الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 217 |  |  |
| | | from | 217 | | |
Abstract
In the north – eastern part of the Nile delta particularly El-Dakahlia and Damietta governorates, this study area was situated; the habitat classified according to the measured conductivity (salinity) for each one as mesophytic, moderately saline and saline habitats. Field survey was carried out during March and April 2015 where the Malva parviflora, Rumex dentatus and Portulaca oleracea plants were collected from different habitats. Plant and soil samples were collected from different localities in plastic bags, transferred directly to the laboratory, where they prepared for the studied determinations. -The results showed variations in physical and chemical soil characteristics at different habitats. The maximum content of total carbohydrate and soluble sugars as well as proline and electrolyte leakage of M. parviflora, R. dentatus and P. oleracea was estimated in the saline habitat and the minimum content was estimated in mesophytic habitat. There is a significant increase in the determined antioxidant enzymes; peroxidase, polyphenol oxidase and catalase in saline habitats as compared with mesophytic habitat. - The highest nitrogen content of all studied plants recorded at mesophytic habitat and the lowest content at saline habitat, while, the highest content of phosphorous was recorded for M. parviflora and R. dentatus at mesophytic habitat and the lowest values at saline habitat. On the other hand, the phosphorous content for P. oleracea recorded at saline habitat the maximum content. As for the potassium element, the highest content for all studied plants appeared at mesophytic habitat and the lowest content at saline habitat. Unlike potassium, the sodium and calcium element recorded the highest content for all studied plants at saline habitat. While magnesium element records non-significant difference for R. dentatus and P. oleracea at all studied habitats, but the highest content of this element appeared for M. parviflora at mesophytic habitat and the lowest content recorded at saline habitat. Gibberellic acid for M. parviflora, R. dentatus and P. oleracea showed significant decrease in content at saline habitat as compared with mesophytic habitat. On the other hand, indole acetic acid and abscisic acid showed the maximum significant increase for the studied plants at saline habitat as compared with the mesophytic habitat. The determined plant secondary metabolites (alkaloids, phenols, flavonoids, tannins and anthocyanins) for M. parviflora, R. dentatus and P. oleracea showed the maximum significant increase at saline habitats as compared with the mesophytic habitat. Stomatal frequency for M. parviflora, R. dentatus and P. oleracea showed the maximum number recorded on the lower surface of plants leaves collected from the mesophytic habitat comparing with either its upper surface or with both leaves surface at saline habitat. The maximum M. parviflora and R. dentatus stomatal area and its opening area were on the lower surface of plants leaves collected from the mesophytic habitat when compared with ether the area of the upper surface or with the two surfaces of leaves collected from the saline habitat. On the other hand, stomata of P. oleracea appeared close at mesophytic and saline habitats.