Tunisian Varieties Research Articles

Screening and Profiling of Hydrocarbon Components and Squalene in Developing Tunisian Cultivars and Wild Arachis hypogaea L. Species

AbstractTotal hydrocarbon composition and content of whole peanuts from three Tunisian varieties of peanut (two cultivars: AraC (Virginia type), AraT (Valencia type) and a wild one: AraA) were investigated during maturation. The results show that 30 hydrocarbons were identified from the wild AraA species, while only 27 hydrocarbon were detected in the cultivar ones. The hydrocarbon fraction is essentially composed of squalene, n‐alkenes especially nC14=, nC16=, nC18=, nC20= and nC22=, n‐alkanes such as nC16, nC17, nC18, nC25, nC26 and nC27, and branched saturated hydrocarbon noted (HC1, HC2 and HC3). Among the hydrocarbon components, generally the wild variety AraA presents the highest content of phytochemical squalene during maturation, whereas a maximum was detected from cultivar AraT at 12 days after podding (815.45 mg/100 g of oil). At maturity, the maximum level is reached at about 346.74 mg/100 g of oil for AraA. During maturity, wild AraA is considered to be an excellent source of squalene like olive and pumpkin oil.

Physicochemical composition of different varieties of raisins (Vitis vinifera L.) from Tunisia

Raisins should be of particular interest in the investigation due to their unique phytochemical composition, and their natural qualities make them an appealing source of nutrients. In this study, physicochemical composition including weight, length, diameter, moisture, ash, protein, fat, carbohydrate, total sugar, fructose, glucose and some minerals (Na, Mg, K, Fe, Ca and P) of five Tunisian varieties of raisins were studied. Based upon statistical analysis, all varieties of raisins were a rich source of carbohydrate ranging from 65.86±0.81% (in Meski) to 76.62±0.86% (in Raseki), and glucose was the main sugar ranging from 32.37±0.70% (in Meski) to 37.33±0.28% (in Chriha) followed by fructose from 26.13±1.14% (in Karkni) to 31.21±0.29% (in Chriha). Important minerals were found in raisins include 628–854mg/100g DW potassium; 49.6–95.2mg/100g DW calcium and 28.67–41.79mg/100g DW magnesium. Considering the composition of raisins and the fact that they have no fat, it is no wonder that this fruit was considered a healthy snack.

Salt effect on phenolics and antioxidant activities of Tunisian and Canadian sweet marjoram (Origanum majoranaL.) shoots

Two varieties of Origanum majorana (Canadian and Tunisian) were evaluated for their phenolic, flavonoid and tannin contents, individual phenolic compounds and antioxidant activities under NaCl constraint. The results showed a significant variability in phenolic composition and antioxidant behavior between the two varieties under salt stress. The phenolic composition of methanolic extracts was determined by reversed-phase high-performance liquid chromatography. Amentoflavone was the predominant flavonoid compound; in addition, trans-2-hydrocinnamic acid became the major phenolic acid with salt treatment of the Tunisian variety. In the control, Canadian variety extract was characterized by high levels of gallic acid and amentoflavone. However, under 75 mmol L(-1) NaCl, gallic acid content doubled, whereas amentoflavone content was maintained in the Canadian variety. Stimulation of phenolic acid biosynthesis was observed in these two varieties under salt treatment despite the fact that shoots of the Tunisian variety showed higher antioxidant activities compared to those from the Canadian variety. Tunisian O. majorana might have developed tolerance to salinity and avoided tissue damage by activating enzymes involved in the galactosylation of quercetin into quercetin-3-galactoside and quercetin-3-rhamnoside. Our results confirmed the tolerance of Tunisian O. majorana plants.

Essential oil yield and trichomes structure in two sweet marjoram (Origanum majorana L.) varieties under salt stress

Origanum majorana L. shoots were investigated for their essential oil (EO) yield, composition and the structures responsible for its biosynthesis. Shoots EO was extracted by hydrodistillation and composition was determined by gas chromatography–mass spectrometry (GC-MS) method. Fresh Leaves were observed by light microscopy (LM). Plants were cultivated for 17 days in a basal medium supplemented with 75 mM NaCl. Salt decreased the essential oil yield in Tunisian variety (TV), but an increase was shown in Canadian variety (CV). Salt constraint induced a change in EO chemotype of two varieties. Their anatomical study showed three types of trichomes: (i) non-glandular, simple hairs; (ii) small, capitate glandular trichomes; (iii) and peltate glandular trichomes. Non-glandular trichomes provided of three types at the TV against two at the Canadian one at control. Indeed, with TV we observed; multicellular (M), bicellular (B) and unicellular (U) trichomes. Bicellular trichomes (BT) were observed in CV, and multicellular (MT) and bicellular (UT) in TV at salt constraint. The increase and the decrease of EO yield in CV and TV was respectively due to the presence of three type of EO secretion which seemed to make defect in Tunisian one. Key words: Trichomes, non-glandular, capitate, peltate, glandular, salt, chemotype.

Morphological and molecular characterization of six of the most frequently cultivated hard wheat varieties in Tunisia

To effectively differentiate and characterize six of the most cultivated hard wheat (Triticum durum Desf) varieties in Tunisia, morphological and molecular markers were used. In the former approach, 10 qualitative characters were employed, as recommended by UPOV descriptors. Twelve of the 17 screened simple sequence repeat (SSR) primers showed clear polymorphic patterns following agarose and polyacrylamide gel electrophoresis. Of these 12 primers, 64.3% produced polymorphic bands. Based on pedigree and origin, it was concluded that there was a narrow genetic base between these varieties. Mantel’s test showed a weak correlation between morphological and molecular data (r = 0.24), indicating that these two approaches are complementary and can be used to study polymorphism, even within a small durum wheat collection. This data set is important for Tunisian hard wheat breeders who would seek to expand the genetic base of their breeding material. Key words: Simple sequence repeat (SSR), International Union for the Protection of New Varieties of Plants (UPOV) descriptor, hard wheat, polymorphism.

The validity of using juvenile stages for evaluation of salt stress tolerance of Triticum durum genotypes

The aim of this work was to evaluate eight North African wheat genotypes ( Triticum durum ) on the basis of their salt stress tolerance. The effect of this abiotic constraint was investigated at tillering stage using hydroponic culture. Some growth and development parameters were measured between three and six leaves stages and also at harvest. Data were submitted to a comparative canonic analysis followed by a hierarchical cluster analysis within both aforementioned stages. Some old Tunisian varieties, such as Mahmoudi who was almost completely abandoned in cereal culture, showed more tolerance to stressful conditions than the new and standard productive varieties. This aptitude to tolerate salt was observed as well in the beginning and at the end of plant development cycle. We concluded that some measures at juvenile stage may be used as valid genetic discrimination tool, leading to time and space gain in breeding programs. Key words : Triticum durum , salt stress tolerance, juvenile stage, evaluation.

Chemical composition and profile characterisation of pumpkin (Cucurbita maxima) seed oil

Seeds of a Tunisian variety (Béjaoui) of pumpkin (Cucurbita maxima) were analysed for their main chemical composition and for their oil properties. Expressed on dry weight basis, seed moisture was 8.46%, whereas contents of proteins, fibre, ash, fat, and total sugars established at 33.92%, 3.97%, 21.97%, 31.57%, and 0.11% respectively. Gas chromatography revealed that the major fatty acids were oleic, linoleic, and palmitic acids (44.11%, 34.77%, and 15.97% respectively). Seed oil was also found to be rich in tocopherols with a predominance of δ-tocopherol (42.27%). The sterol marker β-sisosterol accounted for 39.6% of total sterols contained in seed oil of this variety. Six phenolic acids (protocatechuic, caffeic, syringic, vanillic, p-coumaric and ferulic) were detected, the syringic acid being predominant (7.96mg/100g). As a whole, based on its seed oil features, pumpkin may be considered as a valuable source for new multi-purpose products for industrial, cosmetic, and pharmaceutical utilisation.

Salt effects on Origanum majorana fatty acid and essential oil composition

The effects of salt on the essential oil yield and fatty acid composition of aerial parts of two marjoram varieties were investigated. Plants with 6 leaves were treated with NaCl (75mM). Salt treatment led to a reduction in aerial part growth. Salinity increased the fatty acid content more significantly in Tunisian variety (TV) than in Canadian variety (CV). CV showed an increase in double-bond index (DBI) and a decrease in malondialdehyde content under salt stress, while the opposite was observed in TV. The DBI was mainly affected by a strong reduction in oleic and linoleic acids in TV, whereas a strong stimulation of linoleic acid in CV was observed. Salt decreased and increased the essential oil yield in TV and CV respectively. The main constituents of the essential oil of TV were trans-hydrate sabinene and terpinen-4-ol, which showed a significant decrease under salt stress. In contrast, the main constituents of the essential oil of CV were sabinene and trans-hydrate sabinene, which showed a significant decrease and increase respectively under salt stress. Marjoram oil is a rich source of many compounds such as essential oils and fatty acids, but the distribution of these compounds differed significantly between the two varieties studied.

Chemical composition and biological activities of Tunisian Cuminum cyminum L. essential oil: A high effectiveness against Vibrio spp. strains

Essential oil extracted by hydrodistillation from Tunisian variety of Cuminum cyminum was characterized by means of GC and GC–MS. Twenty-one components were identified and C. cyminum contained cuminlaldehyde (39.48%), gamma-terpinene (15.21%), O-cymene (11.82%), beta-pinene (11.13%), 2-caren-10-al (7.93%), trans-carveol (4.49%) and myrtenal (3.5%) as a major components. Moreover, C. cyminum oil exhibited higher antibacterial and antifungal activities with a high effectiveness against Vibrio spp. strains with a diameter of inhibition zones growth ranging from 11 to 23 mm and MIC and MBC values ranging from (0.078–0.31 mg/ml) to (0.31–1.25 mg/ml), respectively. On the other hand, the cumin oil was investigated for its antioxidant activities using four different tests then compared with BHT. Results showed that cumin oil exhibit a higher activity in each antioxidant system with a special attention for β-carotene bleaching test (IC 50: 20 μg/ml) and reducing power (EC 50: 11 μg/ml). In the light of these findings, we suggested that C. cyminum essential oil may be considered as an interesting source of antibacterial, antifungal and antioxidants components used as potent agents in food preservation and for therapeutic or nutraceutical industries.

EFFECTS OF GROWTH CONDITION AND THE DEVELOPMENT STAGE OF TWO TUNISIAN VARIETIES OF ROSMARINUS OFFICINALIS L. ON THE ESSENTIAL OIL YIELD AND ITS CHEMICAL COMPOSITION

This study aims at comparing the yield and essential oils composition of two Tunisian varieties of rosemary (troglodytorum and typicus) under different growth conditions (wild or cultivated) and phenological stages (vegetative or flowering). Seedlings of Rosmarinus officinalis L. collected from Matmata (troglodytorum variety) and Kef (typicus variety) areas were transplanted in an experimental field at the Institut des Regions Arides of Medenine (South Tunisia). The aerials parts were harvested at flowering and vegetative stages. The essential oil was isolated by hydrodistillation and its chemical composition was determined by GC (RI) and GC-MS. The highest yield was recorded in cultivated plants during full vegetative stage (3.26 and 3.23% for troglodytorum and typicus variety, respectively). The chemical composition of the essential oil was dominated by 1,8-cineole, camphor, α-pinene and camphene for troglodytorum variety and 1,8-cineole for typicus variety. It appears that growth conditions (cultivated, wild) and phenological stage (vegetative or flowering) of rosemary plants revealed a similar essential oil composition.

Sterol, Triterpenic Dialcohol, and Triacylglycerol Compounds of Extra Virgin Olive Oils from Some Tunisian Varieties Grown in the Region of Tataouine

The aim of this work was to study some of the chemical characteristics of virgin olive oils produced by three varieties grown in Tataouine (south of Tunisia). The oil samples studied were characterized by high levels of oleic acid (470%) and relatively low percentages of linoleic and palmitic acids (≤13% and ≤10%, respectively). They were also characterized by three primary triacylglycerols: OOO, POO, and OOL, and three secondary triacylglycerols POL + SLL, SOO, and PPO. The sterol and triterpenic dialcohol compositions of all the samples lay within the established regulatory limits. The main sterols found were b-sitosterol, Δ5-avenasterol, and campesterol. The amount of minor sterols present (24-methylenecholesterol, cholesterol, Δ7-avenasterol, and Δ7-stigmastenol) varied widely according to the varieties. The levels of erythrodiol + uvaol were below the upper legal limit of 4.5% in all analyzed samples. The results obtained showed that the great variability in oil composition among the varieties studied are influenced exclusively by the genetic factor.

Genotypic variability within Tunisian grapevine varieties ( Vitis vinifera L.) facing bicarbonate-induced iron deficiency

Morpho-physiological responses to bicarbonate-induced Fe deficiency were investigated in five Vitis vinifera L. Tunisian varieties (Khamri, Blanc3, Arich Dressé, Beldi, and Balta4). One-month-old woody cuttings were cultivated for 85 days on a free calcareous soil irrigated with tap water containing increasing bicarbonate levels (0, 4, 8, 12, and 16 mM NaHCO 3). After this screening, a second experiment compared root biochemical responses of two contrasting genotypes (tolerant-sensitive) dealing with bicarbonate-induced iron deprivation (20 μM Fe ± 10 mM HCO 3 −) for 75 days. Using morpho-physiological criteria, grapevine tolerance to HCO 3 −-induced Fe shortage appeared to be genotype-dependent: Balta4 and Beldi varieties showed the highest leaf-chlorosis score (especially at the extreme HCO 3 − levels), in contrast to Khamri variety. Growth parameters (shoot height, total leaf area, leaf number, and biomass production) as well as juvenile leaf chlorophyll content were also differently affected depending on both genotype and bicarbonate dose. At 16 mM HCO 3 −, Khamri was the less sensitive variety, contrasting with Balta4. On the other hand, chlorophyll content correlated positively with HCl-extractible Fe content of the juvenile leaves, suggesting that the grapevine response to iron deficiency may partly depend on to the plant ability to adequately supply young leaves with this element. Root biochemical responses revealed a relatively higher root acidification capacity in Khamri (tolerant) under Fe-deficiency while no significant changes occurred in Balta4 (sensitive). In addition, Fe(III)-reductase and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activities were strongly stimulated by Fe-deficiency in Khamri, while remaining constant in Balta4. These findings suggest that biochemical parameters may constitute reliable criteria for the selection of tolerant grapevine genotypes to iron chlorosis.

Biochemical Responses to True and Bicarbonate-Induced Iron Deficiency in Grapevine Genotypes

ABSTRACT Biochemical responses to direct or bicarbonate-induced iron (Fe) deficiency were compared in two Tunisian native grapevine varieties, Khamri (tolerant) and Balta4 (sensitive), and a tolerant rootstock, 140Ru. Woody cuttings of each genotype were irrigated with a nutrient solution containing one of the following: 20 μM Fe (control), 1 μM Fe (direct Fe-deficiency), or 20 μM Fe + 10 mM HCO3 − (indirect bicarbonate-induced Fe-deficiency). Under direct Fe-deficient conditions, lower leaf chlorosis score and higher chlorophyll and leaf Fe contents were found in Khamri and 140Ru compared with Balta4. Moreover, indirect Fe deficiency caused similar effects on these parameters, which were more pronounced in Balta4. Both tolerant genotypes, Khamri and 140Ru, showed higher roots-acidification capacity and phenol release under the direct Fe deficiency compared with the bicarbonate-induced condition. In the sensitive variety, Balta4, no significant changes were found between the control and Fe-deficient plants. Root Fe(III)-reductase activity was strongly stimulated by both types of Fe deficiency in Khamri and 140Ru, and displayed no significant changes in Balta4. In the three genotypes, root and leaf activities of two Fe-containing enzymes, catalase and guaiacol peroxidase, were significantly affected under Fe deficiency (either direct or induced), though to a greater extent in the sensitive variety, Balta4. The latter also displayed higher leaf malonyldialdehyde (MDA) content, traducing an important membrane lipid peroxidation.

Tunisian fig (Ficus caricaL.) genetic diversity and cultivar characterization using microsatellite markers

Introduction. Ficus carica L., well adapted to the Mediterranean climate, is ubi- quitous in Tunisia. In spite of the large possibilities of its adaptation to the Tunisian climate, its cultivation remains traditional. In Tunisia, this species is represented by a large number of varieties which are facing genetic erosion. To save these genetic resources, we studied some of the Tunisian varieties using molecular markers. The aim of this analysis was to study the genetic diversity of some cultivars and to characterize them. Materials and methods. Six microsatellites were used to characterize 16 cultivars (Ficus carica L.) belonging to two fig tree collections in the south of Tunisia. Results. The molecular markers used appeared highly polymorphic in common fig trees since 4-12 alleles per locus and a mean of heterozygoty of 0.656 were scored. The resolving power (Rp) of the six microsatellites tested ranged from 2.12 to 3.87 for the 16 cultivars studied, showing a significant genetic diversity (Ht = 0.762). Gene- tic differentiation between geographical groups was low (Gst = 0.032). The factorial corres- pondence analysis showed no well-defined relation between the 16 cultivars and their geographical origin. The genotype patterns allowed us to discriminate all of the cultivars. Conclusion. The characterization of the accessions belonging to different varieties was possi- ble, showing the power and efficiency of the molecular tools used. Tunisia / Ficus carica / genetic resources / identification / microsatellites / genetic markers

Combined effect of alkali pretreatment and sodium chloride addition on the olive fermentation process

Green olives of the Tunisian variety “Meski” were treated according to a Spanish-style green olive preservation process by using an alkaline treatment (1.5, 2 and 2.5% (w/v) NaOH) to eliminate bitterness, combined with different brine concentrations (6, 9 and 12% (w/v) NaCl). A spontaneous fermentation by the environmental microflora took place. Results showed that 2% NaOH solution and 9% sodium chloride brine was an optimal combination inducing the best growth of Lactobacillus species (10 8 CFU/ml) and acidity of 0.726 g lactic acid/100 ml brine. In all trials and independently of the treatment, Lb. plantarum was the most dominant strain of Lactobacillus. Moreover, pretreatment with lye and lactic fermentation of olives contributed to coliform elimination.

Physiological responses of Tunisian grapevine varieties to bicarbonate-induced iron deficiency

Plants are frequently submitted to iron deficiency when growing on calcareous soils, which contain high concentrations of bicarbonate. The purpose of this study was to investigate the variability of physiological responses of Tunisian grapevine varieties to bicarbonate-induced iron chlorosis. Vine woodcuttings of seven autochthonous Tunisian varieties (Khamri, Mahdaoui, Blan3, Saouadi, Arich Dressé, Beldi and Balta4), two rootstocks (140Ru and S.O.4), and an introduced table variety (Cardinal) were cultivated on inert sand for 2 months using a complete nutrient solution (20 microM Fe) that was either well supplied or not supplied with 10 mM HCO3-. Young leaves of plants cultivated on bicarbonate-enriched medium showed characteristic symptoms of iron chlorosis, although the intensity of the symptoms depended on the variety and the rootstock. Chlorosis score confirmed these observations since the most sensitive varieties showed the highest values. This variability in tolerance to iron deficiency was also displayed when analysing the physiological parameters (shoot length, plant dry weight, and chlorophyll concentration) and the iron contents in the 4th leaf. Analysis of morphological and physiological parameters showed three behaviour groups. The first one corresponded to tolerant varieties (Khamri, Mahdaoui, and the root-stock: 140Ru), the second included moderately tolerant vines (Saouadi, Arich Dressé, Blanc3, and the rootstock: S.O.4) and the third represented the sensitive ones (Balta4, Beldi, and Cardinal).

Rapid Construction of a Random Genomic Library from Date-Palm (Phoenix Dactylifera L.)

A random genomic library of Tunisian date-palm varieties has been built from total cellular DNA, previously amplified according to an RAPD procedure. The resultant recombinant DNA is characterised by a size ranging from 200 to 1600 bp inserts. This DNA would constitute a large number of anonymous probes useful in Southern hybridisation experiments. It would also provide potential markers aimed at the molecular characterisation of date-palm varieties, aid the search of those associated with bayoud disease and suggest a sex determination of trees.

Evidence for salt tolerance in pepper varieties (Capsicum annuum L.) in Tunisia

Salt tolerance in pepper (Capsicum annuum L.) is described in terms of yield, mortality and root weight. Significant differences in absolute and in relative salt tolerance were demonstrated between Tunisian varieties. Relative salt tolerance of ‘Beldi’ was found to be due to its root system which remained unreduced under stress condition; local adaptation could be involved. ‘D'hirat’ showed interesting levels of absolute salt tolerance and low mortality. An ECw-value \s-> 7.63 dS/m was critical for almost all characters observed, with reductions of approximately 50%. Fruit weight and shoot-root ratio were not significantly affected by high salt concentrations of the irrigation water.