Torrential rains (in January 1980) that had suddenly swept a limited area in the eastern desert facing Qena Province (Upper Egypt) resulted in enriching the vegetation of some extremely dry wadies at this location. Vegetation survey carried out shortly after this event (in April) revealed the prevailance of annuals which are hardly recognizable in such usually dry habitats and in considerable abundance. The normally scarce perennial vegetation has flourished too. The investigation revealed that the wadies studied are potential shelters of 3 community types, one of which seems to be a segetal part of an "Alliance" wide-spread in other wadies of this desert. Distribution of such vegetation units seems to be controlled by relative aridity of the soil as well as by soil depth.

The increase in prices of petroleum based fuels, future depletion of worldwide petroleum reserves and environmental policies to reduce CO2 emissions have stimulated research into the development of biotechnology to produce chemicals and fuels from renewable resources. The most commonly used metabolically derived biofuels are hydrogen, acetone, butanol and ethanol. Biofuel is produced biologically from renewable biomass by Clostridium spp. under strictly anaerobic condition. Substrate costs can make up to about 63% of the total cost of biofuel production. This is not because of the expense of the substrate itself, but mainly because of the low efficiency of Clostridium to convert substrate into biofuel, i.e. the yield of biofuel is often low, and this together with the formation of by-products leads to a high cost for butanol recovery. In addition, the maintenance of strict anaerobic conditions for Clostridium requires special conditions e.g. addition of costly reducing agents, and flushing with N2 gas, which increase the cost of the fermentation process. Hence, substrates such as agricultural residues, including wheat straw, barley straw, maize stover, wood hydrolysate, and switchgrass as well as dairy industry waste offer potential alternatives. To reduce the costs of producing hydrogen and ABE from fermentation, include using a low cost fermentation substrate and/or optimizing the fermentation conditions to improve the efficiency of converting substrate to biofuel. The facultative anaerobes are able to consume O2 in a medium and so a steady anaerobic condition in a fermentor was attained without addition of any reducing agent. Significant progress has been made towards genetically engineering clostridia to utilize a variety of substrates, and to reduce the need for pretreatment processes as well as reduce the application of reducing agents for creation anaerobic conditions. Among the cheap and readily available substrates for biohydrogen and liquid biofuel production, agro-industrial wastes are possibly one of the better choices. The possibility of using cheaper resources, such as lignocelluloses, whey cheese or any agro-industrial and domestic organic wastes, as the alternative substrates for biofuel production over more expensive substrates . Selection of cellulolytic clostridia in applying biotechnology to acetone-butanol fermentation revived interest in research on solvent production by fermentation.

The increase in prices of petroleum based fuels, future depletion of worldwide petroleum reserves and environmental policies to reduce CO2 emissions have stimulated research into the development of biotechnology to produce chemicals and fuels from renewable resources. The most commonly used metabolically derived biofuels are hydrogen, acetone, butanol and ethanol. Biofuel is produced biologically from renewable biomass by Clostridium spp. under strictly anaerobic condition. Substrate costs can make up to about 63% of the total cost of biofuel production. This is not because of the expense of the substrate itself, but mainly because of the low efficiency of Clostridium to convert substrate into biofuel, i.e. the yield of biofuel is often low, and this together with the formation of by-products leads to a high cost for butanol recovery. In addition, the maintenance of strict anaerobic conditions for Clostridium requires special conditions e.g. addition of costly reducing agents, and flushing with N2 gas, which increase the cost of the fermentation process. Hence, substrates such as agricultural residues, including wheat straw, barley straw, maize stover, wood hydrolysate, and switchgrass as well as dairy industry waste offer potential alternatives. To reduce the costs of producing hydrogen and ABE from fermentation, include using a low cost fermentation substrate and/or optimizing the fermentation conditions to improve the efficiency of converting substrate to biofuel. The facultative anaerobes are able to consume O2 in a medium and so a steady anaerobic condition in a fermentor was attained without addition of any reducing agent. Significant progress has been made towards genetically engineering clostridia to utilize a variety of substrates, and to reduce the need for pretreatment processes as well as reduce the application of reducing agents for creation anaerobic conditions. Among the cheap and readily available substrates for biohydrogen and liquid biofuel production, agro-industrial wastes are possibly one of the better choices. The possibility of using cheaper resources, such as lignocelluloses, whey cheese or any agro-industrial and domestic organic wastes, as the alternative substrates for biofuel production over more expensive substrates . Selection of cellulolytic clostridia in applying biotechnology to acetone-butanol fermentation revived interest in research on solvent production by fermentation.

The increase in prices of petroleum based fuels, future depletion of worldwide petroleum reserves and environmental policies to reduce CO2 emissions have stimulated research into the development of biotechnology to produce chemicals and fuels from renewable resources. The most commonly used metabolically derived biofuels are hydrogen, acetone, butanol and ethanol. Biofuel is produced biologically from renewable biomass by Clostridium spp. under strictly anaerobic condition. Substrate costs can make up to about 63% of the total cost of biofuel production. This is not because of the expense of the substrate itself, but mainly because of the low efficiency of Clostridium to convert substrate into biofuel, i.e. the yield of biofuel is often low, and this together with the formation of by-products leads to a high cost for butanol recovery. In addition, the maintenance of strict anaerobic conditions for Clostridium requires special conditions e.g. addition of costly reducing agents, and flushing with N2 gas, which increase the cost of the fermentation process. Hence, substrates such as agricultural residues, including wheat straw, barley straw, maize stover, wood hydrolysate, and switchgrass as well as dairy industry waste offer potential alternatives. To reduce the costs of producing hydrogen and ABE from fermentation, include using a low cost fermentation substrate and/or optimizing the fermentation conditions to improve the efficiency of converting substrate to biofuel. The facultative anaerobes are able to consume O2 in a medium and so a steady anaerobic condition in a fermentor was attained without addition of any reducing agent. Significant progress has been made towards genetically engineering clostridia to utilize a variety of substrates, and to reduce the need for pretreatment processes as well as reduce the application of reducing agents for creation anaerobic conditions. Among the cheap and readily available substrates for biohydrogen and liquid biofuel production, agro-industrial wastes are possibly one of the better choices. The possibility of using cheaper resources, such as lignocelluloses, whey cheese or any agro-industrial and domestic organic wastes, as the alternative substrates for biofuel production over more expensive substrates . Selection of cellulolytic clostridia in applying biotechnology to acetone-butanol fermentation revived interest in research on solvent production by fermentation.

The increase in prices of petroleum based fuels, future depletion of worldwide petroleum reserves and environmental policies to reduce CO2 emissions have stimulated research into the development of biotechnology to produce chemicals and fuels from renewable resources. The most commonly used metabolically derived biofuels are hydrogen, acetone, butanol and ethanol. Biofuel is produced biologically from renewable biomass by Clostridium spp. under strictly anaerobic condition. Substrate costs can make up to about 63% of the total cost of biofuel production. This is not because of the expense of the substrate itself, but mainly because of the low efficiency of Clostridium to convert substrate into biofuel, i.e. the yield of biofuel is often low, and this together with the formation of by-products leads to a high cost for butanol recovery. In addition, the maintenance of strict anaerobic conditions for Clostridium requires special conditions e.g. addition of costly reducing agents, and flushing with N2 gas, which increase the cost of the fermentation process. Hence, substrates such as agricultural residues, including wheat straw, barley straw, maize stover, wood hydrolysate, and switchgrass as well as dairy industry waste offer potential alternatives. To reduce the costs of producing hydrogen and ABE from fermentation, include using a low cost fermentation substrate and/or optimizing the fermentation conditions to improve the efficiency of converting substrate to biofuel. The facultative anaerobes are able to consume O2 in a medium and so a steady anaerobic condition in a fermentor was attained without addition of any reducing agent. Significant progress has been made towards genetically engineering clostridia to utilize a variety of substrates, and to reduce the need for pretreatment processes as well as reduce the application of reducing agents for creation anaerobic conditions. Among the cheap and readily available substrates for biohydrogen and liquid biofuel production, agro-industrial wastes are possibly one of the better choices. The possibility of using cheaper resources, such as lignocelluloses, whey cheese or any agro-industrial and domestic organic wastes, as the alternative substrates for biofuel production over more expensive substrates . Selection of cellulolytic clostridia in applying biotechnology to acetone-butanol fermentation revived interest in research on solvent production by fermentation.

Sewage sludge collected from El-Salhya sewage station at Qena city in Egypt , was applied in a pot experiment to investigate the uptake and translocation of certain mineral nutrients and some heavy metals in different organs of Gossypium barbadence plants. The sludge was mixed with sand at three levels: 10%, 20% and 30% and the sand was used (without sludge) as control. Results revealed that the distribution pattern of PO4 and NO3 in cotton plants indicated that the major fraction was transported from roots into the shoots of plants, and vise versa in case of Cl and SO4. The distribution of Na and K was in another way, and mostly Na accumulated in roots while more K transported into shoots of the plants. Results indicated also that Na/K ratio was higher in plant roots than in shoots. Mg and Ca distributed along the plant axes with significant change from the roots toward the shoots, and also between both organs in plants grown on sludge and their analogous in control plants. Results of heavy metals analysis in this study indicated that heavy metal accumulation was more in roots than shoots under sewage sludge amendment. Data indicated that Fe, Zn and Pb accumulated in roots of plants more than shoots. In contrast to these metals, Ni was transported up to the shoots, while low amounts were detected in roots. The accumulation of heavy metals in cotton plants grown on sandy soil amended with sewage sludge was generally arranged in the following preference: Fe Zn Pb Ni which reflected the concentrations of these metals in sludge. Correlation analysis between the contents of heavy metals in both organs of cotton plants and that in the sand-sludge mixture showed different relationships.

Ochradenus baccatus (family Resedaceae) is a dioecious or bisexual shrub and represent the characteristic species in wadi Qena. It presented in 13 stands in the study area. To study the ecophysiological characters of the investigated plant in this area, two visits were arranged during Wi (Winter) and Su (Summer) of 2010. Data showed that soil water content and organic matter in wadi Qena was very low over the year. pH values in the soil solution at the different studied stands in wadi Qena tended to be slight alkaline. O. baccatus plants tended to increase significantly their content of Chl. a in Wi, while in Su Chl. b increased but Chl. a/b ratio was maintained one in both seasons. The chlorophyll (a or b) stability index was significantly higher in Wi than that in Su. The results indicated that Ca2+ and Mg2+ were accumulated in considerable amounts in the investigated plants while K+ accumulated in fewer amounts compared with Na+. O. baccatus accumulated SO42- in Su more than Wi. Phosphates appeared in plants in a few amounts. Data indicated also that O. baccatus plants tend to increase their soluble sugars, soluble proteins and total free amino acids significantly during Su season than Wi. Proline concentrations were higher in Wi than in Su. It can be concluded that there are close relationships between the presence of, K+, Na+ and Cl- in high concentrations in the plants during the dry season on one hand and the accumulation of soluble sugars and soluble proteins on the other hand. However, this may be primarily related to metabolism of drought resistance in such desert plants.

The purpose of this study was to describe the flora and vegetation of Qift-Qusier roadside in the central part of the Eastern Desert of Egypt, and to relate the floristic composition to the prevailing environmental conditions. A total of 61 species (28 annuals and 33 perennials) belonging to 50 genera and 27 families were recorded. Based on their presence values, classification of the 61 species recorded in 43 stands using the cluster analysis yielded 6 vegetation groups. Results of CCA ordination indicated that organic matter, Na, K, Ca and pH, were the most important factors for the distribution of the vegetation pattern along the road verges in the study area. The DCA and CCA results suggest a strong association between vegetation and the measured environmental parameters.

Physiological adjustments to enhance tolerance or avoidance of drought were studied in three desert plants growing in Wadi Natash (Eastern Desert, Egypt). Studied plants (Zilla spinosa (L. ) Prantl, Citrullus colocynthis (L. ) Schrad and Morettia philaeana (Dalile) DC. ) were collected from four stands. Cell sap osmotic potential, some organic (soluble sugars, total free amino acids, and soluble proteins) and inorganic (Ca2+, Mg2+, Na+, K+, Cl- and SO4 2-) solute concentration were determined. In addition, cover degree of investigated species (according to the cover-abundance scale of Braun-Blanquet) was also estimated. Substantial osmotic adjustment (up to -1 .71 MPa) was observed in Z. spinosa collected from stand 4. Z. spinosa was dependent on soluble sugars, soluble proteins, free amino acids, SO4 2-, K+, Cland Mg2+ to readjust their internal osmotic pressure and to improve its water status. I t preferred Mg2+ more than the two other species. C. colocynthis accumulated inorganic solutes more than Z. spinosa and less free amino acids. The results suggest that osmotic adjustment was the main water relationship adaptation to cope with drought. Accumulation of soluble sugars, soluble proteins, K+, Cl- and SO4 2- at higher concentration often assist in turgor maintenance and helped to enhance drought tolerance. Key words: Adjustment; Chlorophyll; Organic solute; Osmotic potential; Soluble sugars

Physiological adjustments to enhance tolerance or avoidance of drought were studied in three desert plants growing in Wadi Natash (Eastern Desert, Egypt). Studied plants (Zilla spinosa (L. ) Prantl, Citrullus colocynthis (L. ) Schrad and Morettia philaeana (Dalile) DC. ) were collected from four stands. Cell sap osmotic potential, some organic (soluble sugars, total free amino acids, and soluble proteins) and inorganic (Ca2+, Mg2+, Na+, K+, Cl- and SO4 2-) solute concentration were determined. In addition, cover degree of investigated species (according to the cover-abundance scale of Braun-Blanquet) was also estimated. Substantial osmotic adjustment (up to -1 .71 MPa) was observed in Z. spinosa collected from stand 4. Z. spinosa was dependent on soluble sugars, soluble proteins, free amino acids, SO4 2-, K+, Cland Mg2+ to readjust their internal osmotic pressure and to improve its water status. I t preferred Mg2+ more than the two other species. C. colocynthis accumulated inorganic solutes more than Z. spinosa and less free amino acids. The results suggest that osmotic adjustment was the main water relationship adaptation to cope with drought. Accumulation of soluble sugars, soluble proteins, K+, Cl- and SO4 2- at higher concentration often assist in turgor maintenance and helped to enhance drought tolerance. Key words: Adjustment; Chlorophyll; Organic solute; Osmotic potential; Soluble sugars