Vol. 15 Issue 2
M.S. Omar
X-ray diffraction method has been used to determine the crystal structure of the ternary compound Cu₂GeSe₃. A complete poder data is presented; and their analysis by Ito's method gives a Triclinic superlattice for the bended sphalerite unit cell of Cu₂GeSe₃ compound, with the lattice constants of a= 3.9381 A°, b= 22.3796 A°, and c= 11.5626 A° and the angles are α= 90.039°, β= 89.592° and γ= 89.945°.
Shafik I. Abdel-Aal, Ragaa E.A. Sabrah, Rafaat K. Rabie, and Hago M. Abdel Magid
Appraisal of groundwater used for irrigation in El-Gassim region of Central Saudi Arabia was made by chemically analysing 217 representative water samples.
Based on previous water criteria guidelines and a modification by us, the data obtained were intensively processed and transformed. Accordingly, water quality and suitability maps were developed under the conditions of this study with special focus on wheat production.
The water quality parameters investigated revealed the following:
1) water salinity ranged from 210-8200 ppm with an average of 2375 ppm (i.e. between 16.6 and 83 t/ha of salt deposited in soil per season for wheat and alfalfa cultivation);
2) extensive water extraction caused a significant increment in SO4=/ Cl- ratio;
3) accumulation of reactive constituents such as H₂S, FeS and So=4 caused corrosion and damaged the pivot pipeline and
4) irrigation water contributed to soluble potassium which amounted to 475 and 2500 kg K₂SO4/ha/season for wheat and alfalfa crops, respectively.
M.I. Soliman and A.A. Khedr
The anatomical characteristics of leaves of seven xerophytic species namely: Artemisia monosperma, Zilla spinosa, Farsetia aegyptia, Launaea spinosa, Zygophyllum coccineum, Panicum turgidum, and Lasiurus hirsutus are described. Artemisia monosperma, Zilla spinosa and Farsetia aegyptia develop multilayered palisade tissue on both sides of their leaves with compact cells and narrow intercellular spaces. The leaves of Zygophyllum coccineum show large, highly vacuolated, water-storage cells lacking chloroplasts in addition to the photosynthetic mesophyll. Panicum turgidum, Larsiurus hirsutus, Zilla spinosa and Farsetia aegyptia show slightly sunken stomata, whilst in Launaea spinosa and Artemisia monosperma stomata are deeply sunken.
Monier M. Abd El-Ghani
The study deals with the distribution, habitats, and ecological characteristics of natural vegetation along a transect crossing the central part of Hijaz Mountains, Saudi Arabia. Fifty stands were classified on the basis of leading dominant species, using agglomerative cluster analysis, into five distinct and recognizable vegetation groups (vegetation types). A total of 86 plant species were recorded. The present study provides evidence that the vegetation shows discernible zonation. The annuals increase, and the biennials and perennials decrease along the elevation gradient from lower to higher elevations. This appears to be correlated, at least partly, with altitude. Species diversity varies from one vegetation group to the other as well as between stands of the same group. The vegetation type of Ficus salicifolia is the most widespread, diversified and consequently, the most stable vegetation cover in the study area; it, therefore, represents the climatic climax community. Human interference has a prominent role in changing the physical environmental and inevitably destroys the precarious balance among the components of the ecosystem. The environment has deteriorated, and retrogressive changes in the vegetation are recorded.
M.M. Dorgham and M.M. Hussein
Seasonal changes in zooplankton assemblages in Doha Harbour, a neritic area in the Arabian Gulf were studied from December 1987 to November 1988 in relation to the seasonal variations of temperature, salinity and nutrients. The zooplankton community in the study area was characterized by low species diversity and a relatively low numerical density relative to other areas in the Gulf. High salinity seems to be a dominant factor affecting growth and the breeding cycles of the abundant zooplankton species.The average population densities ranged from a maximum of 4705/m³ in June to a minimum of 993/m³ in November. Copepods were the major component, in the ratio of 1:1.7:5.5 harpacticoid : calanoids : cyclopoids. This ratio showed a departure from that usually observed in warm waters. Some deep-water species were occasionally recorded indicating the possibility of adaptation of Indo-Pacific species to the area
Faisal M. Abou-Tarboush
Normal adult inbred SWR/J mice were used in the investigation of the possible teratogenic and other effects of Hiconcil. Pregnant females were treated intraperitoneally (ip) daily from day 7 through day 12 of pregnancy. Hiconcil at a dose of 500 or 650 mg/kg body weight resulted in teratogenic effects in foetuses of treated mother including the development of abnormal hindlimbs, heads and tails. Moreover, some abnormally small foetuses were also obtained from treated mothers given these doses of the drug. However, the drug appeared safe to treated dams at all dose levels and throughout gestation.
M.M. Alfuraiji, I.A. Moussa and M.N. Bakkar
The presence of gonadotropin- releasing hormone (GnRH)- like factors in the seminal plasma of the Arabian camel (Camelus dromedarius L.) has been studied in immature rats. Immature male and female rats treated with the Arabian's seminal plasma (SP) or with synthetic GnRH developed heavier testes and ovaries and large seminiferous tubules than those of the controls. Immature female rats treated with GnRH and those injected with highest two doses of the camel's Sp has developed a greater number of ovarian follicles than those of the corresponding controls. Those receiving the lower three doses of the camel's SP has developed a greater number of small ovarian follicles than in their controls. It is concluded that the Arabian camel's SP contains an ovulation simulation factor.
T. Abdel Khalig and B.H. Ali
The activity of pseudocholinesterase (PCHE) was measured in the plasma of healthy male and female Arabian camels (Camelus dromedarius), cattle (Bos aureus), sheep (Ovis aries), goats (Capra hircus), horses (Equus caballus, bustards (Chlamydotis undulata macqueenii), and rats (Rattus norvegicus). The PCHE activity in both male and female Arabian camels increased by about 40% with age. There were no differences in PCHE activity between young and old, or between male and female camels. The enzyme activity was about 90% greater in 6-month old female rats than in male rats of the same age. It was also higher in bustards and horses thanin the ruminants studied, including the Arabian camel.
Hashim Al-Sayed, Mohammad Al-Rumaidh and Nagappan Nayar
Pearl oyster spat (Pinctada radiata) settlement under different environmental conditions was studied at several locations around Bahrain during 1989. A variety of spat collectors were tested and evaluated. Collectors made from empty oyster shell, nylon rope, coir rope type, steel wire, plastic baskets, wooden frames and cement coated oyster cages were laid during July 1989 at Fasht Al-Jarim, Khor Fasht, Sitra Beason, Buoy No. 3 and Ras Hayan. Spat settlement took place over a long period (July to November 1989)as evident from occurrence of small-sized oysters each time collectors removed but intense spat settling was recorded throughout August 1989 giving indirect evidence that spawning commenced toward end of July 1989, and August 1989. Although settlement was reported on a wide range substrates, empty oyster shells enhanced maximum settlement (80 spat per oyster shell) indicating that ready to sit larvae exhibited some degree of substrate preference by settling primarily on rough surfaces such as empty shells. Moreover most of the settlement took place in the mid-depth (0.5-1.5 m) region. However, based on average of 50 spat per shell, a total of 1 million spat could be conveniently collected using collectors made of empty oyster shells during settlement season. Spatial differences in spat settlement was recorded with Fasht Al-Jarim exhibiting heaviest settlement of larvae drifted from offshore oyster beds, in the north and northwest areas of Bahrain. Seasonal changes in pattern of post settlement growth was found to be closely related to changes in water temperature, as indicated by Spearman's correlation coefficient r = 0.5 at p < 0.05. After settlement in summer (July - August 1989) the spat showed accelerated rate of growth (0.204 - 0.248 mm/day) until the following winter (December- January) when growth has slowed down but at steadily rate mainly as a result of drop in water temperature from 27 - 33°C to 17 - 18°C, respectively. Eighteen months after settlement a shell length of 57.69 mm was attained, and there was an indication that growth slowed down during the second year.
S.A. Kabli, S.M. Al-Garni and F.A. Al-Fassi
Nine species of cyanobacteria were isolated from agricultural soil of Western region in the Kingdom of Saudi Arabia. Except for Phormidium sp. and Oscillatoria sp., all the isolated species were able to fix atmospheric nitrogen. The seven nitrogen fixing species exhibited different potentialities for atmospheric nitrogen fixation. The descending order for their potencies was as follows: Anabaena cylindrica; Anabaena sp.; Gloeocapsa sp.; Synechococcus sp.; Chroococcus so.; Lyngbya sp.; Nostoc commune.
It was also found that there was a correlation between the efficiencies of cyanobacteria species for atmospheric nitrogen fixation and their biological activities.
Results obtained revealed the biomass of some cyanobacteria species to have stimulatory effect on the rate of respiration of cyanobacteria and other soil microbes, while the biomass of other cyanobacteria species had inhibitory effect.
Upon testing efficiency of these atmospheric nitrogen fixers in fulfilling the requirements of wheat plant for nitrogen, in the absence of this element in the growth medium, it was found that Nostoc commune and Anabaena cylindrica could supply wheat plant with atmospheric nitrogen to maintain its vegetative growth. Therefore, these species of cyanobacteria could be used as biofertilizers instead of utilizing expensive industrial chemical manures.