Department of Botany
Permanent URI for this communityhttps://dspace.psgrkcw.com/handle/123456789/26
Browse
5 results
Search Results
Item 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 RSoil 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.Item ARBUSCULAR MYCORRHIZAL AND DARK SEPTATE ENDOPHYTE FUNGAL ASSOCIATIONS IN FERNS AND LYCOPHYTES OF PALNI HILLS, WESTERN GHATS, SOUTHERN INDIA(Brazilian Journal of Botany, 2014) Muthukumar T; Sathiyaraj G; Priyadharsini P; Uma E; Sathiyadash KWWe assessed the arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal associations in 57 ferns and 3 lycophytes (belonging to 15 families in 39 genera) of different life forms (epiphytic, saxicolous and terricolous) occurring in Palni Hills of Western Ghats. Fungal symbiosis was absent in all the three lycophytes examined. Fifty-five of the 57 ferns (91.66 %) examined had AM and 37 (64.91 %) had DSE fungal association. This is the first report on AM and DSE fungal association for 22 and 30 species, respectively. In addition, AM morphology was evaluated for the first time in 34 species. Sixty-five percentage of the mycorrhizal ferns had intermediate- type AM and 19.30 % had typical Paris-type AM morphology. Both Paris- and intermediate-type AM morphologies were observed in 10.53 % of ferns. The root length colonized by AM and DSE fungal structures significantly varied among species, and a significant negative relation existed between the root length colonized by AM and DSE fungi.Item ARBUSCULAR MYCORRHIZAL FUNGAL STRAINS AND SOIL TYPE INFLUENCE GROWTH, NODULATION, AND NUTRIENT UPTAKE OF CASUARINA EQUISETIFOLIA(Springer, 2013) Muthukumar T; Uma E; Priyadharsini PThe effects of arbuscular mycorrhizal (AM) fungal species and strains on seedling growth and uptake of nutrients were determined for Casuarina equisetifolia under nursery conditions. Seedlings of C. equisetifolia were inoculated individually with four strains each of Acaulospora scrobiculata and Glomus aggregatum in two soil types (alfisol and vertisol). Seedling height, root collar diameter, nodulation, dry weights, nutrient contents, nutrient uptake efficiencies, mycorrhizal inoculation effect (MIE), and seedling quality were determined at harvest. Seedlings inoculated with different AM fungal strains invariably had significantly higher plant growth, and nutrient parameters measured. Nevertheless, the response was higher for seedlings inoculated with strains of G. aggregatum compared to those inoculated with strains of A. scrobiculata. The mycorrhizal response as measured by MIE was significantly affected by soil types. These results suggest the importance of selecting a specific AM fungal strain suited for a soil type in forest nurseries for the production of high-quality seedlings.Item TREE SPECIES AS HOSTS FOR ARBUSCULAR MYCORRHIZAL AND DARK SEPTATE ENDOPHYTE FUNGI(Journal of Forestry Research, 2012) Uma E; Sathiyadash K; Loganathan J; Muthukumar TA survey of 35 tree species (belonging to 28 genera in 19 families) in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal status. All the tree species examined had AM association. AM and DSE colonization is reported for the first time in 20 and 14 species respectively. Cooccurrence of AM and DSE was observed in 14 (40%) tree species. The extent of DSE colonization was inversely related to the extent of AM fungal colonization. Six tree species had Arum-type, 18 had intermediate type and 11 had typical Paris-type AM morphology. AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil. AM fungal spore numbers were not related to the extent of AM colonization and Glomus dominated spore diversity. AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species. The occurrence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this association in future conservation programmes of these species.Item INFLUENCE OF ORGANIC POLLUTANTS ON ARBUSCULAR MYCORRHIZAL FUNGI(Nova Science Publisher, 2010) Uma E; Jaison S; Muthukumar TThe numerous benefits contributed by arbuscular mycorrhizal (AM) fungi has lead to recognition of their benefits in sustainable agriculture and various natural environmental processes. Application of anthropogenic and other compounds intentionally in the form of pesticides, fungicides, fertilizers or unintentionally like polycyclic aromatic hydrocarbons (PAH) which affect soil fungi have shown varying effects on AM association. Not all organic pollutants are detrimental to AM fungi. Some fungicides such as Fludioxonil have a stimulatory effect on mycorrhizal formation and function. Rapid decrease in the metabolic activity of AM fungi, a decline in arbuscule production, which is the main site of nutrient exchange between the host plant and the fungus, reduction in the total root length colonized and slow colonization rates are the negative effects shown by certain fungicides. Pesticides generally inhibit AM colonization and spore numbers. Slow release mineral fertilizers though benefit AM fungi, their excessive use can result in suppression of the AM fungi. Certain PAH especially anthracene reduce the development of extra radical mycelium, sporulation, root colonization and spore germination. Different AM fungal species show differential sensitivity even within a particular class of organic pollutant. Caution should also be exercised while irrigating soils with effluents as these could affect AM fungi. A reduction in our dependency on conventional agricultural practices especially organic pesticides by using AM fungi as a biological tool which is possible only by maintaining low levels of organic pollutants in the soil. Minimal use of organic pollutants especially pesticides would enable the maintenance of a healthy AM fungal populations essential for sustainable plant production systems.