Changes in Antioxidant Enzymes Activity and Oxidative Damage in Four Argania spinosa Ecotypes Under Water Stress Conditions

_Argania spinosa_ L. Skell, a tree endemic of Morocco, grows in semiarid and arid areas. Biochemical response to drought in four ecotypes of the _A. spinosa_ was compared. Choice of ecotypes was based on evident differences in geographical features in south-west Morocco: two coastal ecotypes (Essaouira and Agadir) and two paralittorale ecotypes (Aoulouz and Lakhssas). Lipid peroxidation (malonyldialdehyde (MDA)), content of endogenous hydrogen peroxide (H2O2) and antioxidant enzyme system (Catalase (CAT), Ascorbate peroxidase (APX), Total peroxidase (POD) and Polyphenoloxidase (PPO) were measured in control (100% relative humidity (RH) at field capacity (FC)) and water-stressed plants (50 and 25% RH at FC). For all ecotypes, drought stress significantly increased the contents of MDA and H2O2 and an ecotype effect was noted. According Two-way ANOVA analysis, the ecotype x watering regime interaction was highly significant. We found an increase in the activities of the four ROS-scavenging enzymes and an ecotype effect was noted. Ecotype x watering regime interaction shows that only the CAT and APX activities were significant. Highest values of POD and PPO activities were found in both paralittorale ecotypes. Increase in antioxidant enzyme activities appears to be an adaptive response to restore the reactive oxygen species in their homeostasis. The four study ecotypes were separated by two discriminant functions obtained by canonical discriminant analysis. Coastal ecotypes are separated from the paralittorale ecotypes mainly by POD and PPO activities and MDA content

De L’effort Au Potentiel Fiscal AuMaroc: Evaluation Empirique

La situation contemporaine des finances publiques nécessite une évaluation des effets de la fiscalité sur le financement de l’économie par la création des espaces budgétaires. En effet, avec une pression fiscale de 18,6% en 2016, et un déficit commercial record de 20% du PIB, il semble légitime de s’interroger sur le niveau potentiel de la pression fiscale au Maroc. Ainsi, l’étude de l’effort fiscal est nécessaire pour l’appréhension de la contrainte budgétaire publique. A travers cette étude, nous avons estimé via une modélisation structurelle en données de Panel à effet aléatoire, durant la période de 2000- 2016 pour évaluer le niveau de pression fiscale optimale. Selon nos résultats, l’évolution annuelle du potentiel fiscal en moyenne géométrique, au Maroc durant la période d’étude est de 1,65%., traduisant ainsi, un niveau de prélèvement effectif supérieur à la pression fiscale des pays de comparaison, et créant structurellement de ce fait, un espace budgétaire additionnel pour l’économie nationale. The contemporary situation of public finances requires an assessment of the effects of taxation on the financing of the economy through the creation of budgetary areas. With a fiscal pressure of 18.6% in 2016 and a record trade deficit of 20% of GDP, it seems legitimate to question the potential level of the tax burden in Morocco. This makes the study of the tax effort necessary for the apprehension of the public budget constraint. Through this study, structural modeling was used to estimate the Randomized Panel data during the period 2000-2016 to assess the optimal tax burden level. According to the results obtained, the annual evolution of the geometric average tax potential in Morocco during the study period is 1.65%. This reflects an effective levy level which is above the tax burden of the comparator countries, and it creates an additional fiscal space for the national economy structurally

reuse study of sustainable wastewater in agroforestry domain of marrakesh city

The current work aims to perform a feasibility study of sustainable urban wastewater reuse in agroforestry domain of Marrakesh city in order to assess the environmental and the sustainability of urban wastewater reuse in agroforestry irrigation. To this end, wastewater physicochemical characteristics from Marrakesh full-scale wastewater treatment plant, soil physicochemical analysis and climate analysis were investigated. Finally, treated urban wastewater potential production in Marrakesh WWTP and challenge related to its reuse are provided. The obtained results of the present study reveals the feasibility of this practice in Marrakesh region. Regarding the actual situation, climate analysis highlight that the local climatic conditions is an ultimate challenge for water resources; soil analysis reveals a loss of soil fertility due to the decline in soil organic matter. To face this condition, treated urban wastewater reuse is a sustainable and promising strategy to face water scarcity, enhance soil fertility, preserve natural resources, develop local products and improve living conditions of agriculture and farmers. Keywords: Urban wastewater, Physicochemical analysis, Wastewater reuse, Climate analysis, Arid climate, Marrakes

DE LA CONTRAINTE BUDGETAIRE AU POTENTIEL FISCAL : QUELLE RELATION EMPIRIQUE POUR LE MAROC ?

The contemporary situation of public finances requires an assessment of the effects of taxation on the financing of the economy through the creation of budgetary areas. Indeed, with a fiscal pressure of 18.6% in 2016, and a record trade deficit of 20% of GDP, it seems legitimate to question the potential level of the tax burden in Morocco. Thus, the study of the tax effort is necessary for the apprehension of the public budget constraint. Through this study, we estimated through structural modeling in Randomized Panel data, during the period 2000-2016 to assess the optimal tax burden level. According to our results, the annual evolution of the geometric average tax potential in Morocco during the study period is 1.65%., Thus reflecting an effective levy level above the tax burden of the comparator countries, and thus structurally creating an additional fiscal space for the national economy

Physiological and photosynthetic response of quinoa to drought stress

Water shortage is a critical problem touching plant growth and yield in semi-arid areas, for instance the Mediterranean región. For this reason was studied the physiological basis of drought tolerance of a new, drought tolerant crop quinoa (Chenopodium quinoa Willd.) tested in Morocco in two successive seasons, subject to four irrigation treatments (100, 50, and 33%ETc, and rainfed). The chlorophyll a fluorescence transients were analyzed by the JIP-test to transíate stress-induced damage in these transients to changes in biophysical parameter's allowing quantification of the energy flow through the photosynthetic apparatus. Drought stress induced a significant decrease in the maximum quantum yield of primary photochemistry (Φpo = Fv/Fm), and the quantum yield of electron transport (Φeo). The amount of active Photosystem II (PSII) reaction centers (RC) per excited cross section (RC/CS) also decreased when exposed to the highest drought stress. The effective antenna size of active RCs (ABS/RC) increased and the effective dissipation per active reaction centers (DIo/RC) increased by increasing drought stress during the growth season in comparison to the control. However the performance index (PI), was a very sensitive indicator of the physiological status of plants. Leaf area index, leaf water potential and stomatal conductance decreased as the drought increased. These results indicate that, in quinoa leaf, JIP-test can be used as a sensitive method for measuring drought stress effects

Electrolyte ions and glutathione enzymes as stress markers in Argania spinosa subjected to drought stress and recovery

Understanding the mechanisms underlying Argania spinosa responses to drought stress is essential for its regeneration and domestication. Toward that end, an integrative study of tolerance responses to drought stress in four A. spinosa ecotypes (2 contrasting coastal ecotypes (Adm and Rab) and 2 contrasting inland ecotypes (Alz and Lks)) have been conducted. Responses to soil drying and re -watering were measured at physiological and biochemical levels. Soil drying resulted in significant increase in leaf concentrations of potassium (K+), calcium (Ca2+) and magnesium (Mg2+) with differential responses between ecotypes. The glutathione-related enzymes: glutathione peroxidase (GP), glutathione reductase (GR) and glutathione S-transferase (GST) showed a significant increase in their enzymatic activity in A. spinosa plants subjected to drought stress. Additionally, a significant increase in thiol protein content in the four ecotypes was recorded, during drought stress. These antioxidant traits responded differently depending on ecotype. However, rapid and significant changes in the studied physiological and biochemical traits were observed during recovery from drought, only after four days. According to the traits having the most discriminating power, the both inland ecotypes, especially Lks ecotype, seem to be potential candidates for regeneration of argan forest and their domestication in arid and semi-arid environments.Key words: Argania spinosa, drought stress, glutathione enzymes, thiol compounds, recovery

Land spreading of olive mill wastewater (OMW): Biodegradation of organic matter and polyphenols in soil and effect on the activity of the total soil microflora

Agricultural spreading of olive mill wastewater (OMW) can represent a promising alternative solution, provided that the operation is controlled and the doses applied are respected. However, a reserve toward OMW spreading remains, for fears of possible microbiological negative incidences on the soil. To contribute to assessing this area, we have tried to study their microbiological impact and the fate of OMW polyphenols in soil in a greenhouse. In comparison with untreated soil with OMW (control), the application of 50, 100, and 200 m3/ha was studied for two months. The results obtained revealed that phenolic extracts from raw OMW showed five major peaks by HPLC at 280 nm, which were present only in trace amounts after 2 weeks of treatment at neutral pH. The phenols and organic matter (OM) from OMW were biodegraded or reorganized, and the bacterial population of soil treated with 50 and 100 m3/ha OMW was significantly higher compared to the soil that received water. However, a dose of 200 m3/ha did not affect soil microflora. Consequently, using OMW by direct spreading can be recommended at doses of 50 and 100 m3/ha. Doses higher than those studied, which are considered excessive and not recommended, could have undesirable repercussions. HIGHLIGHTS Soil microflora is responsible for biodegradation of OMW polyphenols.; Spreading OMW to 100 m3/ha on alkaline soil stimulated the activity of soil microflora.; Application of OMW to 100 m3/ha could be recommended as a soil biofertilizer.; For 200 m3/ha of OMW, particular attention must be paid to polyphenols and to electrical conductivity.; This study has removed all fears and ambiguities about the spreading of OMW on the soil.

Influence of salicylic acid on seed germination of Vicia faba L. under salt stress

Seed germination is the critical stage for species survival. Salinity affects germination and seedling growth and yield of several crop species, such as broad bean. That is why this study was carried to evaluate the effects of NaCl on seed germination and influence of salicylic acid on seed in order to improving salt tolerant on broad bean. Vicia faba L. is an important pulse crop in the Mediterranean region. In many cases broad bean is grown on saline soils where growth and yield are limited by salinity. The results showed that Irrigation with saline water significantly reduced all seed germination parameters in comparison with the respective control. Alleviation of growth arrest was observed with exogenous applications of salicylic acid (SA) under salt stress conditions. Overall, the positive effect of SA towards resistance to the salinity of V. faba L. will provide some practical basis for V. faba L cultivation

Évaluation des potentialités mycorhizogènes en lien avec les paramètres physico-chimiques des sols de palmeraies du Maroc (Marrakech et Tafilalet)

Plusieurs études ont montré que les champignons mycorhiziens arbusculaires (CMA) aident les plantes hôtes à tolérer les contraintes biotiques et abiotiques notamment le déficit hydrique et la fusariose vasculaire du palmier dattier ou bayoud. Notre étude a permis l'évaluation des potentiels mycorhizogènes des sols de palmeraies du Tafilalet et de Marrakech. Des échantillons de sols rhizosphériques des palmiers ont été analysés pour les quatre sites prospectés. Le nombre de propagules mycorhiziennes des palmeraies du Tafilalet est plus élevé que celui des palmeraies de Marrakech. De plus, les fréquences de mycorhization des racines du maïs repiquées dans les sols des palmeraies du Tafilalet sont plus importantes (98–100 %) que celles des palmeraies de Marrakech (29–64 %). Le genre Glomus est plus répandu au niveau des sols prospectés que les genres Sclerocystis et Acaulospora. Les teneurs en phosphore assimilable et en azote total sont très faibles au niveau des sols des palmeraies du Tafilalet par rapport à celles des sols de palmeraies de Marrakech. Celles en chlore, calcium et en fer sont élevées partout. Les teneurs en macroéléments sont voisines pour le potassium, le phosphore total et le soufre. Pour les oligo-éléments, les teneurs en zinc et en cuivre sont moyennes à faibles partout ; les teneurs en zinc et en fer sont élevées au niveau de la palmeraie Nord-Ouest de Marrakech. La concentration en Pb est faible partout. Les sols de la palmeraie du Tafilalet, qui sont pauvres en N et en P assimilable, ont montré des potentiels mycorhizogènes et des capacités d'infectivité plus importants que ceux des sols de la palmeraie de Marrakech

Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide.

The rate of photosynthesis (A) of plants exposed to water deficit is a function of stomatal (gs) and mesophyll (gm) conductance determining the availability of CO2 at the site of carboxylation within the chloroplast. Mesophyll conductance often represents the greatest impediment to photosynthetic uptake of CO2, and a crucial determinant of the photosynthetic effects of drought. Abscisic acid (ABA) plays a fundamental role in signalling and co-ordination of plant responses to drought; however, the effect of ABA on gm is not well-defined. Rose, cherry, olive and poplar were exposed to exogenous ABA and their leaf gas exchange parameters recorded over a four hour period. Application with ABA induced reductions in values of A, gs and gm in all four species. Reduced gm occurred within one hour of ABA treatment in three of the four analysed species; indicating that the effect of ABA on gm occurs on a shorter timescale than previously considered. These declines in gm values associated with ABA were not the result of physical changes in leaf properties due to altered turgor affecting movement of CO2, or caused by a reduction in the sub-stomatal concentration of CO2 (Ci). Increased [ABA] likely induces biochemical changes in the properties of the interface between the sub-stomatal air-space and mesophyll layer through the actions of cooporins to regulate the transport of CO2. The results of this study provide further evidence that gm is highly responsive to fluctuations in the external environment, and stress signals such as ABA induce co-ordinated modifications of both gs and gm in the regulation of photosynthesis