We found mycoheterotrophic seedling growth (initial mycoheterotrophy) of Gentiana zollingeri, a spring-flowering photosynthetic species of Gentianaceae family. Small seeds (about 300 µm in length) were buried in a habitat by using seed packets, and development of the subterranean seedlings to form shoots, more than 3 cm in length, was observed in symbiosis with arbuscular mycorrhizal (AM) fungi in the dark (i.e., underground of a field). Hyphal coils and their degenerations were observed in the root cortical cells of the subterranean seedlings as well as those of adult plants. Among the mycobionts identified on the basis of partial small subunit rDNA sequences, it was found that AM fungi of a lineage in Glomeraceae dominantly colonized, and the AM fungi were also dominant in adult individuals of G. zollingeri in three habitats separated one another by 17.2, 34.7, and 49.6 km. Though initial mycoheterotrophy in symbioses with AM fungi has been observed in some pteridophytes, this is the first study to demonstrate this type of symbiosis in a photosynthetic seed plant. The mycoheterotrophy means that an energy distribution occurs through the hyphal bridges of AM fungi among different photosynthetic seed plants, which may be important in constructing plant species diversity in some ecosystems.

我们发现了龙胆科春季开花的光合物种龙胆属的真菌异养幼苗生长（初始真菌异养）。使用种子包将小种子（长约 300 µm）埋在栖息地中，在黑暗中观察到地下幼苗发育成超过 3 厘米长的枝条，与丛枝菌根 (AM) 真菌共生（即，田地的地下）。在地下幼苗和成年植物的根皮层细胞中观察到菌丝卷及其退化。在根据部分小亚基rDNA序列鉴定的真菌生物中，发现在Glomeraceae中的一个谱系的AM真菌占优势，并且AM真菌在成年个体中也占优势。三个栖息地中的G. zollingeri彼此相距 17.2、34.7 和 49.6 公里。尽管在一些蕨类植物中观察到了与 AM 真菌共生的初始真菌异养，但这是首次在光合种子植物中证明这种共生的研究。真菌异养意味着能量分布通过 AM 真菌在不同光合种子植物之间的菌丝桥发生，这可能对构建某些生态系统中的植物物种多样性很重要。