IRANIAN JOURNAL OF BIOLOGY
Year:2006 | Volume:18 | Issue:4|Papers Count:12

Hypocotyledon explants of Eucalyptus camaldulensis Dehnh., E. froticetorum E. Muell and E. viminalis Labill were cultured on LS medium with three hormonal treatments at 24 0C and were used to produce callus and root. The non-structural carbohydrates were extracted. These sugars were quantitatively and qualitatively analyzed based on spectrophotometry, thin layer chromatography and gas liquid chromatography. A hormonal treatment with a combination of 0.88 µM BA, 2.6 µM NAA, 2.8 µM IBA, and 0.9 µM 2, 4-D which produced the dark woody callus, induced the highest growth rate. Whereas in 20 µM 2,4-D the light-fresh callus were produced. At IBA 10 µM the explants produced too much root. The major sugars in the nonhydorized of soluble sugars extraction were sucrose and glucose and a little amount of romnose, fructose, ribose and glucoronic acid. Also in this fraction there was no any galactose. In the its hydrolyzed fraction there was no galactose, whereas glucose and fructose which was produced from sucrose were the major sugars in this fraction. In ydrolyzed nonstructural - polysaccharide fractions, galactose, glucose, mannose – arabinose, xylose and one uronic acid were appeared in all treatments and species. Contrary to sugars in intact plants of Eucalyptus tree, there was no any galactose in the hydrolyzed soluble sugars fraction in the tissue culture extractions, but it was appeared in the hydrolyzed nonstructural - polysaccharides fraction of explant extractions. The absence of galactose in the hydrolyzed or unhydrolized soluble extraction sugars could serve as a marker or an indicator for optimum conditions of growth of explants.

Brassinosteroids are a new class of plant hormones with unique biological effects on plant growth and development. Brassinosteroids also can increase plant tolerance for water stress. The effects of 24-epibrasinolide on lipid peroxidation and content of proline, soluble sugars, chlorophyll and carotenoids were investigated in Colza (Brassica napus L. cv. Fusia) plant under water stress. The seeds were sown in plastic pots containing sand, clay and peat (in proportion of 1:1:1). Solution of 24-epi-brassinolid at 10-7 M concentration containing 0.01% Tween-20 (polyoxyethylene sorbitan) was sprayed on leaves at intervals of 1, 2 and 3 weeks after sowing. Control plants were sprayed with 0.01% Tween-20. One month after sowing, plants were harvested. Lipid peroxidation level significantly increased under water stress but decreased when 24-epibrassinolid were applied, revealing that less oxidative damage occurred in this group. Proline and carotenoids content was decreased when 24-epibrassinolide were applied even under water stress and was higher than control plants. Chlorophyll content was significantly decreased under water stress but increased by 24-epibrassinolide application. Additionally, the soluble sugar content of 24-epibrassinolide-treated plant under water stress was lower than well-watered plant under the same treatment. Results suggested that, 24-epibrassinolide can considerably alleviate oxidative damage induced by water stress conditions.

The objective of this study was to assess species diversity of woody plants in district No.1 forests of Kelardasht, Mazandaran. After numerous forest surveyings, areas with occurring changes in species composition have been designed, and were classified into five elevational classes. In addition, these forests were classified to six regions regarding to interventions. Then, a sampling plot was selectively established in each elevational class and selected regions with the highest tree species richness and diameter of breast height (dbh) of trees and individuals number of shrubs were recorded and the woody species type identified. Tree regenerations were counted in each microplot at the center of plot. The diversity indices were used to calculate woody species diversity. Also, species and familial importance values were obtained in studied areas. Results indicated that 21 trees species and 9 shrubs were found in these forests, and number of woody species has been increased in during time. There was the highest value of tree diversity in 500-1000 m a.s.l and the lowest value was in 1500-2500 m a.s.l elevation class, however, there was the highest value of shrub diversity in 2000-2500 m a.s.l and the lowest value was in 1000-2000 m a.s.l elevation, also, the highest value of tree regeneration was found in 500-1000 m a.s.l and the lowest value found in 1500-2500 m a.s.l elevation class. In addition, there was the highest value of tree diversity in improvement and once done intervention regions and the lowest value was in oak-hornbeam type and village margin, and the highest value of shrub diversity was found in oak-hornbeam and the lowest value found in reference and depleted regions, and the highest value of tree regeneration was found in improvement and once done intervention regions and the lowest value found in reference region and village margin. Eventually, the highest value of tree species importance was belonged to Fagus orientalis, Carpinus betulus, Acer velutinum,and the lowest value belonged to Ulmus glabra, Acer campestre, Quercus macranthera, Sorbus torminalis, and the highest value of shrub importance belonged to Ilex spinigera and the lowest value belonged to Berberis vulgaris and Crataegus microphylla. Also, the highest value of family importance was belonged to Fagaceae, Betulaceae, Aceraceae and the lowest value belonged to Ulmaceae, Tiliaceae, Oleaceae, Hamamelidaceae and Ebenaceae.

Fifteen species from 10 genera belonging to the tribe Rhinantheae (Scrophulariaceae) and Orobanche anatolica and Cistanche eremodoxa (both from Orobanchaceae) as well as Lindenbergia indica (Scrophulariaceae-Gratioleae) as an outgroup for reconstructing phylogenetic relationships were studied. A total of 22 morphological characters were chosen and scored based on the examination of herbarium and living specimens as well as available published materials. Phylogenetic analyses showed that the tribe Rhinantheae is not monophyletic, due to inclusion of the orobanchacean taxa of Orobanche anatolica and Cistanche eremodoxa. Lathraea squamaria is positioned as the sister group of these two taxa with high bootstrap support. Our results showed that genera Rhynchocorys, Pedicularis and Euphrasia, each sampled herein with two species, are well supported monophyletic taxa. While Odontites and Parentucellia are apparently not monophyletic taxa. The phylogenetic analysis of characters with successive reweighting by rescaled consistency index, revealed that Rhynchocorys is allied weakly with Pedicularis. Relationships among other genera of Rhinantheae were no clearly resolved and statistically well supported.

During 2003-2004, a total of 392 specimens of Syrphidae were collected from Mashhad and its suburb. The specimens were collected from gardens, parks, field crops as well as already collected material deposited in the insect collection of the laboratory of entomology of the facultry of Agriculture of Mashhad University. The characters of specimens used for classifications were wing veins, frons (face), legs, thorax, antennae and abdomen. Two statistical softwares, Biomeco and SPSS were used for evaluation of similarities, and drawing Dendrogrom. Cluster analysis confirmed the classical different groups. The results showed the greatest similarities between Syrpus and Eupeodes generathere is and they were at the same group with Episyrphus, Scaeva and Sphaerophoria. Eristalis, Eristalinus, Myothropa and Syritta were as second group. Genus Paragus despite of locating in the subfamily of Syrphinae, was more similar to Melisinae than the groups. This genera actually is an intermediate taxon between subfamilies in this study. Ordination analysis (Analysis of Correspondent Factors) based on I , II axis showed dependencies of specimens to two distinct subfamilies . Final results of statistical analysis revealed the priority of the use of ordination analysis upon cluster analysis.

Jimpson weed has dormant seeds at maturity. Seed dormancy is a problem in controlling of this weed. The present work tries to find out the effective methods of breaking seed dormancy. This study examines the effects of different treatments under constant temperature in darkness and alternate temperatures in light .The treatments which were done under two above mentioned conditions include: potassium nitrate in different concentrations, embryo culture, cutting by scalpel, holling by needle, grinding between two marble stones, scarification in sulfuric acid 98% and 70% in various time intervals and boiling water in various time intervals. The treatments which were done only in constant temperature were as follows: gibberlic acid in different concentrations, stratification, leaching, ethylene and methonal with different concentrations, scraching by sandpaper. In alternate temperature, only embryo culture and scalpel treatments were effective where the first case resulted in 100 % germination. In constant temperature of 25, sodium azide (10 M) and GA (50 ppm) were also effective. Embryo culture resulted only in 53 % germination of seeds. Overall, alternate temperature treatments were more effective in breaking dormancy than the constant temperature treatments.

Ferula ovina is one of grazing plants that belongs to umbeliferae. This plant is important for fooder and prevention of running sands. According to ISTA reports, all seeds of this species have shown dormancy that causes reduction in seed viability. Prior to this study, relatively few information has existed on dormancy breaking of Ferula ovina. Because of the beneficial effects of cold and soaking for seed dormancy breaking of other umbeliferae plants, in this research effect of pre-chilling was investigated on seed germination of Ferula ovina. In this experiment were evaluated effects of factors: soaking (12, 24, 48 h), cold temperature (1-3, 5-7, 8-10 °C) and cold period (0, 3, 5, 7, 9, 11 weeks) by lying seeds on filter paper in petri dishes. Data analysis showed that soaking did not have significant effect and 7 weeks pre-chilling in 1-3 °C was the best treatment for seed dormancy breaking of Ferula. The higher temperature and smaller cold period had lower influence on stimulation of Ferula seed germination.

Pseudomonas aeruginosa is gram negative and opportunistic bacteria, causing a wide variety of infections.This bacteria produces biofilm. A biofilm is a population of cells growing on a surface and enclosed in an exopolysaccharide matrix. Biofilm infections are difficult to eradicate with antimicrobial treatment. In this study 42 clinical isolates of P. aeruginosa were collected from hospital. P. aeruginosa strain 214 producing higher biofilm was selected for further study. We investigated biofilm production with scanning electeron microscope and the bactericidal activity of β-lactam and aminoglycoside against biofilm and planktonic cells. The result showed high difference in antibiotic susceptibility between planktonic and biofilm populations.Biofilm cells were complety eradication by treatment with 128 MIC gentamicin and 64MIC amikacin,whereas the biofilm still remained during treatment at a concetration 2560μg/ml of β-lactam (Imipenem and ceftazidim).

The Hevigh river is lied in south-west Caspian Sea and it is too important for migration of some fish species, feeding and spawning of estuary fishes and resident fish population. Main purposes of this study were: determination of fish diversity, spatial and temporal distribution and present role of the river in recruitment. Studied fishes have been sampled in 7 stations from Fall 2001 until Summer 2002. Electroschoker, cast net and beach seine were used to catch them. Results showed that 19 species and subspecies fish belonging to 8 families exist in the river so that Cyprinidae, Salmonidae, Mugilidae 11, 2 and 2 species respectively and others had one represent. Cyprinidae comprised 92.06 % of total populations and it was the prominent in all stations and seasons. Among the identified species, Alburnoides bipunctatus, Neogobius gorlap, Capoeta capoeta gracilis and Barbus lacerta cyri being river natives, had the most dispersion respectively and A. bipunctatus, C. capoeta gracilis and Chalcalburnus chalcoides respectively with 42.18%, 16.63% and 15.95% comprised dominant fishes. There were 11 species of freshwater resident species, 5 species of migratory or anadromous fishes and 3 species of marine or estuary fishes in Hevigh River and 4 species were identified as alein, too.