Department of Botany

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    ZINC INFLUENCES REGENERATION OF TALINUM PORTULACIFOLIUM STEM CUTTINGS IN NUTRIENT SOLUTION
    (AcademicPres- Notulae Scientia Biologicae, 2018-12-21) Muthukumar T; Jaison S; Dinesh Babu Selvam
    Zinc (Zn) is an essential micronutrient for plant growth and development, but toxic at high concentrations. The present study focused to underline the direct effect of different concentrations (0-50 ppm) of Zn on the regeneration ability and morphological characteristics of Talinum portulacifolium stem cuttings in hydroponic solution over a period of 35 days without the interference of other soil factors. High concentrations of Zn (40-50 ppm) affected callusing, root initiation, root and shoot development to varying levels. At high concentrations, Zn caused stem decay, stunting and browning of roots, wilting, withering and necrotic spots on leaves. Increasing concentrations of Zn inversely affected the lateral shoot development, stem elongation, leaf, root numbers and total root length of the stem cuttings. Though Zn had no significant influence on fresh or dry weights of stem, low concentration (15 ppm) of Zn increased the fresh and dry weights of leaves by 11.17% and 26.79% respectively, compared to 0 ppm and with 77.06-243.80% and 47.92-255.00% compared with those raised in 20-50 ppm. Zn concentrations >10 ppm reduced the root fresh weight by 28.57-90.47% and dry weight by 27.27-90.91% than those at 0 ppm. The Zn content in leaves and stems increased linearly with increasing concentrations of Zn and ranged from 1.09-125.62 ppm and 1.00-110.26 in stems and leaves respectively. The tolerance index varied between 81 and 138 for different concentrations of Zn. The results of the study clearly indicate that high concentrations of Zn inhibit the regeneration of T. portulacifolium stem cuttings.
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    CHROMIUM ACCUMULATION IN PLANTS OF THERAPEUTIC VALUE GROWING NATURALLY ON TANNERY POLLUTANT CONTAMINATED AND NON-CONTAMINATED SOILS
    (Springer- Biological Trace Element Research, 2016-05-25) Jaison S; Muthukumar T
    Herbal preparations used to treat human ailments globally can be contaminated with various heavy metals (HMs) originating from the raw materials or from the manufacturing processes. Therefore, we assessed 22 medicinal plants growing naturally on tannery pollutant contaminated (Site-C) and non-contaminated (Site-NC) sites for their ability to accumulate chromium (Cr). The Cr contents in soil and various plant parts were estimated using an atomic absorption spectrophotometer. Translocation and bioconcentration factors were calculated. The soil at Site-C had 27-fold higher concentration of total Cr than at Site-NC. Chromium accumulation is reported for the first time in 50 % of the medicinal plants examined and varied significantly among the sites. Shoots of Ricinus communis and Amaranthus viridis had maximum concentrations of Cr at Site-C, whereas in Site-NC, none of the plants had Cr accumulation >30 ppm. Ricinus communis, Amaranthus viridis, and Amaranthus spinosus had translocation factor (TF) greater than the one in the Site-C and Lantana camara had TF >1 in Site-NC. The bioconcentration factor (BCF) was >1 only for Ricinus communis at both the sites. The majority of the medicinal plants at Site-NC had Cr content exceeding the permissible limit of 2 ppm suggested for herbal raw material. The results of the study clearly emphasize the need for screening plants of therapeutic value for the presence of HMs even when collected from non-contaminated soils. Moreover, proportional allocation of Cr in different plant parts provided an insight on the safety of these parts when specifically used in herbal preparations.
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    ASYMBIOTIC SEED GERMINATION, MYCORRHIZATION AND SEEDLING DEVELOPMENT OF ACAMPAE PRAEMORSA (ROXB.) BLATT. & MC CANN, A COMMON SOUTH INDIAN ORCHID
    (Elsevier- Asian Pacific Journal of Reproduction, 2013-06-20) Sathiyadash K; Muthukumar T; Bala Murugan S; Sathishkumar R; Uma E; Jaison S; Priyadharsini P
    To develop conservation strategies for orchid species. Methods Seeds of Acampae praemorsa (Roxb.) Blatt. Mc Cann ( A. praemorsa ) were obtained from mature pods collected from Velliangiri hills and germinated on Murashige and Skoog (MS) medium supplemented with various concentration of Benzylaminopurine (BAP). Results Maximum seed germination (85%) was observed on MS media supplemented with 2 mg/L BAP. Seed germination percentage increased with increasing concentrations of BAP (0.5 mg/L to 2 mg/L), but 3 mg/L of BAP inhibited seed germination. Variations observed were significantly ( P ex vitro conditions. Conclusions In present study all the mycorrhizal seedlings survived, because orchid mycorrhizal fungi enhance growth of orchid plantlets and present study gives an effective protocol for seed germination and plantlet regeneration from immature seeds which can be used for establishing A. praemorsa populations in Velliangiri Hills and elsewhere.
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    MORPHOLOGY, ANATOMY AND MYCORRHIZAE IN SUBTERRANEAN PARTS OF ZEUXINE GRACILIS (ORCHIDACEAE)
    (University of Murcia, Spain-Anales de Biologia, 2011-12-14) Muthukumar T; Uma E; Karthikeyan A; Sathiyadash K; Jaison S; Priyadharsini P; Ishworani C; Muniappan V
    Zeuxine gracilis (Berda) Bl., is an endemic, terrestrial green orchid whose morphology, anatomy and mycorrhizal status is unknown. So we investigated: (a) root and rhizome anatomy; (b) root hair characteristics and mycorrhizal colonization patterns in Z. gracilis plants collected from Western Ghats region of southern India. The prominent anatomical characters in the roots were: absence of velamen, spiranthosomes, and the presence of single layered exodermis and nine arched protoxylem. The rhizome had an uniseriate epidermis, abundant spiranthosomes in the inner cortical cells, a distinct endodermis with casparian strips and biseriate vascular bundles. The presence of fungi both in the roots and rhizomes was revealed. The entry of fungi was chiefly through root hairs and through epidermis in the rhizome. Fungi formed pelotons and monilioid cells in the root cortex. Additionally, arbuscular mycorrhizal (AM) fungi characterized by the presence of aseptate hyphae, vesicles and spores were present occasionally in roots. The lack of arbuscules in Z. gracilis indicated the AM to be non functional.
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    THE MYCORRHIZAL STATUS OF SOUTH INDIAN EPIPHYTIC ORCHIDS
    (The Postgraduate & Research Department of Botany, St. Thomas College, Kozhencherry, Kerala, India, 2009-10-28) Sathiyadash K; Uma E; Muniappan V; Sarah jaison; Muthukumar T
    The study is to screen certain orchid species growing naturally in southern India for their mycorrhizal status and to assess the role of root morphology in determining the mycorrhizal status of orchids
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    ARBUSCULAR MYCORRHIZAL FUNGAL ASSOCIATIONS IN ZINGIBERACEAE AND COSTACEAE
    (The Postgraduate & Research Department of Botany, St. Thomas College, Kozhencherry, Kerala, India, 2009-10-28) Uma E; Sathiyadash K; Muniappan V; Sarah jaison; Muthukumar T
    We provide information on the AM fungi incidence exclusively in Zingiberaceae and Costaceae, which will provide an opportunity to extend our knowledge on the AM association in these plant families
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    MORPHOLOGY, ANATOMY AND MYCOTROPHY OF PSEUDOBULB ANDSUBTERRANEAN ORGANS IN EULOPHIA EPIDENDRAEA AND MALAXIS ACUMINATA (EPIDENDROIDEAE, ORCHIDACEAE)
    (Flora, 2015-10-03) Uma E; Rajendran R; Muthukumar T
    The pseudobulbs and subterranean organs (roots and rhizomes) of Eulophia epidendraea, and Malaxis acuminata in subfamily Epidendroideae (Orchidaceae) were investigated to determine morphology,anatomy and mycorrhizal occurrence. The examined sections showed the following common anatomi-cal characteristics. The pseudobulbs had a uniseriate epidermis. The assimilatory cells were scattered inthe form of mucilage/water storage cells in the ground tissue. The vascular bundles were collateral andembedded in the ground tissue. Raphides occurred as idioblasts. Rhizomes had an uniseriate epidermis,parenchymatous ground tissue differentiated into outer and inner zones with polygonal intercellularspaces. Vascular bundles scattered, collateral and discontinuous form in both the taxa. Aeration cellswere present in roots and rhizomes of M. acuminata. The transverse section of E. epidendraea roots hadmulti-layered velamen with spiral thickening followed by uniseriate exodermis with passage cells that had webbed tilosomes. The parenchymatous cortex contained raphides and water storage cells. Vascular bundles were 11–15 arched. Roots of M. acuminata had an uniseriate velamen, exodermis, parenchyma-tous cortex, endodermis and pericycle. The vascular bundles were radially arranged, and 11–12 arched.The xylem and phloem were embedded in sclerenchymatous tissue. The entry of the mycorrhizal fungiwas chiefly through root hairs in roots and epidermis in rhizomes of M. acuminata, and in E. epidendraea.Fungi formed pelotons in both the taxa and microsclerotia and monilioid cells in the root cortex of E.epidendraea. Additionally, Glomus- type vesicles were occasionally present in the roots of M. acuminata.Description of characteristics arising from this investigation may provide additional morphological andanatomical means of identification.
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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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    ARBUSCULAR MYCORRHIZAL (AM) AND DARK SEPTATE ENDOPHYTE (DSE) FUNGAL ASSOCIATION IN LYCOPHYTES AND FERNS OF THE KOLLI HILLS, EASTERN GHATS, SOUTHERN INDIA
    (American Fern Journal, 2014) Muthuraja R; Muthukumar T; Sathiyadash K; Uma E; Priyadharsini P
    We examined the extent and type of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal associations in three lycophyte and 44 fern species collected from three different sites in the Kolli Hills, Eastern Ghats, southern India. Of the 47 plant taxa (belonging to 21 families and 33 genera) examined, 46 had AM fungal and 33 had DSE fungal associations. But, fungal structures were absent in the aquatic fern Azolla pinnata (Azollaceae). This is the first report of AM and DSE fungal status for 16 and 28 species, respectively. Among terrestrial lycophytes and ferns, 26 species had dual association of both AM and DSE fungi, whereas 11 species had only AM fungal association. Vittaria elongata from epiphytic habitats had dual association of AM and DSE fungi. Likewise, Cheilanthes tenuifolia (saxicolous or terrestrial), Cheilanthes opposita, Lepisorus nudus, Pyrrosia lanceolata (terrestrial or epiphytic), and Asplenium lanceolatum (saxicolous or epiphytic) examined from different sites or habitats also had dual association of AM and DSE fungi. Seventy two percent of the mycorrhizal lycophytes and ferns had intermediate-type AM and 15 percent had both Paris- and intermediate-types at different sites. Significant variations in AM fungal structures were evident in 16 ferns occurring in two or more sites. Nine AM fungal spore morphotypes belonging to Acaulospora, Funneliformis, Glomus, Gigaspora, and Sclerocystis were found to be associated with lycophytes and ferns
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    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 K
    WWe 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.