BEN GHORBAL KLOULA SALMA¹

WERHANI RIM ¹

CHATTI ABDELWAHEB¹

¹Laboratoire de Traitement des Eaux Usées, Centre de Recherches et Technologies des Eaux Usées, Technopole Borj Cedria, BP 273-Soliman 8020.

DOI: https://doi.org/10.55416/sunb.jns01.2204.08805

Abstract – The biofilm formation and development might vary in presence of UVc radiations, since this biofilm could be considered as a form of adaptation and resistance of microbial organisms to stress exposure. The study of bacterial biofilm was investigated to determine the potential UVc effects on bacterial biofilm formation and development. Moreover, the protective role of superoxide dismutase (SOD) against UVc radiations has been studied in wild-type and mutant strain of Pseudomonas aeruginosa lacking cytosolic Mn-SOD (sodM), Fe-SOD (sodB), or both SODs (sodMB), forming biofilm. Pseudomonas aeruginosa PAO1 and its isogenic mutants sodM, sodB and sodMB were exposed to incremental UVc doses. To measure biofilm formation, samples of suspension were taken at indicated times during irradiation and used for both qualitative and quantitative biofilm tests.Our results showed that inactivation of sodM gene increase the sensitivity of P. aeruginosa toward stress induced by UVc radiations. Furthermore, our results showed an enhancement of biofilm production, after exposure to UVc radiations, in wild-type and sod B mutant which maintained significantly higher levels of biofilm production than sodM mutant strain. The overall results showed that Mn-SOD isoform has a protective role against a stress induced by UVc radiations in P. aeruginosa biofilm.

Keywords: Biofilm, P. aeruginosa, sod mutants, UV.

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Etude des changements de l’occupation du sol et du ravinement au niveau du bassin versant de Lubudi-Basoko en République Démocratique du Congo à partir des données spatiales

PAUL LEMBHI KIDIADI ¹

TAOUFIK HERMASSI²

FATHIA JARRAY²

MOHAMED LASSAAD KOTTI²

MOHAMED MECHERGUI¹

¹Institut national agronomique de Tunis, 43 avenue Charles Nicolle, Tunis 1082, Tunisie.
² Institut national de recherche en génie rural eaux et forêts, Rue Hedi Karray Ariana. 2080 Tunisie

DOI: https://doi.org/10.55416/sunb.jns01.2204.08804

Abstract – Gully erosion occurs on hill slopes due to the high concentration of surface runoff, the development of drainage along the surface of roads and adjacent ditches as well as the high erodibility and fragility of soils in hilly areas of the Lubudi-Basoko watershed to the south-west of Kinshasa.As a result, large amounts of sediment are uprooted and transported to surrounding valley systems, causing significant damage to water quality and riparian ecosystems. This study establishes the relationship between the evolution of land use and the extent of gully system and the sediment balance of the watershed over twenty years (between 2000 and 2020) based on a diachronic analysis of satellite images. The sediment volumes are estimated between 2000 and 2010 at around 837,117 tons of sediment, and between 2010 and 2020 a volume of 3,294,034 tons of sediment, i.e. a loss of land of around 30 tons/year/ha over the first period and 116 tons/year/ha over the second period. These gullies continue to cause damage to habitats, roads and other human settlements in areas of high population density, to the detriment of the semi-rural environment.

Keywords: land cover, gullies, remote sensing, Lubudi-Basoko, RDC

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INÈS GHARBI^1,2

MOHAMED ELLOUMI ²

JEAN-YVES JAMIN ³

¹University of Carthage, Higher School of Agriculture of Mograne, 1121 Mograne Zaghouan,Tunisia

²University of Carthage, National Agricultural Research Institute of Tunisia, LR16INRAT07, Rural economics laboratory, rue Hédi Karray, 1004 El Menzah, Tunisia

³CIRAD, UMR G-eau, Montpellier-France

DOI: https://doi.org/10.55416/sunb.jns01.2204.08803

Abstract – The aim of this study is to investigate the impact of indirect land tenure on irrigated farms sustainability in Tunisia. This analysis is based on the farm sustainability assessing method (IDEA-Indicateurs de Durabilité des Exploitations Agricoles= Farm Sustainability Indicators) adapted to the Tunisian context. It is based on the calculation of indicators scores for the three sustainability dimensions: agro-ecological, socio-territorial and economic.Faced with land constraints, 40% of farmers sort to indirect land tenure through diverse a range of land contracts (rental and sharecropping). Our results showed that the lowest sustainability scores are found for indirect farming (31/100) and are related to the agro-ecological and socio-territorial dimensions. Conversely, these exploitations showed the highest score (72/100) for the economic dimension, much better than those obtained by landowners, with incomes reaching 3 times the Tunisian Guaranteed Agricultural Minimum Wage and an economic efficiency reaching 80%. Thus, access to land, through indirect tenure, leads, on the one hand, to improve the economic sustainability, but on the other hand, to low agro-ecological performances and negative externalities (soil degradation and overexploitation of resources). These findings reflect a degree of “conflicts” between both the economic and agro-ecological objectives. In fact, lessees seek to maximize their production in the short term and neglect the agro-ecological dimension, knowing that they will exploit these lands only for a few years. Conversely, landowners are more concerned with the agro-ecological dimension, as their lands and they are sure to keep them.

Keywords: sustainability, agro-ecological, economic, evaluation, land contracts.

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Etude de la variabilité morphologique de seize provenances de fenouil (Foeniculum vulgare Mill.) poussant à l’état spontané en Tunisie 

MARWA KHAMMASSI¹

MOUNA SOUIHI²

ISMAIL AMRI²

BASSEM JAMOUSSI³

ABDELHAMID KHALDI⁴

¹Nutritional Surveillance and Epidemiology Laboratory, National Institute of Nutrition and Food Technology, 11 rue Jebel lakhdhar Tunis

²Laboratory of Nuclear biotechnology, National Center for Nuclear Sciences and Technologies, BP 72, 2020 Sidi Thabet, Ariana, Tunisia

³Department of Environmental Sciences, Faculty of Meteorology, Environment Arid Land Agriculture, King Abdulaziz University, Jeddah 21589, Saudi Arabia

⁴Laboratory of Management and Valorization of Forest Resources. National Institute of Researches on Rural Engineering, Water and Forests, BP.10 Ariana 2080, Tunisia

DOI: https://doi.org/10.55416/sunb.jns01.2204.08802

Abstract – Fennel, Foeniculum vulgare Mill., is a very abundant aromatic and medicinal plant that grows spontaneously in several regions of Tunisia. The aim of this study is to describe the morphological variability of Foeniculum vulgare which seems to be essential to ensure a very appropriate sampling for a better exploitation of this species, especially since the morphological variability is often associated with a chemical variability of the active molecules. Therefore, our sampling concerned the different aerial parts of the species (stems, umbels and seeds) from sixteen provenances which are spread over different bioclimatic stages: humid, sub-humid, upper semi-arid and medium semi-arid. Several characters of morphological variability have been described for each plant part. For the stems : the length and the number of nodes and umbels per stem have been assessed, for the umbels: the diameter, the number of umbellules and the number of seeds per umbel have been described and for the seeds: the length and the seed width and the weight of 100 seeds were measured. The main results obtained were the subject of a principal component analysis. This study revealed a clear morphological variability linked to the different origins of tested plants.

Keywords: Foeniculum vulgare Mill, morphological variability, bioclimatic stages, stems, umbels, seeds.

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WALID YEDDES^{1, 2}

HAMZA GADHOUMI¹

TAYCIR GRATI AFFES ¹

HAMMAMI MAJDI¹

SAIDANI-TOUNSI MOUFIDA¹

¹Laboratory of Aromatic and Medicinal Plants, Borj Cedria Biotechnology Center, BP901, 2050 Hammam-Lif Tunisia.

²Faculty of Science of Bizerte, University of Carthage, Jarzouna7021Tunisia.

DOI: https://doi.org/10.55416/sunb.jns01.2204.08801

Abstract – The aim of our investigation is to determine the effects of grinding and bioclimatic variation on the quality and composition of the Tunisian rosemary essential oils. The composition of essential oils of rosemary (Rosmarinus officinalis. L) populations varied significantly according to seasons and bioclimatic stage (sub-humid, upper-semi-arid and upper-arid). Essential oils were extracted by Clevenger from entire or grinded dried rosemary leaves. The composition of essential oils was determined by gas chromatography coupled with mass spectrometry (GC-MS). Our results showed that the main compounds found are: 1.8 cineol, camphor, alpha terpinol, bornyl acetate and linalool. The number of compounds was higher during the flowering stage in January. The grinding of leaves into powder results in increase essential oils yields and releases more rosemary volatile compounds. The heatmaps and hierarchical clustering of total identified volatile compounds in essential oil extracted from rosemary leaves reveals that the sub-humid and the upper-semi-arid climatic regions show the highest yield of 1.8 cineol and the lowest yield of camphor. The opposite result was observed in the upper-arid region.

Keywords: Rosmarinus officinalis L., chemotype, chromatography, essential oil, heatmap

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