الفهرس 
GEOLOGYOnly 14 pages are availabe for public view
 |  | from | 225 |  |  |
| | | from | 225 | | |
Abstract
The present work provides a detailed floristic and ecological study on the aquatic vegetation in north east Nile Delta region represented by four Governorates: Damietta, El-Dakahlyia, El-Sharkia and Al-Qualiopia. Floristically, the total number of hyDROPhytes and terrestrial canal bank plants recorded in the present study is 116 species belonging to 90 genera grouped under 39 families. Gramineae, Compositae, Chenopodiaceae, Cyperaceae, Polygonaceae, Amaranthaceae, Euphorbiaceae and Leguminosae and Convolvulaceae are the major families in the study area. The floristic analysis of the study area revealed that, 35.34% of the total number of the recorded species are Mediterranean taxa (Mono, Bi or Pluriregional), while the pure Mediterranean element is poorly represented. Four vegetation groups yielded by TWINSPAN. The application of Canonical Correspondence Analysis (CCA-biplot) indicated that, the most effective hydrosoil and water variables are soil texture, water-holding capacity, electrical conductivity, pH value, organic carbon, dissolved oxygen, calcium carbonate, soluble anions, total phosphorous, total nitrogen and extractable cations. The assimilating surface area and the biomass of the studied plants (Bolboschoenus glaucus, Veronica anagallis-aquatica, Nymphaea lotus, Pistia stratiotes and Myriophyllum spicatum) increased gradually with advanced age then declined at the beginning of fruiting stage. The most clear anatomical features of the different sections in the studied plants are the abundance of aerenchyma tissues and there is no cork cells. The phytochemical analysis of the studied plants revealed that, Nymphaea lotus attained the highest values of total protein and total lipid content, while Bolboschoenous glaucus attained the highest values of crude fibre content and different estimated carbohydrates. The investigated plants have the ability to absorb and accumulate heavy metals with relatively high concentrations. The concentrations of all estimated heavy metals in all investigated plants are higher than the standard permissible levels and appeared to be harmful for human and consequently, the studied plants are not recommended as a fodder for animal consumption. The presence of sterols, alkaloids, flavonoids, tannins, saponins and resins may be considered as bases for future pharmaceutical or industrial research programs. Bioactivity of the methanolic extracts of the studied plants showed distinct antimicrobial potentialities against tested bacteria and tested fungi. The extract of Nymphaea lotus is found to have the most effective antimicrobial activity. These results may be considered as a bases for future pharmaceutical and medicinal uses