I am Professor of Plant Ecology, much interested with all aspects of wetland ecology and diversity of natural habitats in arid and semi arid countries.
Phragmites australis adapts to different habitats and tolerate drought and/or salt stress. In the... more Phragmites australis adapts to different habitats and tolerate drought and/or salt stress. In the present study, P. australis was collected from mesophytic, brackish water, sand dune, fresh water and salt marsh habitats. The leaf fresh weight was optimum in mesophytic habitats and it was negatively affected by stress found in other habitats. Water content followed the same trend for the fresh weight. The decrease in water content could be a tolerance strategy. Na + content was higher in roots than in leaves for all habitats. In contrast, K + content was higher in leaves than in roots. K + /Na + ratio was higher than unity in leaves for all habitats even within roots collected from salt marsh. Except for leaves collected from mesophytic habitats, K + /Na + ratio was less than one (1.1). NHX1 expression level was higher in roots than that in leaves suggesting that this plant may accumulate Na + inside root vacuoles to restrict its movement to shoot. However, the transcript level of SO...
ABSTRACT Processes limiting the distribution and abundance of plants are directly linked to landf... more ABSTRACT Processes limiting the distribution and abundance of plants are directly linked to landform characteristics. The relationships between soil characteristics and dominant xerophytes were assessed in the major landforms in the hyper-arid deserts of the Northern Emirates (NE) of the United Arab Emirates, northeast of the Arabian Peninsula. Dominant and co-dominant perennial plants were recorded in a total of 1058 stands in 13 landforms. Soil texture, electrical conductivity (EC) and pH were assessed in each stand. Two methods of multivariate analysis (TWINSPAN and DCA) classified the landforms into four groups, each with specific indicator(s) species. Canonical Correspondence Analysis ordination showed positive correlations of the halo-xerophytic shrubs along a gradient of EC. Zygophyllum qatarense and Salsola drummondi showed the highest correlation with soil salinity. The psammophytic species Cyperus conglomeratus and the shrubby Calotropis procera and Calligonum comosum are correlated along gradients of high sand content, high pH, and low EC. Acacia tortilis is correlated with increasing silt and clay and it prefers soils with low EC. The grasses Pennisetum divisum and Panicum turgidum are located around the middle of the soil texture, pH and EC gradients. The associations between A. tortilis and other species, e.g. C. comosum, Prosopis cineraria, and S. drummondi, were correlated along gradients of silt and clay. More perennials were associated with both the keystone trees A. tortilis and Prosopis juliflora, but the association was more for the first, compared to the latter species.
... environmental factors along the Suez Canal and the Red Sea Coast of Egypt By MOHAMED ALI DEYA... more ... environmental factors along the Suez Canal and the Red Sea Coast of Egypt By MOHAMED ALI DEYAB, ABDEL-HAMID A. KHEDR and MAMDOUH AHMED EL-NAGGAR Mansoura University, Faculty of Science at Damietta, Botany Department, New Damietta, Egypt ...
The cultivated varieties and landraces of Cucurbitaceae growing in Egypt are presented, 27 taxa, ... more The cultivated varieties and landraces of Cucurbitaceae growing in Egypt are presented, 27 taxa, belonging to three genera, six species, and five subspecies. These characters are arranged according to their usefulness for identifications as follow: fruit characters, seed characters and trichome type. Fruit characters are a good taxonomic tool at varietal level when combined with the other vegetative characters. Two keys to 27 cultivated varieties of Cucurbitaceae (Cucumis, Cucurbita and Luffa) were constructed using the ...
The macrophyte distribution of Lake Manzala is described in relation to water depth, salinity, di... more The macrophyte distribution of Lake Manzala is described in relation to water depth, salinity, dissolved oxygen, pH, C1-, NO~-and PO43-. Changes in species composition of macrophytes are visualised by means of multivariate analysis. The TWINSPAN classification and CANOCO ordination programs (DCA & CCA) were used to analyse the data set. The classification of 100 stands revealed 8 vegetation groups which indicated eleven dominant communities. These are Phragmites australis, Typha domingensis, Scirpus maritimus, Echinochloa stagnina and Ludwigia stolonifera as emergent hydrophytes; Eichhornia cras-sipes and Azollafiliculoides as floating hydrophytes. The dominant submerged hydrophytes are Potamogeton pectinatus, Najas armata, Ceratophyllum demersum and Ruppia maritima. The northern part of the lake with low depth and relatively high salinity has low species diversity (mainly emergent species), Species diversity increases with decreasing salinity and increasing eutrophication near the mouths of the drains in the western and southern parts of the lake. The recent changes in species distribution can be attributed to the effects of salinity, water depth and drainage water. A checklist of macrophytes in the lake is appended.
Phragmites australis adapts to different habitats and tolerate drought and/or salt stress. In the... more Phragmites australis adapts to different habitats and tolerate drought and/or salt stress. In the present study, P. australis was collected from mesophytic, brackish water, sand dune, fresh water and salt marsh habitats. The leaf fresh weight was optimum in mesophytic habitats and it was negatively affected by stress found in other habitats. Water content followed the same trend for the fresh weight. The decrease in water content could be a tolerance strategy. Na + content was higher in roots than in leaves for all habitats. In contrast, K + content was higher in leaves than in roots. K + /Na + ratio was higher than unity in leaves for all habitats even within roots collected from salt marsh. Except for leaves collected from mesophytic habitats, K + /Na + ratio was less than one (1.1). NHX1 expression level was higher in roots than that in leaves suggesting that this plant may accumulate Na + inside root vacuoles to restrict its movement to shoot. However, the transcript level of SO...
ABSTRACT Processes limiting the distribution and abundance of plants are directly linked to landf... more ABSTRACT Processes limiting the distribution and abundance of plants are directly linked to landform characteristics. The relationships between soil characteristics and dominant xerophytes were assessed in the major landforms in the hyper-arid deserts of the Northern Emirates (NE) of the United Arab Emirates, northeast of the Arabian Peninsula. Dominant and co-dominant perennial plants were recorded in a total of 1058 stands in 13 landforms. Soil texture, electrical conductivity (EC) and pH were assessed in each stand. Two methods of multivariate analysis (TWINSPAN and DCA) classified the landforms into four groups, each with specific indicator(s) species. Canonical Correspondence Analysis ordination showed positive correlations of the halo-xerophytic shrubs along a gradient of EC. Zygophyllum qatarense and Salsola drummondi showed the highest correlation with soil salinity. The psammophytic species Cyperus conglomeratus and the shrubby Calotropis procera and Calligonum comosum are correlated along gradients of high sand content, high pH, and low EC. Acacia tortilis is correlated with increasing silt and clay and it prefers soils with low EC. The grasses Pennisetum divisum and Panicum turgidum are located around the middle of the soil texture, pH and EC gradients. The associations between A. tortilis and other species, e.g. C. comosum, Prosopis cineraria, and S. drummondi, were correlated along gradients of silt and clay. More perennials were associated with both the keystone trees A. tortilis and Prosopis juliflora, but the association was more for the first, compared to the latter species.
... environmental factors along the Suez Canal and the Red Sea Coast of Egypt By MOHAMED ALI DEYA... more ... environmental factors along the Suez Canal and the Red Sea Coast of Egypt By MOHAMED ALI DEYAB, ABDEL-HAMID A. KHEDR and MAMDOUH AHMED EL-NAGGAR Mansoura University, Faculty of Science at Damietta, Botany Department, New Damietta, Egypt ...
The cultivated varieties and landraces of Cucurbitaceae growing in Egypt are presented, 27 taxa, ... more The cultivated varieties and landraces of Cucurbitaceae growing in Egypt are presented, 27 taxa, belonging to three genera, six species, and five subspecies. These characters are arranged according to their usefulness for identifications as follow: fruit characters, seed characters and trichome type. Fruit characters are a good taxonomic tool at varietal level when combined with the other vegetative characters. Two keys to 27 cultivated varieties of Cucurbitaceae (Cucumis, Cucurbita and Luffa) were constructed using the ...
The macrophyte distribution of Lake Manzala is described in relation to water depth, salinity, di... more The macrophyte distribution of Lake Manzala is described in relation to water depth, salinity, dissolved oxygen, pH, C1-, NO~-and PO43-. Changes in species composition of macrophytes are visualised by means of multivariate analysis. The TWINSPAN classification and CANOCO ordination programs (DCA & CCA) were used to analyse the data set. The classification of 100 stands revealed 8 vegetation groups which indicated eleven dominant communities. These are Phragmites australis, Typha domingensis, Scirpus maritimus, Echinochloa stagnina and Ludwigia stolonifera as emergent hydrophytes; Eichhornia cras-sipes and Azollafiliculoides as floating hydrophytes. The dominant submerged hydrophytes are Potamogeton pectinatus, Najas armata, Ceratophyllum demersum and Ruppia maritima. The northern part of the lake with low depth and relatively high salinity has low species diversity (mainly emergent species), Species diversity increases with decreasing salinity and increasing eutrophication near the mouths of the drains in the western and southern parts of the lake. The recent changes in species distribution can be attributed to the effects of salinity, water depth and drainage water. A checklist of macrophytes in the lake is appended.
Uploads
Papers by Abdelhamid khedr