Vol. 23 Issue 3
Mohamed Ahmed Hassnen El-Beheiry
The potential of mortality and seedling survival of three salt marshes species (Atriplex farinosa, Aeluropus brevifolius, and Juncus rigidus) as affected by timing of precipitation were measured. Three separate (14)-day experiments were conducted using (1), (2), (3), (4), and (5) days wet followed with (5) days dry. The number of emerging seedlings growing from (100) seeds placed in sand media in small plastic pots were counted daily total of (50) to (70%) of Juncus seeds emerged in the initial wet period, but over (50%) of the seedlings died in the following (5) days dry period, resulting in less than a (35%) survival rate. The Atriplex was slower to germinate and seedling survival rate resulted (40%) - (60%), while it was slower than (20%) in Aeluropus brevifolius. The (1) and (2) days wet sequences the maximum until the final rewet period. The information offers the possibility of incorporating the probabilistic aspects of timing of precipitation and soil water relations into a description of the seedling environment.
Mohammed Juma Al-Rumaidh, A.B. Yule and G. Walker
Studies on the biometric relationships of the blue swimming crab Portunus pelagicus from Bahraini waters, have been undertaken in the present investigation in order to understand the growth pattern of this species in terms of carapace length-width (CL-CW) and carapace width-weight (CW-Wt.) relationships, in this part of the world. From the (759) male and (1,233) female crabs that were collected from the offshore study region from October to November 1999, data have indicated that slopes of (CL-CW) relationships are found to be similar in both genders. The average slopes for crabs in areas (A) and (B) had exhibited an isometric growth with (CW) being (1.7) times (CL). The slope recorded for area (C) proved to be significantly less than (1), indicating an allometric growth with (CW) getting relatively longer in bigger crabs. As for the (CW-Wt.) relationship, the total of (2,070) male and (3.005) female crabs, which were collected over a period of (14) months (i.e. March 1999. April 2000), showed that males are heavier than females at (2) cms (CW), becoming more so above (6) cms (CW). Male exponents varied significantly between study areas and from one month to another, unlike those for females which are found to be similar across the study areas and months, except for area (B), June 1999, where the exponent was at lowest at (2.71). The higher exponents of males throughout most of the study period indicate their better condition over females. Both genders were found to be heavier during the Summer months, i.e. May-September. However, male and female slopes for (CW-CL) and many exponents for (CW- Wt) exhibited small differences which prove statistically significant. This is attributed to the large number of observations that make small differences significant, yet the biological significance may be less obvious.
Hassan Ibn Yahia Al-Ayedh
:Trapping efficiency of seven different colored sticky traps (Green, Fluorescent yellow, Orange, Pink, Red, White and Yellow) was evaluated in some Solanaceae plants, tomatoes (Lycopersicon esculentum, eggplant (Solanum melongena) and sweet pepper (Capsicum spp.) crops, for whitefly (Bemisia argentifolii), leafminers (Liriomyza trifolii, thrips (Thrips tabaci) in Riyadh, Saudi Arabia. The traps were placed at four different heights (0.5, 1.0, 1.5 and 2.0 m above the ground). The experiment was laid out in a Completely Randomized Block Design (CRBD) with four replications during Autumn 2001, Spring and Autumn 2002. Significantly high insect populations were trapped on fluorescent yellow, yellow and green colored sticky traps. No significant differences were witnessed between mean number of various insects caught on sticky traps placed at different heights but more insects were trapped at 0.5-1.5m.
Sahera Fathallah Mohamed
The concentration of Iron (Fe), Zinc (Zn). Cobalt (Co), Lead (Pb), Cadmium (Cd) and Copper (Cu) were determined in specimens of four marine brown algae. Turbinaria decurrense, Sargassum dentifolium, Sargassum latifolium and Padina pavonia. The four algal species were collected from two sites: The Red Sea coasts at Hurghada in Egypt, an area slightly influenced by anthropogenic activities, and Gizan in the Kingdom of Saudi Arabia, an area which requires intensive study, especially in ecological terms. In order to gain a complete picture of the quality of the aquatic environment in both studied sites, heavy metals concentrations were determined in the selected algal species. The picture of bioavailable metal loads in the different sites of the selected areas provided by the four algal species was rather univocal. An overall trend of increased all-determined metal concentrations in Gizan was clear. Lead (Pb) was considered to be the influenced pollutant in Gizan, where its concentration in (T) decurrense, (S), dentifolium, (S) latifolium and (P) pavonia was (54.5), (45.17), (55.28) and (56.8) fold than that in the same species in Hurghada. On the other hand, the metal concentrations recorded at Hurghada, a site expected to be uncontaminated, generally fall in the lowest values available in the literature and may be considered as a useful reference for intraspecific comparison within the Red Sea area.
Uli Joger, Zuhair S. Amro & Ratib M. Al-Oran
The objective of this paper is to study seven species of Venomous snakes belonging to three families, Atractaspididae, Elapidae and Viperidae. They are known to occur in Jordan. Up-to-date data on their distribution are provided. For each species, the study highlights diagnostic features, characteristics, habitat preference and distribution, moreover taxonomy of each family are given. Accordingly, it could be considered as complication of researches on medical awareness of snake bits accidents.
Abdul Aziz B. 0. Al-Harby, Ali M. Al-Darby, and Reda A. bdel- Aziz
Dry desert climate zone require search for the best ways to conserve water. This study was conducted to minimize evaporation using mulching with different rates in two soils loamy sand (S1), and sandy clay loam (S2). Sawdust mulch rates used were (zero, 2, and 4 cm) depth. Tape water was added to soil columns on the basis of required water to saturate soil. After the leach ate (free water drainage) ceased, evaporation experiment was started until stable weight of the control (no mulch) was achieved (83days). The cumulative evaporation (E) was determined by daily weighing soil columns. The soil water (e), and salts (ECE) distribution on soil profiles were determined each (10cm) increments before and after evaporation experiments. Results indicated that the two soils had different hydro physical properties, such that sandy clay loam soil(S2) was higher in water retention. The study revealed that sawdust mulching reduced evaporation significantly on both soils. Mulching with (2 cm) depth was enough for evaporation reduction to a rate lower than that of water flow toward soil surface. Results indicated that there is a linear relationship between (E) and the square root of time (t) (E = bt'/2) for all mulching rates of both soils. It has been found that the soil water profile distribution was significantly higher with mulched soil columns compared with the control for both soils. However, there were no significant differences between sawdust mulching with (2 or 4 cm) depth. These results were reflected on the soil water storage, where mulched soil columns were higher than that of the control. In general, results of evaporation. soil water distribution and water storage proved that sawdust mulching with (2cm) depth was enough to limit evaporation and conserve water for both soils. This effect was more pronounced in loamy sand soil. Generally, the results of the (EC) and salt distribution (EC) after the leach ate ceased showed that salts were decreased on the upper soil layers, and increased on the lower soil layers for both soils and also in leach ate. Results also showed that salts were redistributed after evaporation period, where salts, moved toward the upper soil layers especially in the control soil columns. Results revealed that salt distribution reached equilibrium state in mulched soil columns of loamy sand soil, whereas sandy clay soil did not reach such equilibrium in loam soil. This study emphasizes the importance of mulching to limit evaporation, increase soil water storage and thus availability of water for plant growth. (2cm) depth (28.41 Mg/ha) sawdust mulch was found to be enough to achieve that target.