NBU Journal of Plant Sciences, Vol. 02

Permanent URI for this collectionhttps://ir.nbu.ac.in/handle/123456789/4395

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Author: search.filters.author.Mandal, P.

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    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, fungus
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    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.