Anissa Boubaya

Polyploidy induction of Tunisian Trigonella foenum- greaum L. populations

Polyploidy plays an important role in plant evolution and constitutes an important mechanism of diversification and creation of genetic variability. Artificial polyploidy can be induced using the colchicine. The aim of this study was to determine the Trigonella foenum-greacum (2n= 16) population which resists better to colchicine treatment and which has the highest rate of polyploid formation among 38 populations collected from different Tunisian regions. The comparative study between treated and control plants showed significant increases (p < 0.05) for the parameters survival rate, rate of malformed leaves appearance, stem height and seeds number by pod. The 38 treated populations showed significant variations (p < 0.05) between them for the parameters survival rate, branches number, stem height and seeds number by pod. Results also showed that treatment of the shoot meristem by colchicine allowed to obtain diploid (2n= 16) and mixoploid plants having mixoploid branches (4n = 32 and 2n= 16) and branches entirely tetraploid (4n = 32). The obtained rate of mixoploidy was 65.79% of treated plants. Among the 38 analyzed fenugreek populations, the population 15 of Menzel Temime presented the highest rate of mixoploids formation and survival rate to colchicine treatment.

Antibacterial activity of extracts of diploid and induced autotetraploid Tunisian populations of Trigonella foenum-graecum L.

Trigonella foenum-graecum L. is a medicinal plant known for its various pharmacological properties, including the anti-bacterial and the anti-microbial effects. This study aimed to determine and compare the antibacterial activities of extracts of two Tunisian T. foenum-greacum populations, diploid (2 n=16) and its induced autotetraploid (4 n=32). Aqueous and organic extracts (petroleum ether, ethyl acetate and methanolic fractions) prepared from seeds and leaves were assayed to determine their antibacterial potential against Staphylococcus aureus , Staphylococcus epidermidis , Enterococcus faecalis , Escherichia coli and Salmonella Typhimurium using agar disk diffusion method. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined. The results showed that the organic extracts had no antibacterial potential against the tested bacteria contrary to the aqueous extracts. The extracts prepared from the seeds were more active compared to those prepared from the leaves against all tested strains. And the induced autotetraploid population presented an antibacterial activity higher than that of the diploid population.

Performance physiologique du génotype autotétraploïde induit de Trigonella foenum-graecum L. comparée aux génotypes diploïdes

Abstract Polyploid plants are distinguished from diploids by an improved photosynthetic capacity related to the increase of the photosynthetic enzymes and pigments quantities. The aim of this work was to study the physiological performances accompanying the experimental polyploidisation of Trigonella foenum- graecum by comparing the induced autotetraploid, the diploid resulting from the treated plants and the parent. Total chlorophylls content, photosynthesis rate, transpiration rate and stomatal conductance were measured for each genotype. Results showed highly significant variations (p < 0.01) between the different genotypes for the studied physiological characters. PCA and UPGMA method structured the genotypes in two groups. The first group is formed by the autotetraploids and the second is consisted by the parents and the diploids resulting from the treated plants.

Induction de la polyploïdie chez Trigonella foenum-graecum L.: comparaison morphologique et chimique entre les diploïdes et les autotétraploïdes induits

Abstract Trigonella foenum graecum L. is a diploid leguminous plant (2 n = 16) used as forage and vegetable. The objective of this study was to produce a polyploid cultivar of this plant and to evaluate its morphological and chemical potentialities. Polyploidy induction was carried out by using a 0.5% colchicine solution. Tetraploids and diploids seeds resulting from the obtained mixoploids and the control seeds were used for the comparative study extended on 4 plant generations. The autotetraploid cultivar has larger leaf area and larger productivity compared to the diploids concerning seed number, pod number and branch number. Its leaves are richer in potassium, sodium, calcium and phosphorus. Polyploidy induction is an effective method to increase the yield and the mineral contents of Trigonella foenum-graecum.

Répercussion de la polyploïdie artificielle sur la tolérance au stress salin chez Trigonella foenum-graecum L en Tunisie

Abstract Salinity is a global problem that limits crop production, especially on irrigated area in the world. The artificially induced polyploidy could make Trigonella foenum-graecum more tolerant to the salinity increase provoked by irrigation. The objective of this study was to compare salt stress tolerance of the induced autotetraploids, the diploids resulting from treated plants and the control diploids of Trigonella foenum-graecum. Morphological descriptors of these cytotypes, irrigated with water of 25, 50 and 100 mM of NaCl concentrations, was evaluated. The three cytotypes manifested a decrease of morphological characters measured values with the increase of NaCl concentration in irrigation water. Autotetraploid cytotype presented significant increases of these values compared to parent cytotype for the majority of studied characters. It seems more tolerant to NaCl salinity than its diploid parent.

Morphological and chemical diversity among South Tunisian mulberry tree (Morus spp.) cultivars

Abstract In Tunisia, the mulberry tree culture is threatened by the extension of urbanization. To contribute to a better knowledge of mulberry tree diversity in the south of Tunisia, morphological and mineral characterizations were performed for twenty three collected cultivars. The studied cultivars belong to the species Morus alba, M. nigra and M. rubra. Twenty two leaves, flowers and fruits morphological characters and four nutrients were studied for each cultivar. The leaf surface varies from 44 cm2 to 254.68 cm2. The fruit weight varies from 1.091 g to 6.245 g. P, K and Cl contents of majority of the cultivars are respectively higher than 0.3, 1.5 and 0.3% of the leaves weight, Na content of 60.68% of the cultivars is less than 0.1% of the leaves weight. Statistical analysis reveals six groups of cultivars with no Mantel correlation between morphological characters, nutrient contents and geographic distances.

Analyse de la diversité chimique des cultivars de mûriers du Sud tunisien

Abstract The dietetic and therapeutic importance of mulberry tree carried out us to study the fruit content variability in sugar and vitamins in the Tunisian South. The blackberries studied cultivars manifest a richness in reducing sugars. The average contents of glucose and fructose are respectively 4.96 g/100 g and 5.75 g/100 g. This study also shows that the blackberry is rich in vitamin B6 and vitamin C and presents fewer contents in vitamins B1 and B2. The average contents were 12 mg/100 g for vitamin B6, 0.56 mg/100 g for B1 and 0.67 mg/100 g for B2. The contents of vitamin C are higher than 16 mg/100 g for 15% of studied cultivars, and vary from traces to 7.4 mg/100 g for the 85% of cultivars. Statistical analysis reveals four groups of cultivars with a significant correlation between fruits contents in sugars and vitamins and geographic distances between the collected cultivars.

Répercussion de la polyplïdie sur le profil moléculaire ISSR et sur les contenus en vitamines et en protéines chez Trigonella foenum-graecum L.

Abstract Polyploidy constitutes a significant mechanism of genetic diversification and variability generation. The objective of this study is to compare molecular profiles, vitamins and proteins contents between the induced autotetraploids, the diploids resulting from treated plants and the control diploids. Molecular variability between these cultivars was studied using ISSR (Inter Simple Sequence Repeat) markers. Vitamins B6, B9 and C contents of the seeds were analysed by HPLC (High Performance Liquid Chromatography). Proteins contents of the seeds were analysed by the Bradford method. The mean heterozygosity between the three cultivars evaluated by the whole of the studied primers was weak (0, 06). The autotetraploids presented mean heterozygosity values higher than those of the diploïdes for 50 % of the studied primers. They presented higher vitamins B6 and B9 and higher albumin, prolamin and glutelin seed contents compared to the diploids resulting from the treated plants and the diploids parents.