IRANIAN JOURNAL OF BIOLOGY
Year:2006 | Volume:19 | Issue:1|Papers Count:12

In this investigation, effects of root temperature, corm size and gibberellin on underground organs of saffron were studied, in a growth chamber, by using a split-plot factorial design. Three levels of temperatures (10, 15 and 20 degree Centigrade) were applied as main plots. Subplots were a factorial combination of corm size (with two levels large and small), and corm treatment with gibberellin (with two levels 0 or 500 ppm of gibberellin). The results showed that large corms, which were treated with gibberellin and grown in 15°C or 20°C, had more root number, fresh and dry weight than the other corms. Large corms, which were grown in 10°C, had maximum active bud number and daughter corm. Minimum active bud number was detected on corms, which were treated with gibberellin. Higher dry weight of daughter corm was produced by large corms, which were grown in 10°C, and treated with gibberellin. Therefore, 15°C or 20°C during the beginning stages of growth and 10°C at the end stage of growth can improve size and number of daughter corm of saffron.

In this investigation, Effects of different concentrations of essential oils prepared from leaves of Zhumeria majdae on seed germination and seedling growth of Lycopersicon esculentum and Triticum aestivum were studied. Besides, effects of essential oils on the leaf chlorophyl content and peroxidase activity in roots of above mentioned plants were investigated. In post-emergence treatment, Effects of different concentrations of essential oils on fresh and dry weight of above mentioned plants were studied. Essential oils prepared from leaves of Zhumeria majdae inhibited seed germination and seedling growth. In the Wheat, in the presence of 50 and 100 percent of stock solution, Seed germination rate was reduced to zero. Using different concentrations of essential oil as post-emergence treatment reduced both amounts of fresh and dry weight in plants tested. The most inhibitory action was obsereved on dry weight of Lycopersicon esculentum. The amount of chlorophyl was reduced in all post-emergence treated plants. The activity of peroxidase enzyme extracted from the above mentioned plant roots in Lycopersicon esculentum was increased and in Triticum aestivum was reduced.

Identification of resistance sources against Ascochyta blight pathotypes is necessary to use in chickpea breeding programs. Plant breeders accept screening of crop germplasm as useful gene pool against biotic and abiotic stress. Ascochyta rabiei is one of the most important constraints to chickpea production in the most area of world especially in Iran. In this study, reactions of 420 chickpea accessions and 97 lines and cultivars from Ferdowsi University of Mashhad were evaluated to find resistant sources against six pathotypes of Ascochyta rabiei by artificial infection using mix spore suspension in field and greenhouse conditions, during two years (2003 and 2004). In first step, the seeds were sown in field and inoculated using mix spore suspension of six pathotypes in five to seven leaf stages. The humidity and the temperature were regulated using mist irrigation system during a week after inoculation to distribute disease in field. The disease severity was scored on a scale of 1 to 9, when susceptible lines death. In this step 63 accessions with the scales 2 to 4 showed high resistant levels against the pathotypes. These accessions were inoculated again by the spore suspension in greenhose in different developmental stages i.e., planting, flowering and podding. The diseases symptoms were scaled two weeks after each step of inoculation. Nine accession showed high resistant level in greenhouse. The average of disease severity was higher in greenhouse compared to that of the field. Differentiation of resistant and susceptible accessions was correctly done in podding stage. According to filed and greenhouse evaluations two desi accessions (MCC 54 and MCC 523) and six Kabuli accessions (MCC 496, MCC 133, MCC 299, MCC528, MCC 3.11 and MCC 142 were resistant against six pathotypes of ascochyta blight. These accessions can be used as resistant sources in chickpea breeding programs.

Ultraviolet radiation is energetically capable of disrupting proteins. Ultraviolet radiation divides to three bands UV-A (320-390 nm), UV-B (280-320 nm) and UV-C (254-280 nm). Several studies have indicated that enhanced UV-B radiation can deleteriously affect physiological processes and overall growth in a number of plant species. In this research, the effects of different bands of UV-radiation were studied on the germination growth parameters, Sugar and Protein contents of plant Pepper (Capsicum annuum L.). The plants were grown in vermiculite medium using pots. Before applying the UV treatments, plants were subjected to a based nutrient solution (Hoagland solution) for 5 weeks. After 5 weeks, plants were for 2 weeks under treatment UV. Data were analyzed using SPSS software, and averages were compared by Duncan test. In each experiment were used 4 replicates. The results indicated that, UV light sped the germination of these seeds but the subsequent growth of the seedlings was markedly retarded. The results showed that under our experimental conditions UV-B and UV-C radiation decreased shoot and root dry weight. Furthermore, this treatment induced significant decreased of Leaf area. Content of soluble Sugar decreased significantly in leaves and roots of treated plants in comparison with control. The different bands ultraviolet radiation decreased Protein content. By considering to obtained results in this study we concluded that UV-A often harmful in plant, but UV-B and UV-C have serious effects on plant.

Among crop plants, canola contain allelochemical compounds as glucosinolate that under special condition is released to enviroment and effects to seed germination and plant growth. Enzyme myrosinase catalyses hydrolysis of glucosinolate and resulting in the production of inhibitor compounds such as isothocyanate and thiocyanate and nitrile. The researches show that soybean planting after canola reduce soybean germination and growth. The aim of this research was to study the inhibitory effects of water extracts of two cultivars of canola (PF and Hyola401) and decompositions extracts of two cultivars during different times on soybean germination and radicle growth. Two cultivars of canola (PF and Hyola) were planted on farm and in 5 leaf stage shoots were separated from roots and dried at room temperature and their water extract were prepared.5 ml of these extracts was added to petri dish. 10 soybean seeds (Gorgan 3) were included in each petridish. Percentage germination and radicle growth of soybean seedling in 24±2 C during 7 days was evaluated. Our results showed that inhibitory effect of shoot water extract in two cultivar was more than root and this effect in Hyola was more than PF. In other experiment 1 kg of each two cultivars was mixtured in 10 kg soil. After one, two and three weeks of these mixtures (decompositions) were extracted.5 ml one of each extracts was added to each petridish includes 10 soybean seeds. Percentage germination and radicle growth of soybean seedling in 24±2 C during 7 days was evaluated. Result showed that extract of first week decomposition had inhibitory effect more than other weeks on germination and radicle growth. As inhibitory effect of decomposition of PF in first week on germination was more than Hyola and on radicle growth was less than Hyola.

Synthetic fungicides are primary means to control post harvest disease of fruits. The application of fungicides to fruits after harvest to reduce decay has been increasingly curtailed by the development of pathogen resistance to many fungicides and the lack of replacement fungicides. In addition, negative public perception regarding the safety of pesticides and consequent restrictions on fungicide use motivated the search for alternative approach. Biological control of post harvest diseases has emerged as one of the most promising alternative to chemicals. The yeast, M. pulcherrima was evaluated for biological control capability in apple against the post harvest pathogens Botrytis cinerea and Penicillium expansum. In this study, the effect of different treatments of yeast M. pulcherrima was evaluated in challenge with 5×104 or 1×105 spores/ml of B.cinerea and P expansum and effect of pathogen and yeast concentration on yeast biocontrol activity in artificial wounds. However, the growth of B. cinerea and P.expansum on the apple artificial wounds inhibited by washed cell suspensions (1×108 Cell per ml) of antagonism after storage in 1C and 23C, But there was no such Inhibition using the same concentration of washed cell suspension of antagonism. The concentrations of antagonist and pathogen spores had significant effects on biological control effectiveness. Culture filtrate of the yeast failed to provide protection against the two pathogens. Population dynamics M. pulcherrima in the artificial wounds was recorded in different time after inoculation at both 1C and 23C. M. pulcherrima multiplied rapidly in apple wounds in the present and absence of B. cinerea and P.expansum.

Microbiological studies of hygienic detergents resulted in isolation of two strains of Pseudomonas spp. After morphological and biochemical examinations, these microorganisms were tentatively identified as Pseudomonas putida strain MP2 and Pseudomonas aeruginosa strain MS1. Further experiments on microbial resistance of both strains showed a wide but different spectrum of resistance to antibiotics and biocides. The strain MS1 was resistant to Tubramycin and Afluxacin and showed partial tolerance to Carbenicillin, Neurfluxacin, and Ceftazidim (all are specially used against Pseudomonas aeruginosa). Meanwhile, the strain MP2 was sensitive to mentioned antibiotics, but it showed higher tolerance to biocides. This strain was able to grow well in TSB containing the highest tested concentration of Formalin (800 μg ml-1) and DMDM (1276 μg ml-1). Occurrence of such dual contaminations in a same place should be considered as a high risk phenomenon. Because it provides the possibility of horizontal gene transfer among microorganisms and the result will tremendously affect public health. Thus, the study emphasize again on adverse effects of application of biocides in composition of hygienic products.

During 1999-2001 taxonomic inverstigations on meloid beetles in Tehran province, collected specimens as well as those in the Hayk Mirzayans Insect Museum (HMIM) were studied in detail. As a result 29 species belonging to 9 genera from 2 subfamilies were identified and an identification key for the species was provided.

Locomotor activity is an important physiologic phenomenon. In previous study we showed that the matricaria chamomilla (chamomile) hydroalcholic extract acts differently in male and female mice. Since sex hormones are important in most of physiological phenomenons, so in this study, the role of sex hormones and chamomile hydroalcholic extract were investigated on motor activity behavior in absence of sex glands in adult male and female NMRI mice. Gonadectomized male and female mice were divided to groups of seven mice including, receiving hydroalcholic extract of chamomile (30 and 50 mg/kg i.p), testosterone (2 mg/kg S.C.), estradiol benzoate (0.1 mg/kg S.C.), and progesterone (0.5 mg/kg S.C.). Motor activity monitor system was used to evaluating locomotor activity parameters in all groups. Results showed that: Testosterone in presence and absence of chamomile hydroalchlic extract had no any effect on motor activity parameters in testctomized male mice. Estradiol benzoate in presence and absence of chamomile hydroalchlic extract increased locomotor activity parameters in ovariectomized mice. Progesterone also did not change locomotor activity in presence and absence of estradiol benzoate and /or chamomile hydroalcholic extract in ovariectomized mice. It seems the both chamomile hydroalcholic extract and estradiol enhance some locomotor activities and probably act through same system and modulate or potentiate the effect of each other. Also it seems there are interaction between estradiol and progesterone and also between chamomile extract and progesterone.

In a comparative study the Barbus species of Iran were revised. Nearly all information about all nominal species which previously had been described or were reported in Iran and adjacent country were compared and reviewed. The specimens were caught from western Iran and the specimens were deposited in Canadian Museum (CMN) were examined. The object of this paper is to outline the taxonomically differences between Barbus plebejus and Barbus lacerta. B. plebejus, originally described in 1839 from lake Como in Italy, and redescribed in 1995. The lectotype of Barbus plebejus was designated in 1995. No subspecies and species of B. plebejus have been reported in Iran. In this paper the locality and description of the Iranian population of B. plebejusis given. The differences between B.s plebejus and more related species, B. laserta are outlined. The difference between this two species, lies mainly in body shape, the relative head length, the body depth, the forth dorsal ray. Also the specimens in Iran are compared with another population form Turkey the differences and similarities are given.