不同内生真菌对齿瓣石斛幼苗生长的效应

Effects of different endophytic fungi on seedling growth of Dendrobium devonianum

石斛属植物根部存在大量功能未知的内生真菌,从中筛选获得生长阶段有效共生真菌是药用石斛仿生态栽培深入开展的关键。该研究利用单菌丝团分离法从齿瓣石斛植株根部分离得到的6株内生真菌,与齿瓣石斛无菌播种幼苗进行共生培养实验。培养90 d以后,与对照组相比,FDd S-1,FDd S-2,FDd S-4菌株处理对幼苗产生明显致死或致病作用,而接种FDd S-5,FDd S-9,FDd S-12菌株处理的齿瓣石斛幼苗则健康生长,并表现出不同的生长效应,其中,FDd S-5菌株对幼苗的株高、鲜重、干重、茎粗和根数都有显著的促进作用,FDd S-9菌株仅对幼苗的株高有显著促进作用,而FDd S-12菌株则对齿瓣石斛幼苗的生长产生抑制作用。显微观察发现FDd S-5菌株处理的幼苗根部皮层形成菌丝团共生结构,可以判定FDd S-5为齿瓣石斛的菌根真菌。经分子鉴定,菌株FDd S-5和FDd S-9分别和蜡壳菌属Sebacina的2种真菌相似度最高。将FDd S-5菌株应用于齿瓣石斛的仿生态栽培,可望能有效的促进齿瓣石斛幼苗生长和缩短幼苗生长周期,研究结果为齿瓣石斛的野外回归和人工栽培提供了技术支撑。

To obtain seedling growth-promoting fungi is a key step in restoration-friendly cultivation of medicinal Dendrobium species, since there are a large number of functionally-unknown endophytic fungi in the roots of Dendrobium plants. In this study, six functionally-unknown endophytic fungal strains were isolated from roots of D. devonianum using single peleton isolation technology, and used in inoculation experiments to test their effectiveness for seedling growth in D. devonianum. After 90 days of inoculation, comparing with the control treatment, FDdS-1, FDdS-2 and FDdS-4 showed strong pathogenic or fatal effects on seedlings; while, FDdS-12, FDdS-9 and FDdS-5 had different effects on seedling growth. FDdS-5 had significant promoting effects on height, fresh and dry weight, stem diameter and root numbers, while FDdS-9 only had significant promoting effect on seedling heighf, and FDdS-12 had a negative effect on seedling growth. According to the anatomical features of the inoculated roots, FDdS-5 fungi could infect the velamina of seedlings and the existence of symbiosis pelotons in the cortex cells, suggesting that FDdS-5 is a mycorrhiza fungi of D. devonianum. FDdS-5 and FDdS-9 were identified as Sebacina vermifera and Sebacina sp. by molecular technologies. By using FDdS-5 in the restoration-friendly cultivation of D. devonianum, it could effectively promote seedling growth and shorten the seedling growth periods. The results will aid in reintroduction and cultivation of D. devonianum.