Germination and growth in control and primed seeds of pepper as affected by salt stress

Salinity is an important abiotic stress which can affect crop production in the world. One of the simplest methods for improving salinity tolerance of plants is seeds priming. This experiment was conducted to evaluate the effects of seeds priming with three solutions (KCl , NaCl and CaCl2) in germination and later growth of three pepper (Capsicum annuum L.) cultivars: Beldi, Baklouti and Anaheim Chili. Seeds germination was conducted in a completely randomized design under seven salinity levels (0, 2, 4, 6, 8, 10 and 12 g L-1) at room temperature for primed and control seeds. Plants derived from these germinated seeds (control and primed) were transplanted and cultivated in a greenhouse for 4 months and were irrigated permanently with seven salinity levels (0, 2, 4, 6, 8, 10 and 12 g L-1). The results showed that salinity affected all parameters under study like total germination percentage and chlorophyll level (a and b). As well, proline content increased as response to increasing salinity. The plants derived and grown from primed seeds showed a considerable tolerance to salt stress and gave better results. In fact, priming improved the salt resistance of pepper owing to more chlorophyll and proline accumulation. These results suggest that seed priming induced possible physiological adjustments in pepper seeds, especially in the early stages of development, and could be used as a suitable tool for improving germination and growth characteristics under salt stress conditions

La baisse de la densité osseuse au cours des maladies inflammatoires chroniques de l’intestin : prévalence et facteurs de risqué

Introduction: La baisse de la densité minérale osseuse représente la principale manifestation osseuse décrite au cours des maladies inflammatoires chroniques de l'intestin. En Tunisie, très peu d'études ont rapportés sa prévalence et ses facteurs de risque. Le but de ce travail était de déterminer la prévalence de la perte osseuse au cours des maladies inflammatoires chroniques de l'intestin, et rechercher ses facteurs de risque. Méthodes: Patients et méthodes: étude ouverte transversale, réalisée de 2007 jusqu'à 2012. Résultats: 146 cas étaient colligés, dont 105 avaient une maladie de Crohn (71,9%) et 41 avaient une rectocolite hémorragique (28,1%). Il s'agissait de 62 hommes et 84 femmes. L'âge moyen était de 33,18 ans. La perte osseuse était trouvée chez 85 patients (58,2%). Il s'agissait d'une ostéopénie dans 57 cas et d'ostéoporose dans 28 cas. Les facteurs de risque de perte osseuse étaient une activité physique limitée  (p=0,013), un indice de masse corporel '20 kg/m2 (p=0,015), une maladie active (p=0,035), l'étendue de l'atteinte intestinale (p=0,006) et une dose cumulée de corticothérapie dépassant 4,5g de Prednisone (p=0,003). Conclusion: La déminéralisation osseuse est une complication fréquente mais non constante. Ceci justifie un dépistage précoce chez les patients à risque, qui pourront ainsi bénéficier d'un traitement substitutif.Key words: Maladie de Crohn, recto-colite hémorragique, densité minérale osseuse, ostéopénie, ostéoporos

Germination and Growth in Control and Primed Seeds of Pepper as Affected by Salt Stress

Salinity is an important abiotic stress which can affect crop production in the world. One of the simplest methods for improving salinity tolerance of plants is seeds priming. This experiment was conducted to evaluate the effects of seeds priming with three solutions (KCl , NaCl and CaCl2) in germination and later growth of three pepper (Capsicum annuum L.) cultivars: Beldi, Baklouti and Anaheim Chili. Seeds germination was conducted in a completely randomized design under seven salinity levels (0, 2, 4, 6, 8, 10 and 12 g L-1) at room temperature for primed and control seeds. Plants derived from these germinated seeds (control and primed) were transplanted and cultivated in a greenhouse for 4 months and were irrigated permanently with seven salinity levels (0, 2, 4, 6, 8, 10 and 12 g L-1). The results showed that salinity affected all parameters under study like total germination percentage and chlorophyll level (a and b). As well, proline content increased as response to increasing salinity. The plants derived and grown from primed seeds showed a considerable tolerance to salt stress and gave better results. In fact, priming improved the salt resistance of pepper owing to more chlorophyll and proline accumulation. These results suggest that seed priming induced possible physiological adjustments in pepper seeds, especially in the early stages of development, and could be used as a suitable tool for improving germination and growth characteristics under salt stress conditions

The impact of paper constituents on the efficiency of mechanical strengthening by polyaminoalkylalkoxysilanes

International audienceThe aim of the research was to evaluate the influence of certain components of paper such as lignin and papermaking additives (fillers and sizing) on the efficiency of a recently proposed treatment for simultaneous deacidification and mechanical strengthening with polyaminosiloxane copolymer networks. Mixed mechanical and chemical pulp papers containing various additives were treated with aminoalkylalkoxysilanes (AAAS) by immersion or by spray. Upon treatment, the deposited alkaline reserve varied from 0.34 to 1.14 mol kg−1. For all the papers, copolymers formed from binary mixtures of a di- and a tri-functional AAAS provided the best improvement in the mechanical properties, i.e. in the tensile strength and the folding endurance, indicating an increase in the interfiber bonding energy and in the paper flexibility and plasticity, respectively. It was found that fillers had no influence while sizing hampered the efficiency of the treatment. The presence of mechanical pulp was shown to have a significant impact on the effect of the treatments as well by increasing the tensile resistance more than the folding endurance, indicating an increase in the paper rigidity. This observation was attributed to the response of lignin to the treatment

Preferential hydration fully controls the renaturation dynamics of collagen in water-glycerol solvents

Glycerol is one of the additives which stabilize collagen, as well as globular proteins, against thermally induced denaturation --an effect explained by preferential hydration, i.e. by the formation, in water/glycerol solvents, of a hydration layer whose entropic cost favors the more compact triple-helix native structure against the denatured one, gelatin. Quenching gelatin solutions promotes renaturation which, however, remains incomplete, as the formation of a gel network gives rise to growing topological constraints. So, gelatin gels exhibit glass-like dynamical features such as slow aging of their shear modulus and stretched exponential stress relaxation, the study of which gives us access to the re(de)naturation dynamics of collagen. We show that this dynamics is independent of the bulk solvent viscosity and controlled by a single parameter, the undercooling $\Delta T$ below the glycerol-concentration-dependent denaturation temperature. This provides direct proof of i) the presence of a nanometer thick, glycerol-free hydration layer, ii) the high locality of the kinetically limiting process governing renaturation