Diversity and Characterization of Ectomycorrhiza Morphotypes in Castanopsis inermis (Lindl. ex Wall.) Benth. & Hook.f. from the Batang Toru Forest, Indonesia

Abstract Castanopsis inermis is a member of the Fagaceae and is endemic to Sumatra, which serves as a food source for forest-dwelling animals. C. inermis forms an ectomycorrhizal symbiosis to support the uptake of water and nutrients. This research aimed to assess the diversity of ectomycorrhizae associated with C. inermis by studying root tip morphotypes. The methodology involved sampling the root tips of C. inermis from the natural forest. The analyses were focused on the type of ramification, colour, type of surface, type of rhizomorphs, and length of the ectomycorrhizal system. The observations revealed 15 distinct morphotypes. The length of the root tips varies from 0.21 to 2.80 mm, and the diameter ranges from 0.12 to 0.49 mm. The mantle hyphae developed in C. inermis exhibit a plectenchymatous, a pseudoparenchymatous, and a transition between plectenchymatous and pseudoparenchymatous types. The mantle hyphae thickness varied between 16.61 and 62.94 μm, while the Hartig nets length measured from 11.40 to 54.93 μm. There are only two varieties of cystidia present, specifically awl-shaped and thin-walled. The diversity of ectomycorrhiza root tip morphotypes of C. inermis is high. The results of this research can be used in forest management, conservation strategies, and rehabilitation of degraded landscapes.