Egyptian Journal of Botany Review 43 E NVIRONMENTAL pollution is exacerbated by the rise in petro... more Egyptian Journal of Botany Review 43 E NVIRONMENTAL pollution is exacerbated by the rise in petroleum hydrocarbons due to exploration, production, transportation, and industrialization. This requires immediate remediation. Although crude oil removal using conventional techniques is efficient for cleaning up aquatic and terrestrial ecosystems, it is costly and requires specialized staff and equipment. Despite their negative environmental consequences, chemical compounds such as dispersants, cleansers, emulsifiers, biosurfactants, and soil oxidizers are highly utilized. Phytoremediation and bioremediation have emerged as cost-effective and environmentally friendly technologies. This paper aims to review the impacts of crude oil pollution and the phytoremediation of polluted ecosystems. We have reviewed various phytoremediation/bioremediation mechanisms and environmental factors. Additionally, we have discussed the degradation of crude petroleum, factors affecting petroleum hydrocarbon bioremediation, and the environmental consequences, such as DNA and epigenetic mutations. We have also compared the economics of phytoremediation and restoration of polluted sites with conventional technology. Plants can remediate the environment through phytodegradation, phytostabilization, phytovolatilization, evapotranspiration, and phytoaccumulation. The microbial activities in the plant rhizosphere enhance the degradation and accumulation of the pollutants and modulate their bioavailability, thereby remediating the polluted areas and stabilizing the soil fertility.
The encroachment of urbanization over the rural environment and deterioration of large areas of w... more The encroachment of urbanization over the rural environment and deterioration of large areas of wilderness in the Middle East make many people weaned away from appreciation of wild plant food resources. The studies on wild edible fruits are deemed essential and open the possibility for its use as source of nutritional and pharmaceutical materials. Fruits of three species Arbutus pavarii , Ficus palmata and Nitraria retusa were analyzed for evaluation of their nutritive values and antioxidant capacities. The protein, carbohydrate and lipid content of the fruits may exceed or coincide the reported values of other wild and cultivated edible fruits. The energy content reached 790 kcal/ 100 g fresh weight. The mineral composition reaches high quantities of K, Ca, Mg, Na and other essential elements including P, Fe, Zn and Cu. The total antioxidant phenolic compounds content ranged from 10.31 to 16.46 mg/g with major constituents of tannins, anthocyanins and carotenoids. Vitamin C content...
The excessive use of herbicides is a major cause of many environmental problems. The use of isopr... more The excessive use of herbicides is a major cause of many environmental problems. The use of isoproturon herbicide as a weed controller has been a common practice globally. Phytoremediation technology can help in cleaning up polluted areas. In this paper the ability of CYP1A2 transgenic A. thaliana plants in the phytoremediation of isoproturon herbicides has been investigated. We tested the capability of P450-1A2 overexpression on the detoxification and degradation of isoproturon. We explored the toxic effect of isoproturon on the plant phenotypic characteristics, including the primary root length, rosette diameter, and fresh, dry weight for transgenic and wild type A. thaliana. The results revealed that no morphological changes appeared on CYP1A2 transgenic plants with a high tolerance to isoproturon herbicide applications either via foliar spraying or supplementation of the growth medium. Deleterious effects were observed on the morphological characteristics of plants of the wild t...
The pollution of freshwater resources with crude petroleum oil is a major environmental issue in ... more The pollution of freshwater resources with crude petroleum oil is a major environmental issue in oil-producing countries. As a result, the remediation of polluted aquatic ecosystems using eco-friendly and cost-effective technology is receiving increased global attention. In this study, the ability of Azolla pinnata R. Br. to remediate petroleum-polluted freshwater was assessed. The remediation potentiality was determined by evaluating the total petroleum hydrocarbon degradation percentage (TPH%) and changes in the molecular type composition of saturated and aromatic hydrocarbon fractions. TPH% was estimated gravimetrically, and changes in the molecular type composition of saturated and aromatic fractions were measured using gas chromatography and high-performance liquid chromatography, respectively. The results reveal that A. pinnata has the potential to phytoremediate freshwater polluted with low levels (up to 0.5 g/L) of petroleum hydrocarbons (PHs). After seven days of phytoremed...
Understanding the strategies and mechanisms of invasive species could guide their control and man... more 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. ochr...
Background: The lives of the "Fur", indigenous people of Darfur, Sudan are intimately connected t... more Background: The lives of the "Fur", indigenous people of Darfur, Sudan are intimately connected to local wild plants, but the traditional uses of these plants are, so far, poorly documented. Many species are indigenous to the region, but others are introduced, and have naturalized over millennia. Methods: For a month each summer from 2014-2016, using questionnaire interviews, direct observation of practices, and a literature review, 58 species were identified. An "importance value" for each was determined, based on the intensity and season(s) of use, in eight use categories. For each species, a "concordance ratio" characterized the degree of agreement between indigenous knowledge and our current "scientific understanding" of their value. Results: All species were multi-use; animal forage, "other functional uses", traditional medicine, and construction predominated. Some species are declining due to overharvesting by the growing local population, exacerbated by conflict and refugee encampments. Most of the species are used in traditional medicines, but active ingredients have been scientifically confirmed for only half of them. Surprisingly, several species with known medicinal ingredients are not used locally. The "Fur" people have long combined agriculture with pastoralism and wildcrafting. For this to be sustainable, it is critical to understand cultural contexts and recognize multi-use species. This can help identify new medicines, and guide sustainable development of local resources, adapted to local conditions. Naturalized wild fruit trees may have evolved drought resistance in this increasingly dry savanna climate; such genes might usefully be incorporated in crop strains elsewhere as climate change proceeds.
Crude oil pollution of water bodies is a worldwide problem that affects water ecosystems and is d... more Crude oil pollution of water bodies is a worldwide problem that affects water ecosystems and is detrimental to human health and the diversity of living organisms. The objective of this study was to assess the ability of water hyacinth (Eichhornia crassipes (Mart.) Solms) combined with the presence of magnetic nanoparticles capped with natural products based on Myrrh to treat fresh water contaminated by crude petroleum oil. Magnetic nanoparticles based on magnetite capped with Myrrh extracts were prepared, characterized, and used to adsorb heavy components of the crude oil. The hydrophobic hexane and ether Myrrh extracts were isolated and used as capping for magnetite nanoparticles. The chemical structures, morphologies, particle sizes, and magnetic characteristics of the magnetic nanoparticles were investigated. The adsorption efficiencies of the magnetic nanoparticles show a greater efficiency to adsorb more than 95% of the heavy crude oil components. Offsets of Water hyacinth were...
This study was designed to examine the subtle effects of habitat, aspect and altitude on plant di... more This study was designed to examine the subtle effects of habitat, aspect and altitude on plant diversity and the timing of phenological stages. In this increasingly arid region, within-species differences would cause more reproductive isolation of local populations, making species more vulnerable to regional extinction. Fifty-two sites in the Jebel Marra region of the Central Darfur state of Sudan were compared in terms of species diversity and local variation in the phenology of plant communities. Five habitat types were compared: sandy plains, clay plains, wadis, north-facing slopes and southfacing slopes. Sites were classified into five altitudinal zones ranging from 750 m to > 1,150 m above sea level, and the phenology of three categories of plant life form (phanerophytes, chamaephytes and therophytes) was tracked in terms of the duration of each phenophase (vegetative, reproductive and dormant). Overall, most plants were dormant from December to April. Peak vegetative growth was in July, coinciding with peak rainfall in all study sites in the region (July-August). This was followed by peak reproduction in October. Life form and habitat type significantly affected the length of all phenological phases; altitude significantly affected all stages except the duration of dormancy. Some of the interactions between these factors were also statistically significant, indicating subtle regulation of the duration of phenophases. The possible impacts of overgrazing and ongoing climate change are discussed, with the concern that initiation of vegetative growth in most habitats (except the clay plains) appears to be triggered by day length, 'anticipating' the beginning of the rainy season. Further climate change may uncouple this signal and the beginning of the rainy season, impacting plant survival. Keywords phenology . arid savannah . life form . altitude . habitat type . Darfur . Sudan
Anastatica hierochuntica is a monocarpic desert annual whose dry skeletons, enclosing mature frui... more Anastatica hierochuntica is a monocarpic desert annual whose dry skeletons, enclosing mature fruits, often persist for a number of years. The aerial seed bank in these hygrochas-tic 'resurrection plants' therefore persists too. Life tables and fecundity schedules were constructed for A. hierochuntica populations raised under four water treatments, equivalent to 100, 200, 500 and 1000 mm rainfall. Seedling survivorship showed a Deevey type III curve for 100 mm, and a type II curve for 200 mm, while 500 and 1000 mm treat-ments produced Deevey type I curves. Fewer seeds germinated and seedling survivorship was lower in the low water treatments. The stage-specific mor-tality rate reached 0.75 under the 100 mm treat-ment in the seed germination stage, compared to 0.08 under the 1000 mm treatment. Increased water availability resulted in greater plant growth and reproductive output, in terms of both number of seeds per individual and reproductive value. In field studies, aerial se...
The effect of chloride and sulfate salts of Na + , K + and Mg 2+ on seed germination of a halophy... more The effect of chloride and sulfate salts of Na + , K + and Mg 2+ on seed germination of a halophytic grass Phragmites karka was studied under different dark/light conditions and a range of temperature regimes. Seeds germinated better at 20/30ºC and their germination decreased with increases in salinity. This reduction in germination could be attributed to specific ion toxicity as well as variable osmotic stress due to the composition of salts. Among cations, K + was generally most toxic followed by Mg 2+ and Na + but such generalizations could not be made in case of anions. Potassium sulfate was inhibitory than Mg 2+ salts for seed germination. A better germination recovery from salt stress was found in 10/20ºC. More seeds recovered when transferred from NaCl to distilled water at all temperature regimes. Seeds treated with magnesium sulfate showed better recovery at 10/20 ºC, while recovery in Na 2 SO 4 and MgCl 2 treated seeds was better in moderate temperatures. The salts did not...
Unlike the dispersal mechanisms of many desert plants, the whole dead skeleton of Anastatica hier... more Unlike the dispersal mechanisms of many desert plants, the whole dead skeleton of Anastatica hierochuntica is involved in seed dispersal and preservation. This process depends on the hygrochastic nature of the lignified conducting tissue that bends when dry and straightens under wet conditions. An anatomical interpretation of this mechanical movement was investigated. An anatomical study of the stem was conducted on the juvenile plants raised under different water treatments and on the branch-orders of adult A. hierochuntica size-classes. In the juvenile stem of A. hierochuntica, the area of cortex, conducting tissue and pith increased with water availability. However, the hydraulic conductance decreased, resulting in a better withdrawal of water in water-stressed plants. The anatomical investigation of the hygrochastic mechanism revealed an asymmetric distribution of the cortical tissues, with the conducting tissues of the stem of juvenile and adult plants being larger in the lower...
International Journal of Environmental Science & Technology, 2011
Phytoremediation is increasingly receiving attention as a cost effective technique that uses plan... more Phytoremediation is increasingly receiving attention as a cost effective technique that uses plants to remediate contaminants from wastewater, soil and sediments. In this study, the ability of Typha domingensis to uptake heavy metals as well as its potential application for phytoremediation was assessed. Pollutant elements concentrations were measured in samples of wastewater, sediments and Typha domingensis collected from industrial wastewater ponds, El-Sadat city, Egypt. This study specifically focused on the capacity of Typha domingensis to absorb and accumulate aluminum, iron, zinc and lead. Results indicated thatTypha domingensis was capable of accumulating the heavy metal ions preferentially from wastewater than from sediments. The accumulation of metals in plant organs attained the highest values in roots, rhizomes and old leaves. Rhizofiltration was found to be the best mechanism to explain Typha domingensis phytoremediation capability.
The seed bank of Neurada procumbens, a prostrate annual common in sandy desert habitats, is vulne... more The seed bank of Neurada procumbens, a prostrate annual common in sandy desert habitats, is vulnerable to surface disturbances. Moreover, its seeds are highly heteromorphic, having both spinose and non-spinose sides, which affects both the vertical distribution of seeds and diaspores, and the precise position in which they lie in the soil. Here we explore the ecological implications of two factors, "safe sites" within habitats and seed orientation or "safe sides", on seedling establishment and the seed bank. In three natural populations, the vertical distribution of buried, germinable diaspores decreased with soil depth. Most diaspores occurred at the surface (0-1 cm below the surface), while none were observed below 10 cm. Seedling emergence decreased with depth and reached zero in diaspores below 5 cm. Seedling emergence also proved highly sensitive to the orientation of diaspores in soil. Diaspores lying on their smooth side with the spinose upper side directed upwards reached the highest seedling emergence of 61 %. Root length ranged from 10 to 16 cm, and the root to shoot ratio varied between 22.8 and 30.3 cm, depending on diaspore size. Diaspores near the surface may constitute a more transient component of the seed bank, as few of these remained viable for more than a year. Persistence of Neurada seed banks seems to depend not only on vertical movement of diaspores among habitat "safe sites" but also on different seed position alternatives.
Growth and resource allocation of three black sand plants namely Cakile maritima, Senecio glaucus... more Growth and resource allocation of three black sand plants namely Cakile maritima, Senecio glaucus and Rumex pictus were investigated in a greenhouse experiment. The effect of absorbed radionuclides on the plant growth was monitored at different growth stages including seedling, juvenile, flowering, fruiting and senescing stages. The study reveals that growth attributes including relative growth rate, net assimilation rate, leaf are index and specific leaf area, dry matter allocated to stem and leaves and number of reproductive organs decreased with the increase of radionuclide content of the plant, while the dry matter allocated to root and reproductive organs and root to shoot weight ratio were associated with high level of radionuclides. Because of their tolerance to high levels and accumulation of radionuclides, the species C. maritima, S. glaucus and R. pictus could be potential candidate plants for radio-phytoremediation of soils contaminated with uranium and thorium.
The soil seed bank is an essential functional component of plant communities. In arid ecosystems,... more The soil seed bank is an essential functional component of plant communities. In arid ecosystems, the island-like distribution of shrubs influences the spatial distribution of the soil seed bank. Very little is known about seed banks in deserts of the Middle East. The present study aimed to evaluate the facilitative effects of Haloxylon persicum shrubs on the soil seed bank of annual plants in a sandy desert region in northwestern Saudi Arabia during two consecutive growing seasons (2017-2018 and 2018-2019) with contrasting rainfall. A total of 480 soil samples at 12 stands were collected from two microhabitats, under shrubs and in open areas, soon after the two growing seasons. The germinable seed bank of annual plants was estimated by controlled seedling emergence method. Shrubs significantly facilitated the accumulation of seed bank beneath their canopies after the two growing seasons. In both microhabitats, the size and species richness of soil seed bank were significantly greater after the wet growing season (2018-2019) than following the dry season (2017)(2018). The facilitative effects of shrubs were greater following the moister growing season than after the dry season. The effect of shrubs on seed bank-annual vegetation similarity varied between growing seasons, being greater in shrub interspaces than beneath shrub canopies for the dry growing season, while during the wet season, the similarity of the seed bank with standing annual vegetation was greater in sub-canopy microhabitat than in bare soil.
Perennial shrub-annual plant interactions play key roles in desert regions influencing the struct... more Perennial shrub-annual plant interactions play key roles in desert regions influencing the structure and dynamics of plant communities there. In the present study, carried out in northwestern Saudi Arabia, we examined the effect of Haloxylon salicornicum shrubs on their associated understory annual species across four consecutive growing seasons, along with a record of the seasonal rainfall patterns. We measured density and species richness of all the annual species in permanent quadrats located beneath individual shrubs, as well as in the spaces between shrubs. During wet growing season H. salicornicum shrubs significantly enhanced the density and species richness of sub-canopy species, whereas in the relatively dry seasons they exerted negative effects on the associated species. In all growing seasons, the presence of shrubs was associated with enhanced soil properties, including increased organic carbon content, silt + clay, and levels of nutrients (N, P and K). Shrubs improved s...
Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black m... more Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC) was used to quantify phytotoxins from plant tissues. Seed germination of P. paradoxa was reduced with the lowest concentration of the different extracts. However, the aqueous extract at 4% completely curtailed the germination of all the target species. In general, plant extracts had a concentration-dependent reduction of seedling growth of the target species. However, the ethanolic extract, at the lowest concentration, has stimulated the shoot length of both T. alexandrinum and T. aestivum, and the root length of the forme...
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