菌根真菌对白及种子萌发和幼苗生根的作用

自然条件下,兰科植物需要依赖菌根真菌获得营养才能萌发。本研究对白及根和原球茎中分离的4株菌根真菌（WQ17-33、WQ17-43、JST-3和SL15-7）进行分子鉴定,并评价光照和黑暗条件下不同菌株促白及种子萌发和幼苗生根的效果。结果表明,4个菌株分别隶属于鬼伞属Coprinus、胶膜菌属Tulasnella、腊壳菌属Sebacina和Serendipita。在种子萌发前期（未形成叶子）进行暗培养较光照对菌株JST-13和SL15-7处理组原球茎阶段萌发具有显著的促进作用。不同菌株共生萌发效果不同,菌株SL15-7较其他处理原球茎和幼苗发育阶段的萌发率高。菌株JST-13和SL15-7处理组形成的幼苗较其他处理组强壮,定殖的菌丝团也较多,其幼苗生根效果也较对照组好。该研究表明白及可与多种不同类群的菌根真菌菌株形成共生关系,这些真菌在促进白及种子萌发和生根能力方面存在差异。

Effects of mycorrhizal fungi on seed germination and seedling rooting of Bletilla striata

Under natural conditions, orchid plants depend on mycorrhizal fungi for their nutrition at the germination stage. In this study, four mycorrhizal fungal isolates (WQ17-33, WQ17-43, JST-3 and SL15-7) from roots and protocorms of Bletilla striata were identified based on sequences of internal transcribed spacer (ITS) region, and the effects of the fungi on seed germination under dark and light conditions and seedling rooting were also evaluated. The four isolates were assigned to Coprinus sp., Tulasnella sp., Sebacina sp. and Serendipita sp., respectively. The results of investigation were that JST-13 and SL15-7 treatments obviously promote germination rate of seed and growth of protocorm in the dark condition. Isolate SL15-7 had higher promotive effect on protocorm and seedling development than other isolates. The growth vigor of seedlings treated with JST-13 and SL15-7 was stronger and colonized pelotons were more in comparison with the seedings treated with other isolates. The rooting of seedlings treated with JST-13 and SL15-7 was also better. Facts have proved that different mycorrhizal fungi vary in their ability to facilitate seed germination and root development of B. striata in vitro.