High Institute of Agronomy

Sousse, Tunisia

High Institute of Agronomy

Sousse, Tunisia
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Aguiar F.C.,High Institute of Agronomy | Feio M.J.,University of Coimbra | Ferreira M.T.,High Institute of Agronomy
Ecological Indicators | Year: 2011

The bioassessment and monitoring of the ecological status of rivers using macrophytes has gained new momentum since macrophytes were recognised as biological quality elements for the implementation of the European Water Framework Directive (WFD; EU/2000/60). Our objectives were to test the suitability of two predictive modelling approaches to macrophyte communities as a tool for water quality assessment, and to compare their performance with other more common approaches-the use of macrophytes asindicators of the trophic status of rivers and multimetric indices. We used floristic and environmental data that were collectedin the spring of 2004 and 2005 from around 400 sites on rivers across mainland Portugal, western Iberia. We build two predictive models: MACPACS (MACrophyte Prediction And Classification System) and MAC (Macrophyte Assessment and Classification)based on RIVPACS and the BEAST methods, respectively. Whereas MACPACS is derived from taxa occurrence data, MAC uses a quantitative measure of taxa abundance. Both models showed good performance in predicting reference sites to the correct group and low rate of misclassification errors. However, they performed differently. MAC depicts a reliable response to the overall human-mediated degradation of fluvial systems, as does the multimetric index (RVI, Riparian Vegetation Index), but MACPACS presented only a poor correlation with the Global Human Disturbance Index and with the nutrients input. The incorporation of abundance data in vegetation predictive models appears to be particularly important to the detection of high levels of degradation. The values for correlations with physical-chemical pressure variables were lower than expected for MTR (Mean Trophic Rank) due to an insufficient number of scoring species found in Portuguese fluvial systems. Our results suggest that the most effective methods for bioassessment in Mediterranean-type rivers are either the RVI or the MAC predictive model. © 2010 Elsevier Ltd. All rights reserved.

Mdellel L.,High Institute of Agronomy | Halima Kamel M.B.,High Institute of Agronomy | Assadi B.,High Institute of Agronomy
Annales de la Societe Entomologique de France | Year: 2015

Winter pruning is a cultural practice used to modify vegetative growth, which is likely to affect the development of pests. However, it has been poorly defined as a cultural method for diminishing the population levels of the pomegranate aphid Aphis punicae (Hemiptera, Aphididae) in pomegranate orchards. This study aimed to evaluate the impact of winter pruning of pomegranate on A. punicae population and their natural enemies. The results showed that winter pruning significantly decreased the population of A. punicae (p < 0.05) in pomegranate. Also, number of natural enemies decreased in pomegranate trees after winter pruning. This technical practice affects the number of winged and wingless individuals, the mean relative growth rate, the specific age of the population and the infestation rate. Winter pruning for A. punicae control in pomegranate orchards is highly recommended. © 2015 Société entomologique de France.

Aloui H.,University of Carthage | Souguir M.,High Institute of Agronomy | Hannachi C.,High Institute of Agronomy
Acta Agriculturae Slovenica | Year: 2014

Seed priming is a simple pre-germination method to improve seed performance and to attenuate the effects of stress exposure. The objective of this study was to determinate an optimal priming protocol for three pepper cultivars (Capsicum annuum L.): 'Beldi', 'Baklouti' and 'Anaheim Chili'. Seeds were primed with three solutions of NaCl, KCl and CaCl2 (0, 10, 20 and 50 mM) for three different durations (12, 24 and 36h). Control seeds were soaked in distilled water for the same durations. After that, all seeds were kept to germinate in laboratory under normal light and controlled temperature. Results indicated that priming depends on concentration, duration and cultivar. The best combinations that we obtained were: KCl priming (10 mM, 36h) for 'Beldi' cultivar, CaCl2 priming (10 mM, 36h) for 'Baklouti' cultivar and finally NaCl priming (50 mM, 24h) for 'Anaheim Chili' cultivar. Generally, priming had an effect on total germination percentage, mean germination time, germination index and the coefficient of velocity compared to control seeds. The beneficial effect of seed priming could be used for improving salt tolerance on germination and early seedling growth for pepper cultivar.

Ncibi M.C.,High Institute of Agronomy
Recent Patents on Chemical Engineering | Year: 2010

A review of the production technologies of bioethanol, an eco-friendly automotive fuel, from non-edible and renewable lignocellulosic bioresources and agricultural wastes is presented, based on the recently developed patents and research works. The different technologies such as ammonia fibre/freeze explosion, organosolv process, ozonolysis, acid and/or enzymatic hydrolysis, simultaneous or separate saccharification and fermentation along with consolidated bioprocessing are described along with the major research trends to optimize their efficiencies of producing fuel ethanol from lignocellulosic biomass. Biological, thermo-chemical and enzymatic engineering aspects will be critically reviewed regarding the lignocellulosic biomaterials conversion into renewable and pollution-free fuel, bioethanol. © 2010 Bentham Science Publishers Ltd.

Souguir M.,High Institute of Agronomy | Fraj H.,High Institute of Agronomy | Hannachi C.,High Institute of Agronomy
International Journal of Vegetable Science | Year: 2016

Sesame (Sesamum indicum L) is used for its leaves as a vegetable and its oil in Africa but soil salinity is a major abiotic stress limiting growth and productivity. Seed of sesame from cvs. Maroc (from Morocco), Tunisie (from Tunisia), and Ispahan (from Iran) were evaluated for enzymatic and biochemical responses to 0, 2, 4, 6, 8, and 10 g·L−1 of NaCl for 7 days to determine how germination and early seedling development were affected. Final germination percentage decreased in all cultivars at 10 g·L−1. Water content, lengths of radicles and plumules and, chlorophyll a and b contents were decreased when NaCl concentration was above 6 g·L−1. Enzyme activities were associated with elevated proline, total soluble sugars, and protein concentrations for cvs. Tunisie and Ispahan and total soluble sugars and proteins decreased for cv. Maroc. Protease activity was increased as NaCl concentration increased for all cultivars and was highest for cv. Maroc, which could indicate involvement of these enzymes in synergic adjustment. ‘Tunisie’ exhibited better germination and growth, which may be attributed to its capacity for osmotic adjustment and to mobilize higher sugars and reserve proteins during germination. © 2016 Taylor & Francis

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