Fig. S4 (IMAGE) Shinshu University Caption Developed ectomycorrthizal root system and shiro structure in the non-axenic 4.1-L jar system. a: A seeding that grew showed a shiro structure > 10 cm in diameter at the central region of the root system in the upper soil depth and two small shiro structures in the acropetal position of the root system at the lower soil depth. b: Extraradical mycelium at the outer surface area of the shiro structure. c: External features of an ectomycorrhizal root tip. Bars 5cm (a), 0.2 mm (b, c). Credit Copyright © 2021, Akiyoshi Yamada et al., under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature Usage Restrictions The image may only be used with appropriate caption or credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.