Cyrtopodium paludicolum germination with two Tulasnella isolates

ABSTRACT Symbiosis between orchid seeds and mycorrhizal fungi has been reported to be a determining factor in the success of germination and protocorm development in vitro. The aim of this study was to isolate and identify by molecular analysis the mycorrhizal fungus associated with Cyrtopodium paludicolum, and to evaluate its efficiency in facilitating seed germination and development. Germination experiments were carried out using a fungus isolated from C. paludicolum (CH01) and Epidendrum secundum (M65), which has been successfully used a number of times in symbiotic germination. The experiments were conducted in a completely randomized design with treatments of CH01, M65 as well as under asymbiotic conditions. The mycobiont CH01 was successfully isolated from Cyrtopodium paludicolum and identified as Tulasnella sp. Treatments with both fungi reached a higher germination percentage than under asymbiotic conditions, indicating no specificity in the relationship between Cyrtopodium paludicolum and the fungi. The results presented have the potential to advance research into the propagation and conservation of C. paludicolum, a native of the Cerrado biome.

摘要：已有研究表明，兰科植物种子与菌根真菌（mycorrhizal fungi）的共生关系是影响离体（in vitro）条件下种子萌发及原球茎（protocorm）发育成败的关键因素。本研究旨在分离并通过分子分析鉴定与沼泽卷瓣兰（Cyrtopodium paludicolum）共生的菌根真菌，并评估其促进种子萌发与发育的效能。本研究分别采用从沼泽卷瓣兰中分离得到的真菌CH01，以及多次成功应用于共生萌发实验的直立树兰（Epidendrum secundum）共生菌M65开展萌发试验；试验采用完全随机设计，设置CH01处理组、M65处理组及非共生培养对照组。研究成功从沼泽卷瓣兰中分离得到共生真菌CH01，并经鉴定为胶膜菌属（Tulasnella sp.）真菌。两种真菌处理组的种子萌发率均高于非共生培养组，表明沼泽卷瓣兰与该类真菌之间不存在宿主特异性关系。本研究结果可为塞拉多生物群系（Cerrado biome）特有物种沼泽卷瓣兰的繁殖与保护研究提供推进助力。