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Author: search.filters.author.Chakraborty, BNEnd date: 2009

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Now showing 1 - 3 of 3
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    Arbuscular mycorrhizal fungal association in rhizosphere of Hevea brasiliensis
    (University of North Bengal, 2009-03) Chakraborty, BN; Sunar, K
    Occurrence of VAM spores in Hevea brasiliensis growing soils and percent colonization in roots of three varieties (RRII 105, RRIM 600 and GT 1) were studied. Spore population varied from 30 to 45/g soil and the root infection of all the three varieties ranged from 70 to I00 % in both mature and young plants. Percent of root infection was found to be more in the drought resistant varieties RRII 105 followed by RRIM 600 and the less drought resistant variety GT-1. Nine different types of glomalean spores were recovered from the soil samples, including five from the genus Glomus, three from Acaulospora, one from Gigaspora and few undefined species of Sclerocystis. The scanning electron microscopic observations of the most commonly occurring spores of Glomus fasciculatum revealed smooth wall character with number of pits.
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    Pathogenesis-related proteins of tea triggered by Exobasidium vexans
    (University of North Bengal, 2009-03) Chakraborty, BN; Sharma, M; Das Biswas, R; Ghosh, AN
    The defense strategy of tea plants against Exobasidium vexans are multifold and include accumulation of pathogenesis-related (PR) proteins. A study on the association of defense enzymes with resistance in tea plants triggered by E. vexans revealed significant changes in the level of β-1.3-glucanase (PR 2) and chitinase (PR 3) exhibiting antimicrobial activity. Accumulation of defense proteins differed in time and magnitude. Time course studies points towards accumulation of PR-2 and PR-3 in the early hours, PR-9 later on and finally the antifungal metabolites that confer resistance to the plants. Treatment with salicylic acid (SA) stimulates a multicomponent defense response in tea leaves which was confirmed by immuno-localization of PR 2 and PR 3 in tea leaf tissues following induction of resistance. Induction of PR-3 in suspension-cultured tea cells following SA treatment was confirmed immunologically using antibody probes (PAb-chitnase). Subcellular localization of PR-3 and PR-2 in tea leaves were also confirmed by indirect immunogold labeling. Marked increase in frequency of gold particles following elicitation by SA treatment was evident. Cell defense responses associated with systemic acquired resistance induced by SA against E.vexans has been discussed in relation to the possible role of PR-proteins in immunizing tea plants
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    A Cytogenetic Study of Seven Tea Clones [Camellia sinensis (L.) 0. Kuntze|
    (University of North Bengal, 2009-03) Roy, SC; Chakraborty, BN
    Karyotype analyses in seven cultivated clones (cv. T78, T383, TV30, HV39, TecnAli17/1/54, TV29, und UPASI-26) of tea (Camellia sinensis) are investigated for their cytogenetic characterization. Karyotypes of the chromosomes (2n = 30) were grouped arbitrarily on the basis of their length and position of the centromere into four types (A-D). Centromeric index (F %). total centromeric index (TF %), disparity index (DI) and total haploid chromosome length (TCL) were calculated. Chromosomes were found to be short to medium in size varied in length from 1.24 μm to 4.20 μm. Karyotypes were gradate and asymmetric in nature with median to nearly submedium chromosome. On the basis karyotype analysis, varietal distinction can be marked to some extent.