In vitro vegetative growth and flowering of olive tree in response to GA3 treatment

The phytohormone gibberellin is involved in the regulation of many physiological process including flower induction and shoot growth. In this study, gibberellic acid (GA3) was used in order to induce thereversion of olive tree vegetative buds towards a floral ones in vitro. For this, six varieties (Marsaline, Chemchali, Picholine, Chemlali, Zalmati and Oueslati ) was tested and explants, consisting of a singlenode segments, were grown in media containing three concentrations of GA3 (1, 2 and 10 mg/l). Results show that Marsaline seems to be the most able variety in regenerating floral structures. For this variety,5 cases of reversion were observed mainly on the medium containing 10 mg/l GA3. This same medium was also favorable for this transformation for the other varieties (3 cases on Picholine, one each on Chemchali , Zalmati and Oueslati). The examination of the histological sections confirmed this transformation. In addition, this experiment showed that GA3 can be at the origin of an interestinggrowth rate of vegetative buds, which elongation depend on variety as well as GA3 concentration

Traitement Chirurgical De L\'hyperparathyroidie Primaire : Techniques Et Resultats

L\'hyperparathyroïdie est secondaire à une sécrétion élevée de parathormone. Le diagnostic positif est biologique et le diagnostic de localisation est radiologique et isotopique. Le traitement chirurgical est la règle. Le but : de ce travail est d\'étudier notre stratégie thérapeutique en cas d\'hyperparathyroïdie primitive et ses résultats. Patients et méthodes : Nous avons mené une étude rétrospective à propos de 34 patients traités pour hyperparathyroïdie primitive durant la période entre 1992 et 2004. Résultats : L\'âge moyen de nos patients était de 51 ans avec une nette prédominance féminine. Notre stratégie chirurgicale était l\'exploration sous anesthésie générale des 4 glandes parathyroïdes. Les glandes pathologiques ont siégé au niveau des compartiments inférieurs dans la majorité des cas. Histologiquement l\'aspect adénomateux a été observé chez 26 patients. L\'examen extemporané était systématique. Son résultat était concordant avec l\'examen anatomopathologique final lui conférant une fiabilité de 100 %. L\'hypocalcémie post-opératoire immédiate a été rencontrée chez 11 patients. Elle était transitoire dans 8 cas. Un seul patient avait une hypercalcémie persistante conférant à notre stratégie chirurgicale un taux de succès de 97,15 %. Discussion : le risque d\'hypocalcémie immédiate varie dans la littérature de 3 à 50%. Dans notre série il était de 32,35%. Ceci est surtout expliqué par notre technique opératoire exposant les parathyroïdes à la dévascularisation. D\'autres techniques chirurgicales moins invasives ont été essayées visant à diminuer le risque d\'hypoparathroidie transitoire ou définitive. Elles sont basées sur un bilan localisateur performant actuellement surplombé par la scintigraphie au sestamibi.Primary hyperparathyroidism is secondary to an elevated secretion of parathormone. The positive diagnosis is biologic. The diagnosis of localization is radiological and isotopic. The surgical treatment is the rule. The aim : of this work is to study our therapeutic strategy in cases of primary hyperparathyroidism and its results. Patients and methods: We proceed to a retrospective study about 34 patients treated for primary hyperparathyroidism during the period between 1992 and 2004. Results: The middle age of our patients was of 51 years with a female predominance. Our surgical strategy was the exploration under general anaesthesia of the 4 parathyroid glands. The pathological glands were in the lower compartments in the majority of cases. Histologically, adenoma has been observed at 26 patients. Extemporary exam was systematic. Its result was in agreement to the final anatomopathological result conferring him a reliability of 100%. The immediate post-operative hypocalcaemia has been observed at 11 patients. It was transient in 8 cases. One alone patient had an obstinate hypercalcaemia conferring to our surgical strategy a rate of success of 97,15%. Discussion: the risk of immediate hypocalcaemia varies in the literature from 3 to 50%. In our study it was 32,35%. It is especially explained by our operative technique exhibitor parathyroïd to the devascularisation. Other operative techniques less invasiveness have been tried aiming to decrease the risk of transient or definitive hypoparathroidy. They are based currently on a effective exam of localization overhung by the scintigraphy to the sestamibi. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 8-1

The Regulation of Ion Homeostasis, Growth, and Biomass Allocation in Date Palm Ex Vitro Plants Depends on the Level of Water Salinity

The date palm, a central plant in the fragile oasis ecosystem, is considered one of the fruit species most tolerant to salt stress. However, the tolerance mechanisms involved are yet to be addressed and their evaluation until now was mainly based on heterogenous plant material such as seedlings or limited to in vitro experiment conditions. For these reasons, we propose to deepen our knowledge of the morphological and physiological responses to salt stress using acclimated ex vitro plants resulting from the propagation of a single genotype. The plants were irrigated with 0, 150, 300, or 450 mM NaCl solutions for four months. Our results showed that the influence of water salinity on growth and ion-homeostasis regulation was very dependent on stress levels. The 150 mM NaCl concentration was found to improve dry biomass by about 35%, but at higher salt concentrations (300 and 450 mM) it decreased by 40–65%. The shoot:root dry mass ratio decreased significantly at the 150 mM NaCl water concentration and then increased with increasing water salt concentration. The leaf:root ratio for Na+ and Cl− decreased significantly with increasing water salinity up to a concentration of 300 mM NaCl, and then stabilized with similar values for 300 mM and 450 mM NaCl. In contrast to Na+ and Cl−, leaf K+ content was significantly higher in the leaf than in the root for all salt treatments. Unlike Na+ and K+, Cl− was expelled to the surface of leaves in response to increased water salinity. Overall, date palm plants appear to be more capable of excluding Cl− than Na+ and of changing biomass allocation according to salt-stress level, and their leaves and roots both appear to play an important role in this tolerance strategy.All authors are funded through the Small Research group project from the Deanship of Scientific Research at King Khalid University under research grant number (R.G.P.1/295/43).Peer reviewe

In vitro cryopreservation of date palm caulogenic meristems

Cryopreservation is the technology of choice not only for plant genetic resource preservation but also for virus eradication and for the efficient management of large-scale micropropagation. In this chapter, we describe three cryopreservation protocols (standard vitrification, droplet vitrification, and encapsulation vitrification) for date palm highly proliferating meristems that are initiated from vitro-cultures using plant growth regulator-free MS medium. The positive impact of sucrose preculture and cold hardening treatments on survival rates is significant. Regeneration rates obtained with standard vitrification, encapsulation-vitrification, and droplet-vitrification protocols can reach 30, 40, and 70%, respectively. All regenerated plants from non-cryopreserved or cryopreserved explants don't show morphological variation by maintaining genetic integrity without adverse effect of cryogenic treatment. Cryopreservation of date palm vitro-cultures enables commercial tissue culture laboratories to move to large-scale propagation from cryopreserved cell lines producing true-to-type plants after clonal field-testing trials. When comparing the cost of cryostorage and in-field conservation of date palm cultivars, tissue cryopreservation is the most cost-effective. Moreover, many of the risks linked to field conservation like erosion due to climatic, edaphic, and phytopathologic constraints are circumvented. (Résumé d'auteur

Genetic diversity at the Dhn3 locus in Turkish Hordeum spontaneum populations with comparative structural analyses

We analysed Hordeum spontaneum accessions from 21 different locations to understand the genetic diversity of HsDhn3 alleles and effects of single base mutations on the intrinsically disordered structure of the resulting polypeptide (HsDHN3). HsDHN3 was found to be YSK2-type with a low-frequency 6-aa deletion in the beginning of Exon 1. There is relatively high diversity in the intron region of HsDhn3 compared to the two exon regions. We have found subtle differences in K segments led to changes in amino acids chemical properties. Predictions for protein interaction profiles suggest the presence of a protein-binding site in HsDHN3 that coincides with the K1 segment. Comparison of DHN3 to closely related cereals showed that all of them contain a nuclear localization signal sequence flanking to the K1 segment and a novel conserved region located between the S and K1 segments [E(D/T)DGMGGR]. We found that H. vulgare, H. spontaneum, and Triticum urartu DHN3s have a greater number of phosphorylation sites for protein kinase C than other cereal species, which may be related to stress adaptation. Our results show that the nature and extent of mutations in the conserved segments of K1 and K2 are likely to be key factors in protection of cells

Effect of foliar Boron application on growth, phenology, yield and oil quality of olive trees (cv. Arbequina) conducted under a high density planting system

1 .pdf (3 Tabls.) copia del póster original presentado por los autores en el Simposio Internacional.Foliar boron fertilization is commonly used in intensive olive orchards without knowledge about the efficiency of this fertilization on olive production.Peer reviewe

A first investigation for reducing e-learning environment complexity by Multiscale

International audienceNo abstrac