Tarek M. Galal

Floristic composition and vegetation analysis in Hail region north of central Saudi Arabia.

In this study, 19 sites representing different habitats in Hail region were regularly visited for two years, in each site 2-5 stands were selected for investigating floristic composition and vegetation types in the area. A total of 124 species representing 34 families were recorded. The family Asteraceae is represented by the highest number of species (21 species) followed by the Poaceae (17 species) and the Brassicaceae (10 species) whereas, 15 families including Acanthaceae, Convolvulaceae, Moraceae, Nyctaginaceae and Primulaceae, are represented by a single species each. Chronological analysis of the vegetation in the area revealed the domination of Saharo-Sindian elements in the wild vegetations and of weedy species in the cultivated plots. Therophytes and chamaephytes are the dominating life forms of the vegetation spectra; therophytes represent 49.20% and chamaephytes represent 29.00% of the total species in the study area. Application of TWINISPAN and DECORANA classification and ordination techniques to the data produced seven vegetation groups. Ruderal habitats comprised two small groups A and F dominated by Phragmites australis and Imperata cylindrical (A), Euphorbia peplus and Sisymbrium irio (F), respectively. Two vegetation groups (B and G) have been recognized in the mountains and slopes dominated by Launaea mucronata, Trigonella stellata (B) and Ficus palmate and Fagonia bruguieri (G). Other two groups (C and E) inhabit the desert and mountainous wadies; these are represented by Gymnocarpos decandrus and Ochradenus baccatus (C) and Senecio glaucus subsp. coronopifolius and Rumex equisetiforme (E). On the other hand, one group (D) inhabits the cultivated plots and is represented by Plantago albicans and Rumex vesicarius, the last group also includes species restricted to the sand dune habitat of the Al-Nafud desert north of Hail city and represented by Calligonum polygonoides and Halyxolon salicornicum. The vegetation analysis indicated the invasion of Hail Flora by some foreign weeds such as Solanum nigrum, Lactuca serriola and Amaranthus lividus. The presence of these weeds points out the need to monitor the vegetation change in Hail region, and also other regions of Saudi Arabia, in order to elucidate the human impact on the wild plants diversity as human activities change with the fast development in the kingdom.

The invasive macrophyte Pistia stratiotes L. as a bioindicator for water pollution in Lake Mariut, Egypt

The present study was conducted to evaluate the potentiality of the aquatic macrophyte Pistia stratiotes to accumulate trace metals, perspective of phytoremediation, and the probability for using it as a bioindicator for the different pollution types. Plants were collected from the different Lake Mariut basins (main basin, south-west, north-west, and fish farm), through five quadrats each, for measuring some growth parameters such as plant density, rosette diameter and height, root length, number of living and dead leaves per individual, and leaf length and width. In addition, nutrients and heavy metals in plant organs as well as water samples were analyzed. The bioaccumulation and translocation factors of trace metals were calculated. Water physicochemical data of Lake Mariut showed significant variations of all variables, except temperature and pH as well as Cd metal, among the lake basins. Fish farm was characterized by the highest plant density, individual size, biomass, and the number of living leaves, while the north-west basin had the lowest, except the number of dead leaves. In contrast to trace metals, P. stratiotes accumulated concentrations of macronutrients in the leaves higher than in roots. The bioaccumulation factors of the investigated metals, except Cu, were greater than one, while the translocation factors (TFs) of all trace metals were less than unity, and this may render P. stratiotes suitable for rhizofiltration. In addition, the significant positive correlation of Ni and Cd in water with those in plant roots and leaves as well as the growth response of this plant to the different pollutants may suggest its potential use as bioindicator for these pollutants in water.

Growth and nutrients accumulation potentials of giant reed (Arundo donax L.) in different habitats in Egypt

ABSTRACT Arundo donax L. has a high biomass production and a tendency toward community dominance in many habitats and thereby a tolerance to a wide range of environmental conditions. Therefore, the present study investigated the potentiality of A. donax to accumulate nutrients and trace metals in its biomass. Six main habitats (Nile Bank, Drain Bank, Canal Bank, Field Edges, Railways and Roadsides) were recognized. At each habitat, six quadrats (each 1 m2), distributed equally in two sites, were selected for growth measurements (e.g., density, shoot height, diameter, leaf area and biomass), plant and soil analyses. Plants from Nile, Canal and Drain Banks had the highest values of most growth measurements, while those from Railways and Roadsides had the lowest. Canal Bank plants accumulated the highest concentrations of P, Cu and Pb in their leaves; Zn in the stem; and Mg, Cd and Fe in the rhizome. The bioaccumulation factor (BF) of A. donax, for Cd, Fe, Mn and Zn, was greater than 1, while the translocation factor (TF) of most trace metals was less than unity in most habitats. In conclusion, A. donax showed morphological plasticity in response to habitat heterogeneity, and its growth was most vigorous in the riparian habitats. The high BF, as well as the significant positive correlations between trace metals, especially Cd, in soil and plant, renders A. donax a powerful phytoremediator.

Phytostabilization of heavy metals by the emergent macrophyte Vossia cuspidata (Roxb.) Griff.: A phytoremediation approach

ABSTRACT The present study was conducted to investigate the potential of Vossia cuspidata as a phytoremediator to accumulate heavy metals from polluted water bodies. Thirty-two quadrats, distributed equally in eight sites (six polluted sites along the Ismailia canal and two unpolluted sites along the Nile River) were selected seasonally for plant, water, and sediment investigations. Winter plants recorded the highest values of shoot height, diameter, and leaf width, but the lowest shoot density. Plants collected in autumn had the lowest values of leaf length, width, and area, while those collected in spring had the highest shoot density, with the lowest shoot height. Summer populations had the highest fresh and dry plant biomass, while winter plants had the lowest. Fresh production and dry biomass of V. cuspidata in the unpolluted Nile were significantly higher than those in polluted canals. Chlorophyll a and carotenoid concentrations were reduced under pollution stress. Spring plants accumulated the highest concentrations of Cr, Cu, and Pb in their root, and the lowest concentrations of Al, Cd, Cr, and Zn in their shoot. The bioaccumulation factor for most investigated metals, except Al, Cr, and Fe was greater than 1, while the translocation factor of all metals was less than 1, therefore this plant is considered to be a potential for these metals phytostabilization.

The biology of Calotropis procera (Aiton) W.T.

Key messageThis review article contributes in more understanding of most aspects ofCalotropis procerabiology and extend our knowledge about its behavior.AbstractCalotropis procera (Aiton) W.T (Asclepiadaceae) (Giant milkweed) is a xerophytic perennial shrub or small tree. It is native to tropical and subtropical Africa, Asia and common in the Middle East. It grows on a variety of soils, from fine to coarse texture, with varying degrees of salinity. The importance of C. procera in the functioning of ecosystems is reflected in its hosting of butterflies, while it also acts as a food plant for arthropods. In addition, it is used for medicinal purposes in many arid countries. Potential new uses of this species in semi-arid regions include the phytoremediation of soils contaminated with trace elements and the use of biomass as a source of renewable energy.

Biomass, nutrients and nutritive value of Persicaria salicifolia Willd. in the water courses of Nile Delta, Egypt

In the present study, we evaluate the biomass and nutritive value of the living and dead shoots of Persicaria salicifolia and their capacity to accumulate heavy metals and nutrients to be used as phytoremediator. The living and dead parts attained their highest phytomass during autumn. The dead parts accumulated higher amounts of copper, manganese and zinc than the living parts. On the other hand, the living parts had higher amounts of carbohydrates, ether extract, crude fibers and total protein. Due to its higher nutritive value, the living parts were considered excellent forage. Furthermore, the plant in the drains accumulates more nutrients and heavy metals than that in the canals. Some constituents (calcium, iron, digestible crude protein and crude fibers) had significant positive correlation with phytomass. The ability of the dead parts of P. salicifolia to accumulate higher values of nutrients renders this plant as a powerful phytoremediator for removal of pollutants from the aquatic ecosystems.

Evaluation of the Nutrient Status of Some Hydrophytes in the Water Courses of Nile Delta, Egypt

The nutritive values of three dominant hydrophytes along the water courses in Nile Delta, Egypt (Echinochloa stagnina, Eichhornia crassipes, and Ceratophyllum demersum) were evaluated in terms of estimating their phytomass, organic, and inorganic chemical compositions. Shoots were collected seasonally from 25 permanent stands representing the distribution of the three species along 15 canals and 10 drains distributed in 5 localities within the Nile Delta. Living and dead parts and total phytomass were estimated. Their inorganic (Na, K, Ca, Mg, P, Cu, Mn, and Pb) and organic (carbohydrates, total nitrogen, total protein, ether extract, digestible nutrient, digestible energy, metabolized energy, and net energy) contents were estimated. The vegetative phase of E. stagnina extended during winter, spring, and summer, while it is flowering and fruiting during autumn. On the other hand, E. crassipes and C. demersum attained their maximum flowering during spring and maximum fruiting during summer, while maximum vegetative phase during autumn and winter. E. stagnina had the highest mean annual phytomass, while C. demersum had the lowest. The living parts of C. demersum had the highest concentrations of Na, Ca, and Mg, while the living parts of E. crassipes had the highest of K and N. C. demersum had the ability to accumulate more concentrations of heavy metals than the other studied species. E. crassipes had the highest values of total carbohydrate and total proteins, while E. stagnina had the highest of crude fibers, and C. demersum had the highest of ether extract and ash contents. The living parts of E. crassipes and C. demersum were considered as excellent forages, while the dead parts of all species and the living parts of E. stagnina were evaluated as poor forage.

Bioaccumulation and rhizofiltration potential of Pistia stratiotes L. for mitigating water pollution in the Egyptian wetlands

ABSTRACT The bioaccumulation and rhizofiltration potential of P. stratiotes for heavy metals were investigated to mitigate water pollution in the Egyptian wetlands. Plant and water samples were collected monthly through nine quadrats equally distributed along three sites at Al-Sero drain in Giza Province. The annual mean of the shoot biomass was 10 times that of the root. The concentrations of shoot heavy metals fell in the order: Fe < Mn < Cr < Pb < Cu < Zn < Ni < Co < Cd, while that of the roots were: Fe < Mn < Cr < Pb < Zn < Ni < Co < Cu < Cd. The bio-concentration factor (BCF) of most investigated heavy metals, except Cr and Pb, was greater than 1000, while the translocation factor (TF) of most investigated metals, except Pb and Cu, did not exceed one. The rhizofiltration potential (RP) of heavy metals was higher than 1000 for Fe, and 100 for Cr, Pb and Cu. Significant positive correlations between Fe and Cu in water with those in plant roots and leaves, respectively were recorded, which, in addition to the high BCF and RP, indicate the potential use of P. stratiotes in mitigating these toxic metals.

Coastal Lakes as Hot Spots for Plant Diversity in Egypt

Five lakes (Mariut, Edku, Burullus, Manzala, and Bardawil) of global importance for migratory birds extend along the Egyptian Mediterranean coast. Burullus and parts of Lakes Manzala (i.e., Ashtum El-Gamil) and Bardawil (i.e., Zaranik) are managed protected areas. In addition, Burullus and Bardawil are Ramsar sites for the conservation of migratory birds. These lakes are evaluated for their plant diversity and ecosystem services. About 402 plant species, categorized into 45 plant communities, were identified in these lakes. Five of these species are endemics, while three are near endemics. Although the areas of these lakes (2,449 km2) contribute <0.003 of the total area of Egypt (one million km2), they are inhabited by 19% of the whole Egyptian flora; thus they are important hot spots for the Egyptian flora, particularly the aquatic plants. In addition, 70% of the total plant species offer, at least, one potential or actual good (e.g., grazing, medicinal drugs, human food, fuel, and timber), while 60% have at least one aspect of the environmental services (e.g., sand controllers, shaders, weed controllers, bank retainers, nitrogen fixers, and water purifiers). Most of these lakes receive excessive amounts of agricultural and industrial drainage water that is loaded with different pollutants, while Bardawil is still characterized by near-pristine conditions. The vegetation and sediment of these lakes are effective as carbon sinks; therefore, they play, in contribution with the other worldwide wetlands, a vital role in mitigation of global warming.

Human health risks from consuming cabbage (Brassica oleracea L. var. capitata) grown on wastewater irrigated soil

ABSTRACT The present study investigated the impact of cumulative irrigation with wastewater on the soil properties and, its health hazards on the consumers of cabbage plants at south Cairo Province, Egypt. Irrigation water, soil and cabbage plants were sample d from two polluted and other two unpolluted farms. The physicochemical properties of water and soil were analyzed and the growth parameters, as well as nutrients and heavy metals concentration in cabbage were investigated. In addition, the daily intake of metals (DIM) and health risk index (HRI) were estimated. Wastewater posed a decrease in the availability of N, P and K, but increases heavy metals in the soil solution. Cabbage stem and root lengths as well as the number of leaves and biomass were greatly reduced in the polluted farms. In addition, the photosynthetic pigments, carbohydrates and proteins were decreased under pollution stress. The concentration of most investigated metals in the leaves and roots were increased with translocation factor greater than one for Pb, Cd, As, Cr, Ni, Fe, and Co. The study revealed that the HRI exceeded one for Pb and Cd in polluted and unpolluted plants; and Fe in polluted ones. Irrigation with wastewater is not suitable for cabbage as it has health risks on humans due to accumulation of heavy metals. It worth noting that, the high ability of cabbage plants to accumulate Pb and Cd from both polluted and unpolluted soils should be taken into consideration when consuming this plant.