Arbuscular mycorrhizal relations of mangrove plant community at the Ganges river estuary in India

Abstract

Mangroves are climax formation of hydrohalophytes inhabiting estuarine or marine salt marshes in the tropics and subtropics. As a terrestrial plant community inhabiting tidally inundated estuarine or marine sediments, mangroves show considerable adaptation to salinity, water-logging and nutrient stress. Thirty-one species of mangrove and mangrove associates and 23 species of transported flora, belonging to 25 families at four physiographic stages of succession of the mangrove plant community at the terminal part of the Ganges river estuary in India were examined for arbuscular mycorrhizal (AM) root association. Dominant members of the mangrove plant community were all AM, mostly with 'Paris' type structures. Many of the known non-mycotrophic plant families, except the Cyperaceae, also showed AM association, with intracellular hyphae and vesicles as the most discernible endophyte structures. Intensity of AM colonization varied both with the species and situations of their occurrence, being more intense and also more extensive in less saline dry ridge mangroves than in more saline formative and developed swamp mangroves. Introduced exotic trees on the ridges and embankments were infected by AM, but less than the declining mangroves in the same location. Seven species of AM fungi in common with those of the upstream mesophytic plants were isolated from root-free rhizosphere soils of the mangroves, three of which predominated in root association. These species, individually and as mixtures, infected roots of salinity tolerant herbs and trees in both locational silt and upstream alluvial soil with obvious improvements in their biomass yield and phosphorus nutrition. AM infective potential of root-free rhizosphere soils of the dominant members of the mangrove community were negatively related to salinity level of the sediment soil of the successional stages. The evidences of AM association of mangroves and other salt marsh plants obtained here and those reported elsewhere are discussed.

Mangrove tannins in aquatic ecosystems: Their fate and possible influence on dissolved organic carbon and nitrogen cycling

“…Mangrove roots sometimes associate with mycorrhizae (Sengupta and Chaudhuri 2002;Kothamasi et al 2006). Despite the refractive character of tannin-protein complexes against microbial degradation, some mycorrhizae can produce exoenzymes that degrade tannin-protein complexes and utilize the released N (Bending and Read 1996;Wu et al 2003).…”

Anatomically and morphologically unique dark septate endophytic association in the roots of the Mediterranean endemic seagrass Posidonia oceanica

“…This requires the formation of specific exchange interfaces by the mycobiont inside the host root (Peterson and Massicotte 2004). It has been estimated that mycorrhizae are present in some 86 % of angiosperm species (Brundrett 2009), including freshwater plants (Søndergaard and Laegaard 1977;Beck-Nielsen and Madsen 2001;Sudová et al 2011;Kohout et al 2012) and plants from salt marshes (Radhika and Rodrigues 2007;Welsh et al 2010;Eberl 2011) and mangroves (Sengupta and Chaudhuri 2002;Kothamasi et al 2006). On the other hand, certain plant guilds do not require mycorrhizal symbioses for nutrient uptake (e.g.…”

Salt tolerance mechanisms in mangroves: a review

“…Mangroves grow in the intertidal zone between land and sea. They are frequently inundated by tide leading to waterlogging and fluctuation in salinity (Naidoo et al 2002;Sengupta and Chaudhuri 2002;Paliyavuth et al 2004;Jagtap and Nagle 2007). Like other marine organisms, they are exposed to the air and thus to the risk of desiccation and overheating; on the other hand they face waterlogging and salinity (Naidoo et al 2002;Sengupta and Chaudhuri 2002;Paliyavuth et al 2004;Jagtap and Nagle 2007).…”