MPhil Thesis

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2016 - 20196

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Start date: 2016End date: 2019

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Now showing 1 - 6 of 6
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    Evaluation of antifungal activities of extracts of some medicinal plants on Neurospora Crassa
    (University of Dhaka, 2016-01-10) Sultana, Razia
    Antifungal activity was investigated using the leaf extracts of five different medicinal plants namely, Ocimum sanctum Linn., Coccinia cordifolia (Linn.) Cogn, Andrographis paniculata (Burm. f.) Wall., Centella asiatica (Linn.) Urban., Azadirachta indica A. Juss. against two fungi Neurospora crassa and Helminthosporium oryzae. The in vitro study revealed the presence of antifungal activity against Neurospora crassa in the leaf extracts of all the plants used during the study. The non sterilized leaf extracts was more effective than sterilized leaf extracts. The antifungal effect of these plant extracts enhanced gradually with the application of increased concentration and best antifungal activity was observed in the leaf extracts of Azadirachta indica A. Juss. as compared to all the tested plants. It inhibited the radial growth of both Neurospora crassa and Helminthosporium oryzae at 25% concentration. Antifungal activity was observed in the proteins present in the proteins of third fraction after (NH4)2SO4 gradient centrifugation and 200 µg of the total proteins of this fraction was found effective in controlling the fungal growth in vitro. Two proteins of the third fraction e.g., 40 and 37 kDa were found to be effective to control the fungal radial growth of both the Neurospora crassa and Helminthosporium oryzae.
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    Comparative eco- physiology of two cultivars of wheat (triticum aestivum cv. bari 26 and cv. pradip) in relation to soil moisture and salinity
    (University of Dhaka, 2016-01-13) Hafiz, Shamima
    Experiment has been done with two cultivars of wheat cv Bari 24 and Bari 26 in relation to salinity and soil moisture to study the growth, yield and water relations. Salinity experiment was done in the laboratory in Petri dishes. Two cultivars of wheat, Triticum asetivum (cv. Bari-24 (Pradip) and cv. Bari- 26) were grown in the different concentrations of sodium chloride solution and the seedling growth was observed. Shoot and root length of the seedlings of both cultivars of wheat showed a significant (P= 0.05) decrease at the highest salinity treatment but at the lowest salinity treatment i.e. at 0.05 M NaCl both shoot and root length increased. It is suggested that the growth of both cultivars of wheat seedling is favoured by low NaCl salinity. Seeds of two cultivars of Triticum aestivum (cv. Bari- 24 and cv. Bari- 26) were grown in the field under wet (watering everyday) and dry (watered once in a week) treatments. Six harvests were done with an interval of 7 days. Growth analysis from successive harvest of plants showed that early pattern of growth was influenced by moderate restriction in the availability of soil water and was associated with marked shift in the allocation of growth resources in favour of root development. Plant height, total dry weight, shoot and root dry weight, relative growth rate, and root: shoot ratio were analyzed after every harvest. In wet treatment, the number of lateral roots showed luxurious growth from those of dry treatment. Root and shoot length of both cultivars was significantly (P= 0.05) higher than dry treatment. Apart from total dry weight, the root and shoot dry weights were also higher in wet treatment than that of dry treatment. Relative growth rate (RGR) did not show significant difference between wet and dry treatments. Root/ Shoot ratio of both cultivars in all treatments from 3rd harvest onward showed an increasing tendency. Spike length and weight were maximum in cv. Bari 24 under wet condition and minimum was in cv. Bari 26. The maximum value of Flag leaf area was found in cv. Bari-26 in wet treatment and lowest was in cv. Bari 24 in dry condition. The area of flag leaf did not show any significant difference (P= 0.05) between the treatments but an increasing tendency of flag leaf area was noted under wet condition. Tissue water relations in wet and dry treatments were examined in leaf material collected from the field, with a view to obtaining comparative data on the mechanism of adaptation to drought. The relative water content was significantly (P=0.05) lower in cv. Bari 24 under wet condition than dry treatment and was highest in cv. Bari 26 in dry treatment plants. Wet treatment plants showed the maximum rate of loss of water, while dry treatment plants showed the lowest. The plants of these two cultivars of wheat showed a significant difference in their growth and yield in relation to soil moisture.
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    Aeromycoflora of Dhaka city, Bangladesh
    (University of Dhaka, 2016-01-17) Sultana, Tania
    The air influences every aspect of life and the activities of organisms affect the air. Sources of air borne microorganisms are everywhere. They are in food, water, on utensils and on bed sheets. The indoor and outdoor air is an important source of aeroallergens and pathogens. During the present investigation, monthly sampling of air borne mycoflora of Dhaka Metropolitan City, during February 2013 to January 2014 was recorded. The fungal colonies developed in PDA media were isolated from five different locations in the morning and evening in monthly intervals. The total number of counted fungal colonies were 6648 out of which in the morning was 3268 and in the evening it was 3380 and 156 colonies were sterile mycelia. The sampling sites were Sher-e Bangla Agricultural University, Gulistan, Dhaka Medical College, Sadarghat and DOHS, Mohakhali. The qualitative nature of the mycoflora, their mean, standard deviation, percent frequency and correlations to the total mycoflora, monthly periodicity have been described in this investigation. In this study, fifteen genera have been recorded viz. Alternaria, Arthrinium, Aspergillus, Bipolaris, Chaetomium, Cladosporium, Colletotrichum, Curvularia, Fusarium, Nigrospora, Penicillium, Pestalotia, Rhizopus, Syncephalastrum and Trichoderma under the class Ascomycetes, Zygomycetes and Deuteromycetes. Local fluctuations of the air borne fungi in relation to some meteorological parameters were also studied. The three most dominant fungal species were Aspergillus, Cladosporium and Penicillium contributing 30.71, 18.10 and 12.79% in the evening and in the morning it was 28.82, 15.78 and 11.53% in twelve months counting of the total colonies, respectively. Aspergillus was found in the highest frequency in the present investigation among the identified genera. In the present study Cladosporium was found 2nd position in term of its percent frequency. Maximum number of fungal colonies were found in Gulistan and Sadarghat in the morning and evening. During the twelve months investigation maximum fungal colonies were found in August and September as all the climatic factors were favorable for the fungal growth, their dispersal and survival. Among the fungi, found in the present investigation Alternaria, Aspergillus, Chaetomium, Cladosporium, Curvularia, Fusarium, Penicillium and Rhizopus were reported as pathogenic to plants and/or human and strongly allergenic to human. Bipolaris, Colletotrichum, and Pestalotia were reported as only plant pathogens. The present study contributes to our knowledge of air borne spores in the Dhaka City. Regular monitoring of air borne fungi can be helpful in the prevention of fungal allergic diseases in the city.
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    Development of in vitro plant regeneration system and agrobacterium–mediated genetic transformation in Mungbean (Vigna radiata (L.) wilczeck)
    (University of Dhaka, 2017-11-01) Begum, Setara
    An efficient protocol has been developed for Agrobacterium-mediated genetic transformation of two important mungbean (Vigna radiata (L.) Wilczeck) varieties cultivated in Bangladesh, namely, Binamoog-5 and BARI mung-6. Prior to transformation an efficient in vitro regeneration protocol was developed for these two mungbean varieties. Cotyledonary node, shoot tip and cotyledone attached decapitated embryo were used as explants for direct regeneration of shoot. MS medium with various combinations and concentrations of BAP, Kn and NAA were used for direct regeneration of shoots. MS medium supplemented with 10.0 μM BAP and 0.5 μM NAA was found to be the best towards the development of highest number of multiple shoots. Full strength of MS medium supplemented with 2.0 μM IBA was found to be the most effective for healthy root induction from the regenerated excised shoots. Following root induction the in vitro regenerated plantlets were successfully transplanted to soil. Transformation experiments with cotyledone attached decapitated embryo, cotyledonary node and decapitated embryo explants were conducted using Agrobacterium tumefaciens strain, namely, LBA4404 harboring the binary plasmid pBI121 conferring GUS (β-glucuronidase) and nptII (neomycin phosphotransferase II) genes. Transformation experiments were monitored through GUS histochemical assay since the strain of Agrobacterium contained GUS gene. Different factors influencing successful transformation such as, density of bacterial suspension, incubation and co-cultivation periods were optimized. Maximum responses towards transformation were obtained with bacterial suspension having an optical density of 0.56 at 600 nm. Moreover, 30 minutes of incubation period followed by 72 hours of co-cultivation period were found to be the most effective towards transformation as determined by transient GUS assay. Selection of transformed shoots was carried out using different concentrations of kanamycin as the Agrobacterium strain contained nptII gene. Transformed shoots were selected using 150 mg/l kanamycin. The survival of green shoots on the optimum selection medium indicated the production of transformed shoots. Stable expression of the GUS gene was detected in various parts of transformed plantlets. Putatively transformed shoots were rooted on full strength of MS medium containing 2.0 μM IBA and 100 mg/l ticrecilin. Rooted transformed plantlets were successfully transferred to soil. Genomic DNA was isolated from the putatively transformed mungbean shoots and stable integration of GUS and nptII genes was confirmed by polymerase chain reaction (PCR) analysis.
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    Mycoflora of maize (Zea Mays L.) seeds in different storage conditions and their management
    (University of Dhaka, 2019-10-10) Sadia, Ummay
    An investigation was carried out to find the association of fungi with different varieties of maize seeds in storage during the period of 2011-2015. Samples were collected from Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur. Fungi associated with seeds of maize were isolated following “Blotter” and “Tissue planting” method. A total of seven fungi were isolated from the seeds of maize in storage. The isolated fungi were Aspergillus flavus, A. fumigatus, A. niger, Curvularia lunata, Fusarium sp., Penicillium sp. and Rhizopus stolonifer. The frequency percentage of association of Aspergillus niger isolated from maize seeds was higher than any other fungi. Pathogenic potentiality of the isolated fungi was carried out following seed inoculating technique. Among the isolated fungi C. lunata and Fusarium sp. were found to be pathogenic to the maize seeds. Five fungicides viz., Bavistin 50 WP, Dithane M-45, Greengel 72 WP, Ridomil MZ Gold and Tall 250 EC were selected to evaluate their in vitro efficacy at different concentrations against the test fungi. In this study, out of five fungicides Tall 250 EC showed best inhibiting effect on the test fungi followed by Bavistin 50 WP, Dithane M-45, Greengel 72 WP and Ridomil MZ Gold. Five plants extracts viz., Azadirachta indica A. Juss, Allium sativum L., Citrus medica L., Datura metel L. and Tagetes erecta L. were selected to evaluate their in vitro fungitoxicity at 5, 10 and 20% concentrations against test fungi. In this study, Allium sativum and Datura metel showed 100% radial growth inhibition of A. fumigatus at 20% concentration. The present investigation suggests that out of five fungicides, Tall 250 EC can be used as best inhibiting chemical agent against the fungi associated with different maize varieties. Out of five plant extracts, Allium sativum identified as best botanicals for further investigation against the fungi associated with different maize varieties.
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    Effects of salinity on the nodulation in lentil (Lens Culinaris Medik.) and the diversity of its compatible nitrogen-fixing Rhizobium
    (University of Dhaka, 2019-10-07) Ferdous, Jannatul
    Salinity in soil causes risk for growth, nodulation and biological nitrogen fixation in legumes. Biological nitrogen fixation occurs through the symbiotic association between legumes and Rhizobium. Legume-rhizobia symbiosis and the efficiency of biological nitrogen fixation are influenced by a number of environmental factors including salinity. This study was carried out to evaluate the effects of salinity on the growth parameters and nodulation of lentil plants (Lens culinaris Medik.) at various NaCl concentrations. Seeds of lentil were sown in the experimental plots at the Botanical Garden of University of Dhaka. Each of the four salt treatments (0 mM, 50 mM, 100 mM and 200 mM NaCl) was applied in three replicate plots. Treatments were applied once in every seven days. The size of each plot was 0.0625 m2. Plants were grown for 2 months in the field. Shoot and root growth parameters including length, fresh and dry weight of shoot and root, leaf chlorophyll content, root to shoot ratio, root nodule number and proline content of leaf were compared among the different salt treatments. This study also examined the effects of soil salinity on the number of bacterial colonies obtained from root nodules, rhizosphere soil and bulk soil of lentil plants. The suspensions of root nodules were cultured in the nutrient agar medium and then bacterial colonies were isolated and counted. Bacterial DNA were isolated from pure isolates of bacterial colonies obtained from soils collected from different areas of Bangladesh. PCR amplification using bacterial DNA samples as template was done by targeting 16s rRNA gene. After purified PCR product was achieved, the sequences of different strains of rhizobia were identified by using NCBI blast. Phylogenetic tree was also constructed based on the 16S rRNA sequencing of isolated bacteria. In comparison to control (0 mM), shoot height, root fresh weight, number of nodules and chlorophyll content of leaf decreased with the increase of salt treatment although no significant difference appeared. Proline concentration of leaf of lentil increased significantly with the increase of salt concentrations. Number of bacterial colony increased with the increase of salt concentration. Compared to bulk soil, rhizosphere soil showed higher number of bacterial colonies. The result thus indicates that soil salinity can influence bacteria associated with the root nodule and rhizosphere of lentil plants. The clusters of phylogenetic tree indicated the genetic diversity of rhizobia associated with root nodules collected from different sites. Result of this study is expected to provide valuable information and may be useful to the researchers as well as the policy makers of both Government organizations and Non-government organizations for formulating appropriate policy for widespread cultivation of lentil in Bangladesh.