NBU Journal of Plant Sciences, Vol. 02
Permanent URI for this collectionhttps://ir.nbu.ac.in/handle/123456789/4395
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Item Open Access Antagonism of fluorescent Pseudomonas BRL-1 against Curvularia lunata(University of North Bengal, 2008-03) Sen, S.; Tahsin, K.S.; Acharya, K.A potato rhiszospheric isolate, fluorescent Pseudomonas BRL-I, showed in vitro antagonistic activity against Curvularia lunata. Microscopic studies of the mycelium after antagonism illustrated hyphal shriveling, swelling, vaculation, short branching and granulation of cytoplasm resulting in lysis of hyphae of C. lunata.. Association of antagonistic property of the isolate has been found to be coupled with chitinolytic and proteolytic activity as weii as by the production of indole acetic acid and spiderophore.Item Open Access Ethnic uses of some pteridophytic weeds of tea gardens in Darjeeling and Terai(University of North Bengal, 2008-03) Ghosh, C.; Biswas, R.; Das, A.P.Pteridophytes occupy a recognisable position in the flora of Terai and the hills of Darjiling. They are also well represented as weed in the Tea Gardens of this area. Recent survey recorded the occurrence of 86 species of pteridophytes from nine such gardens covering both Terai and Darjiling Hills. Of these, 25 species (30%), covering 21 genera and 20 families, are used by the Tea Garden workers in different manner like (i) 10 species as food, (ii) 02 species for fermenting traditional liquor, (iii) 01 species as fodder and (iv) 22 species as medicine for human diseases. In addition, some of these plants are used for basketry, playing carom, ceremonial decoration, ornamentals etc.Item Open Access Influence of culture media and environmental factors on mycelial growth, sporulation and spore germination behaviour of Curvularia eragrostidis (P. Hennings) Mayer(University of North Bengal, 2008-03) Saha, A.; Dasgupta, S.; Mandal, P.; Saha, D.Curvularia eragrostidis is a foliar fungal pathogen of young tea plants. It causes leaf spot disease of tea. Mycelial growth, sporulation and spore germination behaviour of the pathogen were studied. Six different media were tested for mycelial growth. Among these, potato carrot agar (PCA) was found best for the mycelial growth and sporulation. Maximum mycelial growth was attained after 15 days of incubation. Mycelial growth was also studied in different temperatures and pH. Optimum temperature of growth was 25 °C and best growth was obtained at pH 6.0. Glucose and peptone were best carbon and nitrogen sources respectively for growth and sporulation of the fungus. The optimum conditions of spore germination were found to be at pH 7.25 and at incubation temperature of 25 °C. Keywords: Sporulation; Curvularia eragrostidis; Mycelial growth, fungusItem Open Access Bacterial strain isolated from the Mango field and identified on the basis of 16S rDNA sequence information and optimization of the alkaline cellulase production(University of North Bengal, 2008-03) Roy, S.C.; Chattopadhyay, A.A bacterial strain was isolated from the soil of mango (Mangifera indica) orchards. The isolate was identified as Paenibacillus ahvei [MTCC 7809] through phylogenetic analysis based on the 16S rDNA gene sequencing and also by conventional biochemical processes. The scanning electron microscopic analysis revealed the morphological details of the strain. The isolate is Gram positive. motile, rod shaped, spore forming bacterium with extreme salt tolerance. It can hydrolyze starch and gelatin, and catalase and oxidase were produced. The cellulase activity of the culture broth was determined by measuring the reducing sugar released from carboxymethyl cellulose (CMC). Different cultural conditions were tested to reach the optimum growth conditions in order to obtain large-scale production of alkaline cellulase for commercial importance. Crude cellulase from Paenibacillus alvei (MTCC 7809) showed activity and stability at moderately high temperature and pH and the activity remained stable at 40°C and pH 8 after 2h of incubation making the strain a good choice for industrial applications. The rDNA sequence of 1509bp is submitted into the NCBI GenBank database (Acession no. EF429201).Item Open Access Variation of antioxidant properties and phytochemical constituents of tea cultivated under various agronomic conditions at Terai region of North Bengal(University of North Bengal, 2008-03) Misra, T.K.; Saha, A.; Nanda, A.K.; Mandal, P.The studies were conducted during 2007-2008 in three cultivars of tea (Camellia sinensis) namely, TV26, TV29 and Dangri Manipuri Jat, at tea estates of Terai, North Bengal. Commercial standard plucked tea leaves were assayed to determine antioxidants activity and related phytochemical constituents. DPPH was used to determine the antioxidant properties of bud+leaf (B+L), bud+two leaves (B+2L), bud+three leaves (B+3L) and matured leaves (L). Subsequently, total phenolics, flavonols and hydrolysable tannins were estimated using standard methods. The result showed that free-radicals scavenging potentiality and chemical composition varies significantly at different growing conditions and leaf maturation. Statistical analysis showed significant relation between antioxidant and some phytochemical composition of dry tea leaves, among which phenolics (R2 =0.904, P< 0.001), tannins (R2= 0.567, P< 0.05) and flavonols (R2= 0.314, P< 0.05) bear significant correlation. Soil physicochemical parameters like pH (R2=0.537, P< 0.05), nitrogen (R2=0.618, P< 0.01), K2O (R2=0.106, insignificant), P2O5 (R=0.730, P< 0.01), S (R2=0.157, insignificant) and soil moisture (R2=0.745, P< 0.01) influence free-radical scavenging activity in tea leaves. Antioxidant quality of tea varies with maturation stages of leaves and the pattern is specific for a selected varietes. From our observation it may be concluded that antioxidant quality is dependent on some fertility parameters of soil and maturation of leaf. These results suggests that appropriate agronomic practices and proper choice of plucking may help to preserve the tea antioxidant quality.Item Open Access Diversity ofTrees in the Darjeeling Foothill Region of Eastern Himalaya(University of North Bengal, 2008-03) Rai, U.; Das, A. P.Phytosociological investigation using 20 x 20 m quadrats has been made on seven major forest types of Darjiling foothill region within an altitudinal range of 135 m to 1200 m leading to the record of 215 species of trees, 11 species of liana and three species of palms. Analysis of data revealed that the East Himalayan Sal forest showed highest species diversity but have moderate species richness and concentration of dominance. High species diversity and species richness were recorded from Semi Evergreen Mixed forest, Wet Mixed Deciduous Forest & Lower Bhabar Sal Forest with correspondingly low concentration of dominance. Bamboo brake had the lowest species diversity with high concentration of dominance. Computation of similarity index showed a poor relation between different forest types and reflected the developing nature of vegetation. Also, these forests have a high regeneration status with a good species composition. It has also been predicted that the anthropogenic interferences may cause the abrupt change in the structure of these vegetation types.Item Open Access Searching for phosphate solubilizinz tungal isolates from soil(University of North Bengal, 2008-03) Chakraborty, B. N.; Chakraborty, U.; Saha, A.; Dey, P. L.; Sunar, K.A total of 354 fungal isolates were obtained from soil samples collected from forests, river basins and agricultural fields of North Bengal using serial dilution, direct soil plating, serial root washing and root maceration techniques. Cultural characteristics of the isolated fungi were studied and microscopic observations were made for identification of these isolates. All the isolates were screened for their phosphate solubilizing activities in vitro. A total of 70 fungal isolates showed phosphate solubilizing activities as detected in Pikovskaya's agar medium. Quantitative evaluation of phosphate solubilization in liquid medium supplemented with two phosphate sources (tricalcium phosphate and rock phosphate) was carried out for all the isolates showing phosphate solubilizing activity. Maximum phosphate solubilizing capacity was shown by three isolates of A. niger while A. clavatus showed minimum activity. Genomic DNA was extracted from sixteen isolates showing high activity and PCR amplification of DNA from nine isolates was done.Item Open Access Anthrax and Bioterrorism(University of North Bengal, 2008-03) Chowdhury, J.; Sen, A.Bioterrorism is the deliberate discharge or dissemination of viruses, bacteria, or other germs used to cause sickness or death in people, animals, or plants. Though these agents are found in nature they are usually modified to increase their ability to cause disease, make them resistant to current antibiotics, or to increase their ability to be spread into the environment. Biological agents can be spread through the air, through water, or in food. Terrorists may use biological agents because they can be extremely difficult to detect and do not cause illness for several hours to several days. Among these biological agents, Anthrax is considered to be the Category-A agent because of its high potency for adverse public health impact and serious effect on large-scale dissemination. Though there is a big hue and cry in the recent past about bioterrorism particularly after 9/11 attack, the history of bioterrorism is fairly old. In the present paper, we have sketched the history and the evolution of bioterrorism with reference to anthrax, particularly microbiology and pathogenesis of the disease causing agent and its clinical symptoms and treatments.Item Open Access Plant Defense Proteins(University of North Bengal, 2008-03) Chakraborty, B.N.Plants are compelled to withstand stresses of all kinds, be it biotic, abiotic or anthropogenic as a consequence of their immobility. The initial infection process involving adhesion/recognition events between plants and fungal pathogens is essential for the establishment of pathogenesis. The extracellular matrix (ECM) is a biologically active part of the cell surface composed of a complex mixture of macromolecules that, in addition to serving a structural function, profoundly affect the cellular physiology of the organism. During the past two decades it has become evident that the cell wall is a dynamic organization that is essential for cell division, enlargement and differentiation as well as responding to biotic and abiotic stress. ECM is also the source of signals for cell recognition within the same or between different organisms. Cell walls are natural composite structures, mostly made up of high molecular weight polysaccharides, proteins and lignins. Lignins are only found in specific cell types. Arabidopsis thaliana cell wall proteins (CWP) that can be involved in modifications of cell wall components, wall structure and signaling as well as interactions with plasma membrane proteins at the cell surface has been reviewed.