Ecophysiological studies on some desert plant species native to the Mediterranean area in Egypt

Phytosociological studies were carried out on nine plants having different distributional and life-form patterns in northern Egypt. Plant productivity and summer/winter mean water content were studied in addition to the soil characteristics of the 12 habitats where the nine species were recorded. Pl ant density, frequency, cover and importance values indicated narrow (at 1- 2 habitats) or wide distribution (at 7-10 habitats) depending on species co ntrol on water loss and adaptation to soil characteristics. Salinity adapte d plants exhibited great control on water loss and acquire high dry/wet sea son (summer/winter) water content. Water content depended mainly on the pla nts life-form and with less extent on soil characteristics. Productivity wa s affected greatly by soil characteristics and plant life-forms; less so by the variations in photosynthetic pigments of the plants resulting from the spatial heterogeneity of the habitats. Plant photosynthetic pigments were mainly chlorophyll a which was not affected greatly by habitat stress. The variation in the total pigments could not be a sign of edaphic stress on th e plant. (C) 2001 Academic Press.