Galam is an indigenous peatland species which is able to adapt to acidic conditions. Besides galam, peatland is also covered with exotic plants, such as Sengon. Both plants can live with arbuscular mycorrhizal fungi (AMF) association. The potential growth of galam and sengon can be seen from the abundance of AMF. Arbuscula mycorrhizal abundance can be seen from the value of infective propagules. The propagules value can determine the effectiveness of AMF in increasing the growth of a plant. The aim of this study is to compare the abundance of arbuscular mycorrhiza (in the form of infective spores and propagules) under sengon (F. moluccana (Miq.) Barneby & Grimes) stands and galam (M. cajuputi Powell) and describe symbiotic forms of AMF colonization on the roots of sengon and galam. This study used the MPM method (Most Probable Number), stepwise filtering (wet sieving) and root staining from the modification of Vierherlig et al., 1996 and the calculation of mycorrhizal colonization in the roots by gridline technique. The research used Complete Randomized Design(CRD) with a 5-fold factorial patterns. The results of this study indicated a significant difference between the abundance of FMA under sengon and galam stands at the depth of 0-15 cm and 15-30 cm respectively. The results of spores identification showed 4 genera of spores, namely:Glomus, Gigaspora, Scutellospora, and Acaulospora. The structure of root colonizations were hyphae, spores, vesicles, and arbuscula.

Keywords: galam, peatlands, mycorrhizal, MPN, sengon