Ziziphus lotus L. (Lam.) and Z. mauritiana Lam., as a widespread species in Tunisia, are well known for their medicinal and food uses. The aim of the present study was to screen the content of total polyphenols, flavonoids, and condensed tannins together with the radical scavenging capacity and the antimicrobial activity of leaves, fruits and seeds extracts of Z. lotus and Z. mauritiana from different localities. Results showed that leaves extracts presented the highest phenolic compounds content for both species. Furthermore, LC-ESI-MS analysis allowed the identification of 28 bioactive compounds regardless of species and organs, with the predominance of quinic acid and rutin. Leaves extract of Z. mauritiana possessed the highest total antioxidant capacity. The antimicrobial tests showed that leaves extracts of Z. mauritiana and Z. lotus from Oued Esseder exhibited the highest activity against four bacterial strains (Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and Escherichia coli). The main results showed that the studied species of Ziziphus genus are an excellent source of natural bioactive molecules that could be an interesting material for industrial and food purposes.

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Purpose Date palm (Phoenix dactylifera L.) is one of the predominant fruit trees grown in oases ecosystems (Southern Mediterranean regions) and produces several wastes during practicing cultivation since fruit and bunch thinning is frequently applied. Yet, the valorization of date palm wastes as bioresources has received little attention. The main objective for the present research is to assess palm trees compost (P-compost) as organic fertilizer for alfalfa (Medicago sativa L.). Methods The experiment was carried out in an experimental field involving four replicates and three soil amendment treatments (1) control, conventional mineral fertilizer diammonium phosphate, (2) 30 t ha -1 of cow manure, and (3) 30 t ha -1 of palm tree compost (P-compost). Plots were planted on with alfalfa and the measurements of studied traits (growth, yield, seed yield and minerals uptake) were determined for two crop seasons (2010 and 2011). Results Compared with untreated soil, the palm compost application at 30 t ha -1 improved significantly both organic matter and water retention capacity of the soil and decreased the electrical conductivity (-70%).Furthermore, palm compost supply significantly increased fresh biomass production of alfalfa by 21 and 28%, respectively, during the first and second seasons. Also, it enhanced the grain yield and growth rate (stem length and leafs expansion) of this species. At the first crop season, the palm compost application had a positive impact on minerals nutrition compared to the control treatment, with improving rates of ? 32% for phosphorus, ? 25% for potassium and ? 6% for nitrogen. In addition, these contents were higher than in plants grown under cow manure amendment. However, at the second season, the palm compost improved only P and N contents. Conclusions This preliminary finding suggests that palm compost at moderate dose (30 t ha -1 ) could be highly beneficial for forage plant yield.

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Alfalfa (Medicago sativa L.) is one of the most important forage crops in the world. It has been originated from the Caucasus region (Michaud et al., 1988). The species presents purple flowers, a tap root, an erect growth habit, coiled pods and no winter dormancy. This plant improves the yield and quality of the following crops by atmospheric nitrogen fixation (Bruulsema and Christie, 1987 AbstractVariability in germination under controlled conditions with and without salt, seeds characteristics and field emergence were evaluated for 20 landraces of Medicago sativa ssp sativa, a forage legume collected from three sites in Tunisia. Highly significant differences were recorded among the landraces (p < 0.001) for all the characters studied except tegument colour. Number of seeds produced per plant ranged between 378 and 460 seeds g -1 . Emergence responses of seeds were different among landraces and sites and their values ranged between 12 to 45%. Salt stress (150 mM) caused substantial reduction in final and rate of germination of all the landraces with an average decline of 62.4 and 69.7%, respectively. Final germination values ranged from 26.5 to 75.75% when supplied distilled water. However, final germination values ranged from 10.75 to 32.5% when the seeds were exposed to saline water (150 mM). Rate of germination ranged from 12.75 to 63.25% and from 6.25 to 21.25% at non-saline and salt stress, respectively. Cluster analysis separated the 20 landraces into four clusters. Three landraces in the first cluster had the lowest germination and the greatest field emergence. One landrace composed the second cluster and showed both high germination and field emergence. Two landraces in the third cluster presented greater germination and low emergence. The other landraces constituted the fourth cluster and had intermediates emergence and germination.Additional key words: arid land; diversity; salt stress; seeds. Resumen Variabilidad en la germinación y en la emergencia de variedades autóctonas de Medicago sativa en diferentes oasis de TúnezSe evaluó la germinación en laboratorio con y sin estrés salino, así como las características de las semillas y la emergencia de 20 poblaciones de la leguminosa forrajera Medicago sativa ssp sativa, procedentes de tres localidades de Túnez. Se observaron diferencias altamente significativas entre las poblaciones (p < 0,001) en todos los caracteres estudiados excepto en el color del tegumento. El número de semillas por gramo varió entre 378 y 460. La emergencia de las semillas fue diferente entre las poblaciones y las localidades (variaron entre el 12 y el 45%). El estrés salino (150 mM) causó una fuerte reducción en todas las poblaciones, tanto en la germinación final como en el porcentaje de germinación, con una reducción media del 62,4 y 69,7%, respectivamente. Los valores de germinación finales variaron entre 26,5 y 75,75% y entre 10,75 y 32,5% con agua destilada y estrés salino, respectivamente. El porcentaje de germinación varió desde el 12,75 al 63,25% y del 6,25 al 21,25% en ...

Thirty-one rhizobial isolates nodulating native Lupinus angustifolius (blue lupine) plants growing in Northern Tunisian soils were isolated and analysed using different chromosomal and symbiotic gene markers. Phylogenetic analyses based on recA partial sequences grouped them into at least five groups: four of them within the genus Bradyrhizobium (26 isolates) and one into the genus Microvirga (5 isolates). Representative strains were analysed by multilocus sequence analysis of three housekeeping genes rrs-recA-glnII and rrs-gyrB-dnaK for Bradyrhizobium and Microvirga isolates, respectively. Based on this analysis, eight isolates clustered with the previously described strains Bradyrhizobium lupini USDA3051 and Bradyrhizobium canariense BTA-1. However, five of the isolates clustered separately and may constitute a new species within the Bradyrhizobium genus. The remaining five isolates were closely related to the strain Microvirga sp. LmiM8 and may constitute a new Microvirga species. The analysis of the nodC gene showed that all Bradyrhizobium strains nodulating blue lupine belong to the symbiovar genistearum, whereas the Microvirga isolates are associated with the symbiovar mediterranense. The results of this study support that the L. angustifolius root nodule symbionts isolated in Northern Tunisia belong mostly to the B. canariense/B. lupini lineages. However, new clades of Bradyrhizobium and Microvirga have been identified as L. angustifolius endosymbionts.

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