Test Beam Results Using an RPC Semi-Digital HCAL

We report on the development of an GRPCs (Glass Resistive Plate chambers) Semi- Digital hadron calorimeter for the future International Linear Collider (ILC).Two types of GRPCs (small and 1m2) were tested in PS beam at CERN. Detector performances are presented here in terms of efficiency, pad multiplicity, homogeneity and stability in time

Influence of salicylic acid pre-treatment on cadmium tolerance and its relationship with non-protein thiol production in flax root

Dose-dependent changes in cadmium (Cd) tolerance, non-protein thiol (NP-SH) production and their relationship were investigated in sixteen-day-old flax (Linum usitatissimum L.) seedlings derived from seeds pre-soaked with various salicylic acid (SA) doses and grown hydroponically under increased Cd concentrations (0, 50 and 100 μM CdCl2). The results show that single Cd subjection decreased root elongation as expressed by tolerance index (TI). Moreover, an overproduction of NP-SH was detected in both roots and shoots. These Cd toxicity effects were directly related to the high levels of Cd amounts in flax tissues as expressed by root and shoot Cd bioaccumulation factors (BAF). In addition, Cd-tolerance of roots TI was negatively correlated with changes in root BAF but positively correlated with shoot BAF. However, positive correlation was illustrated between root TI and NP-SH contents. SA considerably reversed the Cd-induced decrease in root growth parameters and TI. Moreover, in Cd-treated plants, SA pre-soaking prevented Cd accumulation in the shoot as consequence of significant decreases in BAF of roots, Cd transport estimated by the translocation factor (TF) and shoot BAF, respectively. Interestingly, SA pre-treatment reduced BAF of roots and shoots, enhanced NP-SH production in roots and decreased it in leaves. These results suggest that SA might play a preventive role in Cd uptake, sequestration and translocation processes based primarily in roots where SA-enhanced NP-SH contribute to the improvement of flax tolerance to Cd stress.Key words: Cadmium, salicylic acid, bioaccumulation, growth, non-protein thiols, Linum usitatissimum

Étude du potentiel biotique du parasitoïde Encarsia sophia dans des conditions contrôlées

Bemisia tabaci Gennedius (1889) est un ravageur phytophage affectant diverses cultures partout dans le monde. La lutte biologique contre B. tabaci se base sur l’utilisation de ses ennemis naturels surtout les parasitoïdes et les prédateurs.  Dans ce contexte, plusieurs espèces parasitoïdes du genre Eretmocerus et Encarcia et des prédateurs (comme Nesidiocoris tenuis) dont l’efficacité a été prouvée, sont utilisées dans la lutte contre cette mouche blanche.  L’évaluation des potentialités du parasitoïde indigène Encarsia sophia a montré une performance à limiter les populations de B. tabaci dans les serres géothermiques dans le Sud Tunisien. Cependant à 25°C et à une humidité relative variable entre 55 et 75%, le taux de parasitisme d’E. sophia des larves L2, L3 et L4 de B. tabaci sur culture d’aubergine est de 14,72 ± 5,60%. Il est conclu que l’usage cet ennemi indigène de B. tabaci peut remédier la multiplication de ce ravageur

Biotic potential of an exotic date palm pest specie: Oryctes agamemnon (Coleoptera: Scarabaeidae)

In Tunisia, particularly in southern regions, the culture of date palms plays an important role, both at socioeconomic and ecological levels. In spite of its importance, this agro-system is still threatened by many species of insects and diseases. Among these phytosanitary problems figure the exotic pest Oryctes agamemnon. This insect causes severe damage on palm tree mainly on the collar and the root system. The aim of this work is to study some parameters of the biotic potential of the insect.  A number of ten couples were used in this survey. Follow-up of the experiment under the following conditions (Relative humidity = 40 +/- 6%, Temperature = 28 ° C +/- 2 ° C and a photoperiod: 16/8) allowed to study the reproductive potential, the larval survival rate and the adult lifetime.  The follow-up of the experiment shows that the average pre-oviposition period and the average post-oviposition period are 25.3 ± 9.85 and 7.3 ± 5.39 days, respectively. The developmental cycle comprises, the egg, 3 larval stages L1, L2 and L3, prenymph and nymph respectively lasted 13,742 ± 2,011 days, 26,591 ± 3,142 days, 43,361 ± 3,237 days, 137,047 ± 6,132 days, 7,487 ± 0,909 days and 21,390 ± 2,655 days. Survival rates for the various stages ranged from 83.631 to 93.886%. Adults lived on average 55.18 days for males and 60 days for females. The average number of eggs laid per female was 28.7 ± 17.13 with an average fertility rate of 81.184%

Changes in henna (Lawsonia inermis L.) morphological traits under different deficit irrigations in the southern Tunisia

Henna plant belongs to continental oases where water shortage constitutes the essential limiting factors of its agricultural production. Lawsonia inermis L. (Lytraceae) is often exposed to severe drought stress in Gabes; a Tunisian arid region. The present study was carried out to evaluate the impact of water stress on the morphology of Tunisian henna plants. Thus, an experiment of four months was carried out under greenhouse at the Institute of Arid Region in Medenine, Tunisia. Henna was exposed to three different irrigation regimes, whereby the plants where irrigated to field capacity (control, T0), 50% of the control (moderate stress, T1) and 25% of the control (severe deficit irrigation, T2). Results showed that, leaf area (LA), leaf number and stem length of henna, decreased in response to the studied stress. The effect of water stress was clearly observed on those parameters. Moderate drought (T1) did not damage henna morphology, and the plants grew better than without water limitation (T0). Furthermore, the water stress-typical responses were shown as time and severity dependent in all the measured parameters. Indeed, lowest water availability treatment (T2) induced significant decrease in total number of leaves, as well as reductions in LA. Under this severe water stress (T2); LA was reduced by 65.79%, compared to control, at 60 days after the initiation of the bioassay. Stem length decreased significantly in the most severe water stress, this reduction was about 44%. Globally, we conclude that henna plant growth decreased progressively to long-term water limitation

Effectiveness of pheromone traps against Tuta absoluta

International audienceIn the Tunisian south, the heated greenhouses are an important axis of development of agriculture thanks to the big geothermal potential of this zone. Currently, this sector suffers from several phytosanitary problems. In the last years, a new insect, Tuta absoluta, threaten the cultures of cultivated tomatoes in heated greenhouses. To improve control of T. absoluta, the effectiveness of pheromone traps (associated or not with a source of light) and luminous traps (associated or not with water, with limed buckets for limed covers) were compared. The results show that the traps with pheromones significantly catch more adults of T. absoluta compared to all the other types of traps (average number of trapped adults of T. absoluta = 73.4 (± 142)). The luminous traps associated with water, with limed buckets as with limed covers show, as for them, an intermediate effectiveness. In spite of this slightly less effectiveness, the luminous traps have the advantage of low costs of production as well as the advantage of simultaneously capturing males and females of T. absoluta. ; Peer reviewe

Cadmium stress tolerance in plants: a key role of endogenous and exogenous salicylic acid

Cadmium (Cd) has become one of the major metal stresses which pose a serious threat to plants and animals. In this context, endogenous and exogenous salicylic acid (SA) could play an important role in mitigating the uptake of the Cd ions and providing immunity to plants against the heavy metal stress. SA enhances the resistance capacity of contaminated plants, which, however, depends on the metal concentration and the duration of the treatment. Moreover, SA is considered as a promising signal molecule for improving the efficiency of phytoremediation, and, consequently, growing of safe crops in metal polluted areas. The recent developments in the probable mechanisms by which SA could enhance the tolerance of plants to heavy metals and how it could have an effect on phytoremediation of Cd from contaminated soils are discussed

Effectiveness of Flonicamid 50 wg against Bemisia tabaci (Genn.) under greenhouse conditions in Tunisia.

Flonicamid is a systemic insecticide that acts as a feed blocker with potential use against whiteflies in an IPM program. The efficacy of flonicamid against populations of Bemisia tabaci in geothermal greenhouses in southern Tunisia. Flonicamid was tested in irrigation and foliar spraying on a greenhouse tomato crop. The use of the insecticide in irrigation or foliar spraying showed significant insecticidal activity on eggs, larvae and adults of B. tabaci. They are comparable to those caused by the reference insecticide confidor and different from those of the control on the different stages of development of B. tabaci. It is advisable to use flonicamid in an integrated pest management program in a heated greenhouse

Cellular and signaling mechanisms supporting cadmium tolerance in salicylic acid treated seedlings

This review spotlights on recent indications that recognizes potential cellular mechanisms that may be involved in the tolerance of salicylic acid (SA)-treated seedlings to the presence of cadmium (Cd) in their environment. It appears probable that SA stimulates signaling systems implicated in plant defense-related actions against Cd-induced oxidative stress. These include mechanisms that reduce uptake of metals into the cytosol by extracellular chelation through extruded ligands and binding onto cell-wall constituents. Cellular chelation of metals in the cytosol by a range of ligands (peptides, phytochelatins (PCs)), or increased efflux from the cytosol out of the cell or into sequestering compartments are also key mechanisms improving tolerance. Free-radical scavenging capacities through the activity of antioxidant enzymes or production of peptides and PCs add another line of defense against the toxic effect of Cd. The SA signaling events can be attributed to the extracellular SA perception model in which reactions between SA and apoplastic proteins result in acute oxidative burst under Cd stress