, the citrate and total OA concentrations significantly increased at 4 h, but showed a pronounced decrease at the 8 h time point. Based on our findings, we propose that multiple responses, including Al exclusion by Al accumulation in root cells and citrate efflux, may contribute towards higher Al resistance in maize. The rapid OA changes in responses to short-term Al treatment may not be responsible for Al tolerance. However, increased OA synthesis observed in this study may be involved in diminishing the stress triggered by Al. The molecular aspects underlying Al resistance mechanism via Alinduced expression of the enzymes catalyzing OA synthesis and metabolism remain to be elucidated.
2

Roots volatiles and fatty acids of coriander (Coriandrum sativum L.) grown in saline medium

100%
Neffati M., Marzouk B.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 3
An hydroponic culture was conducted to investigate the effect of saline stress on the essential oil and fatty acid composition of Tunisian coriander (Coriandrum sativum L.) roots. Ten days old coriander seedlings were treated during 3 weeks with different NaCl concentrations (0, 25, 50 and 75 mM). Roots volatile components and fatty acids were analyzed. The essential oil yield was 0.06% in the control, on the basis of dry matter weight, and did not changed at low concentration (25 mM), while it increased significantly with increasing NaCl concentrations to reach 0.12 and 0.21% at 50 and 75 mM NaCl, respectively. The major volatile component was (E)-2-dodecenal with 52% of total essential oil constituents, followed by decanal, dodecanal, (E)-2-tridecenal and (E)-2-dodecenal. Further, the amount of these compounds was affected differently by the NaCl level. Total fatty acid amount of coriander roots increased significantly only with 50 and 75 mM NaCl. Three major fatty acids: linoleic (43%), oleic (25.5%) and palmitic (21.6%) were identified. Linoleic acid amount remains unchanged at 25 mM, while it increased with raising NaCl concentrations. However, oleic acid amount decreased only at 25 mM and no effect was observed at 50 and 75 mM. Fatty acid percentages were differently affected by salt. The oleic/linoleic ratio was reduced with raising NaCl concentrations.
3

Physiological changes and essential oil composition of clary sage (Salvia sclarea L.) rosette leaves as affected by salinity

81%
Taarit M. B., Msaada K., Hosni K., Marzouk B.
Acta Physiologiae Plantarum
|
2011
|
tom 33
|
nr 1
Since soil salinity is a widespread problem, we proposed to focus on its effect on seedling growth, mineral composition and particularly on essential oil composition known to be reliable to abiotic conditions. Clary sage seedlings were hydroponically cultivated under different salt concentrations (0, 25, 50, and 75 mM NaCl). The dry biomass and the mineral element contents were determined. The essential oils were extracted and analyzed by GC and GC–MS. Results showed that growth was reduced by 42% at 75 mM. This growth decrease was accompanied by a decrease in tissue hydration and a slight restriction in K⁺ uptake, as well as an increase in Na⁺ levels. Concerning essential oil yields, the application of 25 mM NaCl increased significantly the oil yield which decreased with increasing salt concentration. Besides, the chemical composition of clary sage was found to be also strongly affected by salt treatment since each salt concentration appeared to induce a different new chemotype in clary sage essential oil.
4

Effect of salinity on plant growth and biological activities of Carthamus tinctorius L. extracts at two flowering stages

71%
Salem N., Msaada K., Dhifi W., Limam F., Marzouk B.
Acta Physiologiae Plantarum
|
2014
|
tom 36
|
nr 02
In the present study, we were interested in the effect of salt stress on phenolic and carotenoid contents, antioxidant and antimicrobial activity of two varieties of Carthamus tinctorius (Jawhara and 104) flowers. For this purpose, C. tinctorius flowers from plants grown under four saline treatments (0, 5, 10 and 15 g/L NaCl) were collected at two development stages. As salinity increased up to 10 g/L, results showed that total phenols, flavonoids, condensed tannins and carotenoid contents increased with salinity. Such variability might be of great importance in terms of valorizing this plant as a source of naturally secondary metabolites. Furthermore, our results showed an enhancement of antioxidant activity which was evaluated by four different test systems (DPPH, β-carotene–linoleic acid, chelating and reducing power assays) with increasing stress severity. Obtained results showed that, for the two varieties, salt effect was more pronounced at post flowering stage than full flowering one. The sensitivity test of the methanolic extracts of the harvested flowers was applied against seven human pathogenic bacteria and three yeast strains. Salinity reduced significantly the antimicrobial activity of flower extracts.
5

Drought effects on polyphenol composition and antioxidant activities in aerial parts of Salvia officinalis L.

71%
Bettaieb I., Hamrouni-Sellami I., Bourgou S., Limam F., Marzouk B.
Acta Physiologiae Plantarum
|
2011
|
tom 33
|
nr 4
Salvia officinalis L. is a medicinal plant containing several compounds with important pharmacological activity. In this study, we investigated the effects of water deficit (moderate and severe water deficits) on the contents of total and individual polyphenols of the aerial parts. Also, we studied the effect of drought on the antioxidant activity of methanolic extracts. Our results showed that water deficiency, as estimated by the decrease in water potential, resulted in a reduction of the biomass, plant height and total chlorophyll contents. In general, drought increased the level of total and individual polyphenols and this increase was more pronounced under moderate water deficit. These findings suggest that S. Officinalis is a sensitive species and that a severe water deficit could result in a decline in the activity of enzymes involved in the biosynthesis of phenolic compounds. On the other hand, our results showed an enhancement of reducing power and the radical scavenging activity as assessed using the DPPH assay with increasing stress severity. Finally, the evaluation of the chelating capacity of the extracts was found to be altered significantly under severe treatment by 39.71%. Based on these results, it seems that drought tolerance of S. officinalis is related to the capacity of the plant to modulate its phenolics in order to face to oxidative stress caused by water limiting conditions.
6

Salt effects on the growth, mineral nutrition, essential oil yield and composition of marjoram (Origanum majorana)

71%
Baatour O., Kaddour R., Wannes W. A., Lachaal M., Marzouk B.
Acta Physiologiae Plantarum
|
2010
|
tom 32
|
nr 1
The aim of this work was to investigate the growth, mineral nutrition and essential oil composition of marjoram aerial part. Seedlings were cultivated for 20 days on nutrient solution, and then transferred to hydroponic solution with different NaCl concentrations (0, 50, 100, 150 mM). Plants were harvested after 17 days of treatment. Mineral nutrition and essential oil composition of shoots were determined. Results showed that growth, water content and development of the different organs of marjoram plant were affected just at the highest NaCl concentration (150 mM). Furthermore, salt did not seem to affect leaf area and root length but reduced the number of leaves. An increase in the total leaf surface and its thickness was observed at different NaCl concentrations. At 50 mM NaCl, sodium was primarily accumulated in roots but at 150 mM, it was strongly accumulated in leaves. However, Cl⁻ accumulation was lower at higher NaCl concentrations. Essential oil yield of marjoram shoots was 0.12% in the control and 0.10% at 50 mM but an important decrease was observed at 100 mM (0.05%). Thirty-three components were identified belonging to different chemical classes. In the control, the essential oil was found to be rich in trans-sabinene hydrate (47.67%), terpinen-4-ol (20.82%) and cis-sabinene hydrate (7.23%). The proportions of these main compounds were differently affected by salt.
7

Effects of two sodium salts on fatty acid and essential oil composition of basil (Ocimum basilicum L.) leaves

61%
Tarchoune I., Baatour O., Harrathi J., Hamdaoui G., Lachaal M., Ouerghi Z., Marzouk B.
Acta Physiologiae Plantarum
|
2013
|
tom 35
|
nr 08
The effects of two sodium salts on growth, fatty acids, and essential oil compositions were investigated in a medicinal and aromatic plant, Ocimum basilicum cultivated in hydroponic medium. Plants were subjected to an equimolar concentration of Na2SO4 (25 mM) and NaCl (50 mM) for 15 days. Our results showed that leaf growth rate was more depressed by 25 mM Na2SO4 than by 50 mM NaCl. The total fatty acid contents did not show any change in plants. a-Linolenic, palmitic, and linoleic acids were the major fatty acids. The identification of basil leaf fatty acids has not been previously studied and this work revealed the predominance of polyunsaturated fatty acids. Under both salts, leaf fatty acid composition remained unchanged. Regarding the essential oil yield, it decreased significantly by 28 % under 25 mM Na2SO4 and showed an increase by 27 % under 50 mM NaCl. The major volatile compound in leaves was linalool with 34.3 % of total essential oil constituents, followed by eugenol (19.8 %), 1.8-cineole (14.4 %) and methyl eugenol (5.2 %). Further, levels of eugenol and methyl eugenol were most modulated by salt, and the negative correlation between these two compounds reflects the stimulation of O-methyltransferase activity under both salts.
8
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Phytochemical characterisation and bioactive properties of Solanum sodomaeum L. fruits at two stages of maturation

61%
Ouerghemmi I., Farhat M. B., Harbeoui H., Hammami M., Hamdaoui G., Marzouk B., Tounsi M. S.
Herba Polonica
|
2018
|
tom 64
|
nr 3
Introduction: Solanum sodomaeum L. has been observed to have several medicinal properties, in particular, in the treatment of several types of human skin cancer. Objective: The influence of the maturation stage of S. sodomaeum fruits on the total lipid contents, fatty acid profiles, essential oil yields and compositions, as well as the antibacterial and antioxidant activities of the essential oils, was investigated. Methods: The fatty acid and essential oil constituents were identified using gas chromatography (GC) and GC–mass spectrometry (GC–MS). The antioxidant properties of essential oil and vegetal oil were assessed using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging and reducing power assays. The antibacterial ac-tivity of essential oil was tested using the disc diffusion assay for resistance in human pathogenic bacteria. Results: Mature fruits showed higher total lipid content (17%) and were characterised by polyunsaturated fatty acids (53.87%), represented mainly by linoleic acid (53.11%). Similar yields of essential oils were detected for immature (0.43%) and mature (0.45%) fruits. Tetrahydronaphthalene (41.79%) was detected as the major essential oil component at the immature stage versus dihydrocoumarin pentane (18.27%), hexadecanoic acid (17.43%) and 2-undecanone (13.20%) in mature fruits. The DPPH test showed that essential oils had better antioxidant properties; however, the vegetal oils showed better performance in the reducing power assay. Moreover, the essential oil of S. sodomaeum mature fruits was active against bacterial strains. Conclusions: S. sodomaeum fruits could be a valuable source of natural antioxidants and antibacterial agents.
9

Effect of salt stress on growth, fatty acids and essential oils in safflower (Carthamus tinctorius L.)

61%
Harrathi J., Hosni K., Karray-Bouraoui N., Attia H., Marzouk B., Magne C., Lachaal M.
Acta Physiologiae Plantarum
|
2012
|
tom 34
|
nr 1
This study examined the influence of salt treatment on the growth parameters (fresh and dry weights), the mineral content (K⁺ and Na⁺), total lipid contents, fatty acid composition, yields and chemical composition of the essential oil of safflower (Carthamus tinctorius L.) grown in hydroponics for 2 weeks. Results showed that the application of 50 mM NaCl reduced the fresh weight of aerial parts (shoots and leaves) while it enhanced those of the roots. The reduction of dry weight was found to be more pronounced in the aerial parts. Salt treatment increased markedly the concentrations of Na⁺ in both plant parts while it reduced those of K⁺ which resulted in a sharp reduction of K⁺/Na⁺ ratio. In response to salt treatment, total lipids contents decreased in both plant parts and great qualitative changes in the fatty acids profiles were observed. Whatever the plant parts analysed, a redirection of the lipidic metabolism towards synthesis of unsaturated fatty acids as revealed by the increase of double bond index and linoleic desaturation ratio was pointed out. The increased unsaturation index was found to be more important in roots than in aerial parts. Such treatment also reduced the essential oil yields and induced marked quantitative changes in the chemical composition of the essential oils from both plant parts. Of all the identified components, oxygenated components display a prominent salt-induced synthesis and/or accumulation in both roots and aerial parts.
10

How salt stress represses the biosynthesis of marrubiin and disturbs the antioxidant activity of Marrubium vulgare L

61%
Rezgui M., Majdoub N., Ben-Kaab S., Marzouk B., Gouia H., Araujo M. E. M., Ben-Kaab L. B.
Polish Journal of Environmental Studies
|
2017
|
tom 26
|
nr 1
We investigated the effects of different concentrations of NaCl (25, 50, 100, and 150 mM NaCl) on growth, phenolic content, and antioxidant activities of horehound (Marrubium vulgare L.). The long-term salt treatment (up to 100 mM NaCl) resulted in significant (p<0.05) reduction of height, fresh weight, total chlorophyll, and total phenol contents. The negative effect of NaCl was accompanied by a significant restriction in K⁺, Ca²⁺, Fe²⁺, and Zn²⁺ ion uptake, and by an increase in Na⁺ ion concentrations – the effects of which were most pronounced at the highest NaCl level. The content of the main bioactive compound marrubiin decreased with increased NaCl concentrations. The antioxidant activity of the methanol extracts from untreated and salt-treated plants revealed that the extracts from a salt-treated plant with 100 mM exhibits the strongest activity in the DPPH and β-carotene bleaching assays, while it showed no reducing power. The present results suggest that salt treatment negatively affects the morphological, physiological, and biochemical traits of M. vulgare, which appears to be highly sensitive to salinity.
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