Effects of salt and water stress on seed germination of Hedysarum flexuosum (Fabaceae ).— Hedysarum flexuosum L ., commonly called Sulla has been the subject of numerous studies which have demonstrated its forage and pastoral potential . Previous researches on the biochemical composition of this species have revealed a high nutritional value and positioned it as an alternative to the imported food for goat and sheep raising . The authors mention the richness of Sulla in proteins (22.5 % g / Kg of dry matter ), lipids and minerals . They also note a digestibility rate very similar to those of other forage legumes grown such as alfalfa . The species H . flexuosum or Sulla is reported in Algeria and Morocco on marl and marl-limestone substrates in regions with average rainfall greater than 550 mm . This study consists of an ecophysiological evaluation of the seed germination phase of H . flexuosum through the effects of salt and water stress on the germination rate (GT ) of this species . H . flexuosum pods were collected at maturity at a station in Ouadhia commune in northern Algeria . The seeds extracted from the pods were treated with 5 % sodium hypochlorite for 5 minutes and then rinsed three times with distilled water . In order to avoid any integumentary dormancy , a slight scarification of the seed surfaces was carried out . They were then watered with increasing concentration NaCl solutions (2 , 4 , 6 , 8 , and 10 g / l ), for the salinity test and by solutions of polyethylene glycol 6000 (PEG -6000 ) corresponding to pressures of : -1 bar, -3 bars, -7 bars , -9.25 bars respectively for the water stress . A batch of control seeds was watered with distilled water . The results of the germination rate (GT ) and mean germination time (MGT ) were analysed by an ANOVA using the stat box software (one parameter analysis : NaCl concentration for salt stress and PEG concentration for water stress ). The ANOVA analysis was completed by the Newman and Keuls test when it reveals a significant variation . Results show that GT variation as a function of NaCl concentrations is highly significant (P < 0.001 ). Seed GT decreases in response to increased NaCl concentration in the imbibitions substrate . The higher osmotic pressure is , the greater the rate of reduction of the germinative capacity increases . The influence of salinity is in fact significantly perceptible from 2 g / l with a GT of 74 % corresponding to a reduction rate of 18.7 %. The concentration inducing the reduction of the germination of 50 % (LD 50 ) is between 4 and 6 g / l of NaCl . The germination is practically inhibited at the highest concentration tested (10 g / l ). Analysis of the variance of the MGT factor of H . flexuosum shows that it increases significantly with elevated environmental salinity . In the controls , MGT is 2.37 days but extends to 8 days at the dose of 10 g / l of NaCl . The effect of salinity on germination kinetics is manifested by the germination retardation caused by the increasing concentrations of NaCl and PEG substrate (first phase of germination ). It could be explained by the prolongation of the latency phase corresponding to the time required for the imbibition of the seeds to trigger the germination process . Our results show that the highest GT is obtained in the control seeds (94 %). At the osmotic pressure of -1 bar , the germinative capacity is reduced by 60.63 % compared to the control . GT decreases with increasing osmotic pressure of the seed imbibitions substrate . At the pressure of -3 bars the germination drop reached 90.42 %. The germination is completely inhibited at the pressure of -9.25 bars . Like GT , the MGT required for H . flexuosum seeds increases with osmotic pressure . This is tripled at -7 bars pressure compared to the controls . H . flexuosum appears to be more sensitive to salinity compared to several Tunisian cultivars of H . coronarium (LD 50 to -2.11 bars for water stress ).

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Many plant species produce phenolic compounds in their various organs and their use in crop protection. These plant secondary metabolites may serve as toxins against the insect pests. The objective of this study was to evaluate in vitro the bio-insecticidal effect of an aqueous extract of wild Olive leaves on Psylla larvae (Euphyllura olivina), a primary pest of the cultivated Olive tree (Olea europaea L. subsp sativa). Two concentrations of 0.05g/ml and 0.1g/ml leaves grinding powder in distilled water were sprayed on branches infested with Psylla larvae. The obtained results revealed a very significant mortality rate of the larvae 24 hours after spraying. The chemical composition of Oleaster leaves aqueous extracts is determined by HPLC-DAD. The results show in majority the presence of phenolic compounds represented by oleuropein and its metabolite hydroxytyrosol. The phenolic compounds of the crude extract were at the origin of this mortality. The Analysis of Variance revealed highly significant results both between the sampled trees and between the tested concentrations. The Principal Component Analysis (PCA) revealed a close relation between the physiological state of the studied trees and the degree of their infestation by the phytophagus. Taking into account, the physical and chemical characteristics of the sampled soils, data analysis showed that trees growing on nitrogen-rich soils were more infested than those growing on soils rich in organic carbon (Corg) and phosphorus (Porg).

To determine the effect of some physic-chemical parameters of fruits such as fruit weight, fruit diameter, thickness and the essential oil content of the peel, we followed the infestation by C. capitata

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