Vol. 14 Issue 1
Alwadi, H.M. and Abdulfatih, H.A.
Nine morphological characteristics namely: plant height, leaf length, leaf width, leaf dry weight, fruit diameter, seed number per fruit, seed weight per fruit, corolla length and corona length were used to test the influence of environmental conditions on the performance of Calotropis procera plants. The comparison was made on the plant materials collected from low altitude (0-300 m) and from high altitude (1700-2000 m). The comparison showed no significant differences between these two groups of plants, indicating that Calotropis procera can endure a wide range of environmental conditions, without showing any obvious morphological differences.
W. Zahran, A.B. Shahin, H. Schneider, M. Gabri and M. Soliman
Genetic variation among natural populations of Scincus scincus was demonstrated according to the electrophoretic analysis of 27 enzymatic and non-enzymatic proteins encoded by 40 structural gene loci. With respect to polymorphism and heterozygosity, the populations were moderately variable compared with other genera of skinks. The populations were polymorphic for only 7 loci and the overall mean proportions of polymorphic loci (P) and heterozygosity (H) were 7% and 3%. The mean values of the coefficients of genetic distance (D) and similarity (S) were 0.032 and 0.968. Significant geographic heterogeneity in allelic and genotypic frequencies was observed at several polymorphic loci over all populations. Factors affecting this heterogeneity are genetic drift, diversifying selection and mating behaviors.
Fayez A.M. Shoukr
The sea anemone Anemonia sulcata (Pennant), inhabiting marine-waters of Egypt can sting human skin by their numerous adherent tentacles. They cause erythema, urticaria, itching and scattered patches of dermatitis over the abdomen and hands during swimming or collection of specimens. Tentacles of this species are firstly studied by transmission electron microscopy in Egypt. The present paper describes the ultrastructure of two types of cnidae and mucous cells. The cnidae include the adhesive spirocysts and the stinging nematocysts namely micro basic b-mastigophores. The structure and function of these specialized cells are discussed.
Ahmad K. Hegazy
In recent years, there has been growing interest in studying local plants as a substitute for introduced species to be used in restoration of degraded lands in the Gulf region. The terrestrial ecosystems suffer strong degradation caused either by rapid social agricultural and industrial developments or natural resource explorations. There is a critical need to start the restoration programs by using local wild plants which have adapted to the prevailing environmental conditions. The studied species, Zygophyllum qatarense (Hadidi) has wide ecological amplitude and is widespread in almost all terrestrial habitat types of Qatar.
The use of theoretical models in the form of equations, illustrated graphs or matrices are useful and non-destructive tools to study, assess and manage the plant populations for degraded ecosystems restoration. These models provide:
i) a satisfactory description and monitoring of natural and experimental plant populations;
ii) an enlightenment on aspects of population dynamics; and
iii) a system which can be incorporated into complex models.
The application of exponential and sigmoid growth equations, transition matrix, life table and fecundity schedule indicated the possibility of using Zygophyllum qatarense as a local species for restoration programs of degraded terrestrial ecosystems in the Gulf region. The results showed that this species has high reproductive rates in different adult age classes, long life span lasts for more than one generation, increased survivorship and future expectations of life. This is beside its wide ecological amplitude, drought and salinity tolerance.
A.A. Al-Aql, Z.H. Dughaish, A. Al-Jufali, K.M. Al-Sheibani, E.M.A. Hameida and A. Flimban
The crystal structure of the compound Cs3Mg2Cl7 is studied and found to consist of layers of distinct double perovskite type formed parallel to the plane (001) and the following layers are displaced by a/√2 in the direction [110].
The compound is tetragonal of the space group 14/mmm and the lattice parameters are:
a=0.505(1)nm
c=2.630(5)nm
The experimental density, Dm= 3.40 g/cm and the theoretical density Dx= 3.45 g/cm. The number of molecules per unit cell Z=2 and the reliability factor Rw= 5.8%.
The Mg++, Cs+ (1) amd Cs+ (2) lie in different layers perpendicular to c-axis with Z=0 for Cs+(2), Z=0.1899 (6) for Cs+ (1) and Z=0.4021 (8) for Mg++. The Mg++ is surrounded approximately octahedrally by six chlorine ions, while Cs+(1) by nine chlorine ions and Cs+ (2) by twelve chlorine ions.