Vol. 20 Issue 1

T Youssef
Stomatal behavior, growth performance and accumulation of polynuclear aromatic hydrocarbons (PAHs) were evaluated in seedlings of the mangrove Avicennia marina (Forssk.) Vierh, treated with the water soluble fraction (WSF) of Abu-Dhabi light Arabian crude oil through foliar spraying or soil application. Irregular stomatal behavior and weak stomatal control over transpiration were observed during the first 24 hours, where stomatal resistance of plants sprayed with 150 and 300 (g PAHs plant-1 was significantly lower than that of the control plants. After six weeks, all treated plants showed no significant difference in their relative growth rate (RGR) or in the net assimilation rate (NAR) compared with the control plants. Tri-aromatic hydrocarbons were the most accumulated in tissues of the treated plants. Penta- and hexa-aromatics, on the other hand. were undetectable in the WSF and consequently in the treated plants. A linear relationship was observed between the dose applied to plants and the amounts of tissue accumulated PAHs (r^2=0.515 for soil application and r^2=0.984 for foliar spray). In plants sprayed with 300 (g PAHs plant-1, the total PAHs accumulated were more than that accumulated in plants treated through soil application. These findings suggest that: 1. Aqueous extraction of crude oil tends to signify the percentage of the low molecular weight PAHs, e.g. naphthalene to the total PAHs. 2. Disturbed stomatal behavior in the first day of the treatment may be due to the venting of the volatile low molecular weight aromatic hydrocarbons (e.g. benzene, toluene, and xylenes) through the stomata. 3. Uptake of water-soluble hydrocarbons by plants is equally possible through both the root system and the foliage. The ecological implications of these findings are discussed in relation to oil pollution of mangrove stands under field conditions.

A. Al-Busaidi and P. Cookson
Determination of pH assists in understanding many reactions that occur in soil. Soil pH values are highly sensitive to the procedure used for determination . In this study, pH was measured in different electrolytes [distilled water (pHw,), 0.01M CaCl2 (pHca), 1M KCl (pHk) , and 0.01M BaCl2 (pHba)] with different soil electrolyte ratios (i.e. 1:1, 1: 2.5, and 1:5). The objective was to determine the effect of each electrolyte and dilution ratio on pH of saline and non-saline soils from Oman. It was found that pH values varied significantly between electrolytes and with different dilution ratios. Linear regression equations were generated between electrolytes, dilution ratios and were mostly significant. Soil pH values determined in different electrolytes were significantly interrelated. Water appeared as a highly suitable solvent for soil pH measurements because it is simple and values are familiar to soil users. However, alkaline errors and electrode instabilities, due to liquid junction and soluble salt effects, affected soil pH measurements in water. Soil salinity affected pH measurements, especially in water, and resulted in alkaline errors during pH measurements. Errors were minimized when pH was measured in electrolytes rather than in water.

M. Kardousha and S. El-Tantawy
During a comprehensive survey carded out on helminth parasites of Arabian Gulf fishes mainly from the coasts of the Emirates and Qatar, two microsporeans and three myxosporeans Protozoa were reported and described for the first time. The microsporeans included Nosema sauridae and Glugea stephani. Nosema sauridae was very common among lizard fish Saurida undosquamis which were caught from the Emirati coasts (56%) and also Qatari coasts (28%). Glugea stephani infected Psettodes erumei at the Emirati coasts with a prevalence of 10%. The myxosporideans comprised Myxobolus arabicus n. sp. from the body cavity of Plectorhynchus schotaJ (Emirati coasts, 11 %), Kudoa sp. from the musculature of Lutjanus Julviflamma (Emirati coasts, 8%) and also the heart wall of Caranx malabricus (Qatari coasts, 11 %) and Henneguya sp. from the gills and mouth skin of Epinephelus tauvina (Emirati coasts, 7%). Fresh cysts and spores were described and photographed in situ.

H Abulfatih, E Abdel Bari, A Alsubaey, and Y Ibrahim
Zygophyllum qatarense Hadidi maintains enormous ecological plasticity. It is the most widespread, succulent shrubby species in Qatar, adapted to various habitats and a wide range of soil types: sandy, sandy-rocky, and sandy-loam; and inhabits dry areas which receive sporadic scanty winter rain, as well as permanently moist soil. It stands soil salinity ranges from non-saline to very strongly saline (1.0 - 11.85 dS/m), and pH ranging from 7.5 to 7.8. However, it evades mobile sands, highly saline salt flats (Sabkha), depressions of fine-textured soil (Rawda), agricultural land and stagnant waters.

A Abdel-Karim and G Dobosi
The Paleogene volcanic and subvolcanic alkaline basalt rocks of the west Shalatein comprise mainly Olivine-rich and olivine dolerite and/or basalt and normal basalt. The pyroxenes of the ultrabasic and basic rocks follow the augite-diopside-hedenbergite fractionation trend which is significant for the undersaturated rock suites with low silica activity. The studied basalts are characterized by the presence of very peculiar zoned clinopyroxenes of megacrysts and groundmass grains. This pyroxene exhibit clear decrease of Si, Mg, Ca and Cr from cores to rims. The Ti and Al content increases in pyroxenes with crystallization, but the coprecipitation of other Ti- and Al-bearing phases deplete the pyroxenes of outer rims as well as the ground mass in these elements in the later stage of fractionation. The incorporation of both Ti and Al into the pyroxene lattice is indicative of nonequilibrium crystallization (e.g. sector zoning). The clinopyroxenes exhibit a trend of fractionation analogous to that of the non-orogenic, intraplate-type basalts from undersaturated alkaline suites. Cr-bearing cores of clinopyroxene reveal that the present basalt were derived from deep-seated mantle source magma under early high pressure and low fO2 conditions.

M. Al-Dagal
This work was conducted on different parts of hexagonal-spotted grouper and Spanish mackerel fish from 10 major fishery shops in Riyadh City to assess the presence of vibrios and aeromonas using the API 20E and Biolog system. Also, pH and total psychrotrophs were assessed as two indexes of quality. Similar data were obtained from both identification systems except for Aeromonas media-like and Vibrio anguillarum which are not included in the API20E database. Aeromonas hydrophila, A. media-like, V. alginolyticus, V. anguillarum, V. damsela and V. fluvialis were recovered from fish samples with A. media-like and V. damsela most predominant. Unexpectedly, V. cholera and V. parahaemolyticus were not recovered. The number of skin samples of grouper having more than 7 log CFU/gm were much higher than that of mackerel skin samples. Similar psychrotrophic counts were noticed in gut samples of the two fish types, indicating similarity in growth habitat. Most of the grouper flesh samples had a pH in the range of > 6.40-7.02, whereas 95% of mackerel samples had a pH at 6.40 or below.

R Metwali
Fifty one water samples were collected from production wells used for human Consumption from Taiz city and its surroundings, Yemen Republic. The water quality was investigated with respect to bacteriological and physico-chemical parameters. The achieved results revealed that most water samples, especially from private wells, contain a high number of total coliforms (TC) which exceed the permissible limit recommended by the World Health Organisation, WHO (1996). Also, faecal coliforms (FC) were recorded in the majority of polluted samples. A quantitative estimation was done for each of temperature (18-26°C), pH (6.12-8.79), total hardness (58-2200 mg/L), electrical conductivity (218- 4600M. Mohs), total dissolved solids (117-3700 mg/L). nitrate (10-187 mg/L) and type of aquifer (rocky and alluvium). It is worthy to notice that from the total of fifty-one wells, there was pollution in (65%) of them. Recommendations were suggested for the treatment of the water of such polluted wells and rigid government control in a trial to prevent human and animal illness.

M. Bacha, A. Al-Darby and A. Al-Amoud
This investigation was carried out on mature Seleg date palm trees grown in the Riyadh region, Saudi Arabia, using three irrigation systems namely; basin, bubbler and trickle. Three water regimens 50, 100 and 150% of class (A) pan evaporation rate were used to study the effects of these treatments on leaf composition of some macro-nutrient elements (N, P, K, Ca, Mg and Na) and some micro-nutrient elements (Fe, Cu, Zn and Mn) during three successive years. Data indicated that, in the first year, significant differences were found only in Ca and Na leaf contents, whereas no significant differences were obtained in the other nutrient elements among the irrigation systems. The irrigation regimens did not affect the leaf contents of all determined nutrient elements. In the second year, significant differences were found regarding the leaf contents of K, Ca, Na and also the leaf contents of Cu, Zn and Mn among the irrigation systems. Concerning the irrigation regimens, the only significant difference was found in the Cu leaf content. In the third year, concentrations of N, P, K and Ca and also Cu and Mn in the leaves were significantly different among the irrigation systems. On the other hand, irrigation regimens did not affect the concentrations of both macro and micro nutrients element contents of the leaves

B. Ibrahim and A. Yacoub
Field and Laboratory evaluation of the impact of soil cracking on drainage and improvement of hydraulic conductivity of the heavy clay soil was conducted on the clay soils of Lattakia (region of Mediterranean). This research was to investigate the spatial and temporal variability of water movement in cracking field soil and study the impact of cracks as vertical drains in soil and to develop a correction factor for equation of drainage spacing.