Vol. 22 Issue 4
M.A.Fahmy, N.E.Abdel-Aziz and M.M.Dorgham
The Dekhaila Harbour, which was recently constructed in Alexandria, has become a highly atrophied area due to intensive maritime activities, and the effect of a mixture of nutrients and different pollutants reaching the harbour through land-based effluent. Environmental observations which were carried out monthly from April 1998 to March 1999 demonstrated extremely high nutrient level and productive phytoplankton, showing wide temporal and spatial variations. The variability of surface salinity was one of the characteristic features of the harbour, falling within the range of 17.3 - 39.2 ppt. Nutrients sustained pronouncedly high values, with annual average of 19.22 nano M for nitrate, 4.16 nano M for nitrite, 38.69 nano M for ammonia, 6.44 nano M for phosphate and 49.52 nano M for silicate. Chlorophyll a was exceptionally high (up to 1323.7 nano kg/l), having an annual average of 107.5 nano g/l. The harbour water was relatively turbid most of the year The concentrations of dissolved oxygen revealed the alternation of good (5-10 ml/l) and relatively bad (1.9- 4 ml/l) aeration conditions. Consequently, low zooplankton abundance was found in the Dekhaila Harbour (annual average 22,640 ind./m3). Statistical analysis showed that the environmental factors controlling both phytoplankton and zooplankton biomass had different seasonal patterns.
Gamalat A. Abd-Elaah and Samya Soliman A.
Seventy-three fungal species belonging to 43 genera were isolated from 40 samples of Saccharum officinarum collected from Naage-Hamadi canal in Qena Governorate) on 10g/l glucose (20 species, 15 genera) in Winter and (23/15) in Summer and on 40 g/l sucrose (42/28) in Winter and (27/18) in Summer on Czapek's agar media at 25°C. Aspergillus, Trichoderma, Mucor and Pythium were the most common genera on the two isolation media. The dominant of Aspergillus were A niger, A. flavus, Aulus, A. Terrens and A. wentii. Some species were dominant on 40 g/l sucrose such as Aspergillus niger, A. flavus, Emericella nidulans, Trichoderma viride, Torula herbarum and Mamana echinoeotryoides, while the dominant species on 10 g/l glucose were Mucor circinelloides, Aspergillus niger Torula herbarum and Trichoderma viride. Mycotoxins including aflatoxins B1, B2, G1 and G2, zearalenone and diacetoxyscirpenol were detected in the examined samples of Saccharum officinarum. The mycelial growth of Aspergillus flavus, A. niger, Fusarium moniliforme and Torula harbarum decreased with the increase in Dimethoate concentrations, although 25 ppm was less effective than the higher levels of the insecticide (75 - 200 ppm). Dimethoate stimulated the activity of Go-T in Aspergillus niger, Fusarium moniliforme and Torula harbarum, while the Go-T activity inhibited in A. flavus with the Dimethoate treatments.
Mohamed A. El Sayed and Ali S. Basaham
Total and potentially mobile fractions of Fe, Mn, Cu, Zn and Pb were analyzed in 28 sediment samples collected from the coastal area of Jeddah. Sampling sites were selected to represent heavily sewage polluted areas and areas far from the effect of direct sewage dumping. Total concentrations reflected the degree of contamination and were particularly high in the confined environments. Concentrations in the mud fraction (<63 nano m) were 3 to 6 times higher than that in the sand fraction. The repartition of the elements between the exchangeable, reducible, oxidizable and residual fractions depends on the element nature and prevailing environmental conditions. Iron was mainly found in the residual fraction either as constituent of the detrital material and/or trapped in the form of insoluble sulphides. Dominance of the exchangeable fraction characterized the speciation of Mn. Mobilization of Mn under reducing conditions and its reabsorption on the particle surface is a probable explanation. Cu and Zn appear to have comparable distribution between the different fractions, however, Cu seems preferentially associated with the oxidizable fractions while reducible Zn was slightly more important than the other forms. Pb was particularly distributed between the oxidizable and the exchangeable fraction. Residual Pb participation was very low and sometimes totally absent. The interest behind the use of speciation schemes is that it permits the distinction between the fraction of the element that could be released into the water when the physico-chemical conditions are modified and the part that is permanently or quasi permanently fixed in the sediments. Most of the Fe was found held in the residual unavailable form while most of Mn, Cu, Zn and Pb were distributed between the environmentally unstable exchangeable, oxidizable and reducible fractions. Therefore, these elements are supposed to have greater mobility and may, under particular conditions, greatly influence the environmental characteristics
A. M. Al-Omran, S. M. Al-Matrood and M. I. Choudhary
A laboratory experiment was conducted to test the effect of three water types (tap water, well water and sewage water) on the infiltration rate of three soils varying in texture (sand, loamy sand and sandy clay loam). A stationary rainfall simulator dispensing water at a rate of 45mm h-1, connected to the different sources of water, was used to measure the infiltration rates. A total of 5 runs were carried out using each water quality. The volume of runoff against the time was recorded at each 5 minute interval. The infiltration rate was calculated as the difference between the water applied and the excesses water measured as surface runoff. Infiltration rates at the first run were rapid in all the three soils and then progressively declined as the number of runs increased. The same trend was observed for each water quality tested. The reduction in infiltration rate with increasing number of runs for pre wetted surface than for the initial dry surface was attributed to the break down and settling of fine particles that took place earlier during prewetting. The infiltration curves for all the three soils when irrigated with different qualities of water was not distinguishable. The relationship between infiltration rate as a function of time for the treatments applied were tested using Kostiakov equation 1 = Bt-n. The infiltration data gave a coefficient of determination R2 > 0.90 for all the treatments. The infiltration parameters B, and n varied strongly with respect to soil texture Values of B decreased with changing soil textures, being highest for the sandy soil and lowest for the sandy clay loam soil, whereas n values showed the opposite trend. It was concluded that the effect of soil texture on infiltration rate was very pronounced while water qualities showed a little effect.
A.l. Al-Humaid
Two field experiments were conducted during two successive seasons to study the effect of the environmental conditions prevailing in Al-Qassim region on the behavior of reproduction and flowering characteristics of Eurovision, Rose Supreme, Prosperity and Nova Lux Gladiolus cultivars. The cultivars were planted on three different dates (October, November, and December), in order to examine their possible adaptation. The results showed that the second planting date (Nov.) substantially improved the length, thickness and dry weight of the flowering-stem for all cultivars. The highest production of corms and cormels was also recorded for the second planting date. Nevertheless, the earliest flowering time was recorded for the first planting date (Oct) for all cultivars. Prosperity was characterized by its better growth and flowering characteristics followed by Rose Supreme, and then Nova Lux. Chemical analysis showed that Nova Lux contained relatively higher N, P and K percentages, whereas the total carbohydrate of Prosperity was higher than that of the other cultivars. The study indicates that not only the genetic structure but also the environmental conditions are important factors determining the success of Gladioli cultivars to grow and flower under the existing field conditions in Al-Qassim.
Nasser El-Banna
A bacterial strain which has been identified as Corynebacterium xerosis NB-2 was isolated from a soil sample from Jerash Private University, Jerash, Jordan. This isolate was found to produce an antimicrobial substance active only against filamentous fungi and yeasts (Aspergillus niger SQ 40, Fusarium oxysporum SQ 11, Verticillium dahliae SQ 42, Saccharomyces cerevisiae SQ 46 and Candida albicans SQ 47). However, all tested gram-positive bacteria and gram-negative bacteria (Bacillus megaterium SQ 5, Bacillus cereus SQ 6, Staphylococcus aureus SQ 9, Streptococcus pyogens SQ 10, Eschericshia coli SQ 22, Klepsiella spp SQ 33 and Pseudomonas mallei SQ 34) were found to be resistant. In batch culture, the isolate NB-2 produced the antimicrobial substance late in the growth phase and accumulated the main portion in their cells. The data presented in the present investigation exhibited a novel antimicrobial activity of Corynebacterium xerosis against filamentous fungi and yeasts which was not previously described.
Matooq Mohammed and Frédéric Mothe
The goal of this work is to study the microdensitometric properties of Thuja of the Maghreb, in a forest area located at the West of Algeria, by the microdensitometric method. The results obtained, by analyzing 1029 annual rings. confirm the influence of ecological factors on the density of wood via their action on the anatomical composition of late wood in the annual ring. Moreover, the factorial analysis showed that high altitude, location with soil rich in limestone and under semi-arid climate had the best intrinsic quality of wood. With these ecological conditions, the average density of the annual rings increases and early wood decreases. The classes of the microdensitometric profiles of this location are characterized by a zone of well developed late wood which contains a significant number of tracheas responsible for the higher density compared to other locations. In this case, selection of provenances should be based on selecting the individual trees having faster growth and higher wood density than the average of the stand in its natural habitat.