Journal of Sciences, Islamic Republic of Iran
Volume:11 Issue: 4, Autumn 2000

The structure and histogenesis of the stigma of Datura stramonium was investigated by light and scanning electron microscopy to determine the developmental origin of the transmitting tissue and “wet stigma”. Four developmental stages were defined on the basis of bud length. Stage one, the histogenesis stage, was comprised of buds 2-15 mm in length. Stage two, signified by the growth and development of the stigma was comprised of buds 15-40 mm long. Stage three, with buds of 40-60 mm in length, represented a receptive and mature stigma. Stage four started with self pollination (occurs prior to anthesis) and ended with stigma senescence. A developing stigma showed a bilobed, papillated surface, covered with sticky secretion. The stigma consisted of two distinct zones; 1) Superficial zone; formed by papillae and 5-8 layers of secretory cells immediately beneath them. This zone was subjected to a gradual lysis in the ontogeny of the stigma. 2) Internal zone; formed by the transmitting tissue of the style. This zone remained intact throughout the development. Transmitting tissue and stigma both originated from the epidermis of the carpels. Similarities in structural organization of the stigma of Datura to those reported in Solanum tuberosum were considerable.

The identification of molecular markers linked to leaf curl virus (CLCuV) disease resistance in cotton has the potential to improve both the efficiency and the efficacy of selection in cotton breeding programs. Genetic analysis suggested that CLCuV resistance is controlled by a single dominant gene. In this study, an interspecific F2 population derived from a cross of Gossypium barbadense and Gossypium hirsutum was phenotypically classified into CLCuV susceptible and resistant plants. A subset of these F2 plants was evaluated by selective genotyping, with restriction fragment length polymorphism (RFLP) to identify DNA markers linked to the CLCuV resistance gene. Sixty seven F2 derived F3 families were evaluated for segregation at 137 RFLP loci. Three DNA marker loci, linked to each other, also showed significant association with CLCuV resistance. Sequencing of linked markers will permit locus-specific DNA primers for use in PCR-based identification of CLCuV-resistant plants in breeding populations.

Somaclonal variation is one of the possible sources of variation in plant breeding. To evaluate the usefulness of somaclonal variation for creating variation in Iranian cultivars of wheat, proteins, enzymes and chromosome number of regenerated and seed-produced plants of wheat (Alamout, Hyrmand and Maroon) were studied. Plantlets obtained from the immature embryos and seed culture were collected and used for studying proteins, peroxidases, polyphenoloxidases and superoxidedismutases by using Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and PAGE. The root tips of plantlets were used for chromosome counting. In the SDS-PAGES system, regenerated plants had 5 additional protein bands. The number of protein bands in PAGE system were less than the SDS-PAGE system but the later system represented a greater difference between seed-produced plants and regenerated plants. Peroxidase had 6 isozymes, 3 of which were similar among all plants. Nine isozymes of superoxidedismutase were found, 5 of which were common in all. Polyphenoloxidase showed no changes in regenerated plants. Cytological study of the three regenerated cultivars indicated the Maroon cultivar to possess a greater chromosome number (2n=54 or 60) than the other two (2n=6x=42). Somaclonal variation was observed in cultivars, but the nature of variation was different.

In order to explore the nature of glucose-6-phosphate dehydrogenase (G6PD) deficiency in one of the coastal provinces of the Caspian Sea (Mazandaran) in Iran, we have analysed the G6PD gene in 74 unrelated G6PD-deficient males (2-6 year children) with a history of Favism, by using PCR and subsequent digestion by appropriate restriction enzymes, looking for the presence of certain known mutations. The results showed that 49 of 74 cases (66.21%) had the G6PD Mediterranean genotype and there were not other known mutations (such as G6PD Aures, G6PD A, and G6PD A–) in rest of the samples. This is the first report on the molecular analysis of G6PD mutations in north of Iran and we have revealed the frequency and distribution of the most common G6PD variant (G6PD-Mediterranean) in this area.

An on-line automated method for photodegradation studies of isoproturon, diuron, atrazine, fenitrothion, and metoxuron by means of liquid chromato-graphy/mass spectrometry (LC/MS) with particle beam (PB) interface is described. Surface water samples were first spiked with 50 μg/l of each pesticide and then exposed to the radiation of the medium-pressure mercury lamp. Next, in regular intervals of 60 min, aliquots of 50-ml sample were enriched on a solid-phase extraction (SPE) cartridge and eluted on-line by a gradient of LC eluent onto analytical column for separation, followed by MS detection. Photodegradation experiment was performed twice with each pesticide, with MS operated in electron ionization (EI) and positive chemical ionization (PCI) modes and ammonia as reagent gas. Additional spectral and quantitative information was obtained from ultraviolet diode-array detector (UV DAD) placed in-line between the outlet of the analytical column and MS detector. A great number of photodegradation products (DPs) of parent pesticides were detected and in numerous instances, tentatively identified. The appearance of several degradation products is reported for the first time.

Nickel (II) and copper (II) complexes of highly unsymmetrical tetradentate Schiff base have been synthesized by the template reaction of half-units N-(1-hydroxy-2-acetonaphtone)-1-amino-2-phenyleneimine (HL) and N-(2-hydroxy-acetophenone)-1-amino-2-phenyleneimine (HL1) with the glyoxalphenylhydra-zone. The complexes have been characterized by elemental analyses, conduc-tance, IR, 1H NMR and UV spectroscopy.

Acritarchs from the Lashkarak, Ghelli and Niur formations of the western part of Kuh-e-Saluk were examined to more precisely determine the stratigraphical age. This study was also undertaken to assess the palaeogeographic relationships of the northeastern Alborz Range to the Southern and Northern Hemispheres during the Palaeozoic interval represented by these formations. A total of 78 acritarch taxa were encountered. Four new species together with two species in open nomenclature are described: Multiplicisphaeri-dium iranicum, Multiplicisphaeridium sp., Veryhachium membranispinum, Stelliferidium persicum, Leiofusa sp., and Estiastra iranicum. The encountered acritarch species have been arranged in six ascending local stratigraphic Zones. Zones I-II occur in the Lashkarak Formation, suggesting an Early Ordovician age (Tremadoc-Arenig). Zones III-V are present in the Ghelli Formation, indicating a Mid and Late Ordovician age. Zone VI appears in the lower part of Niur Formation and suggests the Early Silurian age (Llandovery). The Early Ordovician acritarchs of the Lashkarak Formation were com-pared with those from other parts of world. This comparison indicates a broad similarity with those of the same age in northern Africa, southern Europe and southwestern China. This similarity suggests that the northeastern Alborz Ranges were part of the Peri-Gondwanan supercontinent during the Early Ordovician. The Mid to Late Ordovician and Early Silurian acritarch taxa were also compared with those of the same age from elsewhere. This comparison indicates a broad similarity with those of northern Africa, southern Europe, the Middle East and the United States. This similarity suggests that the Peri-Gondwanan palaeocontinent began to move toward the Northern Hemisphere palaeocontinent during the Mid and Late Ordovician and by the Silurian formed the supercontinent of Pangea. Diverse acritarch taxa in the Early Ordovician (Lashkarak Fm.), Mid and Late Ordovician (Ghelli Fm.) and Early Silurian strata (Niur Fm.) reveal a marine environment for each formation.

In this paper, a nonlinear inverse problem of parabolic type, is considered. By reducing this inverse problem to a system of Volterra integral equations the existence, uniqueness, and stability of the solution will be shown.

Seifert Fibre Groups (SF-Gps) have been introduced and their first derived groups have been worked out in an earlier paper by the author [2,3]. Now we aim to prove that they are residually soluble and residually finite. *

In this paper we study the structure and the commutativity of a ring R, in which for each x,y ∈ R, there exist two integers depending on x,y such that [x,y]1,>≥nkok equals x n or y n.In this paper we study the structure and the commutativity of a ring R, in which for each x,y ∈ R, there exist two integers depending on x,y such that [x,y]1,>≥nkok equals x n or y n.

Applying the variational method, the spinless reduced Bethe-Salpeter (RBS) equation is solved for the mesonic systems, and the mass spectra are obtained. The method is applied to the Hamiltonian with the Gaussian and hydrogen-type trial wave functions, and different potential models are examined. The results for the different potentials are in challenge in light mesons, while they are consistent in heavy mass region. In spite of this, the consistency for all mesons occurs in Power-law (Rosner, …), Logarithmic (Quigg and Rosner), )4.0(GevKMS=Λ and )5.0(GevGMS=Λ potentials and the theoretical results are in general in agreement with the experimental data. The inconsistency in light mesons has the origin in the nonrelativistic treatment of the potential derivations and the reduced form of the Bethe-Salpeter equation. The consistent and non-consistent interquark potentials show a distinct behaviour at both short and long distances.