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The genus Solanum exhibits a wide range of variability in morphology, flavor, and tolerance to biotic and abiotic stresses. Phenotypic and genetic variability using ISSR and RAPD markers of Solanum incanum distributed in Al-Baha province of the Kingdom of Saudi Arabia is assessed. Thirty samples are representing three different locations: Baljershy, Aqeeq, and Tohama, besides twenty-five samples representing five different commercial cultivars tested. Growth type, the number of leaves per plant, fruit size (phenotypic traits), crude protein, carbohydrates, digestive organic matter, and Mg, Ca, P were the principal contributors in the PCA. Molecular analysis showed that 114 ISSR and 80 RAPD alleles with a 100% polymorphism were recorded. The polymorphism information content (PIC) values ranged from 0.84 to 0.91 for ISSR and from 0.59 to 0.89 for RAPD data. Similarity values ranged from 0.16 to 1.00, with an average of 0.47 for ISSR and from 0.01 to 0.97, with an average of 0.36 for RAPD. It resulted in a positive and significant correlation between morphological, molecular, nutritional, and chemical analysis of fruits using Mantel analysis. UPGMA and PCA for morphological traits and molecular data discriminated commercial cultivars and wild relatives. Solanum incanum was more diverse than commercial varieties. This study revealed a wide genetic diversity among and within collected eggplant accessions and may use in breeding programs of eggplants. There is a need to increase the present eggplant collection to widen the genetic diversity of cultivated eggplant varieties in Saudi Arabia.

Mistletoes are epiphytic hemiparasitic plants that are known to negatively affect the growth of their hosts, increase tree mortality, and as a consequence change the community dynamics. Mistletoe alters the mineral nutrition of the host and the nutrient cycle in the soil. In the present study, the elemental nutrient status is described for Acacia asak, A. ehrenbergiana, A. gerrardii, and A. tortilis that were infected with the mistletoe Plicosepalus curviflorus, at three levels of infection (no infection, low and high infection). The nutrients of the mistletoe and the soil under the studied acacias were also determined. The elemental contents of the infected Acacia species were significantly reduced compared to non-infected trees, particularly for potassium and sodium. The reduction in the elemental composition was also species-specific and dependent on infection density. Elemental contents of the mistletoe were significantly higher than their Acacia hosts, particularly for nitrogen, phosphorus, and potassium, and the concentrations of minerals in mistletoe tissues were host- and density-dependent. This study revealed a significant increase in nutrients in the soil beneath the canopy of infected Acacia compared to the non-infected trees. Overall, it appears that mistletoe infection has a dual effect. It threatens the health of the Acacia, potentially killing its host tree due to absorption of host nutrients particularly when the infection intense. It also has a positive effect in that it improves the availability of the micro-habitat of nutrients under the canopy, which in turn may contribute to the maintenance of biodiversity.

The essential oil (EO) of Bassia muricata shoots was extracted via hydro-distillation and then investigated by gas chromatography-mass spectrometry. Thirty-four compounds were recognized for the first time from this plant, representing 100% of the total mass. Terpenoids represented the major components with 69.17% of the total mass, containing oxygenated sesquiterpenes (53.18%), oxygenated monoterpenes (9.77%), sesquiterpene hydrocarbons (5.03%), and diterpenes (1.19%). Additionaly, 6-methoxy-1-acetonaphthone was the only aromatic compound represented in a high percentage of the total identified compounds with 22.35%. Additionally, a percent of 8.48% of the total mass was hydrocarbons. Only one oxygenated sesquiterpene namely hexahydrofarnesyl acetone representing 47.35% of the total mass was identified. It was followed by methoxy-1-acetonaphthone (19.92%), n-dotriacontane (3.58%), endo-borneol (3.24%), 6-methy-α-ionone (3.04%), and α-gurjunene (2.65%). The EO exhibited moderate antioxidant activity comparable with ascorbic acid as a standard, where it attained IC50 value of 20.70 µL L−1 and 16.32 µL L−1, for DPPH and ABTS. The EO of B. muricata significantly reduces the germination and seedling development of the weed Chenopodium murale. The EO showed an IC50 value of 175.60 µL L−1, 246.65 µL L−1, and 308.33 µL L−1 for root growth, shoot growth, and germination, respectively. Therefore, this EO could be a good green resource for the control of weeds.

Reichardia tingitana is an annual plant growing in different habitats of the Egyptian deserts. Little is known about variation among the habitats occupied by this species, its distribution, chemical composition, and allelopathic activity. The present study aimed to (a) assess the vegetation composition of three different habitats (Western Coast, Delta Coast, and Wadi Hagoul) of R. tingitana in Egypt, (b) determine their correlation to soil factors, (c) identify the changes in the bioactive constituents of R. tingitana in the three regions, and (d) evaluate the allelopathic activity regarding the variation in the habitat. Density and cover of all plant species associated with R. tingitana were estimated within 52 plots, representing three regions. Physical and chemical parameters of soil were analyzed in each plot. R. tingitana aboveground biomass was collected from each habitat, and the bioactive composition was analyzed using HPLC. The allelopathic effect against two weeds (Amaranthus lividius and Chenopodium murale) was assessed. The floristic composition showed the presence of 133 species belonging to 27 families. In the Delta Coast habitat of R. tingitana, Zygophyllum aegyptium and Calligonum polygonoides co-dominate, while Lycium shawii dominate the Western Coast habitat and finally the habitat of Wadi Hagoul was dominated by Haloxylon salicornicum. Soil analysis revealed little variations among habitats, especially salinity and organic matter. Fifteen compounds, mainly phenolics (60% of the total identified compounds) were identified from all R. tingitana samples. The major compounds were quercetin, naringenin, ellagic, gallic, chlorogenic, and caffeic acids. These compounds varied in diversity or quantity among different habitats. The Western Coast sample was the richest in species, followed by Delta Coast sample. Our study showed that salinity is the crucial factor that induces the production of bioactive constituents in R. tingitana, especially phenolics and flavonoids. The R. tingitana extracts significantly reduced the germination and growth of Chenopodium and Amaranthus. However, the Western Coast sample showed potent allelopathic activity, where the germination was wholly inhibited at 75 mg L−1 and 50 mg L−1, respectively. Thereby, this extract could be used as eco-friendly bioherbicide and may be integrated into weed control strategies. Keywords: Reichardia tingitana, Edaphic factors, Phytotoxicity, Seconday compounds, Chemical ecology

Wetlands are represented in Saudi Arabia in the form of mangrove, sabkha, and wadi (valleys) systems, and these habitats are considered as a sanctuary for biodiversity. The present study aimed to identify different vegetation groups in a wetland site in Wadi Hargan near Alqurainah, Riyadh, Saudi Arabia, and to relate different plant communities and plant diversity to soil moisture, salinity, and other soil properties. Floristic analysis and vegetation structure were investigated within 15 stands along the wadi and were subjected to correlation analysis with soil factors via multivariate analysis. The floristic survey revealed the presence of 111 plant species belonging to 39 families. The most represented families were Asteraceae, Poaceae, Brassicaceae, Caryophyllaceae, and Papilionaceae, which accounted for the largest proportion (55.4%) of the total species. The therophytes were the dominant life form, where they were represented by 46.9% of the total number of species. The application of cluster analysis (TWINSPAN) to the importance value of each species based on the relative cover and density led to the recognition of four plant communities: (A) Phragmites australis—Tamarix nilotica community, (B) Zygophyllum coccineum—Acacia gerrardii community, (C) Lycium shawii—Zygophyllum coccineum community, and (D) Rhazya stricta community. The soil analysis and correlation test revealed significant variations in the content of salinity, moisture, CO3, Cl, SO4, Ca, Mg, and Na among the plant communities. It can be concluded that soil moisture and salinity factors were the fundamental driving forces for plant community structure in the studied wadi. The wadi was moderately grazed, mainly by camels, thereby, the invasive plant Rhazya stricta dominated the central region of the wadi. Also, human interference was observed at the end of the wadi, where some weeds sprouted such as Malva parviflora. The presence of those two rare wetland species, Adiantum capillus-veneris and Ficus salicifolia, in the study area, showed the unique properties of the studied wadi and necessitate an urgent biodiversity conservation action to protect its natural vegetation from overgrazing and human interference.

Off-road vehicle driving is considered as main contributor to land degradation in arid regions. This study examined the impact of off-road vehicles (ORV) on soil and vegetation in a natural recreational desert meadow of Raudhat Khuraim, Saudi Arabia. Vegetation canopy cover and plant height away from road tracks were assessed. Also, species density and canopy cover, bare ground cover and soil attributes were assessed in four microhabitats; tracks, inter-tracks, verges, and away from vehicle tracks (undisturbed natural areas). Results show that the cover of forbs and grasses was negatively associated with distance from road verges. It was observed that the height of woody species responded negatively to distance away from tracks. Cover of native species decreased under verge, inter-track and track microhabitats giving more opportunity for weeds to flourish. Bare ground was highest (60.7%) in tracks. ORV impact on soil bulk density was clear with an increase of 38% under tracks compared to soils of undisturbed natural vegetation and a similar decrease in porosity was observed. On the other hand, soil electrical conductivity was significantly higher (5.45 mS cm−1) under disturbance compared to 1.32 mS cm−1 in undisturbed natural vegetation. Organic matter and nitrogen were not affected significantly by ORV disturbance. The results emphasize that managing off-road vehicle driving is essential for conserving native vegetation. Keywords: Off-road driving, Tyre tracks, Bulk density, Raudhat system, Plant diversity

Essential oils (EOs) from the aerial parts of three Launaea species collected from two different habitats were extracted [Launaea mucronata collected from coastal desert (LMC) and from inland desert (LMD), Launaea nudicaulis collected from coastal desert (LNC) and from inland desert (LND), Launaea spinosa (LS)]. The EOs were analysed by gas chromatography mass spectrometry (GC‐MS) and tested for antioxidant activity as well for allelopathic activity against purslane. A total of 117 compounds were identified from all samples, including 64 from LS, 50 from LMC, 39 from LMD, 24 from LNC, and 20 from LND, representing 100% of the total oil mass. The oxygenated sesquiterpenes were the major compounds of the EOs from LS, LMC, LMD, LNC, and LND, representing 62.73, 61.02, 58.35, 43.22, and 48.33%, respectively, whereas the monoterpene hydrocarbons were minor compounds in all samples. α‐Acorenol (31.42%), trans‐longipinocarveol (12.04%), and γ‐eudesmol (6.31%) represented the major compounds of the EO from LS, whereas hexahydrofarnesyl acetone and n‐heneicosane represented the major compounds from LMC, LMD, LNC, and LND. Correlations between the EOs of the five samples were studied via principal component analysis and agglomerative hierarchical clustering, based on the chemical composition of the EOs. There was a significant variation between Launaea species regarding both the quality and the quantity of EO composition, whereas no significant difference was observed based on the habitats (coastal and inland deserts). The EOs of the five Launaea samples exhibited meaningful antioxidant activities, as follows: LND > LNC > LMD > LMC > LS. Moreover, the EOs of the five Lanaea samples exhibited significant allelopathic activity against purslane weed in a concentration‐dependent manner. LMD and LMC showed the highest effect, with germination inhibition of 96.1 and 87.9% at 250 μL L⁻¹, and radicle growth inhibition of 92.6 and 89.7%, but LS was the least effective extract. Our results showed that the variation in the quality and quantity of EO composition is mainly species specific, with a slight correlation with habitats.

Prunus arabica (Oliv.) Meikle is an endangered shrub with a restricted distribution, which inhabits banks of flood flow channels in small sites of ancient volcanic activity dominated by black basaltic boulders within the Harrat Al-Harrah protectorate, Northern Saudi Arabia. It is with limited information about its ecology and hence, the present study is focusing on its phytosociological behavior and ecological features. The multi-methodological approach comprised species description, vegetation sampling and soil composition of 9 study sites at Harrat Al-Harrah protectorate. The application of TWINSPAN, DCA and CCA multivariate analyses led to identify 3 vegetation groups (VGI: Pulicaria undulata-Prunus arabica, VGII: Prunus arabica–Artemisia seiberi, VGIII: Artemisia seiberi-Achillea fragrantissima) associated with the distribution of P. arabica. The environmental variables that affect P. arabica and its main ecological features had been estimated and discussed. The present study concludes that the main reasons for its threatened and endangerment are seemingly due to overgrazing, poor rainfall, drought, shifting and destruction of its suitable habitat area. Keywords: Autecology, Endangered plant, Floristic diversity, Harrat Al-Harrah

In recent years, the phenomenon of abandonment of arable fields has increased in Saudi Arabia due to low soil fertility, drought, low rainfall, high levels of evapotranspiration, soil salinization, and low level of groundwater. We evaluated the effect of agricultural land abandonment on soil properties, perennial vegetation composition, and population structure in the Al-Kharj region, Saudi Arabia. A total of 11 perennial plant species belonging to 9 families and 11 genera were detected in the different abandoned fields of the study area. Four plant communities were identified after the application of the detrended correspondence analysis (DCA) ordination. The indicator species were (1) Seidlitzia rosmarinus&mdash, Zygophyllum hamiense, (2) Traganum nudatum&mdash, Seidlitzia rosmarinus, (3) Traganum nudatum&mdash, Prosopis farcta, and (4) Calligonum comosum&mdash, Pulicaria undulata. Results of the soil analysis showed significant differences in soil texture, pH, salinity, and nutrient content among the four recognized plant communities. Demographic analysis indicated that populations of Zygophyllum hamiense and Calligonum comosum tended to be either inverse J-shaped or positively skewed which may have indicated rapidly-growing populations with high reproductive capacity. Conversely, the size&ndash, frequency distribution of Traganum nudatum, S. Rosmarinus, and Prosopis farcta was approximately symmetrical (i.e., bell-shaped). The present study sheds light on the necessity of managing abandoned agricultural fields for restoring and improving rangelands with native species that are adapted to the local conditions such as low water demand.

Plants are considered green resources for thousands of bioactive compounds. Essential oils (EOs) are an important class of secondary compounds with various biological activities, including allelopathic and antimicrobial activities. Herein, the present study aimed to compare the chemical profiles of the EOs of the widely distributed medicinal plant Calotropis procera collected from Saudi Arabia and Egypt. In addition, this study also aimed to assess their allelopathic and antimicrobial activities. The EOs from Egyptian and Saudi ecospecies were extracted by hydrodistillation and analyzed via GC-MS. The correlation between the analyzed EOs and those published from Egypt, India, and Nigeria was assessed by principal component analysis (PCA) and agglomerative hierarchical clustering (AHC). The allelopathic activity of the extracted EOs was tested against two weeds (Bidens pilosa and Dactyloctenium aegyptium). Moreover, the EOs were tested for antimicrobial activity against seven bacterial and two fungal strains. Ninety compounds were identified from both ecospecies, where 76 compounds were recorded in Saudi ecospecies and 33 in the Egyptian one. Terpenes were recorded as the main components along with hydrocarbons, aromatics, and carotenoids. The sesquiterpenes (54.07%) were the most abundant component of EO of the Saudi sample, while the diterpenes (44.82%) represented the mains of the Egyptian one. Hinesol (13.50%), trans-chrysanthenyl acetate (12.33%), 1,4-trans-1,7-cis-acorenone (7.62%), phytol (8.73%), and myristicin (6.13%) were found as the major constituents of EO of the Saudi sample, while phytol (38.02%), n-docosane (6.86%), linoleic acid (6.36%), n-pentacosane (6.31%), and bicyclogermacrene (4.37%) represented the main compounds of the Egyptian one. It was evident that the EOs of both ecospecies had potent phytotoxic activity against the two tested weeds, while the EO of the Egyptian ecospecies was more effective, particularly on the weed D. aegyptium. Moreover, the EOs showed substantial antibacterial and antifungal activities. The present study revealed that the EOs of Egyptian and Saudi ecospecies were different in quality and quantity, which could be attributed to the variant environmental and climatic conditions. The EOs of both ecospecies showed significant allelopathic and antimicrobial activity, therefore, these EOs could be considered as potential green eco-friendly resources for weed and microbe control, considering that this plant is widely grown in arid habitats.

Plants are considered green resources for thousands of bioactive compounds. Essential oils (EOs) are an important class of secondary compounds with various biological activities, including allelopathic and antimicrobial activities. Herein, the present study aimed to compare the chemical profiles of the EOs of the widely distributed medicinal plant Calotropis procera collected from Saudi Arabia and Egypt. In addition, this study also aimed to assess their allelopathic and antimicrobial activities. The EOs from Egyptian and Saudi ecospecies were extracted by hydrodistillation and analyzed via GC-MS. The correlation between the analyzed EOs and those published from Egypt, India, and Nigeria was assessed by principal component analysis (PCA) and agglomerative hierarchical clustering (AHC). The allelopathic activity of the extracted EOs was tested against two weeds (Bidens pilosa and Dactyloctenium aegyptium). Moreover, the EOs were tested for antimicrobial activity against seven bacterial and two fungal strains. Ninety compounds were identified from both ecospecies, where 76 compounds were recorded in Saudi ecospecies and 33 in the Egyptian one. Terpenes were recorded as the main components along with hydrocarbons, aromatics, and carotenoids. The sesquiterpenes (54.07%) were the most abundant component of EO of the Saudi sample, while the diterpenes (44.82%) represented the mains of the Egyptian one. Hinesol (13.50%), trans-chrysanthenyl acetate (12.33%), 1,4-trans-1,7-cis-acorenone (7.62%), phytol (8.73%), and myristicin (6.13%) were found as the major constituents of EO of the Saudi sample, while phytol (38.02%), n-docosane (6.86%), linoleic acid (6.36%), n-pentacosane (6.31%), and bicyclogermacrene (4.37%) represented the main compounds of the Egyptian one. It was evident that the EOs of both ecospecies had potent phytotoxic activity against the two tested weeds, while the EO of the Egyptian ecospecies was more effective, particularly on the weed D. aegyptium. Moreover, the EOs showed substantial antibacterial and antifungal activities. The present study revealed that the EOs of Egyptian and Saudi ecospecies were different in quality and quantity, which could be attributed to the variant environmental and climatic conditions. The EOs of both ecospecies showed significant allelopathic and antimicrobial activity; therefore, these EOs could be considered as potential green eco-friendly resources for weed and microbe control, considering that this plant is widely grown in arid habitats.

Understanding the strategies and mechanisms of invasive species could guide their control and management especially in arid ecosystems. This study compares the vegetative and reproductive functional traits of the invasive Mexican poppy (Argemone ochroleuca), in seven habitat types, in southwestern Saudi Arabia. The results showed that the aboveground phenological attributes such as plant height, leaf area, and leaf dry mass attained the highest values in the wadi channels, whereas these attributes attained the lowest values in the mountain ranges. Maximum specific leaf area, root parameters, and all reproductive traits were recorded in the abandoned fields. In contrast to all other habitats, populations from abandoned fields had a greater investment of resources in belowground structures, while the population growing in the wadi channels and mountain ranges habitat allocated more energy to vegetative parts. The plasticity in vegetative and reproductive resource allocation in A. ochroleuca is an important mechanism in determining its colonizing ability in different habitat types and expanding the distribution range. The present data of the functional traits of A. ochroleuca agree with the resource fluctuation hypothesis, where the plant flourished in the abandoned fields that attained the highest values of organic matter and nutrients. Therefore, the restoration of these disturbed habitats could improve the resistance toward invasion by this noxious weed.

The use of drainage water in the irrigation of agroecosystem is associated with environmental hazards, and can pose threats to human health. Nine heavy metals (Fe, Mn, Zn, Cu, Co, Cr, Ni, Cd and Pb) along three main drains in the middle Nile Delta were measures in the sediments, roots and shoots of three common macrophytes (Echinochloa stagnina, Phragmites australis and Typha domingensis). The physicochemical characteristics, as well as the enrichment factor (Ef), contamination factor (Cf), geoaccumulation index (Igeo), ecological risk factor (Er), degree of contamination (Dc) and potential ecological risk index (PERI), were determined for sediment. The metal bioaccumulation factor (BAF) and translocation factor (TF) were assessed for plants. Data revealed high contents of Cr, Zn and Cd in the upstream of the drains, while Mn, Cu and Ni were recorded in high concentrations in the downstream. Mn, Cr, Co, Cu, Ni and Zn were recorded to be within EU (2002), CSQGD (2007) and US EPA (1999) limits, while Cd and Pb showed high a ecological risk index. This high concentration of pollutants could be attributed to unremitting industrial activities, which can bioaccumulate in the food chains and cause serious problems for humans. The root of P. australis showed the effective accumulation of most of the elements, while T. domingensis revealed the highest accumulation of Pb. However, the highest BAF shoot value was found in T. domingensis for most of the heavy metals, except for Fe and Zn in P. australis and Mn in E. stagnina. Thus, P. australis could be used as a potential phytoextractor of these hazardous metals, as an eco-friendly and cost-efficient method for remediation of the polluted drains. Further, T. domingensis could be integrated as a hyperaccumulator of Pb. Strict laws and regulations must be taken into consideration by the policymaker against unmanaged industrial activities, particularly near the water streams in the Nile Delta.

Pulicaria genus (fleabane) is characterized by its fragrant odor due to the presence of essential oil (EO). According to the literature reviews, the EO of Pulicaria somalensis O.Hoffm. (Shie) is still unexplored. For the first time, 71 compounds were characterized in EO derived from above-ground parts of P. somalensis collected from Saudi Arabia. Sesquiterpenes represented the main components (91.8%), along with minor amounts of mono-, diterpenes, and hydrocarbons. Juniper camphor (24.7%), &alpha, sinensal (7.7%), 6-epi-shyobunol (6.6%), &alpha, zingiberene (5.8%), &alpha, bisabolol (5.3%), and T-muurolol (4.7%) were characterized as main constituents. The correlation analysis between different Pulicaria species showed that P. somalensis has a specific chemical pattern of the EO, thereby no correlation was observed with other reported Pulicaria species. The EO showed significant allelopathic activity against the weeds of Dactyloctenium aegyptium (L.) Willd. (crowfoot grass) and Bidens pilosa L. (hairy beggarticks). The IC50 value on the germination of D. aegyptium was double that of B. pilosa. The IC50 values on the root growth of B. pilosa and D. aegyptium were 0.6 mg mL&minus, 1 each, while the shoot growths were 1.0 and 0.7 mg mL&minus, 1, respectively. This variation in the activity could be attributed to the genetic characteristics of the weeds. Moreover, the EO exhibited significant antioxidant effects compared to ascorbic acid. Further studies are necessary to verify if these biological activities of the EO could be attributable to its major compounds.

The genus Solanum exhibits a wide range of variability in morphology, flavor, and tolerance to biotic and abiotic stresses. Phenotypic and genetic variability using ISSR and RAPD markers of Solanum incanum distributed in Al-Baha province of the Kingdom of Saudi Arabia is assessed. Thirty samples are representing three different locations: Baljershy, Aqeeq, and Tohama, besides twenty-five samples representing five different commercial cultivars tested. Growth type, the number of leaves per plant, fruit size (phenotypic traits), crude protein, carbohydrates, digestive organic matter, and Mg, Ca, P were the principal contributors in the PCA. Molecular analysis showed that 114 ISSR and 80 RAPD alleles with a 100% polymorphism were recorded. The polymorphism information content (PIC) values ranged from 0.84 to 0.91 for ISSR and from 0.59 to 0.89 for RAPD data. Similarity values ranged from 0.16 to 1.00, with an average of 0.47 for ISSR and from 0.01 to 0.97, with an average of 0.36 for RAPD. It resulted in a positive and significant correlation between morphological, molecular, nutritional, and chemical analysis of fruits using Mantel analysis. UPGMA and PCA for morphological traits and molecular data discriminated commercial cultivars and wild relatives. Solanum incanum was more diverse than commercial varieties. This study revealed a wide genetic diversity among and within collected eggplant accessions and may use in breeding programs of eggplants. There is a need to increase the present eggplant collection to widen the genetic diversity of cultivated eggplant varieties in Saudi Arabia.

Geophytes are plants with underground storage organs including bulbs, corms, tubers, and rhizomes, often physiologically active and able to survive during harsh environmental conditions. This study is conducted to assess the nutritive value, mineral composition, bioactive metabolites, and antioxidant activity of five wild geophytes (Cyperus capitatus, C. conglomeratus, Elymus farctus, Lasiurus scindicus, and Panicum turgidum) collected from the Nile Delta coast and inland desert. The proximate composition including dry matter, moisture content, ash content, fiber, fat, protein, sucrose, and glucose were determined. Also, total carbohydrates, total digestible nutrients (TDN), and nutritive values were calculated. Macro- and micro-minerals were also determined in the studied geophytes. Total phenolics, total flavonoids, alkaloids, saponins, and tannins were determined. Antioxidant activity was evaluated based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicle scavenging. Based on the nutritive value, the studied geophytes are ranked as follows: E. farctus &gt, C. conglomeratus &gt, L. scindicus &gt, P. turgidum &gt, C. capitatus. The mineral analysis reveals a sufficient amount of macro- and micro-elements in the studied geophytes while the microelements levels in the studied wild plants exist as Fe &gt, Mn &gt, Zn &gt, Cu. Cyperus conglomeratus attained the highest concentrations of all determined secondary metabolites. On the other hand, C. conglomeratus, C. capitatus, and P. turgidum extracts showed strong scavenging activity (EC50 &lt, 1 mg mL&minus, 1), while extracts of E. farctus and L. scindicus exhibited moderate scavenging activity (1 &le, EC50 &le, 2 mg mL&minus, 1). The present data reveal that geophytes under investigation could be used as good forage plants, especially in arid habitats. In addition, C. conglomeratus could be a potentially important candidate for natural antioxidants as it attained high contents of the bioactive constituents.

The variation in habitat has a direct effect on the plants and as a consequence, changes their content of the bioactive constituents and biological activities. The present study aimed to explore the variation in the essential oils (EOs) and phenolics of Heliotropium curassavicum collected from the coastal and inland habitats. Additionally, we determined their antioxidant and allelopathic activity against the weed, Chenopodium murale. Fifty-six compounds were identified as overall from EOs, from which 25 components were identified from the coastal sample, and 52 from the inland one. Sesquiterpenes were the main class in both samples (81.67% and 79.28%), while mono (3.99% and 7.21%) and diterpenes (2.9% and 1.77%) represented minors, respectively. Hexahydrofarnesyl acetone, (-)-caryophyllene oxide, farnesyl acetone, humulene oxide, farnesyl acetone C, and nerolidol epoxy acetate were identified as major compounds. The HPLC analysis of MeOH extracts of the two samples showed that chlorogenic acid, rutin, and propyl gallate are major compounds in the coastal sample, while vanilin, quercetin, and 4&prime, 7-dihydroxyisoflavone are majors in the inland one. The EOs showed considerable phytotoxicity against C. murale with IC50 value of 2.66, 0.59, and 0.70 mg mL&minus, 1 for germination, root, and shoot growth, respectively from the inland sample. While the coastal sample attained the IC50 values of 1.58, 0.45, and 0.66 mg mL&minus, 1. MeOH extracts revealed stronger antioxidant activity compared to the EOs. Based on IC50 values, the ascorbic acid revealed 3-fold of the antioxidant compared to the EO of the coastal sample and 4-fold regarding the inland sample. However, the ascorbic acid showed 3-fold of the antioxidant activity of the MeOH extracts of coastal and inland samples. Although H. curassavicum is considered as a noxious, invasive plant, the present study revealed that EO and MeOH extracts of the H. curassavicum could be considered as promising, eco-friendly, natural resources for antioxidants as well as weed control, particularly against the weed, C. murale.

The Asteraceae (Compositae) family is one of the largest angiosperm families that has a large number of aromatic species. Pulicaria undulata is a well-known medicinal plant that is used in the treatment of various diseases due to its essential oil (EO). The EO of both Saudi and Egyptian ecospecies were extracted via hydrodistillation, and the chemical compounds were identified by GC–MS analysis. The composition of the EOs of Saudi and Egyptian ecospecies, as well as other reported ecospecies, were chemometrically analyzed. Additionally, the phytotoxic activity of the extracted EOs was tested against the weeds Dactyloctenium aegyptium and Bidens pilosa. In total, 80 compounds were identified from both ecospecies, of which 61 were Saudi ecospecies, with a preponderance of β-pinene, isoshyobunone, 6-epi-shyobunol, α-pinene, and α-terpinolene. However, the Egyptian ecospecies attained a lower number (34 compounds), with spathulenol, hexahydrofarnesyl acetone, α-bisabolol, and τ--cadinol as the main compounds. The chemometric analysis revealed that the studied ecospecies and other reported species were different in their composition. This variation could be attributed to the difference in the environmental and climatic conditions. The EO of the Egyptian ecospecies showed more phytotoxic activity against D. aegyptium and B. pilosa than the Saudi ecospecies. This variation might be ascribed to the difference in their major constituents. Therefore, further study is recommended for the characterization of authentic materials of these compounds as allelochemicals against various weeds, either singular or in combination.

Within the semi-desert landscape of northern Libya, two sub-humid escarpments occur: Al-Akhdar in the east and Nafusa (Jabal Al-Gharbi) in the west. This study compares plant communities in the two regions, which are along an elevation gradient, in terms of species composition and diversity, frequency of different Raunkiaer life forms, and reproductive phenology. The two regions differed in species composition and life-form frequency between regions and between elevation zones within each region. Patterns were associated with the lower rainfall and lower moisture-holding capacity of soils at Nafusa, resulting in more xeric conditions. Only 13% of species were shared between the two regional landscapes. Species diversity, life-form frequency, and duration of the flowering–fruiting phenophase were all affected by elevation above sea level. The duration of flowering and fruiting in spring and fall was associated with environmental conditions, although there were different thresholds in the two regions. There was both a spring and fall episode of flowering at Nafusa, but only spring flowering at Al-Akhdar. It is anticipated that there will be a gradual shift of plant communities to higher elevations and loss of certain sensitive species in response to ongoing climate change.

Using synthetic chemicals in industry and agriculture has led to several environmental problems. Thus, plant products derived from volatile oils (VOs) could be a potential green source for bioherbicides. Little is known about the VOs of Lactuca serriola. Hence, the present study aimed to characterize the VOs chemical composition from the aerial parts of L. serriola, assessment of antioxidant activity, and evaluate allelopathic potential against the noxious weed Bidens pilosa. The VOs were extracted by hydrodistillation and analyzed by GC/MS. The VOs from the Egyptian ecospecies of L. serriola were found to comprise 34 compounds mainly oxygenated sesquiterpenes and diterpenes. The major compounds were isoshyobunone (64.22 %), isocembrol (17.35 %), and alloaromadendrene oxide-1 (7.32 %). So, L. serriola can be considered as a good source for isoshyobunone, considering that it has a much higher concentration than any other plants. Also, this plant has a high content of the oxygenated diterpene compound, isocembrol, which is rarely found in the VOs of most plants. The VOs expressed strong antioxidant activity. Also, for the first time, our results showed a strong allelopathic activity of VOs from L. serriola on germination and seedling growth of the noxious weed, B. pilosa. We suppose that the activity of the VOs from L. serriola could be attributed to these previously mentioned major compounds, as they represent about 89 % of the total identified oil constituents. Nevertheless, to evaluate these compounds as new allelochemicals, further study is needed to test the allelopathic activity of authenticated standard of these compounds either singular or in combination on several weeds as well as evaluate the safety, and improve the efficacy and stability at the field scale.

Herbicides are natural or synthetic chemicals used to control unwanted plants (weeds). To avoid the harmful effects of synthetic herbicides, considerable effort has been devoted to finding alternative products derived from natural sources. Essential oils (EOs) from aromatic plants are auspicious source of bioherbicides. This review discusses phytotoxic EOs and their chemical compositions as reported from 1972 to 2020. Using chemometric analysis, we attempt to build a structure-activity relationship between phytotoxicity and EO chemical composition. Data analysis reveals that oxygenated terpenes, and mono- and sesquiterpenes, in particular, play principal roles in the phytotoxicity of EOs. Pinene, 1,8 cineole, linalool, and carvacrol are the most effective monoterpenes, with significant phytotoxicity evident in the EOs of many plants. Caryophyllene and its derivatives, including germacrene, spathulenol, and hexahydrofarnesyl acetone, are the most effective sesquiterpenes. EOs rich in iridoids (non-terpene compounds) also exhibit allelopathic activity. Further studies are recommended to evaluate the phytotoxic activity of these compounds in pure forms, determine their activity in the field, evaluate their safety, and assess their modes of action.

Long-term adoption of intensive agricultural system negatively affects soil fertility, soil microbiome and may compromise the quality and amount of crop production. To avoid these problems, application of organic materials has been proposed as a potential alternative strategy for soil management. Therefore, the objective of this study was to compared the effects of conventional and organic soil management on crop yield of rocket (Eruca sativa), soil fertility, and microbiome structure through a 2-year long mesocosms experiment. Eight organic treatments, different in terms of organic amendment chemistry (i.e., alfalfa hay, biochar, glucose, manure) and application frequency, were compared with conventional management practices based on mineral fertilizer and chemical fumigation. Crop quality was assessed by measuring the NO3− content in leaves, whereas soil chemical and microbiological (i.e., FDA activity and functioning by BIOLOG EcoPlates™) properties were evaluated to understand their effects on soil fertility. Changes in soil microbiota were assessed by high-throughput sequencing of bacterial and fungal rRNA gene markers. Application of organic amendments significantly improved crop yield, especially when alfalfa and glucose were applied as a single dose. NO3− concentration in leaves was decreased with biochar and manure application, and this did not depend on the application frequency. Application of synthetic fertilizer and fumigation induced soil acidification, increased soil salinity, and reduced soil microbiota diversity, activity and functionality, with negative effects on crop yield. In conclusion, this study indicates that long-term application of organic amendments effectively improved soil fertility and promoted the development of a beneficial soil microbiota capable of supporting high plant yield under intensive agricultural system.

We sampled twenty populations of the vulnerable endemic shrub or tree, Arbutus pavarii Pampan., at different elevations and aspects within the Al-Akhdar mountainous region of Libya. Our sampling sites were at elevations ranging from 285 to 738 m above sea level, and several different habitats: vallies (locally known as wadis), north- and south-facing slopes, and mountaintops. All individuals within each quadrat were studied. Population size and structure, and plant functional traits were assessed. None of the populations had a stable distribution of size classes. Some consisted mostly of small plants, with little or no fruit production; others consisted only of mid-sized and large plants, with high fruit production, but no juvenile recruitment. There was a significant increase in percent cover with increasing elevation; reproductive output (the number of fruits per branch and total number of fruits per individual) also generally increased with elevation. In some of these populations the lack of recruitment, and in others the failure to produce fruit, together constituted serious demographic threats. In light of these results, recommendations are made for conservation of this vulnerable endemic species.

The Phoenician juniper (Juniperus phoenicea L.) has long been common in the Al-Akhdar mountain range in NE Libya. Juniper trees in the region are showing signs of dieback, and minimal successful seedling recruitment has occurred. We investigate this effect at the level of individual trees, tree size classes, and populations. At ten sites, population size, growth and reproductive traits, and percentage dieback in different size classes were evaluated. Elevation, distance from the sea, and the interaction between these factors had a significant effect on tree volume, and number of branches, number of female cones per branch and number of female cones per tree. Two groups of populations were recognized: the first (Sites 2, 3, and 4) were near the coast. They appeared to be more recently established, with no individuals in the largest size class, and, at this point, less severe dieback. In contrast, in the rest of the sites there were no individuals (Sites 1, 5, 6, and 9) or very few individuals (Site...

Invasive species are considered as one of the major threats to ecosystems worldwide. Although invasive plants are regarded as a foe, they could be considered as natural resources for valuable bioactive compounds. The present study aimed to characterize the chemical composition of the essential oil (EO) from the invasive plant Argemone ochroleuca Sweet, collected from Saudi Arabia, as well as to evaluate its phytotoxic activity. Seventy-four compounds were characterized via GC-MS analysis of EO representing 98.75% of the overall mass. The oxygenated constituents (79.01%) were found as the main constituents, including mono- (43.27%), sesqui- (17.67%), and di-terpenes (0.53%), as well as hydrocarbons (16.81%) and carotenoids (0.73%). Additionally, 19.69% from the overall mass was characterized as non-oxygenated compounds with mono- (1.77%), sesquiterpenes (17.41%), and hydrocarbons (0.56%) as minors. From all identified constituents, trans-chrysanthenyl acetate (25.71%), &gamma, cadinene (11.70%), oleic acid, methyl ester (7.37%), terpinene-4-ol (4.77%), dihydromyrcenol (2.90%), &alpha, muurolene (1.77%), and &gamma, himachalene (1.56%) were found as abundant. The EO of A. ochroleuca showed significant phytotoxic activity against the test plant Lactuca sativa and the noxious weed Peganum harmala. The EO attained IC50 values of 92.1, 128.6, and 131.6 &micro, L L&minus, 1 for seedling root growth, germination, and shoot growth of L. sativa, respectively, while it had IC50 values of 134.8, 145.7, and 147.9 &micro, 1, respectively, for P. harmala. Therefore, this EO could be used as a bioherbicide against weeds, while further study is recommended for the characterization of the authentic materials of the main compounds in the EO as well as for the evaluation of potency of this oil on a field scale and the determination of its biosafety.

Araucaria heterophylla tree has been used in traditional medicine for several purposes. The essential oil (EO) of the resin is poorly studied, and up to our knowledge, the EO of the resin of the Egyptian ecospecies of A. heterophylla was not explored. In this study, the resin EO of A. heterophylla was analyzed via GC–MS. The correlation of the chemical composition of the EO with those reported in other ecospecies of A. heterophylla was evaluated via Principal Components Analysis (PCA). The in vivo inflammation inhibition and antipyretic activities in a carrageenan-induced rat model were evaluated for both crude EO and its nanoemulsion. Thirty-nine compounds were characterized in the EO. Monoterpenes (66.53 %) represented the main components followed by sesquiterpenes (30.85 %). α-Pinene (44.88 %), germacrene-D (10.25 %), α-copaene (4.72 %) and sabinene (4.44 %) were identified as major constituents of the EO. The PCA analysis showed more correlation of EO of the resin from the present study with that from the leaves of both Egyptian and Australian ecospecies, while it was negatively correlated with the EO from the leaves or resin of the Indian ecospecies. These variations could be ascribed to the environmental, climatic or genetic factors. The EO (100 mg/kg) administration in the rat paw edema and rectal temperature exhibited a significant difference (P

We studied how emergence, survival, and growth of nebkha recruits are spatially affected by prevailing biotic and abiotic ecological drivers in a landscape with vegetation-induced dunes (nebkhas) in Saudi Arabia. Hereto Monte Carlo-based spatiotemporal analyses were performed on four remotely sensed study site maps, including adult nebkhas, recruits and elevation data, acquired over a three-year period. The emergence of new nebkha recruits was found substantially higher in topographic depressions and around adults, which we interpret as being a result of runoff water convergence to depressions and distance-limited seed dispersal from adults. The survival of recruits was also higher nearby nebkhas. However, the growth of already present recruits was suppressed near adult vegetation indicating competition, but unexpectedly increased far away from nebkhas which could be induced by augmented sand burial in these open areas, stimulating the nebkha development and its host plant. Combining the three demographic processes emergence, survival, and growth revealed systematically greater encroachment from nebkha recruits in zones with low vegetation cover, which creates a buffer against local disturbances in nebkha fields.

Phytogenic mounds or nebkhas are formed by spatially isolated burial-Tolerant plants, which have been trapping windborne sediment within their canopies. They occur in drylands all over the world, and nebkha landscapes are considered intermediate between stable grasslands and unstable deserts with mobile dunes. Depending on the previous state of the landscape, they can thus be viewed both as indicators of desertification and as signs of stabilization. While individual nebkha mounds have been studied extensively, little is known about the organization of nebkha landscapes. In this study, we collected spatiotemporal data of vegetation and topography from four self-made remotely sensed maps, created over a three-year period from a study site in central Saudi Arabia dominated by the nebkha-forming shrub Rhazya stricta Decne. Using logistic regressions and t tests, we found that the nebkha shrubs grow in topographic depressions, while they shrink on topographic highs and in locations with high nebkha densities. We propose that this spatial variation in nebkha growth is driven by water availability, as the few extreme rain events that typically make up the bulk of precipitation in deserts would spatially redistribute to topographic lows, and as nebkha density would positively correlate with competition for water. Our data suggest a novel mechanism of biogeomorphological self-organization in deserts. The observed nebkha growth in depressions would lead to increased sedimentation on and in between the nebkhas owing to reduced wind speed, which after a time lag might transform depressions into topographic highs on which nebkhas tend to shrink because of water shortage. Shrinking nebkhas, in turn, could provoke soil erosion, on as well as in between the nebkha mounds, which may ultimately transform topographic highs into depressions, thereby closing the cycle of self-organization. ispartof: Ecosphere vol:7 issue:11 status: published

Euphorbia species were widely used in traditional medicines for the treatment of several diseases. From the aerial parts of Egyptian endemic plant, Euphorbia sanctae-catharinae, three new premyrsinane diterpenoids, namely, euphosantianane E&ndash, G (1&ndash, 3), alongside four known triterpenes, 9,19-cyclolanostane-3&beta, 24S-diol (4), 25-methoxycycloartane-3&beta, 24S-diol (5), 25-methylenecycloartan-3&beta, 24R-diol (6), and 25-methylenecycloartan-3&beta, 24S-diol (7), were isolated and identified. The chemical structures were proven depending upon spectroscopic analysis, including FTIR, HRFABMS, and 1D/2D-NMR. The chemotaxonomic significance of the isolated compounds, especially diterpenes from E. sanctae-catharinae compared to those documented from different Euphorbia species was also studied via agglomerative hierarchical clustering (AHC). The Egyptian endemic Euphorbia sanctae-catharina was grouped with E. bupleuroides, E. fidjiana, E. fischeriana, E. pithyusa subsp. cupanii, E. prolifera, and E. seguieriana, where myrsinol diterpenoids were the characteristic compounds.

Genetic variations in Anastatica hierochuntica populations in Libya, Egypt and Saudi Arabia were investigated among and within multigenerational population cohort’s levels. Considering population demography within-population cohorts, the greatest number of individuals was recruited in the mid-season cohort that received intermediate amount of rainfall compared to the early-season and the late-season population cohorts. Individuals of A.hierochuntica belonging to the same population cohort showed that spatial pattern varied between clumped and random distribution, with minimum separation distance not exceeding 10 cm. The spatial pattern within-population cohorts showed decreased overdispersion from the early-season toward the late-season individuals. Considering the spatial relationships between the within-population cohorts, the spatial relationships between early-season and mid-season, and mid-season and late-season cohorts varied between segregation and random distributions. The gene diversity and the number of recruited individuals were found to be not correlated with the amount of rainfall in the study regions. Nei’s genetic identity and distance varied among sites and population cohort groups. The overall genetic diversity was lower in the mid-season cohort group than in the early- and late-season cohorts. The variations of genetic characters and spatial patterns among and within-population cohorts of A. hierochuntica are regulated by recruitment of individuals from persistent seed output produced from overlapping generations.