Effects of Ectomycorrhizal Inoculation on Shorea macrophylla Seedlings Using Mycorrhizal Trees

Inoculation of ectomycorrhizal fungi to nursery-raised tree seedlings can improve survivorship and growth of them when transplanted into the field. This study investigated the effects of ectomycorrhizal inoculation using mycorrhizal tree on Shorea macrophylla seedlings, planted at different intervals, in a tropical nursery. Forest topsoil and river sand were mixed at a volumetric ratio of 1 : 1 as bedding medium. The non-mycorrhizal seedlings and a mycorrhizal tree were planted in a plastic container (length=75 cm, width=25 cm, depth=14 cm), with the seedlings spaced at 20-cm and 30-cm intervals from the tree. These seedlings were raised for 6 months at a nursery of the Lambir Hills National Park, Miri, Sarawak, Malaysia. Mycorrhizal formation percentage, dry matter weight, and nutrient content of the seedlings and soil properties of the bedding media were measured. The ectomycorrhizal infection could transfer from mycorrhizal tree to the seedlings by the elongation and connection of rhizomorph in both 20-cm- and 30-cm-interval treatments. The ectomycorrhizal inoculation would be better when the seedlings were planted closer to mycorrhizal tree, i.e., at 20-cm interval. Early phase infection and greater mycorrhizal formation might improve nutrient acquisition such as N under poor nutrient condition.