Browsing by Author "Saha, Dipanwita"

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    Copper toxicity in plants: a review and a case study on tea
    (University of North Bengal, 2020-03) Saha, Dipanwita; Mandal, Sima; Saha, Aniruddha
    Copper in trace amounts is essential for various metabolic processes in the plant such as photosynthesis, carbohydrate distribution, and protein metabolism but at high concentration it causes physiological stress through generation of free radicals that induce the production of reactive oxygen species (ROS) via Haber-Weiss and Fenton reactions. Copper-induced generation of hydrogen peroxide, hydroxyl radicals, or other reactive oxygen species has been directly correlated with the damage to protein and lipids that may lead to reduced growth and even death. Tea (Camellia sinensis L. (O.) Kuntze) is an economically important plantation crop in India with round the year productivity. Copper based fungicides are cheap and effective in controlling fungal diseases and are used consistently throughout the year to combat different fungal diseases that pose a major threat to tea production. Excess Cu2+ has been found to alter several physiochemical parameters in the tea plants. A more detailed study on mechanisms of Cu2+ toxicity at the gene level is warranted.
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    Effect of copper on seed germination, root elongation and shoot elongation of seedlings of commercially cultivated tea varieties
    (University of North Bengal, 2013-03) Mandal, Sima; Saha, Aniruddha; Saha, Dipanwita
    Tea (Camellia sinensis L. (0.) Kuntze) is an economically important plantation crop of India but is prone to attack by several fungal pathogens. Copper based fungicides are being used for decades to control fungal disease in tea which may lead to accumulation of copper in the soil. The aim of the present work was to investigate toxic effect of Cu+2 on seed germination, growth and morphological changes in tea seedlings. Different concentration of copper sulphate was applied on three different commercially cultivated tea varieties (TS-462, TS-520 and TS-463). The effect of different concentrations of copper (0.5 – 8 mM) on seed germination, root elongation and shoot elongation of the tea plant were evaluated. Percent germination was found to decrease progressively with increasing concentrations of Cu+2. Maximum reduction of seed germination was showed by TS-463. Several damaging effects such as reduced root hair proliferation, structural deformation and reduction in length of root and shoot were observed when the germinated seedlings were allowed to grow at higher concentrations of copper solutions. Decrease in the dry mass of both root and shoot were also recorded. The results showed that excess copper have negative effect on germination of tea seeds and subsequent growth of the seedlings.
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    Generation and characterization of expressed sequence tags of tea (Camellia sinensis L (O) kuntze)
    (University of North Bengal, 2011) Das, Akan; Saha, Dipanwita
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    Influence of culture media and environmental factors on mycelial growth and sporulation of Alternaria alternata (Fr.) Keissler causing leaf blight disease of niger (Guizotia abyssinica (L.f.) cass)
    (University of North Bengal, 2015-03) Saha, Aniruddha; Choudhuri, Chandrani; Saha, Dipanwita
    Alternaria altermata is isolated from naturally infected niger leaf for their morphological characteristics, mycelia growth and sporulation, spore germination in different culture media and environmental conditions. RMA was best for both growth and sporulation. Excellent sporulation was observed ion PCA. PDB supported best growth among the liquid media tested. Highest mycelia dry weight was recorded at 28°C and pH 6.5. Among several carbon sources tested, Mannitol showed optimum growth and sporulation while peptone produced maximum growth among the tested organic nitrogen sources. The present study will help to maintain the fungus in the laboratory condition for preparation of inoculums for different studies related to the control measures of the pathogen.
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    Phenotypic and molecular characterization of Siri (Bos indious) cattle breed from Eastern Sub-Himalayan region
    (University of North Bengal, 2017) Bera, Prasanta Kumar.; Saha, Dipanwita; Ghosh, Sankar Kumar
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    Studies on the role of bacteria isolated from ulcers of fishes in causing ulcer in Experimental Fish
    (University of North Bengal, 1998) Saha, Dipanwita; Pal, Joydeb