الفهرس 
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Abstract
The current study was performed at Wadi Al-Afreet which located in the North Western Mediterranean Coast of Egypt, precisely between Buqbuq and Sidi Barrani on the Egyptian-Libyan frontier.
The study area is the habitat of 73 species belonging to 68 genera and representing 23 families. The abundant family was Asteraceae, 12 species comprising (16.44 %) of the total number of the recorded species followed by Chenopodiaceae and Fabaceae eight species for each (10.46 %).
Five life forms characterized the plant life of the study area. Therophytes (Th) were the abundant life-form in the study area as it was represented by 29 species (39.73%), followed by chamaephytes (Ch) about (31.51%), hemicryptophytes (He) about (16.44%), phanerophytes (Ph) about (6.85%), and finally cryptophytes (Cr) about (5.48%).
Considering the phytogeographical analysis of the recorded plant species, the biregional affinities recorded the highest species number among the four classes of chorotypes containing 36 species (49.32%), while monoregional affinities were represented by 21 species (28.77%), pluriregional affinities comprised 14 species (19.18 %) and cosmopolitan elements attained the lowest number of the four classes of chorotypes as it scored two species (2.74%).
A data of 16 stands of vegetation occupying Wadi Al-Afreet was analysed using TWINSPAN to classify the stands at the fourth level into seven groups labelled (1-7) with-set each sample group comprising a set of stands with greater homogeneity of vegetation, than when compared with other sample groups, identified by TWINSPAN for each group at each level of hierarchical classification. Application of DECORANA indicated reasonable segregation among these vegetation groups.
Ordination technique (CCA) was used to examine the relationship between the vegetation and the studied ʺenvironmental parametersʺ. The most important environmental variables correlated with vegetational groups in Wadi Al-Afreet were very fine sand, fine sand, coarse sand, silt & clay, HCO3ˉ, Ca+², pH, Mg+², and Clˉ.
Four species biodiversity indices had been used to characterise the plant communities, and vegetational group (2) located at upstream was the most diverse group along Wadi Al-Afreet.
The size structure of the two plant populations has been frequently used to assess regeneration status and to predict future population changes, Ebenus armitagei in elevation (III) showed positively skewed distribution towards small size distribution but J-shaped distribution in elevation II, whereas Periploca angustifolia had different size distribution all over the three different elevation; in elevation (III) showed more or less symmetrical distribution, but in elevation (II) it exhibited reverse J-shaped size-class distribution and the distribution was more or less J-shaped In elevation (I).
The two species showed physiological adaptation via hyperaccumulation of minerals, K+ attained the highest accumulation ratio in both plants, which is the most abundant cation within plant cells.
The two species exhibited different anatomical adaptational traits, Ebenus armitagei depends on the presence of Tannins in stem and leaflets which may help the plant to store excess photosynthates and the presence of tyloses cells in root may indicate an adaptation to a stressful environment, whilst Periploca angustifolia relies on the mechanical support of macrosclereids and laticifer cells which may protect it against pathogens and herbivores.
ASD field spectroradiometer was used to measure various spectral reflectance in the wavelength ranged from 350 to 2500 nm for 33 plant species and 16 soil specimens represent the location stands to assess their status along Wadi Al-Afreet.
Remote Senesing technology was used to detect the environmental changes in (Land Cover) during the growing season for the years 2013, 2014, 2015, 2016 and 2017 which shows a great difference in NDVI along the mentioned years.
In contribution with GIS technique, we developed a weighted overly model to estimate distributional areas in Wadi Al-Afreet which will predict to be suffered from disappearance of the two studied endangered species based on correlations of known occurrences with environmental variables, Ebenus armitagei will face the risk of disappearance at the South-East part of Wadi Al-Afreet (including stands 1 and 3) and the east part of midstream part (middle), whereas the model predicted locations for Periploca angustifolia were at the midstream part of Wadi Al-Afreet.
Various hyperspectral indices for soil and vegetation were calculated to assess the status of sixteen soil samples representing the studied stands and thirty-three plant species.
Attempting to conserve Periploca angustifolia, we collected its seeds from Wadi Al-Afreet and a greenhouse pot experiment was conducted at Botany Department, Faculty of Science, Ain Shams University.
Comparing the cultivated plant with the wild collected from Wadi Al-Afreet whence the mass spectrum of the unknown composition of Periploca angustifolia aerial parts (wild and cultivated) were determined by GS/MS spectrum and showed a great different in their constituents, also we compared their antimicrobial activity for different extracts for both plants, where the cultivated plant exhibited more inhibition to most of the pathogens used.