Wafaa M. Amer

SOIL–VEGETATION RELATIONSHIPS IN A COASTAL DESERT PLAIN OF SOUTHERN SINAI, EGYPT

Abstract The present study provides an analysis of soil, vegetation types as well as structure and species distribution in 19 sites in El-Qaa plain along the Gulf of Suez (south Sinai, Egypt), and focuses on the environmental factors that control the species distribution. A total of 203 species belonging to 39 families of the vascular plants are recorded. Asteraceae, Fabaceae, Chenopodiaceae and Poaceae are the largest families. Grasses constitute only 9% of the recorded species, while the woody perennials (shrubs and sub-shrubs) are highly dominated (46%). Therophytes and chamaephytes are the most frequent, denoting a typical desert life-form spectrum. Floristic composition in the different geomorphologic landscape units showed differences in species richness. The highest mean species richness of 19.7±1.7 is recorded in the wadi channels. The lowest species richness values are recorded in the coastal shore and playas (6.0±1.4) and in the alluvial fans (mean of 8.4±1.6 species). Chorological analysis revealed that 46% of the studied species are uniregional, being native to the Saharo-Arabian region. On the other hand, about 50% of the recorded species are biregional and pluriregional, extending their distribution all over the Saharo-Arabian, Sudano-Zambezian, Irano-Turanian and Mediterranean regions. Classification of the vegetation is analysed using two-way indicator species analysis (TWINSPAN) techniques resulted in the recognition of five vegetation groups, each of definite vegetation and soil characters, and could be linked to a specific geomorphologic unit. Capparis spinosa var. spinosa occupied the terraces, Cornulaca monacantha, Convolvulus lanatus and Deverra tortuosa inhabited the alluvial plains, Launaea nudicaulis and Artemisia judaica characterized the wadi channels, Acacia tortilis subsp. raddiana and Leptadenia pyrotechnica characterized the alluvial fans and Tamarix nilotica, Zygophyllum album and Nitraria retusa on the playas and the coastal shore. Ordination techniques as detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) are used to examine the relationship between the vegetation and studied soil parameters. Nine soil variables are included: electrical conductivity, pH, calcium carbonate, gypsum, organic matter, gravel, fine soil fractions and soil saturation percentage. Analysis with DCA gave results similar to CCA, suggesting that there is a relatively high correspondence between vegetation and soil factors. DCA axis 1 showed significant positive correlation with CaCO3, pH, soil saturation and organic matter, and interpreted as a calcium carbonate—soil saturation gradient. DCA axis 2 showed significant correlation with pH, gypsum and electric conductivity, and interpreted as an electric conductivity—gypsum gradient. Application of CCA indicated that soil surface sediment, CaCO3, soil saturation, pH and organic matter are the main operating edaphic gradients in the area. These gradients are related closely to the first three canonical axes, and accounted for 67% of the species–environment relationship among the sites.

Beer from the early dynasties (3500-3400 cal B.C.) of Upper Egypt, detected by archaeochemical methods

Physical and chemical analyses of beer residues recovered from a vat site at Hierakonpolis (Upper Egypt) were carried out. Radiocarbon dates of the residues suggest a dating of 3500–3400 cal B.C. and are believed to represent the oldest known beer in the world. Macroscopic and microscopic examinations of the residues revealed the presence of intact remains of grains and spikelets of wheat and barley, as well as fragments of dates and grape pips. Chemical analyses included percentages of sample ingredients, pH and total soluble ions, quantitative determinations of sugars, carboxylic acids and free amino acids. A total of 25 compounds were identified, which are components of fermentation processes that are believed to have formed in connection with the preparation of what is called Nekhen-Hoffman beer.

Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt

North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp.) and 30 annuals (e.g. Bromus spp., Erodium spp.). Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs); the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere) and shoot (endophyllosphere) tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium,Bacillus pumilus, Bacillus polymexa,Bacillus macerans,Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans,Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera,Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola.Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the water of El-Salam canal.

Biodiversity of diazotrophs associated to the plant cover of north sinai deserts: Biodiversität diazotropher assoziiert mit der pflanendecke der wüsten nordsinais

Efforts are made to record biodiversity of microflora and diazotrophs associated with the plant cover of the major agricultural development areas in north Sinai, around the El-Salam canal, a newly-constructed canal that brings Nile water westward across the Suez canal. Natural plant communities were collected from three major areas. Ectorhizosphere, endorhizosphere and phyllosphere samples were examined for total microbial population and diazotrophs. The vegetation of South Qantara (area I) is characterized by the dominance of Stipagrostis scoparia followed by Nitraria retusa, Convolvulus lanatus, Cornulaca monacantha and Filago desertorum. Rabaa-Bir El Abd (area II) is dominated by Artemisia monosperma, Panicum turgidum and Zygophyllum album. Euphorbia terracina, Oligomeris linifolia, Astragalus kahiricus, Hyoscyamus muticus and Thymelea hirsuta represent the major plants of El Ser and Al Quarir (area III). Microorganisms colonized root surfaces of all tested plants ranging from > 105 to 1010 cfu g − 1. Diazotrophs were common residents (1010 cfu g − 1), invaded the root tissue and established endophytically (102 – 106 cfu g − 1). Fifty-one N2-fixing isolates were obtained. Among the 32 bacilli isolates, Bacillus polymyxa and Bacillus circulans were more common compared to Bacillus macerans. BNF Gram-negative isolates belonged to Enterobacter agglomerans, Enterobacter gergoviae, Enterobacter amnigenus, Klebsiella pneumoniae, Pseudomonas luteola, Pseudomonas cepacia, Agrobacterium radiobacter and Azospirillum spp.

Altitudinal and Latitudinal Diversity of the Flora on Eastern and Western Sides of the Red Sea

The Red Sea is 1932 km long, and average of 280 km in width. At its widest, in the south near Massawa, it is reaches 354 km wide and this narrows to 29 km at Strait of Bab al Mandab and to about 180 km before it branches to the Gulf of Suez and the Gulf of Aqaba. The latitudinal range of the Sea lies between 30°N and 12° 30’N, it has a long history in association with man’s activities, but the degree of human impact and exploitation has until recently been negligible.

Herbacetin and gossypetin 3-glucuronide-8-glucosides from Roemeria hybrida

Abstract Two new flavonols, herbacetin and gossypetin 3- O -β- d -glucuronide-8- O -β- d -glucosides, have been isolated from Roemeria hybrida .

Allelopathic effect of Nymphaea lotus L. on growth and yield of cultivated rice around Lake Manzala (Nile Delta)

Lotus infestation of ricefields is a major cause of crop failure and decrease of grain yield in the newly reclaimed cut-off areas around lake Manzala, Egypt. This study provides insights in the allelopathic effect of Nymphaea lotus L. on rice (Oryza sativa cavr. Giza-177). Lotus rhizome extracts were inhibitory to seed germination and seedling growth of rice. The degree of inhibition was dependent on extract type and concentration. Ethanol and water extracts were more inhibitory than chloroform extracts. The phenolic fraction of ethanol extracts showed the highest inhibitory effects. In a target (rice)-neighbour (lotus) pot experiment, rice dry mass and relative growth rate were dependent on its age and on lotus rhizome density, with decreased growth at increased lotus density. Field data on infested and non-infested ricefields demonstrated a decreased leaf area index and yield in infested fields. Identification of the potential allelochemical compounds by gas chromatography/mass spectrometry revealed the presence of allelopathic phenolics in lotus rhizomes.

Biodiversity of microorganisms in semi-arid soils of north sinai deserts

North Sinai environment is currently subjected to changes due to the major agricultural development project of El-Salam canal which brings Nile water to the arid deserts of Sinai. Therefore, intensive efforts are made to record biodiversity of natural microflora and diazotrophs associated to the plant-soil system of the major agricultural development areas around the canal. Fourteen soil profiles were made, during the seasons 1997-2000, representing major sites of the area investigated (South Qantara, Rabaa-Bir El-Abd and El-Ser and Al-Quarir). Physico-chemical and microbiological properties of soils tested are presented. Microbiological profiling included total population of Gram positive and Gram negative bacteria, sporeformers, thermophiles, diazotrophs and spore-forming diazotrophs. Results obtained are discussed to relate physico-chemical properties to soil biofertility in an effort to categorize general fertility levels of soils under investigation.

Bridging pheno-plasticity with genetic profile of the hydrophyte Ludwigia stolonifera (Guill. & Perr.) P.H. Raven: with reference to its expansion to new habitats

Abstract Ludwigia L. is a pantropic genus of aquatic and subaquatic herbs. Recently, L. stolonifera (Guill. & Perr.) P.H. Raven became a dominant aquatic macrophyte in Egypt and it expanded from fresh water into salty habitats. Interestingly, the plant showed morphological plasticity in several characters such as leaf shapes, vesicles, flower sex, fertilization efficiency, fruit parameters and number of produced seeds/fruit. Accordingly, in Egypt this species morphologically grouped into seven morphotypes (1–7). The lack of information about the plant genome further complicates the identification of these morphotypes. Thus, it was crucial to investigate the morphotypes in terms of karyotyping and genetic profile to understand if this morphological plasticity is genetically based or it is an impression of habitat diversity. In this study, seven morphotypes located in different Egyptian habitats were compared using karyotyping and random amplified polymorphic DNA (RAPD-PCR) technique. Karyotyping indicated that some morphotypes were tetraploid (2n=32), while others morphotypes were triploid (2n=24). The measured similarity percentage based on RAPD data revealed a highest value (98.6%) between the triploid M4 and M5 morphotypes; similarly between the tetraploid M1 and M2 morphotypes showed 95.4%. Meanwhile, the lowest similarity (73.4%) was between the aquatic morphotype (M2) and the salt affected wetland morphotype (M3). The possible link between the genetic composition and ecological variation of this phenoplastic species will be further discussed.