Abstracts |
This study describes the mycorrhizal associations in five mangrove species namely, Bruguiera gymnorrhiza, Excoecaria agallocha, Heritiera fomes, Phoenix paludosa, and Xylocarpus mekongensis, growing in two distinct ecological sites. One group is growing in non-saline garden soil of the Indian Statistical Institute, Kolkata, West Bengal, India, and the other group in the ridge saline zone of the Sundarbans forest. The vesicular arbuscular mycorrhizal (VAM) status of these plants were evaluated in terms of VA fungal spore number (Sp) per 10 g of rhizospheric soil, frequency of mycorrhiza (F%), intensity of mycorrhizal colonization (M%), arbuscule (A%), vesicle (V%) and hyphal abundance (H%) in the root systems. The soil salinity levels of the garden ranged from 0.32 to 0.96 ppt and were more poor in nutrition (in terms of available nitrogen), whereas salinity levels of forest soils ranged from 5.33 to 10.67 ppt with high concentrations of exchangeable sodium and potassium. The extent of mycotrophy was more in fresh water condition of the garden than that of the saline Sundarbans forest. The garden mangroves showed the mean F% and Sp as 94.91 and 16.73, whereas the mangrove forest possessed only 28.67 and 14.8 respectively, E. agallocha showed high F%, M%, A% and highest Sp in the rhizospheric soils at both the sites. In the saline tracts of the forest. H. fames lacked mycorrhizal colonization in the roots. Both 'Arum' and 'Paris' types of mycorrhizal colonization were common in B. gymnorrhiza, E. agallocha, X. mekongensis at both garden and forest and in H. fomes at the garden. P. paludosa exhibited 'Arum' type at the garden, but 'Paris' type at the forest. Spore numbers showed significant positive correlation with F%, whereas negative correlation with available phosphorus content of the soil. The F%, M%, and H% were highly positively correlated to each other, but were highly negatively correlated to soil salinity, exchangeable Na, K and available P content. The A% was positively correlated to F% and M% but not significantly correlated to any of the soil characteristics. Glomus and Acaulospora were frequent in both garden and forest soils, but Glomus versiforme was predominant in the garden soils and G. mosseae and G. etunicatum in the soils of the Sundarbans.. |