Arbuscular Mycorrhizal (AM) and Dark Septate Endophyte (DSE) Fungal Association in Lycophytes and Ferns of the Kolli Hills, Eastern Ghats, Southern India

Abstract

^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 dual a 1 DSE fungi. Seventy two percent of the mycorrhizal lycoph)rtes 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.

Root fungal associations in some non-orchidaceous vascular lithophytes

“…Like the incidence of AM, DSE fungal associations in lithophytes are also limited to certain plant groups. The occurrence of DSE fungal association in lithophytic fern and fern-allies has been reported recently from the Eastern and Western Ghats of southern India Muthuraja et al 2014).…”

“…One of the harshest habitats is the surfaces and crevices of rock where low moisture, nutrients and high temperatures limit plant's existence. Plants growing on rocks are termed lithophytes and these types of plants occur in diff erent arid (Zwieniecki & Newton 1995;Bashan et al 2002;Lopez et al 2009) and non arid (Tozer et al 2005;Grӧger & Huber 2007;Muthuraja et al 2014) ecosystems. Nevertheless, lithophytes also colonize rocks that are constantly misted by waterfalls or rocks dripping with water.…”

“…Although the roots of several terricolous plant taxa have been examined for the presence of AM fungal association, their occurrence in lithophytic or saxicolous plant species is limited to certain plant groups. For example, the occurrence of AM fungal association has been examined in lithophytic mosses (Zhang & Guo 2007) and ferns (Lehnert et al 2009;Kessler et al 2010;Muthukumar & Prabha 2013;Muthuraja et al 2014). The results of some of these studies suggest that non-mycorrhizal condition appears to be more prevalent in lithophytic than in terricolous taxa (Kessler et al 2010).…”

“…In between these two extremes, there exists a diverse colonization patterns termed as intermediate types. Though AM colonization patterns in terricolous plant species are widely reported, it is rather scanty for lithophytic species (e.g., Muthukumar & Prabha 2013;Muthuraja et al 2014).…”

“…These fungi termed as dark septate endophyte (DSE) fungi form dematiaceous, regularly septate hyphae with microsclerotia and/or moniliform cells in plant roots. Although these fungi have been recorded in roots of more than 1000 plant species growing in a range of habitats (Jumpponen & Trappe 1998;Mandyam & Jumpponen 2005;Muthukumar & Prabha 2013;Muthuraja et al 2014;Kumar & Muthukumar 2014), their occurrences in many plant taxa and habitats are yet to be examined. Like mycorrhizal fungi, DSE fungi also associate with plants under extreme environmental conditions (Read & Haselwandter 1981;Newsham et al 2009).…”