Browsing by Author "Pandey R R"

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    ROLE OF ARBUSCULAR MYCORRHIZAL FUNGI IN ALLEVIATION OF ACIDITY STRESS IN PLANT GROWTH
    (Springer- NewYork, 2014) Muthukumar T; Priyadharsini P; Uma E; Jaison S; Pandey R R
    Soil acidity is a major constraint for crop production worldwide as nearly half of the potential arable lands are acidic. Plant productivity in acid soils is limited by toxic levels of aluminum (Al), manganese (Mn), and iron (Fe) as well as deficiencies of plant available nutrients, especially phosphorus (P). Plants have developed several morphological, biochemical, and physiological adaptations against acidity stress. Among these, symbiosis with arbuscular mycorrhizal (AM) fungi is a strategy plants have evolved to survive and thrive in acid soils. The AM symbiosis increases plant growth in acid soils through enhanced uptake of nutrients. A reduction in Al and Mn phytotoxicities also occurs in response to AM symbiosis through a number of mechanisms such as binding of the toxic ions by the fungal hyphae, vesicles or auxiliary cells, exudation of organic acids, phosphatases, and production of glomalin. However, like plants, AM fungal species and ecotypes also vary to a great extent in their tolerance and ability to impart plant growth benefits in acid soils. It is, therefore, essential to identify suitable AM fungi that could confer tolerance and render maximum benefits to crops in acid soils.
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    ROOT MORPHOLOGY AND MYCOTROPHY OF DISPERIS NEILGHERRENSIS (ORCHIDACEAE) FROM WESTERN GHATS, SOUTHERN INDIA
    (Anales de Biología, 2013-11-13) Muthukumar T; Uma E; Pandey R R
    We examined the root morphology and mycotrophy of Disperis neilgherrensis Wight., growing in the Western Ghats of south India for the first time. The root system was sparse consisting of white to off white, 0.28 ± 0.11 mm thick roots arising from short brown rhizome. The roots were covered by root hairs (19.2 ± 1.5 per mm of root) 161.80 ± 12.68 µm long and 4.55 ± 1.17 µm thick. Root cortical cells contained fungal structures typical for orchid mycorrhizal (OM) and arbuscular mycorrhizal (AM) types. In contrast, rhizomes contained only OM fungal structures. The OM colonization was characterized by both lightly and darkly staining pelotons with regularly septate hyphae of varied diameters. Intracellular aseptate hyphal coils, arbusculate coils and intracellular vesicles characterized AM colonization. The percentage of length with OM colonization was 56.51% for roots and 73.64% for rhizomes, whereas the root length with AM fungal colonization was 30.23%. The AM type in D. neilgherrensis corresponds to the Paris-type.