Ajdallah F.,University of Sfax |
Belgacem A.O.,Institute of Arid Regions |
Chaieb M.,University of Sfax
Acta Botanica Gallica | Year: 2011
Protected areas such as national parks are often assumed to be the best way to conserve plant diversity and maintain ecosystem composition and structure. To evaluate this assertion, we sampled two areas with two different levels of grazing: a national park where the protection level was high and an open area where human populations have unrestricted access to ecosystem resources. Species diversity (Shannon diversity index, species richness), species cover, perennial species density, plant biomass and total plant cover were determined inside and outside the park. Results show considerable and positive effects of protection on the parameters scored. Some species known by it high palatability such as Cenchrus ciliaris, Salvia aegyptiaca, Echiochilon fruticosum and Helianthemum sessiliflorum are more abundant in the protected area.
Hasnaoui N.,Higher Agronomic Institute |
Hasnaoui N.,Laboratory of Molecular Genetics |
Mars M.,Higher Agronomic Institute |
Ghaffari S.,Institute of Arid regions |
And 3 more authors.
Industrial Crops and Products | Year: 2011
Tunisian pomegranate genetic resources consist of sweet and sour cultivars, showing large morphometric variability. In the present work we characterized seeds and juice contents of sugars and organic acids of 5 sour and 7 sweet pomegranate cultivars. Results showed that citric acid was predominant in sour pomegranates, while malic acid was the most prevalent in sweet ones. Paradoxically, sour cultivars have higher sugar content than the sweet ones. A strong correlation was found between sourness and citric acid content, which is assumed to be the major factor that determines sour taste in pomegranate fruits. Besides, some of the seed parameters showed a significant positive correlation with acidity. Sweet cultivars were appropriate for fresh consumption and juice production due to several attributes in addition to their sweetness. Equally, sour pomegranate showed several characteristics that could be of great interest for food and nutraceutical industries. © 2010 Elsevier B.V.
Radhouani A.,Institute of Arid Regions |
Ferchichi A.,Institute of Arid Regions
Journal of Applied Horticulture | Year: 2010
Plants of muskmelon variety "Calypso" were used as scion and non grafted control while two hybrids (Cucurbita maxima x Cucurbita mushata), TZ148 and Ferro as rootstocks. Grafted and non-grafted plants were grown under a monotunnel heated and irrigated by geothermic water in the South of Tunisia. Plants were grown in soilless culture on sand and compost. This trial has revealed that, on sand as well as on compost, grafted plants were more vigorous than self-rooted ones. This vigor was highlighted by values of length and volume of roots, plant height, stem diameter, leaf area and fresh and dry matter of leaves. Indexes of growth represented by LAI, SLA, RGR and NAR were strongly improved by grafting particularly by TZ148. This improvement implied a hasty vegetative growth. Moreover, precocity of production was greater for grafted plants. In addition to their early production, grafted plants produced more fruits on sand and compost. The average weight of fruits was enhanced, too, by this agricultural practice. Thus, the major part of fruits produced by grafted plants had a weight superior to 600g.
Mansour E.,Institute of Arid Regions |
Ben khaled A.,Institute of Arid Regions |
Haddad M.,Institute of Arid Regions |
Abid M.,Institute of Arid Regions |
And 2 more authors.
African Journal of Biotechnology | Year: 2011
Tunisia is one of the main producers and exporters of pomegranate (Punica granatum L.) in the world. Due to its international importance, the selection of both quantitative and qualitative most desirable varieties has become a necessity. To select new cultivars that are most appropriate for commercial use, 21 accessions were collected from different regions of south-east Tunisia. 24 morphological characters of the tree and fruit were studied for each accession. This study has revealed considerable diversity especially concerning the tree vigor, the fruit size and color and the acidity of juice. Taking into account all comments, some trees are considered particularly efficient in south-eastern Tunisia. © 2011 Academic Journals.
Visser M.,Roosevelt University |
Collin P.,Roosevelt University |
Belgacem A.O.,Institute of Arid Regions |
Neffati M.,Institute of Arid Regions
Arid Land Research and Management | Year: 2012
In North African dryland research, few recognize that phosphorus (P) is the main soil nutrient limiting plant growth for legumes, in particular. P-fertilisation of legume reseedings could boost biological N-fixation and N-yield through enhanced biomass production, which, in turn, can benefit the re-establishment of resource-responsive perennial grasses. This is the hypothesis underlying a short-term fertilization experiment carried out with seedlings of Argyrolobium uniflorum, a native palatable legume. A secondary question was whether plant-available P, as measured by the Olsen method, is the best way to assess P-status in arid, calcareous, and nutrient-depleted soils that are renowned for their resource patchiness. Results show a significant effect of phosphorus addition on dry matter and N-yield. Seedlings responded to 25-kg P ha-1 by almost doubling dry matter production, yet no further improvement was observed for 50-kg P ha-1. The better plant growth corresponded with higher numbers of active nodules on P-fertilized seedlings. Plant P-content showed a positive and significant linear correlation with dry matter yield, whereas soil total and Olsen P-content did not, suggesting that plant P-content might be a more sensitive indicator of plant-available P than Olsen soil P-content. The observation that nodulation was efficient even though the land had not carried any legumes for over twenty years suggests that reseeding is feasible without inoculation. The strong response of Argyrolobium uniflorum seedlings to modest doses of phosphorus confirms the role of both legumes and phosphorus as key factors for restoring degraded drylands. © 2012 Copyright Taylor and Francis Group, LLC.
Khadhri A.,Tunis el Manar University |
Neffati M.,Institute of Arid Regions |
Smiti S.,Tunis el Manar University
Acta Physiologiae Plantarum | Year: 2011
Germination studies of Cymbopogon schoenanthus (Poaceae) distributed along southern Tunisia were carried out to assess the effects of salinity. A preliminary experiment showed 30°C as the optimum germination temperature for seeds of this species. After that, seed germination was studied at different salinity levels. Our results revealed a decrease in germination percentage with increasing salinity. Germination rate, however, was maintained up to 200 mM NaCl and drastically declined at 300 mM NaCl. © 2010 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.