Twelve species of salt excreting halophytes were collected from the salt marshes along the Red Sea (arid) and the west Mediterranean (semi-arid) coasts in Egypt. Those species belonged to seven genera and six families. The data revealed that the structure of the salt glands varied greatly among the investigated taxa and can be categorized in five groups. These groups are the vesiculated hairs or bladders of Chenopodiaceae; glands of Tamaricaceae and Frankeniaceae; glands of Plumbaginaceae; glands of Avicennia marina and glands of Aeluropus lagopoides. The results revealed also that the excreted salts are mostly composed of NaCI, but with more or less selectivity among different species. The composition of other ions varied also according to the different species.

Twelve species of salt excreting halophytes were collected from the salt marshes along the Red Sea (arid) and the west Mediterranean (semi-arid) coasts in Egypt. Those species belonged to seven genera and six families. The data revealed that the structure of the salt glands varied greatly among the investigated taxa and can be categorized in five groups. These groups are the vesiculated hairs or bladders of Chenopodiaceae; glands of Tamaricaceae and Frankeniaceae; glands of Plumbaginaceae; glands of Avicennia marina and glands of Aeluropus lagopoides. The results revealed also that the excreted salts are mostly composed of NaCI, but with more or less selectivity among different species. The composition of other ions varied also according to the different species.

Salin irrigation solutio:" pf ICOO, :'tODD. and 6000 p.p.ill. made up of CaClz :md NaCl were supplied To the plants under test. The carbohydrate content. photosynthetic pigments as well as the conc: entralion of chloropbyll.s :lnd internal osmotic pre~.sure of carrot :lnd beet plants were determined :IS grown at the stress levels specified in sand cultures for 17 weeks. The same parameters were also determined when thesc stressed plants wcrc spr:.lyed with GA3 solution :.It 50 p.p.l11. There was :J trend of relative increase in osmotic pressure accompanied with rcduction in the waler content of the treated plants. The carbohydrate level tcnded to increase in carrot shoots, however lhis level shl1wed ;)n irregular sequence of hydrolysablc sugars associ:1(ed with :1 decreasing leyel of soluble sugars of beet shoots at all spt'cified treatments and the vice Jlersa with respect to beet rools. Photosynthctic pigments exhibited increasing sequence cf beet leaves ill lomTliSL with the data or carrot leaves at aU investigated treatment'i. The application of GA3 solution to the plants grown Ullder salin!t!' failed to reverse the salinity effect.

Salin irrigation solutio:" pf ICOO, :'tODD. and 6000 p.p.ill. made up of CaClz :md NaCl were supplied To the plants under test. The carbohydrate content. photosynthetic pigments as well as the conc: entralion of chloropbyll.s :lnd internal osmotic pre~.sure of carrot :lnd beet plants were determined :IS grown at the stress levels specified in sand cultures for 17 weeks. The same parameters were also determined when thesc stressed plants wcrc spr:.lyed with GA3 solution :.It 50 p.p.l11. There was :J trend of relative increase in osmotic pressure accompanied with rcduction in the waler content of the treated plants. The carbohydrate level tcnded to increase in carrot shoots, however lhis level shl1wed ;)n irregular sequence of hydrolysablc sugars associ:1(ed with :1 decreasing leyel of soluble sugars of beet shoots at all spt'cified treatments and the vice Jlersa with respect to beet rools. Photosynthctic pigments exhibited increasing sequence cf beet leaves ill lomTliSL with the data or carrot leaves at aU investigated treatment'i. The application of GA3 solution to the plants grown Ullder salin!t!' failed to reverse the salinity effect.

Increase in foliar osmotic potential to soil osmolality has been previously realized by the senior author and some other investigators. The present study has been carried out to clarify the interactive kinetin and salinity stress on osmotic potential and carbohydrate contents in cotton and millet plants. Kinetin solution (10 ppm) was applied in three different modes; presoaking of seeds, spraying of shoot system and with irrigation water. This study revealed that kinetin increased the osmotic pressure in the two experimental plants when applied by spraying and irrigation with water. However the osmotic pressure was reduced when the seeds were presoaked in kinetin solution. It was concluded that kinetin can alleviate the effect of salinity stress on the osmotic pressure. The carbohydrate contents of various treated plants were also taken into consideration.

Wadi Quena, unique in its north-south orientation among other wadies of the eastern desert of Egypt constitutes a vast catchment system of sporadic rains over the Red Sea mountains. The present study concerns a part of this catchment area, including some eastwest tributaries pouring flood waters into the lower part of the main trunk of the wadi. Due to local physiographic factors, these tributaries harbour two communities newly recognized in this desert. These are: community of Salsola haryosma-Tamarix aphylla and community of Cilrullus colocynlhis-Cleome droserifolia. Elements of the alliance Zygophyllaeion coccini, previously identified in this series of investigations, are well represented in the area under consideration.

Wadi Quena, unique in its north-south orientation among other wadies of the eastern desert of Egypt constitutes a vast catchment system of sporadic rains over the Red Sea mountains. The present study concerns a part of this catchment area, including some eastwest tributaries pouring flood waters into the lower part of the main trunk of the wadi. Due to local physiographic factors, these tributaries harbour two communities newly recognized in this desert. These are: community of Salsola haryosma-Tamarix aphylla and community of Cilrullus colocynlhis-Cleome droserifolia. Elements of the alliance Zygophyllaeion coccini, previously identified in this series of investigations, are well represented in the area under consideration.

Wadi Quena, unique in its north-south orientation among other wadies of the eastern desert of Egypt constitutes a vast catchment system of sporadic rains over the Red Sea mountains. The present study concerns a part of this catchment area, including some eastwest tributaries pouring flood waters into the lower part of the main trunk of the wadi. Due to local physiographic factors, these tributaries harbour two communities newly recognized in this desert. These are: community of Salsola haryosma-Tamarix aphylla and community of Cilrullus colocynlhis-Cleome droserifolia. Elements of the alliance Zygophyllaeion coccini, previously identified in this series of investigations, are well represented in the area under consideration.

The effect of treatment combinations of decreased soil osmotic water potential (Ips) and increased sodicity (SAR) on chlorophyll (ChI) characteristics (ChI a and b contents, Chi a/b ratio, and Chi stability to heat - CSI) of three crop plants (Gossypium barbadense L., Hibiscus sabdarifJa L. and Sorghum bicolor L.) was studied. Chi characteristics in different plant species responded variably to both changes in 1jJs and sodicity. Generally, Chi content was not sensitive to sodicity but both ChI a and b were significantly affected by osmotic stress. Accordingly, the Chi a/b apparent changes at different SAR levels were due to osmotic rather than sodic effects. CSI showed variable trends in response to both decreased 1jJs and increased sodicity according to ChI type and plant species. Decreasing ChI content and increasing CSI, under reduced 1jJs, might indicate the adaptations of plants toward enduring salinity stress, particularly in reference to the ecological origin of such crop plants.

The effect of treatment combinations of decreased soil osmotic water potential (Ips) and increased sodicity (SAR) on chlorophyll (ChI) characteristics (ChI a and b contents, Chi a/b ratio, and Chi stability to heat - CSI) of three crop plants (Gossypium barbadense L., Hibiscus sabdarifJa L. and Sorghum bicolor L.) was studied. Chi characteristics in different plant species responded variably to both changes in 1jJs and sodicity. Generally, Chi content was not sensitive to sodicity but both ChI a and b were significantly affected by osmotic stress. Accordingly, the Chi a/b apparent changes at different SAR levels were due to osmotic rather than sodic effects. CSI showed variable trends in response to both decreased 1jJs and increased sodicity according to ChI type and plant species. Decreasing ChI content and increasing CSI, under reduced 1jJs, might indicate the adaptations of plants toward enduring salinity stress, particularly in reference to the ecological origin of such crop plants.