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1

Potassium deficiency in plants: effects and signaling cascades

100%
Hafsi C., Debez A., Abdelly C.
Acta Physiologiae Plantarum
|
2014
|
tom 36
|
nr 05
Potassium (K⁺) is an important macronutrient for plant growth and productivity. It fulfills important functions and it is widely included in fertilization management strategies to increase crop production. Although K⁺ is one of the most abundant elements of the earth crust, its availability to plants is usually limited leading to severe reduction in plant growth and yield. In plants, K⁺ shortage induces several responses at different levels: morphological, physiological, biochemical, and molecular. Activation of signaling cascades including reactive oxygen species, phytohormones (ethylene, auxin, and jasmonic acid), Ca²⁺, and phosphatidic acid is also triggered. In this review, we summarize the main of these adaptive responses evolved by plants to cope with K⁺ deficiency in the rhizosphere.
2

Osmotic stress affects water relations, growth, and nitrogen fixation in Phaseolus vulgaris plants

100%
Sassi Aydi S., Aydi S., Gonzalez E., Abdelly C.
Acta Physiologiae Plantarum
|
2008
|
tom 30
|
nr 4
The effects of mannitol-mediated osmotic stress on water relations, plant growth and symbiotic N2- fixation in four common bean (Phaseolus vulgaris) lines (Coco Blanc, BAT 477, BRB 77 and Flamingo) were studied. After germination, seedlings were inoculated with a reference strain (Rhizobium tropici CIAT 899) and aerohydroponically grown in a glasshouse. Osmotic stress was applied by 50 mM mannitol. Plants were harvested 4 weeks after osmotic stress application. Measured parameters were plant water relations, growth, nodule development, and symbiotic N2-fixation (SNF) as well as leghemoglobin contents. Osmotic stress induced significant changes in water relations, growth and symbiotic N2-fixation in stressed plants compared to control ones in all lines studied. A noticeable different behaviour was observed in the end of the treatment: Flamingo was the most tolerant line, whereas Coco blanc was the most sensitive, the two other lines exhibited an intermediate behaviour. The four bean lines displayed significant differences in their responses to osmotic stress. This study indicated that the relative tolerance of Flamingo line seems to be due to its ability to maintain higher leaf water potential, adequate leaf area and abundant and efficient nodular system, which in turn determines an important rate of SNF.
3

Cross-tolerance to abiotic stresses in halophytes: application for phytoremediation of organic pollutants

100%
Shiri M., Rabhi M., El Amrani A., Abdelly C.
Acta Physiologiae Plantarum
|
2015
|
tom 37
|
nr 10
Halophytes are plants able to tolerate high salt concentrations but no clear definition was retained for them. In literature, there are more studies that showed saltenhanced tolerance to other abiotic stresses compared to investigations that found enhanced salt tolerance by other abiotic stresses in halophytes. The phenomenon by which a plant resistance to a stress induces resistance to another is referred to as cross-tolerance. In this work, we reviewed cross-tolerance in halophytes at the physiological, biochemical, and molecular levels. A special attention was accorded to the cross-tolerance between salinity and organic pollutants that could allow halophytes a higher potential of xenobiotic phytoremediation in comparison with glycophytes.
4

Antioxidative response of Hordeum maritimum L. to potassium deficiency

88%
Hafsi C., Romero-Puertas M. C., del Rio L., Abdelly C., Sandalio L. M.
Acta Physiologiae Plantarum
|
2011
|
tom 33
|
nr 1
The objective of the present study was to determine the influence of potassium deprivation on the halophyte species Hordeum maritimum grown in hydroponics for 2 weeks. Treatments were with potassium (+K) or without potassium (-K). Growth, water status, mineral nutrition, parameters of oxidative stress [malondialdehyde (MDA), carbonyl groups (C=O), and hydrogen peroxide concentration (H₂O₂) contents], antioxidant enzyme activities [superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), guaiacol peroxidase (GPX, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate peroxidase (MDHAR, EC 1.6.5.4), dehydroascorbate peroxidase (DHAR, EC 1.8.5.1), and glutathione reductase (GR, EC 1.6.4.2)], and antioxidant molecules [ascorbate (ASC), and glutathione (GSH)] were determined. Results showed that the growth of vegetative organs decreased owing to potassium deficiency with roots (-36%) more affected than shoots (-12%). Water status was only diminished in roots (reduction of 24%). Potassium deprivation decreased potassium concentration in both organs, this decrease was more pronounced in roots (-81%) than in shoots (-55%). In contrast to carbonyl groups, MDA content increased owing to potassium deprivation. Except for CAT activity that remained unaffected; SOD, GPX, APX, GR, MDHAR, and DHAR activities were significantly increased. H₂O₂ concentration was negatively correlated with the activities of enzymes and the accumulation of non-enzymatic antioxidants implicated in its detoxification. In conclusion, a cooperative process between the antioxidant systems is important for the tolerance of H. maritimum to potassium deficiency.
5

Photosynthetic activity and leaf antioxidative responses of Atriplex portulacoides subjected to extreme salinity

88%
Benzarti M., Ben Rejeb K., Debez A., Messedi D., Abdelly C.
Acta Physiologiae Plantarum
|
2012
|
tom 34
|
nr 5
Responses of Atriplex portulacoides upon 40-day-long exposure to salinity (0–1,000 mM NaCl) were investigated. Mother plants originated from a sabkha located in a semi-arid region of Tunisia. The plant relative growth rate and leaf expansion increased significantly at 200 mM NaCl but decreased at higher salinities. Interestingly, the plants survived salinity as high as 1,000 mM NaCl without displaying salt-induced toxicity symptoms. Despite significant increase in leaf Na⁺ and Cl⁻ concentrations upon salt treatment, no significant effect on leaf relative water content was registered. Chlorophyll contents and the gas exchange parameters showed a significant stimulation at the optimal salinity (200 mM NaCl) followed by a decline at higher salinities. Extreme salinity hardly impacted the maximal efficiency of photosystem II photochemistry (Fv/Fm), but a marked decrease in the relative quantum yield of photosystem II (ΦPSII) was observed, along with a significant increase in non-photochemical quenching (NPQ). Leaf malondialdehyde and carotenoid contents were generally unaffected following salt exposure, whereas those of anthocyanins, polyphenols, and proline increased significantly, being maximal at 1,000 mM NaCl. Leaf superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11), and glutathione reductase (EC 1.6.4.2) activities were significantly stimulated by salinity, whereas catalase (EC 1.11.1.6) activity was maximal in the 0–400 mM NaCl range. As a whole, protecting the photosynthetic machinery from salt-induced photodamage together with the sustained antioxidant activity may account for the performance of A. portulacoides under high salinity.
6

Response to salt stress is modulated by growth-promoting rhizobacteria inoculation in two contrasting barley cultivars

88%
Mahmoud O. M.-B., Slimene I. B., Zribi O. T., Abdelly C., Djebali N.
Acta Physiologiae Plantarum
|
2017
|
tom 39
|
nr 06
7

Changes in phenolic composition and antioxidant activities of the edible halophyte Crithmum maritimum L. with Physiological stage and extraction method

76%
Jallali I., Megdiche W., M'Hamdi B., Oueslati S., Smaoui A., Abdelly C., Ksouri R.
Acta Physiologiae Plantarum
|
2012
|
tom 34
|
nr 4
Most antioxidant phytochemicals isolated from higher plants are polyphenols exhibiting different biological activities. Previous studies have shown that plant phenolic contents and antioxidant activities depend on several factors, mainly environmental conditions, and post-harvesting procedures. The present study aims to assess the influence of these interfering factors on phenolic composition and antioxidant activities (DPPH test, reducing power) of Crithmum maritimum L., a promising food halophyte which attracts an increasing interest in recent years. Results showed that the summer plants (reproductive stage) were richer on phenolic compounds than spring ones (vegetative stage), and consequently exhibited higher antioxidant activities. The comparison of two extraction methods showed that maceration extracts contained greatest amounts of phenolic compounds, while soxhlet ones exhibited higher antiradical and reducing power capacities. Besides, the analysis of variance disclosed that the effect of extraction method (E) was the predominant contributor to these antioxidant properties than the physiological development stage (D) and their interaction (E × D). Chromatographic characterization of C. maritimum phenolic composition using the RP-HPLC revealed the presence of phenolic acids and flavonoids with epigallocatechin as major component. Almost all of the identified compounds were described in the literature as interesting bioactive natural substances that may be used in several fields, such as nutraceuticals, cosmetics and agro-food industry.
8

Responses of two ecotypes of Medicago ciliaris to direct and bicarbonate-induced iron deficiency conditions

76%
M'sehli W., Dell'Orto M., De Nisi P., Donnini S., Abdelly C., Zocchi G., Gharsalli M.
Acta Physiologiae Plantarum
|
2009
|
tom 31
|
nr 4
Our study investigates the effect of iron deficiency on morpho-physiological and biochemical parameters of two Medicago ciliaris ecotypes (Mateur TN11.11 and Soliman TN8.7). Iron deficiencywas imposed by making plants grow, either in an iron free or by the addition of CaCO₃/NaHCO₃ to the Hoagland nutrient solution. Our results showed that both true and bicarbonate Fe-deficiency induced the characteristic iron-chlorosis symptoms, although the intensity of the symptoms was ecotype-dependent. This variability in tolerance to iron deficiency was also displayed by other morphological parameters such as root biomass and chlorophyll concentration. Besides, iron chlorosis induced an increase in biochemical parameters: the iron reducing capacity (measured in vivo on root segments and in vitro on plasma membrane enriched vesicles) and rhizosphere acidification by enhancement of H⁺-ATPase activity were more pronounced in Mateur ecotype. These findings suggest that Soliman ecotype was more sensitive than Mateur one to iron chlorosis.
9

Salt tolerance of the annual halophyte Cakile maritima as affected by the provenance and the development stage

76%
Megdiche W., Amor N. B., Debez A., Hessini K., Ksouri R., Zuily-Fodil Y., Abdelly C.
Acta Physiologiae Plantarum
|
2007
|
tom 29
|
nr 4
Though halophytes are naturally adapted to salinity, their salt-tolerance limits are greatly influenced by their provenance and developmental stage. In the present study, physio-biochemical responses of two Tunisian ecotypes of the oilseed coastal halophyte Cakile maritima (Brassicaceae) to salinity (0–400 mM NaCl) were monitored during germination and vegetative growth stages. Tabarka and Jerba seeds were collected from humid or arid climatic areas, respectively. Plant response to salinity appeared to depend on the ecotype and salinity levels. Increasing salinity inhibited germination process. Jerba seeds were found to be more salt tolerant than the Tabarka ones. At the autotrophic stage of growth and under salt-free conditions, Jerba was less productive than Tabarka (in terms of dry matter accumulation), but plant biomass production and leaf expansion (area and number) of the former ecotype were progressively improved by 100 mM NaCl, as compared to the control. In contrast, at the same salt concentration, these parameters decreased under increasing salinity in Tabarka (salt sensitive). Leaf chlorophyll content was reduced at severe salinity, but this effect was more conspicuous in the sensitive Tabarka plants. Na⁺ contents in the Jerba and Tabarka leaves collected from the 400 mM NaCl-treated plants were 17- and 12-fold higher than in the respective controls. This effect was accompanied by a significant reduction in the leaf K⁺, Mg²⁺ and Ca²⁺ contents, especially in the salt-treated Tabarka. A significant accumulation of proline and soluble carbohydrates in leaves was found during the period of intensive leaf growth. These organic compounds likely play a role in leaf osmotic adjustment and in protection of membrane stability at severe salinity.
10

Effects of magnesium deficiency on photosynthesis and carbohydrate partitioning

76%
Farhat N., Elkhouni A., Zorrig W., Smaoui A., Abdelly C., Rabhi M.
Acta Physiologiae Plantarum
|
2016
|
tom 38
|
nr 06
11

Starch and sugar accumulation in Sulla carnosa leaves upan Mg 2plus starvation

64%
Farhat N., Rabhi M., Krol M., Barhoumi Z., Ivanov A. G., McCarthy A., Abdelly C., Smaoui A., Huner N. P. A.
Acta Physiologiae Plantarum
|
2014
|
tom 36
|
nr 08
In the present work, magnesium deficiency effects were studied in Sulla carnosa plants grown in nutrient solution containing 1.50, 0.05, 0.01, and 0.00 mM Mg²⁺. After 5 weeks of treatment, fully expanded leaves were harvested to study their morphological and ultrastructural changes, as well as their carbohydrate, pigment, and Mg²⁺ concentrations. In control plants, leaves were well developed with remarkable green color. Down to 0.05 mM Mg²⁺, no chlorosis symptom was recorded, but below this concentration, mature leaves showed an appearance of interveinal chlorosis that was much more pronounced at 0.00 mM Mg²⁺ with the development of necrotic spots. Optima of chlorophyll a, chlorophyll b, and carotenoid concentrations were observed at 0.05 and 1.50 mM Mg²⁺; leaf magnesium concentration was severely reduced at 0.05 mM Mg²⁺. A significant decrease in pigment concentrations was noticed at 0.01 mM Mg²⁺, but the lowest values were recorded at 0.00 mM Mg²⁺. Enzymatic assays showed an increase in the accumulation of soluble sugars and starch with decreasing Mg²⁺ concentration. These results were in accordance with those of ultrastructural studies that revealed a marked alteration of chloroplasts in leaves of deficient plants. These chloroplasts were round and bigger as a result of a massive accumulation of oversized starch grains with disrupted thylakoids. As a whole, 1.50, 0.05, and 0.01 mM Mg²⁺ were found optimal, suboptimal, and deficient concentrations, respectively, the latter showing no significant difference with absolute Mg²⁺ absence (0.00 mM Mg²⁺).
12

Variation of phenolic composition and biological activities in Limoniastrum monopetalum L. organs

64%
Trabelsi N., Falleh H., Jallali I., Daly A. B., Hajlaoui H., Smaoui A., Abdelly C., Ksouri R.
Acta Physiologiae Plantarum
|
2012
|
tom 34
|
nr 1
Changes in phenolic composition and biological activities were investigated in different Limoniastrum monopetalum L. organs. For that, 80% aqueous acetone extracts were used to estimate total phenolic contents and their antioxidant activities were evaluated using DPPH and O₂ radical scavenging activities and reducing power. The efficiency of organ extracts was tested against human pathogen strains. Ultimately, acid hydrolysis of all organs was subjected to RP-HPLC for phenolic identification. Results showed that flower extracts exhibited the highest polyphenol (65.42 GAE/g DW) and flavonoid (35.36 CE/g DW) contents. Stems were enriched in condensed tannin content (21.4 mg CE/g DW) and displayed the best antiradical activities and the highest reducing power. Besides, stem and gall extracts showed the highest efficiency against pathogenic bacteria as compared with those of flower. Concerning the antifungal test, a slight activity was found in gall extracts. The RP-HPLC showed a difference in phenolic compounds that varied as function of organ. In fact, the major phenolic compound varied as function of organ. Results suggest that L. monopetalum could be a promising source of biomolecules for therapeutic and nutraceutical industries and the difference between organs may be related to their physiological role.
13

Risk of municipal solid waste compost and sewage sludge use on photosynthetic performance in common crop (Triticum durum)

64%
Lakhdar A., Slatni T., Iannelli M. A., Debez A., Petrini F., Jedidi N., Massacci A., Abdelly C.
Acta Physiologiae Plantarum
|
2012
|
tom 34
|
nr 3
The effect of composted municipal solid waste (MSW) and sewage sludge (SS) on photosynthetic activity of wheat (Triticum durum L.) was investigated. Chlorophyll fluorescence and gas exchange parameters were assessed following application of up to 300 t ha-1 of MSW compost or SS. 100 t ha⁻¹ MSW compost was optimal for the plant growth, which showed 78% stimulation as compared to the control. This was associated with higher maximum quantum efficiency (Fv/Fm) of photosystem II (PSII) and the actual quantum efficiency of PSII open centers at light adapted state (ΔF/F'm ). Maximal values of net photosynthetic rate and stomatal conductance were recorded at 100 t ha⁻¹ MSW compost (+40 and +116%, respectively). Ribulose bisphosphate carboxylase/oxygenase (RubisCO) activity was also significantly stimulated at 100 t ha⁻¹, while less significant impact was found in SS treatment. A marked accumulation of Ni, Pb, Cu, and Zn in concomitance with membrane lipid peroxidation were observed at 200–300 t ha⁻¹ MSW compost and SS, resulting in lower photosynthetic activity and altered PSII functional integrity. Altogether, these results suggest that the MSW compost at 100 t ha⁻¹ would be suitable for wheat cultivation, within the critical limits of heavy metal accumulation. However, long-term field experiments seem necessary to more accurately evaluate the safety of MSW application.
14

Do carbohydrate metabolism and partitioning contribute to the higher salt tolerance of Hordeum marinum compared to Hordeum vulgare?

52%
Medini W., Farhat N., Al-Rawi S., Mahto H., Qasim H., Ben-Halima E., Bessrour M., Chibani F., Abdelly C., Fettke J., Rabhi M.
Acta Physiologiae Plantarum
|
2019
|
tom 41
|
nr 12
The aim of the present work was to check whether carbohydrate metabolism and partitioning contribute to the higher salt tolerance of the facultative halophyte Hordeum marinum compared to the glycophyte Hordeum vulgare. Seedlings with the same size from the two species were hydroponically grown at 0 (control), 150, and 300 mM NaCl for 3 weeks. H. marinum maintained higher relative growth rate, which was concomitant with a higher aptitude to maintain better shoot tissue hydration and membrane integrity under saline conditions compared to H. vulgare. Gas exchanges were reduced in the two species under saline conditions, but an increase in their water use efficiency was recorded. H. marinum exhibited an increase in leaf soluble sugar concentrations under saline conditions together with an enhancement in the transglucosidase DPE2 (EC 2.4.1.25) activity at 300 mM NaCl. However, H. vulgare showed a high increase in starch phosphorylase (EC 2.4.1.1) activity under saline conditions together with a decrease in leaf glucose and starch concentrations at 300 mM NaCl. In roots, both species accumulated glucose and fructose at 150 mM NaCl, but H. marinum exhibited a marked decrease in soluble sugar concentrations and an increase in starch concentration at 300 mM NaCl. Our data constitute an initiation to the involvement of carbohydrate metabolism and partitioning in salt responses of barley species and further work is necessary to elucidate how their flexibility confers higher tolerance to H. marinum compared to H. vulgare.
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