Search

Seven metal-resistant yeast strains were isolated and selected from Dayet Oum Ghellaz Lake water (northwest of Algeria) known as a highly polluted area by lead and cadmium. The yeast strains were screened on the basis of their resistance to seven heavy metals Hg, Cr, Cd, Pb, Cu, Zn, and Fe and characterized by molecular and phylogenetic analysis. The sequencing of the D1/D2 domain of the 26S rRNA genes revealed the affiliation of the seven yeast isolates to Rhodotorula mucilaginosa, Clavispora lusitaniae, and Wickerhamomyces anomalus species. All yeast strains were halotolerant as they were able to grow in 10-15% NaCl. The yeast isolates were highly resistant to the studied heavy metals and exhibited different tolerance according to the metal type. The highest minimum inhibitory concentrations (MIC) were observed in R. mucilaginosa RO7 and W. anomalus WO2 strains which were then selected for lead removal assays. The present study is the first to investigate the lead elimination by W. anomalus. The lead uptake was significantly affected by biomass concentration in a reverse relationship, with purification percentages estimated at 98.15 ± 0.9% and 97.046 ± 0.47% and removal efficiency of 12.68 ± 0.91 and 15.55 ± 0.72 mg/g for W. anomalus WO2 and R. mucilaginosa RO7, respectively. The investigated metal-tolerant yeast strains proved to be promising candidates for bioremediation processes of heavy metals. This work amends the metal-resistant yeast bank with new strains having interesting abilities to resist to relatively high concentrations of toxic heavy metals and which can be used in the near future as low-cost biosorbents.

The breeding system of Anacyclus linearilobus, an annual and endemic species restricted to dune ecosystems of the Algerian coast were assessed through the effect of self-fertilization and intra- and inter-population artificial crosses on the probability of producing viable seeds in 20 individuals from two populations in a common garden. The breeding system was determined for each individual by the self-incompatibility index (ISI). These results were compared with those published for other species of the genus, A. clavatus, A. homogamos and A. valentinus. Results of experimental crosses showed that there was high variation in the female reproductive success between individuals of A. linearilobus, like that found in its sister species, A. valentinus. Unlike the other species in the genus that are self-incompatible, A. linearilobus showed a mixed mating system, with a majority of self-incompatible individuals, others partially self-incompatible and some self-compatible. We argue that this strategy may be related to reproductive assurance in this endemic, annual species whose effective population size has been reduced probably due to individual mating incompatibilities., Se evaluó el sistema de cruzamiento de Anacyclus linearilo-bus, una especie anual y endémica, de reducida distribución en ecosiste-mas dunares de la costa argelina, mediante la probabilidad de producir semillas en 20 individuos de dos poblaciones, cultivadas en jardín. El sistema de reproducción se determinó para cada individuo por el índice de autoincompatibilidad (ISI). Estos resultados se compararon con los publicados para otras especies del género, A. clavatus, A. homogamosy A. valentinus. Los resultados de los cruces experimentales mostraron que hubo una gran variación en el éxito reproductivo femenino entre individuos de A. linearilobus, como la encontrada en su especie herma-na, A. valentinus. A diferencia de las otras especies del género que son autoincompatibles, A. linearilobus mostró un sistema de cruzamiento mixto, con una mayoría de individuos autoincompatibles, otros parcial-mente autoincompatibles y algunos autocompatibles. Argumentamos que esta estrategia puede estar relacionada con el aseguramiento repro-ductivo en esta especie anual endémica cuyo tamaño efectivo de po-blación se ha reducido probablemente debido a incompatibilidad entre individuos emparentados.

Soluble polysaccharides were isolated from fruit pericarps of the Algerian Argania spinosa. The cell wall fraction was subjected to sequential extractions with H2O (2 × 2 h at 100°C), EDTA (1%, 6 h at 80°C) and KOH (1 and 4 M, 14 h at 25°C). The structures of the obtained polysaccharide fractions were characterized using gas chromatography (GC), infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The presence of arabinose, galactose and rhamnose in the pectin fractions suggests the presence of rhamnogalacturonan, while the abundance of xylose in the hemicellulosic fractions indicates the presence of xylan. The DSC data revealed the endothermal behavior of all the soluble polysaccharides and only two thermal transitions, the glass transition (Tg) and the fusion transition (Tf) have been recorded.

The essential oils, nowadays, are of increasing interest to chemists and biologists due to their use in the treatment of certain infectious diseases. In our study, we evaluated the level and antibacterial activity of the essential seeds oil from Algerian Fenugreek, Trigonella foenum-graecum (L.), in order to estimate their industrial valuation. This species, from the Fabaceae family, is widespread in Algeria and is used by local people for its medicinal and condiment properties. To conduct this study, the cross sections were carried out at seed level. The essential oils were extracted by hydrodistilation and refractive index was also measured. The antibacterial activity was carried out by the diffusion method and the MICs were determined. The anatomical study showed a structure similar to that of the majority of leguminous seeds. The yield of essential oil was 4.2%. The results also revealed that the Gram positive and Gram negative strains of bacteria had different responses to essential oil. The latter inhibited the growth of Staphylococus aureus (Gram positive, ATCC 43300) and Escherichia coli (Gram negative, ATCC 25922) with inhibition zone diameter 12 mm and 11 mm, respectively. The MICs were 56.25 mg/mL and 225 mg/mL, respectively (significant antibacterial activity). We concluded that fenugreek essential oil from seeds could be an important source of antibacterial agents used in food, chemical and pharmaceutical industries.

The objective of this study was to investigate a possible biological activities of oligosaccharides resulting from the hydrolysis of parietal hemicelluloses of the foliar tissue of Aristida pungens. Known for its developed, fiber rich foliar tissue, this perennial grasses is widely distributed on the arid and sub-desertic regions of Algeria. In order to identify added value application for the cell wall hemicellulose of Aristida pungens (Poaceae), the polymers were hydrolyzed enzymatically and after size exclusion chromatography, oligosaccharide fragments were tested for their abilities to modify the germination and growth of barley seeds (Hordeum vulgare). Five fractions were separated with different compositions and molecular weights. The low molecular weight fractions were mostly composed of oligoxylans, while the high molecular weight fractions consisted of oligo-glucuronoarabinoxylans. Biological tests suggested that the oligosaccharide fractions and particularly the low molecular weight fraction could promote germination and increase root bio-mass at low concentrations or reduce it at higher concentrations, suggesting a possible bio-stimulating application.

Retama raetam is a halophyte shrub belonging to the Fabaceae. This medici-nal species develops a particularly important root system and is adapted to arid areas. This adaptation has accompanied by the appearance of new bio-logical functions and specific metabolites. The present work aimed to evalu-ate the antimicrobial effect of hemicelluloses (HCs). The study consisted of extracting, purifying the parietal HCs of R. raetam roots and characterizing them by thin layer chromatography (CCM), as well as by colorimetric deter-mination of total sugars. The uronic acid content of the HCs was also deter-mined. These estimations revealed that HCs were neutral PLs (arabinoxylans). The activity of this polysaccharide (PLs) was investigated against seven bacterial strains and one yeast using disc diffusion method and minimum inhibitory concentration (MIC) was also calculated. HCs of brut residu (HBR) showed a very important inhibitory effect against six bacterial strains tested with maximal inhibition zone of (19±1)mm for Escherichia coli (ATCC25922) and Staphylococcus aureus (ATCC25923) in 100 mg/ml concen-tration, but no activity against Klebsiella pneumonia (ATCC4352) and Candida albicans. In opposite, the highest inhibition zone of (16±1) mm was noticed against E.coli, in HCs of delignified residue (HDR). The MIC of HCs ranged from 8.33 to 20 mg/ml. The activity was found to be in an increasing order from the lower to higher concentration. This is a first report on antimicrobial activity of HBR and HDR from R. raetam roots.

Ricinus communis L. is a shrub of the Euphorbiaceae family. Few works have been devoted to this plant in Algeria. To better know this plant for a better valorization , we proposed to study the composition of cell wall tissues (Cellulose, Hemicelluloses and Pectins) of Ricinus communis L., a qualitative analysis of polysaccharide fractions by thin layer chromatography (TLC) , this component was completed by an anatomical, histochemical study of young shoots and petioles of the Ricinus communis L. The extraction of the cell wall by the protocol of Harche et al, (1991) to give a rate of 64.15%. The extraction of matrix compounds from the plant wall by the Protocol of Chanda et al, (1950) to reveal richness in cellulose with a rate of 52.4% against 15.8% of hemicelluloses. Pectin extraction by the Lamport (1970) and Thibault (1980) protocol gave 0.9% for highly methylated pectins 2.1% for low methylated pectins. The study of the osidic composition of cellulose by C.C.M. reveals the presence of Glucose. The TLC. analysis of hemicelluloses indicates the presence of two oses: glucose and xylose are the more important. Chromatographic analysis of pectins indicates the presence of Galacturonic Acid and Galactose for highly methylated pectins; Galacturonic Acid, Galactose and Rhamnose for low methylated pectins. The histological study of Ricinus communis L. twigs showed that the anatomical structure presents the general characteristics of woody plants Dicotyledons, a significant cell wall lignification of vessels and supporting tissues with the presence of the two lignin monolignols (coniferylalocohol and syringy alcohol).

Retama monosperma is a fabaceous shrub that colonizes dune sands owing to its particularly important root system at depth and on the surface. It establishes symbiotic associations with rhizobia and thus plays a role in the bio -fertilization of soils. The stem fibers of R. monosperma are an interesting material for industry because of their useful biometric, physical, chemical and structural characteristics. The aim of this study was to complete these data with a biochemical analysis of the cell walls tissues of adult branches of R. monosperma. Cellulose, hemicelluloses and pectins were extracted from cell wall. The weight dosage indicated that cellulose remained the major component of the wall (56% from the crude cell wall and 52% from the delignified cell wall) ahead of hemicelluloses (16% from the crude cell wall and 14% from the delignified cell wall) and pectins (5.6% from the crude cell wall and 5% from the delignified cell wall for water extract pectins and 3% from the crude cell wall and 2.4% from the delignified cell wall for oxalate extract pectins). The colorimetric assay of pectins extracted from lignified cell wall of R. monosperma suggested presence of more uronic acids (14.95µg/mL) than pectins extracted from a delignified cell wall (12.37 µg/mL). Gas chromatographic analysis of hemicellulosic extracts showed the presence of xylose as the major ose (54.7% from the crude cell wall and 46.7% from the delignified cell wall). Pectins were represented by homogalacturonan chains and rhamnogalacturonans 1. Data generated in this study are helpful for valorization of this plant.

The area of Algerian western north already subjected to a strong climatic rigour and an excessive anthropic activity for several decades, has been confronted with the threats of the alarming degradation of its natural resources, following the example Pistacia atlantica which occupies today only one quite thin proportion of the territory. The study method was based on the phytoecological approach on a very large scale by approaching the anatomical and biometric study of the leaves of Pistacia atlantica in order to identify and confirm the name of the subspecies. The analysis of the results obtained revealed that this subspeciesis atlantica, phenotypically very variable.

Pericarps of Algerian Quercus ilex (Q. ilex) and Quercus suber (Q. suber) were used as copper adsorbents in artificially contaminated solutions. Exposing accessible lignocellulosic binding sites enhanced adsorption. The lignocellulosic fractions of Q. suber and Q. ilex (36.47±9.1 and 47.66±9.3, respectively) were characterized by FTIR before and after adsorption. The aim was to identify the functional groups adsorbing Cu(II). SEM/EDX determined lignocellulose surface morphology and composition. The amount of adsorbent-bound Cu(II) increased with initial [Cu(II)]. Cu(II) adsorption range was 23.59–48.06 mg.g−1 for Q. Suber and 22.56–38.19 mg.g−1 for Q. ilex when [Cu(II)] was 100–500 mg.L−1. Adsorption isotherms and Langmuir and Freundlich models of the Q. suber and Q. ilex lignocellulosic fractions indicated natural Cu(II)adsorption capacities (Qmax) of 53.76 mg.g−1 and 36.06 mg.g−1 and KF of 5.9 mg.g−1 and 7.43 mg.g−1, respectively.

The present study was carried out to investigate the antioxidant activity of the water and methanol extracts of leaves and fruits extracts of Chamaerops humilis L. by using ABTS cation radicals and cupric reducing antioxidant capacity (CUPRAC). Anticholinesterase effect of the extracts was tested against both AChE and BChE using a microplate-reader assay based on the Ellman method. The methanol extracts of C. humilis leaves contained relatively higher content of flavonoids and total phenolics than those of fruits. All the extracts were found to have different levels of antioxidant activity in the systems tested. The leave extract showed the highest value of antioxidant activity, based on ABTS radical-scavenging activity, while the fruit water extract showed the highest value (0.53±0.50 µg/mL) of cupric reducing antioxidant activity. Our data indicates that both methanol and water fruit extract were active for BChE inhibition (31.65 ± 0.37 and 30.19 ± 0.56%) respectively, whereas, all leave extracts did not show any activity against BChE. The present study demonstrated that the methanol and water extracts fractions of C. humilis have different responses with different antioxidant methods. Our results suggest that the C. humilis could be used as a source of antioxidant agents and may be beneficial in the AD treatment.

The objective of this study was to investigate the effect of addition of sawdust co-composted with sewage sludge and wheat straw on seeds germination. Two mixtures were piled and composted over 90 days. The first mixture (C1) was composed of sewage sludge and wheat straw, while the second mixture (C2) was composed of sewage sludge, wheat straw and wood sawdust. The results showed that the physicochemical parameters of both composts, i.e., temperature (> 55 °C in the thermophilic phase), moisture content (~ 30%). pH (6.73 for C1 and 7.19 for C2) and EC values (1.81 mS cm−1 for C1 and 1.32 mS cm−1 for C2) reached the required maturity standard. The values of C/N were below 12 indicating a high degree of maturity. Also, no bacterial pathogens were detected in the final composts. The concentration of total heavy metals has been reduced allowing the elimination of sewage sludge toxicity, confirmed by the germination index, which reached over 80%. Strong positive correlations were noticed between total Kjeldahl nitrogen of C2 and germination indexes of all the studied species. The obtained results indicate that the addition of wood sawdust increases the nitrogen content leading to slightly alkaline compost which influences seeds germination by reducing the phytotoxicity of sewage sludge.

In this pioneering study, Retama monosperma fibers were used in the preparation of a plaster composite dedicated to the field of civil engineering in order to find a substitute for fiberglass as a reinforcement material. Retama monosperma (Rtam) is one of the plant species abundantly available in Mediterranean regions. The localization of fibers at the organic level, the extraction procedure, physical and mechanical properties were studied to compare them with other vegetable fibers currently used in the manufacture of biocomposites. The results obtained show the possibility of improving the mechanical properties of plaster by using the fibers of Retama monosperma. The purpose of this paper is to promote the fibers of Retama monosperma as a building material in civil engineering in order to boost researchers’ interests in this Mediterranean plant.

Stipa tenacissima L. grows in the Algerian semiarid zones and in Mediterranean countries. It plays an ecological role because it slows down desertification. Their fibre provides a paper of excellent quality; it is also used in the confections of many craft products. Lygeum spartum L. and Aristida pungens Desf. are psammophile, and they grow in arid regions. Their leaves possess fibres that are rich in cellulose. The three plants cover 3 million ha in the Algerian high plateaus. The morphometric tests to evaluate the length of fibres show that the average length of the fibres is 0.30 mm for Stipa tenacissima, 1.70 mm for Lygeum spartum and 1.71 mm for Aristida pungens. The cell wall is pluristratified; the biochemical analysis shows that Stipa tenacissima leaves contain 35.5% of cellulose, Lygeum spartum leaves contain 32% of cellulose and Aristida pungens leaves contain 15% of cellulose. The percentage of hemicelluloses is 47.5 in Stipa tenacissima, 40.7 in Lygeum spartum and 60.5 in Aristida pungens. The pectins represent 3.98% in Stipa tenacissima, 4.01% in Lygeum spartum and 7.9% in Aristida pungens. Currently, these species are in decline because of climatic and anthropogenic conditions (unregulated urbanization, pastoralism …). The first studies have shown that these perennial species can be regenerated by their seeds. The cultivation would offer new perspectives in the socioeconomic and sustainable development of arid regions and the country.

Plants live in association with complex populations of microorganisms, including Plant Growth-Promoting Rhizobacteria (PGPR) that confer to plants an improved growth and enhanced stress tolerance. This large and diverse group includes endophytic bacteria that are able to colonize the internal tissues of plants. In the present study, we have isolated a nonrhizobial species from surface sterilized root nodules of Retama monosperma, a perennial leguminous species growing in poor and high salinity soils. Sequencing of its genome reveals this endophytic bacterium is a Bacillus megaterium strain (RmBm31) that possesses a wide range of genomic features linked to plant growth promotion. Furthermore, we show that RmBm31 is able to increase the biomass and positively modify the root architecture of seedlings of the model plant species Arabidopsis thaliana both in physical contact with its roots and via the production of volatile organic compounds. Lastly, we investigated the molecular mechanisms implicated in RmBm31 plant beneficial effects by carrying out a transcriptional analysis on a comprehensive set of phytohormone-responsive marker genes. Altogether, our results demonstrate that RmBm31 displays plant growth-promoting traits of potential interest for agricultural applications.

Thapsia garganica (L.) is a perennial plant that belongs to the family Apiaceae and is widely used in Saida Province, Algeria because of its important bioactive properties. Traditionally, the root bark of T. garganica is used alone or mixed with olive oil as an analgesic, diuretic, purgative and emmenagogue. In this study, essential oils were extracted from the root bark of T. garganica by hydrodistillation and characterized by gas chromatography mass spectrometry (CG-MS). Thirty-seven compounds representing 97.01 % of the total composition of the oil were identified by CG-MS. Among these compounds, myristicin, β-thujone, and elemicin were the dominant components contributing to 15.07 %, 14.86 %, and 13.06 % of the total, respectively. There have been no other reports of β-thujone as a major constituent in T. garganica.

The objective of this study was to isolate and select Lactobacillus strains with probiotic features for a potential use as starter for the preservation of animal feed. Olives, cow’s and camel’s milk, butter, beer drech and maize silage were used as isolation sources. Molecular identification using 16S rRNA gene sequencing identified four isolates of Lactobacillus plantarum and three of Lactobacillus fermentum. The different screening tests revealed that four strains: Lactobacillus plantarum OV13, Lactobacillus sp. OV15, Lactobacillus fermentum E161 and Lactobacillus sp. E631 are the best probiotic candidates , based on the results of their tolerance to acidic pH between 2 and 3.5, to 0.3% bile, to artificial gastric conditions for 18h of incubation , to their antibiotics resistance, their inhibition power on pathogenic bacteria (Pseudomonas sp., Staphylococcus aureus , Escherichia coli and Listeria ivanovii), and finally to their adhesion capacity to intestinal epithelial cells. The selected probiotic strains are considerate as good candidates for further investigation and should be tested, in vivo, to elucidate their potential health benefits on the animal performance as novel probiotic starters.

Argania spinosa L. Skeels, belonging to the Argania genus of the Sapotaceae family, is a species native to Morocco and Algeria. Due to its perfect adaptation to soil and climate, this tree plays an important ecological role in a constantly threatened encroached desert region. To understand the biological role of polyphenols in making the argan tree adapts to its natural habitat, we conducted a comparative study in two of the tree development stations: Tindouf located in South-western Algeria and Stidia located in Northwest Algeria. High performance liquid chromatography (HPLC) and Gas chromatography-mass spectrometry (GC-MS) used for the analysis of flavonoids led to the identification of six flavonols (two types of myricetin, rutin, hyperoside, quercetin, kaempferol) in the leaves of Tindouf argan tree, and two molecules (myricetin and quercetin) in the leaves of Stidia argan tree. Other molecules presented are few. The determination of flavonoids by spectrophotometry revealed the richness of Tindouf argan in these compounds (20%) compared to that of Stidia argan tree (8.7%). Histolocalisation of the flavonoids, tannins and anthraquinone in the leaves and stems of the tree was done using fluorescence microscope to understand the role of these molecules in the protection of this tree in its environment. Key words: Aragania spinosa L. (Skeels), histolocalisation, polyphenols, high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS).

The existence of two chromosome numbers (2n = 16 and 2n = 40) in Lygeum spartum is confirmed in the Algerian steppe populations of Oran region. Chromosome counts were established for 11 Algerian populations and three supplementary populations from Italy, Spain and Greece. The karyotypes were characterized by chromosome markers obtained using fluorescence in situ hybridization and fluorochrome bandings. The organization of 5S and 18S-5.8S-26S (35S) rDNA was studied in both cytotypes. Six signals of 35S and 2 signals of 5S were observed in 2n = 16 population, while 10 signals of 35S and 4 signals of 5S were detected in the population with 2n = 40. All 35S loci were also strongly marked by chromomycin, but negatively stained by Hoechst, which indicates the presence of GC rich DNA in rDNA regions. The B chromosomes were found in both cytotypes, bearing a 35S locus in 2n = 16 population. Genome size, determined by cytometry of 10 populations, ranged from 9.27 pg for 2n = 16 to 26.63 pg for 2n = 40 populations. The sequencing of plastid and nuclear DNA markers did not reveal major differences among 2n = 16 and 2n = 40 populations. However, given the differences between two cytotypes and based on their morphological and cytogenetic characteristics, the 2n = 16 cytotype merits novel taxonomic treatment., This study was supported by the CMEP (Le Comité Mixte d'Evaluation et de Prospective Franco-Algérien - Programme TASSILI; Nb. 01 MDU/530).

In this study, heated reflux extraction method has been used to identify the phenolic compounds from C. humilis var. argentea leaflets, rachis and fruits. Extractions were performed in both ultrapure water and 80% methanol solvents. The efficiency of procedures was determined in terms of the quality and quantity of phenolic acids and flavonoids identified. Chamaerops extracts have been characterized by high concentrations of phenolic compounds, which play a crucial role in protection against various diseases. LC-MS/MS was used to determine the chemical profile of various extracts obtained from Chamaerops. The results showed that the major components in leaflets and fruits extracts were quinic, malic and chlorogenic acids. In addition, nine minor acidic components were identified. On the other hand, rutin and hesperidin were found to be the major flavonoids. The methanol extract was shown as being the most efficient to identify phenolic compounds in C. humilis.

The aim of the present study was to evaluate the morphological characteristics of seeds of nine populations of north-west Algerian Carob (Ceratonia siliqua L.) and to evaluate the relationship between seeds color and coat dormancy by studying the effect of soaking in pure sulfuric acid (chemical scarification) on seed germination, for several durations (Control, 1, 2, 4, 6, 8, 10, 14, 18, 24, 30 and 36 h). The results showed these seeds were very diverse morphologically. The mean seeds length (range between 0.826 ± 0.058 cm and 0.996 ± 0.055 cm), the mean seeds width (range between 0.656 ± 0.056 cm and 0.710 ± 0.048 cm) and the mean seeds weight (range between 0.143 ± 0.011 g and 0.186 ± 0.011 g) were studied. Four colors of the seed coats have been identified in this study: chocolate brown, clear brown, greenish brown and yellowish brown. The results have revealed that the seeds with clear color (yellowish brown) showed high coat dormancy, their maximum germination percentage were 2%. However, the seeds with a chocolate brown color, does not present dormancy, their maximum germination percentage was between 80 and 88 % without any pretreatment. Moreover, seeds of Ceratonia siliqua with yellowish brown color were more resistant to prolonged periods of soaking in pure sulfuric acid (18, 24 and 30 h), but the chocolate brown seeds are more fragile for prolonged soaking durations, they lose their viability beyond 10 h in acid. The histochemical features of the seed coats have indicated that there are not anatomic differences between the 4 seed colors of different cultivated and spontaneous populations.

Afin de mettre en évidence les potentialités d’adaptation du pistachier fruitier (Pistacia vera L.) à la sécheresse, un stress hydrique osmotique a été induit en conditions in vitro. L’abaissement du potentiel hydrique du milieu de culture se fait par l’adjonction de polyéthylène glycol (PEG-6000). A cet effet, neuf concentrations croissantes ont été étudiées (0; 5; 10; 15; 20; 25; 30; 35 et 40 g l-1). Les résultats essentiels obtenus sont les suivants : la germination des axes embryonnaires n’a pas été affectée par la concentration de PEG-6000. Toutefois, le potentiel hydrique des milieux testés a influencé significativement le taux de survie et l’aspect qualitatif des jeunes plantules germées. En effet, plus la concentration de PEG augmente, plus les taux de mortalité et d’hyperhydrie accentuent. Nos résultats ont montré également un effet très marqué du stress hydrique sur la croissance des vitrosemis de Pistacia vera L. En effet, le taux moyen de réduction de différents paramètres de croissance étudiés par rapport au témoin, est de 51,3% pour la longueur de la partie aérienne, 22,8% pour le nombre de feuilles et 19,9% pour la longueur du système racinaire. En ce qui concerne la production des biomasses, l’analyse statistique a révélé un effet significatif de polyéthylène glycol. Les différentes concentrations étudiées ont entraîné une diminution des biomasses des parties aériennes alors que celles des racines ont été améliorées.

This preliminary study investigated the conservation of Pistacia vera genetic resources using seeds and isolated embryonic axes. First, the effect of storing seeds in ambient conditions on embryo viability was evaluated by in vitro culture. The germination rate of P. vera embryonic axes gradually decreased from 100% to 31% after 30-month stor - age of seeds. Cryopreservation may thus be necessary for the long-term conservation of embryos. A simple protocol was set up using embryonic axes. It included a single dehydration step with silica gel prior to direct freezing in liquid nitrogen (-196°C). The optimal germination rate was obtained after 60 min dehydration (water content of 0.2 grams of water per gram of dry weight (g·g -1 DW)). However, 90 minutes of dehydration (0.14 g·g -1 DW) were necessary to obtain seedlings whose qualitative development was equivalent to that of the control embryonic axes.

The Argan tree, Argania spinosa L., Skeels, is an endemic species in North-West Africa perfectly adapted to aridity and drought. It is in this context that we studied the physiological impact of water deficit on the Argan tree seedlings for eight weeks at a field capacity of 30%. The obtained results reveal that the stressed seedlings manifested by the strategy of the root elongation from the second week, the roots reached 31 cm compared with 15 cm of the control. However, the seedlings showed severe dehydration of 41% in leaves and 45% in roots. Besides, the content of chlorophyll pigments has relatively decreased from the second week, a slight yellowing and leaf drop was observed. The seedlings have accumulated proteins in a very significant way in leaves (from 25 to 107 mg.g-1 by fresh weight) and (from 23 to 90 mg.g-1 by fresh weight) in roots. Proline was also accumulated; the content was 4 and 2 μg.g-1 by fresh weight respectively in leaves and roots compared with 1.3 and 1.1 μg.g-1 1 by fresh weight in control respectively. The accumulation of the protein and proline is higher in leaves than in roots. The content of malondialdehyde was higher in leaves than in roots. This increase is significantly related to the prolongation of the stress period from the second week. The enzymatic activity of peroxidase is in relative increase according to the duration of the water stress applied in both leaves and roots. We deduce from these results that Argan seedlings possess the characteristic of xeropyhte that tolerate aridity. Key words: Argania spinosa, drought stress, proline, chlorophylls, proteins.

The relationship between the antioxidant activity and the phenolic contents (total polyphenol, flavonoid and condensed tannin) of Retama monosperma (Fabaceae), used commonly in the traditional medicine of Mediterranean regions, was investigated. The antioxidant activities of the various fractions (toluene, chloroform, ethyl acetate and butanol) of the hydromethanolic extract of the seeds, stems and flowers have been evaluated using in vitro 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) radical scavenging activities and Phosphomolybdic acid assays and were compared to ascorbic acid. A significant high Pearson's correlations between flavonoid content and antioxidant activities (r = 0.91) with Phosphomolybdic acid assays and (r = - 0.79) with IC50 DPPH radical scavenging activities. However, there was no correlation between condensed tannin and antioxidant activities. The results obtained in the present study indicate that the ethyl acetate fraction of seeds is a potential source of natural antioxidant for R. monosperma.

In spite of the importance of Retama species for dune stabilization and re-vegetation and the contribution to the bio-fertilization of semi-arid and arid ecosystems, the symbiotic interaction of Retama species with rhizobia remains largely unstudied. In this paper, we aim to provide the first detailed study on nodule morphology and anatomy of Retama monosperma. We collected nodules from coastal areas nearby Oran (Algeria) and studied in detail their anatomy and ultrastructure by light and electron microscopy. First, we confirmed the likely identity of the microsymbiont as B. retamae and found that nodules of R. monosperma belong to the genistoid type of indeterminate nodules. Infection threads, typical for most nodules of legumes, are absent in nodules of R. monosperma and bacterial spread is associated with plant cell division. The nitrogen fixation zone is homogenous with only invaded cells and a network of non-invaded cells found in many nodules, is absent. Moreover, endoreduplication does not take place in bacteroids in nodules of R. monosperma. The features observed in this study are compared to the morphology and anatomy of nodules of other legumes and the possible consequences for nodule functioning and the mode of infection during the establishment of the interaction are discussed.

The pectin polysaccharides from leaves of Argania spinosa (L.) Skeels, collected from Stidia area in the west coast of northern Algeria, were investigated by using sequential extractions and the resulting fractions were analysed for monosaccharide composition and chemical structure. Water-soluble pectic (ALS-WSP) and chelating-soluble pectic (ALS-CSP) fractions were obtained, de-esterified and fractionated by anion-exchange chromatography and characterized by sugar analysis combined with methylation analysis and 1H and 13C NMR spectroscopy. The data reveal the presence of altering homogalacturonan (HG) and rhamnogalacturonan I (RG-I) in both pectin fraction. The rhamnogalacturonan I (RG-I) are consisted of a disaccharide repeating unit [→ α-D-GalpA-1,2-α-L-Rhap-1,4 →] backbone, with side chains contained highly branched α-(1 → 5)-linked arabinan and short linear β-(1 → 4)-linked galactan, attached to O-4 of the rhamnosyl residues.

8 p., tablas, fot., mapas, [EN]Artemisia herba-alba is a largely-distributed and often landscape-dom- inating taxon in arid areas of the Mediterranean and Irano-Turanian regions. In Algeria, in 2010 its communities covered 10% of the steppe territory, but its populations have been subjected to overgrazing. A karyological study based on 22 populations together with a cytogenetic characterisation of this species has been performed for the first time in Algerian materials, through genome size and chromosome number determination. Fluorescence in situ hybridisation (FISH) was also used to assess the rDNA loci number and distribution in the two ploidy levels detected. The studied accessions are diploid (2n = 2x = 18 chromosomes, 6 populations) or tetraploid (2n = 4x = 36 chromosomes, 15 popula- tions). One population, occupying a more or less central geographic posi- tion among the studied area, presented both cytotypes. Genome size reflects well the two ploidy levels, with no evidence of downsizing with polyploidy. The karyotypes are rather symmetric (2A Stebbins’ class). FISH analyses detected four signals (2 loci) in diploid and eight signals (4 loci) in tetraploid cytotypes for both ribosomal DNA genes, which present an L-type (linked) organisation, i.e. with loci from both rDNA genes colocal- ised. The presence of two ploidy levels suggest a genomic dynamism and even a possible differentiation underlying the morphological uniformity and despite the dramatic decrease experienced by this plant in Algeria in terms of surface coverage., [ES]Artemisia herba-alba es un taxon ampliamente distribuido y dominante en el paisaje en áreas áridas de las regiones mediterránea e irano-turania. En Argelia, sus comunidades cubrían en 2010 el 10% de su territorio de estepa, pero sus poblaciones se encuentran sometidas a sobrepastoreo. Se ha llevado a cabo un estudio cariológico basado en 22 poblaciones, se han caracterizado citogenéticamente por primera vez poblaciones argelinas de esta especie y se ha estimado el tamaño del genoma y el número cromosomático, además de la determinación por hibridación in situ fluorescente (FISH) del número y la distribución de los loci del ADN ribosómico en los dos niveles de ploidía. Las accesiones estudiadas son diploides (2n = 2x = 18, 6 poblaciones) o tetraploides (2n = 4x = 36, 15 poblaciones), y una, que ocupa una posición más o menos céntrica entre las consideradas, presenta ambos niveles de ploidía. El tamaño del genoma refleja los dos niveles de ploidía y no se observan indicios de disminución con la poliploidía. Los cariotipos son simétricos (clase 2A de Stebbins). Los análisis de FISH detectan cuatro señales (2 loci) en los citoti- pos diploides y ocho señales (4 loci) en los tetraploides para ambos genes del ADN ribosómico, que presenta una organización del tipo L (ligada), es decir, con los loci de los dos genes del ADNr colocalizados. La pres- encia de dos niveles de ploidía sugiere un dinamismo genético e incluso una posible diferenciación más allá de la uniformidad morfológica, con independencia del retroceso experimentado por esta planta en Argelia., This work was supported by the Dirección General de Investigación Científica y Técnica, Spanish government (CGL2013-49097-C2-2-P) and the Generalitat de Catalunya, Catalonian government (“Ajuts a grups de recerca consolidats”, 2014SGR514). Y.B. received a grant from the Algerian government for two short stages in coauthors’ laboratories in Barcelona. S.G. benefitted from a Juan de la Cierva and Ramón y Cajal contracts from the Ministry of Economy and Competitiveness, Government of Spain.

International audience; Thirty-three populations belonging to the three Retama species, Retama monosperma, Retama raetam and Retama sphaerocarpa, were collected to study species differentiation using flow cytometry for 2C DNA assessment and molecular cytogenetics for karyotype organisation. All were 2n=48. Genome size ranged from 1.76 to 1.97 pg and revealed significant intraspecific variation correlated to the geographic distribution of the populations. The number and position of the two ribosomal gene families 5S and 45S were determined by fluorescent in situ hybridization, revealing chromosome reorganisation between species. In R. raetam and R. monosperma, the minor 5S loci co-localised with 45S on the satellite chromosome pair. Fluorochrome banding identified GC- and AT-rich DNA regions. In R. monosperma a unique chromomycin positive GC-rich band was observed associated with the secondary constriction. In contrast, an original pattern showing two chromomycin positive bands localised at each side of the extended rDNA locus was observed in R. sphaerocarpa and R. raetam. The polymorphism revealed in our cytogenetic data allowed us to separate the group of R. raetam and R. monosperma from R. sphaerocarpa

Français. Des études sur la germination et la croissance de jeunes semis de Pistacia vera L ont été conduites au laboratoire et en serre. Elles ont consisté en des tests de germination et, au suivi de la croissance des plantules sur différents substrats. Les résultats obtenus ont révélé que les meilleurs taux de germination ont été enregistrés avec le lot des graines sans téguments. De plus, le semis direct dans le sable a amélioré les résultats mais la vitesse de germination se trouve ralentie. D’un autre coté, un effet marqué de la nature du substrat sur la croissance en hauteur et en diamètre des tiges ainsi que la longueur du système racinaire a été constaté. Les meilleurs résultats ont été enregistrés avec le substrat – sable et le mélange sable/tourbe.English. A study was carried out to determine the germination rate, the average time of germination and latent period of Pistacia vera L. seeds and the effect of tegument on germination. Additionally, the effect of different substrates on growth of young seedlings was also study. The results obtained revealed that the best germination rates were recorded with the seeds without teguments. Moreover, the direct sowing of the seeds in sand improved the germination percentage but the speed of germination was slowed down. Substrate nature seemed to have an effect on the seedlings height and stem diameter as well as the length of the main root. Higher values were obtained with sand-substrate and sand/peat.

Freshly harvested dispersal units of two cytotypes of Lygeum spartum L. were dormant. Their dormancy corresponded to a poor germination at any temperature, including the optimal one (20-25 °C), and to the inability to germinate in a wide range of temperatures. Germination did not occur at all below 10 °C and above 30 °C. At the optimal temperature, germination was markedly inhibited by continuous white light and by decreasing water potential of the medium to – 1 MPa. Breaking of dormancy for 12 months of dry storage at ambient temperature resulted in a widening of the temperature range within which a high rate of germination occurred. However, the optimal temperature remained similar to that of freshly harvested dispersal units, i. e. 20-25 °C. The lemma was mainly responsible for dormancy, but the caryopsis itself also appeared to play a role in photosensitivity of whole dispersal units. The intensity of dormancy depended on the seed origin. It was deeper in seeds originated from the semi-arid zone (polyploid cytotype, 2n = 40) than in those collected in the arid highlands (diploid cytotype, 2n = 16). The ecological role of dormancy and after-ripening is discussed in relation to the establishment of this species in arid environment., Au moment de leur récolte, les unités de dispersion de deux cytotypes de Lygeum spartum L. sont dormantes. Cette dormance correspond à une germination difficile à toutes les températures ainsi qu’à l’optimum thermique (20-25 °C) et à une impossibilité de germer dans une large gamme de températures. Aucune semence ne germe au-dessous de 10 °C et au-dessus de 30 °C. À la température optimale, la germination est fortement inhibée par la lumière blanche continue et une réduction du potentiel hydrique du milieu à – 1MPa. L’élimination de la dormance par une conservation au sec de 12 mois à la température ambiante entraîne un élargissement de la gamme de températures permettant une germination rapide. Cependant, l’optimum thermique reste similaire à celui des semences fraîchement récoltées, c’est-à-dire 20-25 °C. La dormance résulte principalement des enveloppes, mais le caryopse nu joue aussi un rôle dans la photosensibilité des semences entières. L’intensité de la dormance dépend du lieu de récolte ; elle est plus profonde pour les semences récoltées dans la zone semi-aride (cytotype polyploïde, 2n = 40) que pour celles collectées sur les hauts plateaux arides (cytotype diploïde, 2n = 16). Le rôle écologique de la dormance et de la post-maturation au sec est discuté en relation avec l’établissement de cette espèce dans un environnement aride., Djabeur Abderazak, Kaid-Harche Meriem, Côme Daniel, Corbineau Françoise. Environmental control of germination and dormancy of seeds of two cytotypes of Lygeum spartum L., a perennial grass of semi-arid and arid areas in Algeria. In: Ecologia mediterranea, tome 36 n°1, 2010. pp. 89-98.

International audience; In vitro development of isolated embryos and axillary bud proliferation were studied in Pistacia vera L. Different regulator-free nutrient media were compared to determine the effects of the mineral solution, agar and sucrose concentrations on seedling development from mature embryos. Nutrient-rich MS [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tabacco tissue cultures. Physiol. Plant. 15,473-479] and DKW [Driver, J.A., Kuniyuki, A.M., 1984. In vitro propagation of Paradox walnut rootstock. HortScience 19, 507-509] mineral solutions were more efficient for the development of aerial parts than nutrient-poor KN [Knop, W., 1884. Bereitung einer concentrierten nahrstofflosung fur pflanzen. Landwersuhssat 30, 292-294] and WT [Withe, P.R., 1936. Plant tissue cultures. Bot. Rev. 2, 419-437] solutions. Reducing the agar concentration enhanced fresh matter production and balanced seedling development. When tested at different concentrations, sucrose was found to orient mature embryo development, with the best results obtained at concentrations of 2-4%, whereas high concentrations (6 and 12%) mainly inhibited elongation of the aerial parts. Plantlets obtained previously from in vitro cultured embryos were propagated by axillary budding. High bud proliferation (six shoots per explant) was achieved when using 17.8 mu M benzyladenine (BA) combined with 0.5 mu M indole-3-butyric acid (IBA). The addition of 2.9 mu M gibberellic acid (GA(3)) to the propagation medium did not improve axillary shoot yields and on average, media with GA(3) produced 2.3-2.6 elongated stems per cultured explant. Shoots were rooted in vitro in half-strength MS medium containing 12.3 mu M IBA

Resume Afin d'etudier la tolerance a la salinite chez le pistachier fruitier (Pistacia vera L.), des embryons isoles issues de graines matures ont ete cultives in vitro et soumis durant 30 jours a differentes concentrations salines : 0 ; 42,8 ; 85,5 ; 171,1 et 256,6 mM de NaCl. Les resultats acquis montrent que la germination in vitro des axes embryonnaires n'a pas ete affectee par la concentration du sel. Cependant, le taux de survie des embryons germes passe de 100% pour le temoin a 62,9% pour la plus forte concentration saline (256,6 mM). D'autre part, l'estimation de la croissance des vitrosemis (longueur de la partie aerienne et racinaire, nombre de feuilles produites par embryon developpe ainsi que la production des biomasses totales des matieres fraiches et seches de la partie aerienne et racinaire) a decele des differences significatives pour les differentes concentrations du sel. Pour citer cet article : B. Benmahioul et al., C. R. Biologies 332 (2009).

Problem statement: The Lygeum spartum L. represented by a single species occupies several regions of the Mediterranean basin. This plant plays an important ecological role in the fight against desertification and economic development in the manufacture of paper pulp. Approach: However, the cytogenetic studies in mitosis in this species revealed the existence of two ploidy levels: 2n = 40 among the population grows in the coastal region of Oran in the semi-arid climate and 2n = 16 in the high plateaus characterized by an arid climate. Results: The study of the anther, pollen grains and the meiotic division conducted on these two populations of Lygeum spartum L. growing in the two regions has confirmed these data in that the microscopic observations were used to determine the ultrastructure of the anther, the shape and size of pollen grains which morphometric data (L/W) showed significant difference between the two populations. The microsporogenesis was followed on the mother cells of pollen grains in order to understand the formation of tetrads, then the enumeration of chromosomes was carried out in diakinesis (n = 20) for the coastal population of Oran and metaphase I (n = 8 ) for the population of the high plateaus. Conclusion/Recommendations: These results were consistent with what has been observed in mitosis, which suggested that the Lygeum spartum L. may submit two cytotypes to adapt to different geographical and climatic environments.

The aim of this research was to evaluate some technological traits of L. plantarum strains previously isolated from fermented olives. For this purpose, 11 strains were tested for their in vitro antibiotic susceptibility, resistance to low pH values, acidifying activity, proteolytic activity, haemolytic activity, lactic acid and exopolysaccharide production and resistance to freeze-drying .Collectively, the strains were susceptible to most of the antibiotics tested and showed survival at pH 2. Most strains showed high (1.035 ± 0.29 to 0.912 ± 0.21 mmol/l ± sd of lactic acid) or medium (0.556 ± 0.29 to 0.692 ± 0.18 mmol/l ±sd) acidification activity with good proteolytic activity (1.49 ± 0.25 to 5.25 ± 0.11 mg L-1 tyrosine). None of the strains produced exopolysaccharides or haemolysis in sheep's blood.El objetivo de esta investigación fue evaluar algunos aspectos tecnológicos de cepas de L. plantarum previamente aisladas de aceitunas fermentadas. Para este propósito, 11 cepas fueron usadas para estudiar su susceptibilidad a antibióticos in vitro, resistencia a valores de pH bajos, actividad acidificante, proteolítica, y hemolítica, producción de ácido láctico y exopolisacáridos, y resistencia a la liofilización. En general, las cepas fueron susceptibles a la mayoría de los antibióticos ensayados y mostraron supervivencia a pH 2. La mayoría de las cepas mostraron una actividad de acidificación alta (1.035 ± 0.29 a 0.912 ± 0.21 mmol/l de ácido láctico) o media (0.556 ± 0.29 a 0.692 ± 0.18 mmol/l) con una buena actividad proteolítica (1.49 ± 0.25 a 5.25 ± 0.11 mg L-1 tirosina). Ninguna de las cepas produjo exopolisacáridos o hemolisis en sangre de oveja.

Lygeum spartum L. represent a natural barrier in the Algerian high plateaus against the advances of sand and turning into a desert. This species has two levels of ploA¯dy (diploA¯d cytotype 2n = 16 and polyploidy cytotype 2n = 40). Protein profile of several populations of this species have inter and intra specific variability. The polymorphic bands observed in the intermediate and slow zone have a molecular weight (MW) of 25.6, 30.1, 31.2, 37.3, 40.4, 69.3 and 82.7 kDa. This polymorphism exists not only between the polyploids samples (well 1 to 7) and diploids (well 8 and 9), but also inside the polyploids populations. These results showed that modifications of the electrophoretic profile of Lygeum spartum were concomitant with climatic and geographical external factors.

International audience; In the perspective of studying lipid biosynthesis in the argan seed, the anatomy, ploidy level and lipid composition of mature seed tissues were investigated using an experimental design including two locations in Algeria and four years of study. Using flow cytometry, we determined that mature argan seeds consist of two well-developed tissues, the embryo and the endosperm. The lipid content of the embryo was higher than that of the endosperm, but the dry weight of the endosperm was higher. Consequently, both tissues contribute equally to seed oil yield. Considerable differences in fatty acid composition were observed between the two tissues. In particular, the endosperm 18:2 percentage was twofold higher than that of the embryo. The tocopherol content of the endosperm was also markedly higher than that of the embryo. In contrast, the endosperm and the embryo had similar sterol and triterpene alcohol contents and compositions.