Impact of Plantago ovata Forsk leaf extract on morpho-physio-biochemical attributes, ions uptake and drought resistance of wheat (Triticum aestivum L.) seedlings.

The present study was conducted to examine the potential role of Plantago ovata Forsk leaf extract (POLE) which was applied at various concentration levels (control, hydropriming, 10, 20, 30, and 40% POLE) to the wheat (Triticum aestivum L.) seedlings. Drought stressed was applied at 60% osmotic potential (OM) to the T. aestivum seedlings to study various parameters such as growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress and response of various antioxidants and nutritional status of the plants. Various growth parameters such as gaseous exchange attributes, antioxidants and nutritional status of T. aestivum were investigated in this study. It was evident that drought-stressed condition had induced a negative impact on plant growth, photosynthetic pigment, gaseous exchange attributes, stomatal properties, and ion uptake by different organs (roots and shoots) of T. aestivum. The decrease in plant growth resulted from oxidative stress and overcome by the antioxidant (enzymatic and non-enzymatic) compounds, since their concentration increased in response to dehydration. Seed priming with POLE positively increased plant growth and photosynthesis, by decreasing oxidative stress indicators and increasing activities of antioxidant (enzymatic and non-enzymatic) compounds, compared to the plants which were grown without the application of POLE. Our results also depicted that optimum concentration of POLE for T. aestivum seedlings under drought condition was 20%, while further increase in POLE (30 and 40%) induced a non-significant (P < 0.05) effect on growth (shoot and root length) and biomass (fresh and dry weight) of T. aestivum seedling. Here we concluded that the understanding of the role of seed priming with POLE in the increment of growth profile, photosynthetic measurements and nutritional status introduces new possibilities for their effective use in drought-stressed condition and provides a promising strategy for T. aestivum tolerance against drought-stressed condition.

Moringa leaf extract and green algae improve the growth and physiological attributes of Mentha species under salt stress.

Climate change, food scarcity, salt stress, and a rapidly growing population are just a few of the major global challenges. The current study examined into whether Moringa oleifera (L.) leaf extract and green algae (Ulva intestinalis) could help improve salt tolerance in Mentha species (Mentha piperita; Mentha longifolia). Moringa leaf extract (MLE) and green algae (GA) were applied to Mentha seedlings under three different salt treatments: 0 mM, 20 mM, 40 mM, 60 mM, and 90 mM, respectively. For each treatment, three biological replicates were conducted, with each replicate containing at least three plants. Mentha species were negatively affected by salt stress in terms of shoot length, fresh and dry weight, photosynthetic pigments, and antioxidant enzyme activities. However, the use of MLE and GA significantly improved the development and physiology of Mentha species under salt stress conditions. The MLE and GA treatments dramatically (p ≤ 0.001) increased SOD activity by 7% and 10%, CAT activity by 16% and 30%, APX activity by 34% and 56%, GPX activity by 12% and 47%, respectively, in Mentha piperita seedlings, which in turn strikingly increased superoxide dismutase (SOD) activity by 6% and 9%, catalase (CAT) activity by 15%, 28% and 44%, 27%, ascorbate peroxidase (APX) activity by 39% and 60%, glutathione peroxidase (GPX) activity by 23% and 58%, respectively, in Mentha longifolia seedlings, relative to the control. Aiming to answer questions about the relationship between plant extraction and traditional agricultural methods, this research greatly advances the goal of sustainable development for improving plant productivity by providing a much safer and more environmentally friendly adaptability.

Floristic diversity and vegetation of the az Zakhnuniyah Island, Arabian Gulf, Saudi Arabia.

Islands are broadly recognized as hotspots of ecology, biological and geophysical diversity with unique plant species. The present study aimed to address the floristic composition in the Az Zakhnuniyah Island along the Arabian Gulf of Saudi Arabia. A total of 21 quadrats, of 100 m2 each were sampled, and both relative density and cover were determined. Classification (Agglomerative Hierarchical Clustering {AHC} and ordination [Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA)] were applied to identify vegetation clusters and their correlation to the underlying soil factors. Fifty plant species belonging to 21 families were recorded. Amaranthaceae (22.9%), Poaceae (12.5%), Asteraceae and Zygophyllaceae (8.33% each) were the largest represented families. Therophytes and chamaephytes were the most represented life-forms, indicating saline-desert vegetation. Most of the surveyed plant species are used for medicinal purposes and grazing. AHC and DCA allowed identifying three vegetation clusters within three distinct habitats: cluster (A): Halopeplis perfoliata- Suaeda vermiculata in wet salt-marsh habitat, cluster (B): Limonium axillare- Zygophyllum mandaville in sabkha, and cluster (C): Heliotropium bacciferum- Panicum turgidum in sand dune habitat within the island. The CCA results imply strong relationships between floristic composition and salinity measures (CaCO3, electric conductivity, Mg+2, Na+, K+, Cl- and SO4) and soil texture. The current vegetation pattern in Zakhnuniyah Island reflects a salinity gradient with variations in soil texture. Knowledge of the floristic composition and its correlation to the environmental factors within islands should guide future conservation strategy and management efforts.

A Remote Sensing Approach for Displaying the Changes in the Vegetation Cover at Az Zakhnuniyah Island at Arabian Gulf, Saudi Arabia.

In the terrestrial ecosystem, vegetation is the important component of exchanging of water and energy in biogeochemical and climate cycle. A study was conducted to detect the vegetation cover change at Az Zakhnuniyah island by using remote sensing techniques. It includes vegetation analysis using normalized difference vegetation index (NDVI) while comparing with climatological data including temperature, humidity, and precipitation. A clear trend was seen in climatological parameters where temperature and humidity were rising decade by decade although NDVI did not show. In addition, increasing soil salinization over the years was observed when soil salinity index was used. NDVI-based long-term decadal analysis on vegetation cover based on Landsat surface reflectance data showed increase of vegetation cover which was also linked to precipitation trends. Also, the short-term demi-decadal comparison using PROBA-V showed the vegetation cover reduction between 2015 and 2019. Nevertheless, the sea level surrounding the island also showed an increasing trend of 0.34 cm/y, which could be the cause of inundation in some parts of the island in future. Furthermore, all these trends need to be observed in entirety as many of those trends can be interlinked.

Essential Oil Enriched with Oxygenated Constituents from Invasive Plant Argemone ochroleuca Exhibited Potent Phytotoxic Effects.

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%), γ-cadinene (11.70%), oleic acid, methyl ester (7.37%), terpinene-4-ol (4.77%), dihydromyrcenol (2.90%), α-muurolene (1.77%), and γ-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 µL L-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 µL L-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.

Nutritional Value, Mineral Composition, Secondary Metabolites, and Antioxidant Activity of Some Wild Geophyte Sedges and Grasses.

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 > C. conglomeratus > L. scindicus > P. turgidum > 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 > Mn > Zn > 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 < 1 mg mL-1), while extracts of E. farctus and L. scindicus exhibited moderate scavenging activity (1 ≤ EC50 ≤ 2 mg mL-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.

Comparative morphological and anatomical characters of Cakile arabica from different habitat in eastern region of Saudi Arabia.

Morphological, anatomical and physiological plasticity was examined for Cakile arabica from three different sites at the coastal part of the Arabian Gulf near Ad Dammam city in the eastern region of Saudi Arabia. Morphological investigation showed that the size and number of lobes of the leaves are increased in sites (I) which have high salt stress. Also anatomical investigation using a light microscope showed that the plant is adaptive for salt stress by increasing the thickening of the cuticle or epidermis layer and increase in the area of vascular bundles. Physiological studies showed that plant growing under high salt stress is characterized by increase content of electrical conductivity and increase in chlorophyll a, b, carotenoids and proline content in the plant tissues. This can be explained as an osmotic adjustment mechanism for the investigated species growing under high salinity stress.

Effect of water stress by Polyethylene Glycol 8000 and Sodium Chloride on germination of Ephedra alata Decne seeds.

Ephedra alata Decne is a perennial shrub and it is a very effective sand-binder. In Saudi Arabia, the species is associated with sand dunes formation, especially the mobile, non-saline and low moisture content ones. Its geographical distribution in Saudi Arabia includes the Northern, Eastern and Central regions. The aims of this study were to determine the effects of temperature, water potential and Sodium Chloride on germination of E. alata. Seeds were collected from King Khalid Centre of Wildlife Research and Development at Thumama (80 km north east of Riyadh), Saudi Arabia. Seeds were germinated at four alternating temperature regimes (8/22; 9/23; 13/27 and 18/35 °C). Seeds were also germinated under stress of aqueous Polyethylene Glycol (PEG) solutions mixed to create water potentials of 0; -0.3; -0.6; -1.2 and -1.5 MPa. Seed were also germinated in Sodium Chloride solutions of 0, 0.05, 0.1, 0.2 and 0.3 mol l(-1). Optimum germination was attained at 13/28 °C that corresponds to temperatures prevailing during spring time. Seeds germinated in Polyethylene Glycol solutions exhibited significantly lower germination than control especially when water potential fell below -0.3 MPa. Germination was also negatively affected by 0.1 mol l(-1) Sodium Chloride solution or above. Results indicated that the germination temperature responses of the nondormant seeds synchronize the event of germination with the season when environmental conditions are more favorable for subsequent growth and seedling establishment. Germination was also sensitive to both water potential and salinity.