The effectiveness of six species of ectomycorrhizal fungi (Scleroderma columnare, S. dictyosporum, Laccaria laccata, Rhizopogon luteolus, Amanita umbronata and Descomyces sp.) in alginate beads in promoting the growth of four species of dipterocarp seedlings (Shorea pinanga, S. leprosula, S. ovalis and Hopea odorata) were studies.  Different sodium alginate concentrations of 5, 10, 15 and 20 g/l were tested to find out the best bead's elasticity and spore germination.
Seedling height, Realtive Field Mycorrhizal Dependency, percentage of mycorrhizal colonization, nutrient absorption, and formation of Hartig's net and mantle structure of dipterocarp seedlings were observed 4 months after inoculation.
The best elasticity of alginate beads was found in the concentration of sodium alginate of 15 g/l. The best growth increment was found in Hopea odorata inoculated with Amanita umbronata (126.60%) followed by Shorea pinanga inoculated with Descomyces sp. (24.20%) over the control. The highest Relative Field Mycorrhizal Dependency was found in Hopea odorata followed by Shorea ovalis, S. pinanga and S. leprosula.
The highest mycorrhizal colonization was obtained in Shorea pinanga inoculated with Descomyces sp. (75%), while inoculation with A. umbronata on S. leprosula, S. ovalis and Hopea odorata increased mycorrhizal colonization i.e. 64.5, 52.5 and 46.2%, respectively.
Hartig's net and mantle structures were well formed in Shorea leprosula as well as S. ovalis seedlings with all mycorrhizal fungi tested, while in S. pinanga seedlings these structures were only well formed with Descomyces sp.
There is no clear difference in P levels in the leaves following inoculation as compared to the controls.