Variabilité des teneurs en composés phénoliques et des activités biologiques chez six espèces médicinales

M. SAADA ¹

M. KHEMAKHEM ²

R. KSOURI ¹

¹Laboratoire des Plantes Aromatiques et Médicinales, Centre de Biotechnologie de Borj-Cédria, BP 901, 2050 Hammam-lif, Tunisie.

²Université de Carthage, Ecole Supérieure des Industries Alimentaires de Tunis, 58, Avenue Alain Savary, 1003 Tunis, Laboratoire de Chimie Organique Structurale : Synthèse et Etude Physicochimique, Faculté des Sciences de Tunis, Campus Universitaire 2092 - El Manar, Tunisie

Abstract - The main objective of this study is to evaluate the interspecific variability of biological capacities and phenolic composition of the aerial parts of six medicinal species (Retama raetam, Nitraria retusa, Pituranthos tortuosus, Zygophyllum album, Juncus maritimus and Rubia timctorum). At first, a comparison of the total polyphenol, flavonoid and proanthocyanidin contents of these species was carried out. The tests used to evaluate the antioxidant activities of the plants studied consisted in determining the total antioxidant activity, the antiradical power against DPPH, the reducing power of iron and the β-Carotene bleaching test. In a second step, the antimicrobial activity against five pathogenic bacteria was also tested. The obtained results showed a significant variability of the phenolic compound contents between the six species of interest. Indeed, R. raetam was found to be the richest species in total polyphenols and flavonoids (23.93 mg EAG.g^-1MS and 3.58 mg EC.g^-1MS respectively) compared to other species whose contents are less than 9.36 mg EAG.g^-1MS and 3.26 mg EC.g^-1MS respectively. In addition, the analysis of antioxidant capacities confirmed the existence of an important differences between these six species. In fact, R. raetam showed the best anti-radical and iron reducing activities (the IC₅₀ and EC₅₀ are in the order of 23 and 410 μg.ml^-1 respectively) while the extract of J. maritimus was significantly more efficient as to the inhibition of β-carotene bleaching. Moreover, the antimicrobial activity test also confirmed the superiority of R. raetam over other species, as it showed the highest inhibition diameters (ZI between 11.00 and 16.33 mm). All the results obtained attest to the superiority of the specie R. raetam compared to the other studied plants from the point of view of richness in phenolic compounds and biological potentialities.

Keywords: medicinal plants; antioxidant activities; antimicrobial capacity; phenolic compounds.

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I. HAMDENI¹

S. SLIM²

A. BOULILA³

T. BETTAIEB¹

¹Research Laboratory of Horticultural Sciences, National Agronomic Institute of Tunisia, University of Carthage, Tunisia;

²Research Unit of Biodiversity and Valorization of Resources in Mountainous Areas, School of Higher Education in Agriculture of Mateur, University of Carthage, Tunisia;

³Laboratory of Natural Substances, National Institute of Research and Physico-chemical Analyses, Biotechpole of Sidi Thabet, Ariana, 2020, Tunisia.

Abstract - This study investigates the nutritive properties of Aloe vera leaf gel (AvG) used in in vitro propagation from shoot tip explants of A. vera plant. Therefore, induced shoots of A. vera were prolifired on MS medium (Murashige and Skoog, 1962) supplemented with various concentrations of AvG as organic supplement. The highest shoot multiplication was found on M3 containing MS media + 0.2 mg/L IBA (β-indole butyric acid) + 3 mg/L BA(benzylamino-purine) + 50 g/L AvG (13.27 ±5.11). This demonstrated that adding 50 g/L AvG to the culture media has increased the number of shoots compared to the control treatment M1 (5.00 ±2.27). Moreover, the longest shoot (2.50 ±0.89 cm) was found on M2 medium (MS + 0.2 mg/L IBA + 3 mg/L BA + 25 g/L AvG) followed by M3 (50 g/L AvG) and M1 (control) respectively. For microshoots rooting, the effect of the substitution of MS medium by AvG was assessed. The AvG was used as a substitute source of nutrients to the culture media. The maximum number of roots (5.93 ±1.39; 5.73 ±1.75) and the longest root (6.20 ±1.32; 5.90 ± 1.43 cm) were recorded on control medium (Full MS) and 1/2 strength MS medium supplemented with 10% AvG. All of the rooted explants (100%) survived during and after the acclimatization in the pots in the culture room. The regenerated plants looked healthy and they were morphologically similar to the mother plants.

Keywords: in vitro propagation, shoot tip explants, Aloe vera leaf gel, substitution.

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S. SAI KACHOUT¹

A. ENNAJAH²

F. SRARFI¹

A. ZOGHLAMI¹

¹National Institute of Agronomic Research of Tunis, (INRAT).

²National Research Institute for Rural Engineering, Water and Forestry (INRGREF)

Abstract - Pea (Pisum sativum L.) is known as a species that is not competitive with weeds, and certain agronomic levers such as increased seedling density allow peas to be more competitive. This work was conducted to study the response of a variety of field pea (Afila) to plant density. An experimental test on the INRAT site in Mornag-Tunisia, under rain conditions, consists in studying the effect of six seedling densities: 20, 60, 100, 140, 180 and 220 seeds/m^-2 on the agronomic performance of P. sativum. Our objective is to evaluate the yield components of P. sativum in order to identify the planting density that generates optimum yield. The results indicate that the planting density significantly affects the production parameters (number of pods, number of seeds, harvest index..,) of P. sativum. Thus, plants with low planting densities produce more seeds than plants with high-density treatments. On the contrary, emergence rate and dry biomass increase with planting density. The increase in seedling density resulted in a significant increase in seed yield of 145 g/m² for the density of 140 seeds/m² to 273 g/m² for the density of 220 seeds/m². Thus, the average yield was 18 qx/ha against a yield having a ceiling of 30 qx/ha. However, field pea in association with cereals can also improve the agronomic performance of forage crops.

Mots clés :  field pea, seedling density, seed yield, yield components

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L’effet de la culture intercalaire vigne-luzerne sur les paramètres biochimiques de la vigne sur un sol cadmique

S. JEDER^1,2

F. MELKI^1,2

F. LOUATI¹

I. NOUAIRI¹

B. BOUAMAMA-GZARA³

H. MHADHBI¹

K. ZRIBI¹

¹Laboratoire des Légumineuses et Agrosystèmes Durables, Centre de Biotechnologie de Borj Cedria, BP 901, 2050 Hammam Lif, Tunisie

²Faculté des Sciences de Gabès, Université de Gabès, cité Erriadh 6072 Zrig, Gabès, Tunisie

³Laboratoire de physiologie moléculaire végétale, Centre de Biotechnologie de Borj Cedria, BP 901, 2050 Hammam Lif, Tunisie

Abstract - Viticulture is constantly confronted with abiotic stresses. Due to human activities such as industrial waste, chemical fertilizer applications, smelting and sewage disposal. As a result, several heavy metals, such as cadmium, have accumulated more and more in the soils. These heavy metals cause acute and chronic toxic effects on plants grown on these soils. Intercropping is a powerful way to promote a more diverse plant community on the ground, allowing for complementary and facilitating relationships to alleviate the stress implied by heavy metals on plants and soil. In these systems, pulses are a key functional group and are highly valued for the agroecological services they provide. In this study, the application of a cadmium concentration of 1mM to a soil, containing Vitis vinifera in co-culture with Medicago sativa, increased the stress markers MDA, H₂O₂ and proline and decreased the production of soluble proteins. and total sugars. Co-culture and inoculation with RCR2011, a reference strain of Sinorhizobium meliloti, alleviated the stress induced by cadmium.

Key words: Medicago sativa, vine, cadmium, co-culture, biochemical parameters

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Caractérisation phénotypique d’une collection d’isolats de rhizobium sp. nodulant le fenugrec (Trigonella foenum-graecum L.)

F. MELKI^1,2

S. JEDER^1,2

F. LOUATI¹

I. NOUAIRI¹

H. MHADHBI¹

K. ZRIBI^1*

¹Laboratoire des Légumineuses et Agrosystèmes Durables, Centre de Biotechnologie de Borj Cedria, BP 901, 2050 Hammam Lif, Tunisie

²Faculté des Sciences de Gabès, Université de Gabès, cité Erriadh 6072 Zrig, Gabès, Tunisie

Abstract- Fenugreek is a species of the legume’s family having several beneficial interests for the soil, agriculture and human health (fodder, edaphic, medical, aromatic and food). This plant is naturally in nitrogen fixing symbiosis in association with Sinorhizobium meliloti, its specific rhizobial partner. In this work, we present a phenotypic characterization of a collection of isolates of this plant subjected to two types of stress, metallic and saline. Our results showed that most of the isolates tolerate a concentration of 400 mM NaCl and this tolerance gradually decreases with increasing concentrations. Only four isolates were able to grow at 1.2 M NaCl. Regarding heavy metals (Cadmium, Lead and Zinc), it is important to note that isolates from Gzala soil (soil near a mining site) are relatively more tolerant than those from Mateur one (agricultural soil). These isolates tolerate up to 700 µM Cd, 1.5 mM Zn and 2 mM Pb. Likewise, Gzala soil isolates are capable of producing siderophores.

Key words: Heavy metals, rhizobium, Fenugreek, salt stress, fixing nitrogen symbiosis

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