Mohamed A. El-Sheikh

Antioxidant activity and mineral composition of three Mediterranean common seaweeds from Abu-Qir Bay, Egypt.

Antioxidant activity and mineral composition were evaluated seasonally from spring to autumn 2010 in the three common seaweeds Ulva lactuca Linnaeus (Chlorophyta), Jania rubens (Linnaeus) J.V. Lamouroux and Pterocladia capillacea (S.G. Gmelin) Bornet (Rhodophyta). The antioxidant activity was measured with β-carotene, total phenol content and DPPH (2,2-diphenyl-1-picrylhydrazyl). Seaweeds were collected from the rocky site near Boughaz El-Maadya Abu-Qir Bay of Alexandria, Egypt. The results showed maximum increase of β-carotene in P. capillacea during summer. A significant increase in total phenolic content at P ⩽ 0.05 was found in the red alga (J. rubens) during summer. Also, U. lactuca showed the maximum antioxidant scavenging activity especially during summer. Minerals in all investigated samples were higher than those in conventional edible vegetables. Na/K ratio ranged between 0.78 and 2.4 mg/100 g, which is a favorable value. All trace metals exceeded the recommended doses by Reference Nutrient Intake (RNI). During summer season, it was found that Cu = 2.02 ± 0.13 and Cr = 0.46 ± 0.14 mg/100 g in U. lactuca and Fe had a suitable concentration (18.37 ± 0.5 mg/100 g) in P. capillacea. The studied species were rich in carotenoids, phenolic compounds, DPPH free radicals and minerals, therefore, they can be used as potential source of health food in human diets and may be of use to food industry.

Inoculation with arbuscular mycorrhizal fungi alleviates harmful effects of drought stress on damask rose

This study was conducted to examine the role of arbuscular mycorrhiza fungi (AMF) in alleviating the adverse effects of drought stress on damask rose (Rosa damascena Mill.) plants. Four levels of drought stress (100, 75, 50, and 25% FC) were examined on mycorrhizal and non-mycorrhizal plants in pots filled with sterilized soil. Our results showed that increasing drought stress level decreased all growth parameters, nutrient contents, gas exchange parameters, and water relations indicators. Under different levels of drought stress, mycorrhizal colonization significantly increased all studied parameters. Pn, gs, and E of the mycorrhizal plants was higher than those of non-mycorrhizal plants under different levels of drought stress. The increase in those rates was proportional the level of the mycorrhizal colonization in the roots of these plants. Majority of growth, nutrition, water status and photosynthetic parameters had a great dependency on the mycorrhizal colonization under all levels of drought stress. The results obtained in this study provide a clear evidence that AMF colonization can enhance growth, flower quality and adaptation of rose plants under different drought stress levels, particularly at high level of drought stress via improving their water relations and photosynthetic status. It could be concluded that colonization with AMF could help plants to tolerate the harmful effects caused by drought stress in arid and semi-arid regions.

Vegetation, Floristic Diversity, and Size-Classes of Acacia gerrardii in an Arid Wadi Ecosystem

This study focuses on the vegetation ecology, floristic diversity, and dynamics of Acacia gerrardii populations in wadi Huraimla, Central Saudi Arabia. The floristic richness, plant cover, human impact, and demography of A. gerrardii population were monitored in open grazing and managed sites. The applications of TWINSPAN, DCA, and CCA multivariate analysis have produced nine vegetation groups; eight of them were associated with the distribution of A. gerrardii and one group with the surrounding agricultural lands. The plant communities were separated into three major vegetation groups, viz., Acacia gerrardii-Rhazya stricta representing the open grazing sites, Acacia gerrardii-Lycium shawii-Zilla spinosa representing the managed sites, and Cynodon dactylon-Heliotropium bacciferum-Cenchrus ciliaris dominating the agricultural lands. The CCA ordination indicated that the separation of plant species along the first axis was positively affected by EC, K, Na, species richness and human impact, and negatively affected by pH, Mg, and density and age of A. gerrardii populations. Alternatively, the second axis is positively correlated with altitude and Ca content of the soil. Human impact is positively correlated with soil salinity, K and Na contents and negatively correlated with altitude, soil texture, and Mg content. The density of A. gerrardii is positively correlated with pH, Fe, Mn, and Mg contents of the soil, whereas negatively correlated with salinity and K and Na contents, species richness, relative evenness, and human impact. Populations of A. gerrardii demonstrated different size-class distribution patterns with either continuous regeneration inputs or lack of regeneration.

New generic and species records for the flora of Saudi Arabia.

Recent field works in the central and southern regions of Saudi Arabia including agricultural centers have managed to collect four vascular plants new to terrestrial and wetland flora of the country. These new additions include one new genus Malvastrum A. Gray (M. coromandelianum) subsp. capitato-spicatum (O. Kuntze) S.R. Hill, Potamogeton perfoliatus L. (Potamogetonaceae), Euphorbia tirucalli L. (Euphorbiaceae) and Sesuvium portulacastrum (L.) L. (Aizoaceae). Detailed morphological description, distribution and habitat of each of these species are provided along with illustrations and photographs. The report of new additions to the flora of Saudi Arabia indicated that the country needs thorough botanical explorations.

RETRACTED: Vegetation analysis of Wadi Al-Jufair, a hyper-arid region in Najd, Saudi Arabia

THIS ARTICLE HAS BEEN RETRACTED please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Author. Data processing errors have resulted in misleading conclusions. The scientific community in King Saud University has serious concerns regarding the results and the article will be resubmitted for publication after reprocessing of the data.

Efficient and reproducible in vitro regeneration of Solanum lycopersicum and assessment genetic uniformity using flow cytometry and SPAR methods

In the present study, we develop an efficient and reproducible in vitro regeneration system for two cultivars viz., Jamila and Tomaland of Solanum lycopersicum L., an economically important vegetable crop throughout the world. Sterilization of seeds with 2.5% (v/v) NaOCl was found to be most effective, about 97% of seeds germinated on cotton in magenta box moistened with sterile half strength (½)Murashige and Skoog (MS) medium. Regeneration efficiency of cotyledonary leaf (CL) and cotyledonary node (CN) explants derived from 08 days old aseptic seedling were assessed on MS medium supplemented with different concentrations of auxins and cytokinin. CL explants were found more responsive in comparison to CN in both the cultivars. Types of basal media were also assessed and found to have a significant effect on shoot regeneration. Highest regeneration frequency and maximum number of shoots were standardized from CL explants on MS medium supplied with 6-benzyl adenine (BA; 5.0 µM), indole-3-butyric acid (IBA; 2.5 µM) and Kinetin (Kin; 10.0 µM). In vitro regenerated microshoots were rooted on ½MS medium containing 0.5 µM indole-3-butyric acid (IBA). Regenerated plantlets with well-developed roots and shoot system were successfully acclimated to ex vitro condition. Genetic uniformity of tissue culture raised plantlets was first time evaluated using flow cytometry and single primer amplification reaction (SPAR) methods viz., DAMD and ISSR. No significant changes in ploidy level and nuclear DNA content profile were observed between in vitro propagated plants and normal plants of both the cultivars. Similarly, the SPAR analysis also revealed monomorphic banding patterns in regenerated plantlets of S. lycopersicum verifying their genetic uniformity and clonal fidelity. This efficient regeneration system can be used as a fast and reproducible method for genetic transformation of this important vegetable crop.

Endemics and endangered species in the biodiversity hotspot of the Shada Mountains, Saudi Arabia

Shada Mountains in Saudi Arabia, separated by Maleel Wadi into twin mountains (i.e., Shada Alalah and Shada Asfal), are rich in biodiversity. We investigated the diversity of endemics and endangered species of the mountains based on the data collected from 38 stands falling in 8 elevational zones ranging from 500 to 2215 m a.s.l. Results indicated that 495 plant species falling in 314 genera and 76 families occurred in the Shada Mountains, including 19 endemic species and 43 endangered species, and accounting for 22% of the total flora in Saudi Arabia. Canonical correlation analysis indicated that physiographic features, particularly altitude play an important role in the frequency and abundance of species. Endemics were not evenly distributed in the Shada Mountains and mostly restricted in the elevation zone of 1000–1500 or >1500 m a.s.l. When the altitude reached up to 2000 m a.s.l., the endemics decreased substantially due to the significantly low temperature. The endangered species existed three different distribution patterns: (i) most endangered species distributed in the altitudes of 1000–1800 m a.s.l.; (ii) endangered trees, lianas, and shrubs occupied the altitudes 1000–1300 m a.s.l.; and (iii) endangered subshrubs and herbs inhabited the altitudes 1500–2100 m a.s.l. The results demonstrated that the biodiversity of endangered species in the Shada Mountains is high and undisturbed by invasive species, and protective measures should be taken against human disturbances to the small-scale hotspot.

VegEgypt ecoinformatics: contribution to Sinai flora and vegetation

This study is aimed at collection of all available phytosociological data on vegetation of Sinai Peninsula, a region that is still poorly explored. An overview of the plant communities of Sinai is compiled based on additional field work and inventories. The database for Sinai vegetation will serve as a nucleus for the National Vegetation Databank of Egypt—‘VegEgypt’. Aspects like species richness, species turnover, conservation categories, and endemism were given special attention. The database was set up and analysed using the Turboveg and Juice programs. A matrix of 816 relevés and 496 species belonging to 69 families and 281 genera formed the basis for further analysis. Asteraceae, Poaceae and Fabaceae were the most represented families. The lists contain 52 threatened, 16 endemic and 20 sub-endemic species. The percentage of endemic species is highest in insular floras, peninsulas and mountain chains. The vegetation analysis resulted in 21 associations. The plant associations on sand habitats have the lowest species richness and species turnover because of water scarcity. On the other hand, plant communities or associations inhabiting rocky habitats have the highest species richness and species turnover.

Uptake and accumulation of emerging contaminants in soil and plant treated with wastewater under real-world environmental conditions in the Al Hayer area (Saudi Arabia)

In arid and semi-arid areas the use of treated wastewater for crop irrigation and other agricultural practices, such as the use of pesticides, increase the number of emerging contaminants (ECs) in crops. Hazards of these practices to human being are largely unknown since there are few studies yet covering a short range of compounds and most of them under non-realistic conditions. This study aims at assessing this problem that will become global soon in an area of Saudi Arabia heavily affected by the reuse of treated wastewater and pesticide in order to ascertain its scale. The novelty of the study relays in the large number of ECs covered and the variety of crops (cabbage, barley, green beans, eggplants, chili, tomato and zucchini) analysed. Extraction procedure developed provided an appropriate extraction yield (up to 50% of the compounds were recovered within a 70-120% range), with good repeatability (relative standard deviations below 20% in most cases) and sensitivity (LOQ < 25 ng g-1) for the model compounds. Determination by liquid chromatography quadrupole time-of-flight (LC-QqTOF-MS) is able to identify >2000 contaminants. Sixty-four ECs were identified in wastewater but of the sixty-four compounds, six pharmaceuticals (atenolol, caffeine, carbamazepine and its metabolites 10,11-epoxycarbamazepine, gemfibrozil, and naproxen) and seven pesticides (acetamiprid, atrazine deethyl, azoxystrobin, bupirimate, diazinon, malathion, pirimicarb and some of their metabolites) were detected in plants. Furhermore, one metabolite of the ibuprofen (not detected in water or soil), the ibuprofen hexoside was also found in plants. Up to our knowledge, this study demonstrate for the first time the accumulation of ECs in crops irrigated with treated wastewater under real non-controlled environmental conditions.

SaudiVeg ecoinformatics: Aims, current status and perspectives

During the last decade many electronic databases of vegetation plots were established in many countries around the world. These databases contain valuable phytosociological information assisting both governmental and NGO (Non-governmental organizations) agencies to formulate strategies and on-ground plans to manage and protect nature resources. This paper provides an account on aims, current status and perspectives of building of a vegetation database for the Central Region (Najd) of Saudi Arabia – the founding element of the Saudi Vegetation Database (SVD). The data stored by the database are sample plots (vegetation relevés) collected according to the field techniques of the Braun-Blanquet approach (lists of taxa accompanied by semi-quantitative cover assessment), and are accompanied by general vegetation characteristics such as vegetation layering and cover, information on life-form of the recorded species, geographical coordinates, altitude, soil typology, topography and many more. More than 2900 vegetation-plot records (relevés) have so far been collected in the Najd region; of these more than 2000 have already been stored using the Turboveg database platform. These field records cover many habitats such as depressions, wadis (dry river beds), agricultural lands, sand dunes, sabkhas, and ruderal habitats. The ecological information collected in the database is currently the largest set of vegetation data collated into a database in the Middle East. These data are of great importance for biodiversity studies in Saudi Arabia, since the region is recording a loss of biodiversity at a fast rate due to environmental problems such as global warming and land-use changes. We envisage that this database would catalyze further data collection on vegetation of the entire Arabian Peninsula, and shall serve as one of the most important datasets for classification and mapping of the vegetation of the Kingdom of Saudi Arabia.