الفهرس 
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Abstract
The present work provides a detailed investigation of the floristic features, ecological features, phytochemical analysis and economic potentialities of Ochradenus baccatus (Resedaceae) growing naturally in Wadi Hagul located in the North Eastern Desert of Egypt. It aims at the following objectives: 1- Investigation of the floristic characteristics including record of the plant species, distribution pattern, life – span, life – form spectra and chorological affinities of the wild plants associated with Ochradenus baccatus community type in Wadi Hagul. 2-Quantitative analysis of vegetation structure of plant species associated with Ochradenus baccatus community in the study area in terms of spatial variations in abundance using multivariate techniques (classification and ordination). 3-Analysis of variation in soil variables to determine the main edaphic factors controlling the abundance and distribution of vegetation types associated with Ochradenus baccatus. 4- Evaluation of the economic potentialities of Ochradenus baccatus growing naturally in Wadi Hagul by investigating: a-Phytochemical analysis of the shoot system. b-Elementary analysis inducing macro and microelements. Wadi Hagul occupies an area of about 345 km2, representing about 0.15% of the total area of Eastern Desert of Egypt, and lies at the Northwestern part of Suez Gulf. Its main channel extends for a distance of 48.4 km with a width of 5-10 km and runs to south and southeast to debauch into the Gulf of Suez. Floristically, the total number of recorded plant species in the present study was 57 species belonging to 51 genera and 19 flowering families. These species were classified into 46 perennials, 9 annuals and 2 biennials. On the basis of life-form spectra, the recorded species were distinguished into 24 chamaephytes, 13 hemicryplophtes, 11 therophytes, 7 phanerophytes and 2 cryptophytes. Asteraceae includes 15 species, followed by Poacease (5 species), then Asclepiadaceas, Brassicaceae, Fabaceae and Zygophllaceae (4 species each). These six leading families were represented collectively by 37 species (64.91% of the total number of recorded species). The chorological analysis of the current study revealed that the Sahro-Sindian taxa were represented by 25 species, followed by Sudano-Zambezian 11 species, then Irano-Turanian 7 species Mediterranean 7 species, Cosmopolitan 3 species and Palaeotropical only one species. Ecologically, the vegetation analysis by the application of TWINSPAN-classification based on the importance values of 57 species in 36 sampled stands in Wadi Hagul, led to the recognition of four vegetation groups. These four vegetation groups were totally dominated by Ochradenus baccatus but with different indicator and important diagnostic species. The important species in group A include Lavandula coronopifolia, Lotus herbanicus and Calotropis procera. While, the important and indicator species in group B comprise Tamarix nilotica, Iphiona mucronata, Zilla spinosa, Zygophllum coccineum and Panicum turgidum. On the other hand, the important and indicator species in group C include Lavandula coronopifolia, Zilla spinosa, Lasiurus scindicus, Diplotaxis harra, Echinops spinosus and Achillea fragrantissima. Whereas, the important species in group D comprise Zilla spinosa, Zygophyllum coccineum, Zygophyllum decumbens, Retama raetam and Launaea spinosa. It is clear that the identified vegetation groups (A, B, C & D) were markedly distinguished and having a clear pattern of segregation on the DCA ordination diagram. It has been also found that maximum water-holding capacity, sand fraction, pH value, electrical conductivity, lead, calcium and magnesium were the most effective soil variables which have high significant correlations with the first and second axes of CCA diagram. Phytochemically, the proximate constituents in the shoots of Ochradenus baccatus including total ash, crude fiber, crude lipid, crude protein and total carbohydrates were estimated. Also, the elementary analysis including macro and microelements, as well as bioactive secondry compounds comprising tannins, saponins, flavonoids, alkaloids and total phenols were determined in the shoots of this target plant species growing intensively in Wadi Hagul. Therefore, Ochradenus baccatus is important medicinal wild plant species, and it is a main food source for birds and animals in the Arabian Deserts. The demand of Ochradenus baccatus during the last years, thus it is urgent to develop and adopt different strategies for its conservation by restoration and / or rehabilitation in the Egyptian Deserts.