Search

The present study aims to design for the first time the physicochemical properties, fatty acids, tocopherols and phytosterols of cactus juice and seed oil from O. aequatorialis (O.A) and O. leucotricha (O.L) than compared with two other species widely studied [O. ficus indica (O.F.I) and O. megacantha (O.M)]. Fatty acids and phytosterols were quantified by gas chromatography; whereas tocopherols were performed by HPLC. The physicochemical results showed that O.A exhibited the highest levels of acidity and proteins. The highest Vitamin C content was recorded in the juice of O.M species. Total phytosterols and tocopherols content are highest in the seed oil of O.A and O.F.I species with β-sitosterol and γ-tocopherol, the major isoforms detected. Oleic and linoleic acids were detected in fatty acids profile. The juice exhibits strong antioxidant activity. Fruits of O.A and O.L own substantial antioxidant ingredients offering add value for functional foods and contributing to the development of food and nutritional products.

The Argane tree [Argania spinosa (L.) Skeels] is a remarkable essence by its botanical interest, ecological services, and its socio-economic value. This endemic species is known by its adaptive behavior to arid and semi-arid regions where it grows naturally in vast forests in Southwestern Morocco. Although its adaptation has been commonly attributed to various mechanisms in different organs and tissues, whose the root system has a primary role in this whole process. However, the increased aridity and desertification in the Mediterranean region appear to affect the health, growth and functioning of the root system of A. spinosa. In this review, we highlighted morphological aspects and physiological and biochemical mechanisms related to the roots and involved in the abiotic stress tolerance in the Argane tree. The mycorrhizal symbiosis in Argane tree plays a vital role in nutrient uptake and growth of this woody species, ​as well as in the adaptation to its environment. Despite the difficulties encountered in rooting during ​its in vitro propagation, this technique seems to be an attractive alternative for the regeneration of the selected Argane tree.

Argan (Argania spinosa) tree is a horticultural-forestry species characterized by its endemicity and its adaptive behavior to arid and semi-arid environments in the southwest of Morocco. It plays meaningful ecological, economic and social roles. Argan oil has high nutritional and dietetic values; it is thought to be one of the vegetable oils with the highest quality in the world. To characterize and to identify the most drought-tolerant ecotypes of the Argan tree, we focused our work on certain drought tolerance traits by studying the change in stomatal conductance (gs), Rubisco activity, carbohydrate compounds and enzymes in four different Argan ecotypes. These Argan ecotypes were grown under drought stress for 2 months. Under severe drought conditions, we recorded significant reduction in gs and Rubisco activity, the largest decrease was noted in the both contrasting coastal ecotypes. However, drought stress significantly increased the hexoses concentration in stressed plant leaves indicating stimulation of activity of carbohydrate metabolizing enzymes. The correlations obtained suggest that related enzymes of primary carbohydrate metabolism have highly important effects on foliar hexoses concentration in Argania spinosa during drought stress. Based on canonical discriminant analysis, both contrasting coastal ecotypes were distinctly separated from both contrasting inland ecotypes by the traits showing the high discriminatory potential: Rubisco, aldose 6-phosphate reductase, glucose-6-phosphate dehydrogenase and gs. These traits can be efficiently exploited to identify superior ecotypes suitable for drought conditions. Inland ecotypes appear to be more drought tolerants and interesting for regeneration of Argan tree in dryland areas.

In this study, the impact of two water-saving techniques, Regulated Deficit Irrigation (RDI) and Partial Rootzone Drying (PRD) was investigated by comparing their impact on the behavior of three melon varieties (Cucumis melo), Galia, Jucar, and DRG. The morphological, physiological, and biochemical responses to the deficit irrigation systems were considered. The results show that both PRD and RDI constraints increase the plants water-use efficiency without impairing plants’ vegetative growth. These treatments reduced the leaf water content and the stomatal conductance without any significant leaf expansion under the water restriction pressure. An increase in the peroxidase activity was recorded under both treatments without having any influence on the activity of polyphenol oxidase. Besides, the application of both treatments had no significant effect on phenolic compounds compared to the well-watered plants. PRD-treated Galia plants had better results. These results provide useful knowledge on efficient irrigation and water management systems for melon fruit tree cultivation, in particular in a water-limited environment.

This study was carried out in order to investigate the ability of tissues of Argania spinosa (L.) to undergo unlimited cell divisions by triggering their proliferative potential via callogenesis. Axenic cultures were efficiently established using axillary buds cultured on half-strength Murashige and Skoog (MS) medium after 20min of surface sterilization with sodium hypochlorite 6% (v/v). The highest callus rate was achieved with 1.0mgL-1 of naphthaleneacetic acid (NAA) and 1.0mgL-1 of 2,4-dichlorophenoxyacetic acid (2,4D) or similarly with 0.01mgL-1 of 6-benzylaminopurine (BAP) and 1.0mgL-1 of 2,4D at pH of 5.8, under dark conditions. The results of this study show also a significant increase in the callus's antioxidant power under abiotic pressure induced by NaCl. Catalase (CAT), peroxidase (PO), and superoxide dismutase (SOD) activities were significantly triggered, which protected the cells from the stimulated oxidative stress, under hydrogen peroxide (H2O2) significant release. This reaction favors subsequently the tissue recover process linked to the low abundance of polyphenol oxidase (PPO) activity and malondialdehyde (MDA) content. This work proves the efficiency of salt stress in boosting the argan cell's antioxidant status, which could be commercially applied in the field of cells regenerative therapy.

Capparis spinosa is one of the most important species in the genus Capparis owing to its ecological, medicinal and economic values. It spread in the North of Africa and grows naturally in Morocco. In this work, we evaluate the inter-variation, in eight natural Moroccan populations of Capparis spp. from the Fez-Meknes region in north-central Morocco, at the morphological and genetic level. Genetic variation of this species was assessed using Inter-Simple Sequence Repeats (ISSR) markers. The morphological traits submitted to canonical discriminant analysis enabled separation of eight populations of C. spinosa. The AMOVA results revealed that the genetic variation among the populations (13%) was revealed to be significantly less pronounced than that observed within the some populations (87%). The STRUCTURE analysis and cluster analysis assumed from the Unweighted Pair Group Method with Arithmetic Averages (UPGMA) highlighted three groups within the ISSR data. Our results suggested the presence of hybrid forms of C. spinosa in north-central Morocco. The raised levels of genetic variation revealed within the Moroccan Capparis population by ISSR markers indicate that an appropriate conservation program will allow capturing the majority of genetic diversity found within this species to help ensure its long-term breeding success.

The objective of our present study was undertaken to identify and to discriminate the tolerant ecotypes of Argania spinosa in terms of drought tolerance by studying the change of chlorophyll fluore...

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 (Ca 2+ ) and magnesium (Mg 2+ ) 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.

Our study was undertaken to ascertain whether the change of the water status and the activation of superoxide dismutase and their isoenzymes in Argan tree can support edaphic drought tolerance and its recovery under rehydration. An experiment was conducted on four contrasting ecotypes of Argania spinosa plants: two contrasting coastal ecotypes (Admine (Adm) and Rabia (Rab)) and two contrasting inland ecotypes (Aoulouz (Alz) and Lakhssas (Lks)). Drought stress significantly decreased the leaf water potential and stomatal conductance in the four contrasted ecotypes. In terms of biochemical responses, significant accumulation of carbonyl groups, hydrogen peroxide and superoxide radical has been recorded in the leaves of stressed plants reflecting oxidative stress. In parallel, the activities of total superoxide dismutase (SOD) and their isoenzymes Cu/Zn-SOD, Cu/Zn-SOD and Fe-SOD were also found to have increased to scavenging ROS and protecting the cell against induced oxidative stress. The recovery ...

The argan tree (Argania spinosa) plays a crucial socioeconomic and ecological role in southwestern Morocco's arid and semiarid zones. Pot study was undertaken to understand and characterize the physiological and biochemical tolerance mechanisms of this endemic species to drought stress. We adopted a multifactorial approach to study the change of leaf water status, ionic status, chlorophyll a fluorescence, oxidative damage, enzymatic and nonenzymatic defense systems, osmoregulation, carbohydrate metabolism, secondary metabolism, proteins, and certain enzymes and pigments of photosynthesis in four contrasting argan tree ecotypes. A. spinosa plants were subjected to different levels of drought stress on the one hand, and to a dehydration + rehydration process on the other hand to determine the ability to recover after a prolonged edaphic drought. The results revealed significant differences between the four contrasting ecotypes for the set of physiological and biochemical traits involved in tolerance to drought stress in A. spinosa. Significant correlations have been established between the traits that interact between them as well as the different potential interactions between the fixed factors (ecotype, treatment, and time). The canonical discriminant analysis has facilitated the distinction between the four ecotypes in terms of their tolerance to drought stress via the traits having the most significant discriminating power. Our experimental statistical approach has also contributed to conducting a “screening” of adaptive traits to select the most tolerant ecotypes that appear to be very promising for the regeneration of the Moroccan argan tree.

SummaryThis study was carried out to develop an efficient in vitro-selection system for water stress tolerance in Argania spinosa (L.). Calli were induced from nodal explants on Murashige and Skoog medium containing half-strength salts, supplemented with 1.0 mg l-1 _-naphthaleneacetic acid and 1.0 mg l-1 2,4-dichlorophenoxyacetic acid. Increasing concentrations (0, 5, 10, 20, 30, 40, 50, 60, 70, or 80 g l-1) of polyethylene glycol 6000 (PEG 6000) were used to study the effect of simulated water stress on the survival ability of A. spinosa calli. There was a significant reduction in callus growth with increasing concentrations of PEG 6000. Selection for water stress tolerance was achieved by exposing 1- month-old calli to 37.5 g l-1 PEG 6000 (-0.019 MPa) for 3 months. The mechanism(s) of tolerance in the selected calli were studied biochemically. After 8 d of water stress, K+ and Na+ ion concentrations were unaffected in PEG 6000- selected clones (n = 6). The selected calli also showed a significant increa...

The objective of this study was to understand and characterize the physiological and biochemical tolerance mechanisms of Argania spinosa under drought stress for selection tolerant ecotypes. Significant differences were observed among ecotypes in indices of leaf water status studied: stomatal conductance (gs), predawn leaf water potential (Ψpd) and leaf relative water content. There was a significant decrease in these physiological traits with increasing degree of drought stress in all ecotypes. Drought stress significantly increased endogenous H2O2 and lipid peroxidation. Moderate and severe drought stress increased significantly the catalase, superoxide dismutase, peroxidase, polyphenoloxidase and lipoxygenase activities, depending on time. Their constitutive activities were higher in inland ecotypes than in coastal ecotypes. According to canonical discriminant analysis, the inland ecotypes were essentially distinguished from the coastal ecotypes by the following physiological and biochemical traits: Ψp...

The present investigation was undertaken to characterise and to distinguish four contrasting Argania spinosa ecotypes in terms of drought tolerance by exploring the changes of leaf water status, osmoregulation and secondary metabolism. A. spinosa plants corresponding to four contrasting ecotypes (Lks, Alz, Rab and Adm) were subjected to drought stress. The results exhibited that there was a significant decrease in predawn leaf water potential (Ψpd), stomatal conductance (g s) and leaf relative water content under the influence of the intensity and duration of drought stress. Negative and significant correlations were recorded between epicuticular wax load (EWL) and residual transpiration rate. Electrolyte leakage (EL) increased significantly in leaves of plants under drought stress treatment compared to control plants. Furthermore, our data revealed that drought stress can induce shikimate and phenylpropanoid pathways in A. spinosa. A significant induction of phenylalanine ammonium lyase (PAL), shikimate dehydrogenase (SKDH) and cinnamate 4-hydroxylase (C4H) enzymes and an increase in polyphenol content were recorded, of which Lks showed the highest induction and accumulation among ecotypes. Accumulation of polyphenols was positively correlated with the SKDH, PAL and C4H activities. The strong induction of secondary metabolism in Lks might be linked to its better ability of drought tolerance. The proline and soluble sugar content in leaves of all ecotypes increased substantially in parallel with the severity of stress-induced. According to canonical discriminant analysis of our data, the four ecotypes were separated by the following physiological and biochemical parameters: EL, g s, EWL, soluble sugars and polyphenols.