黑松菌根共生体中真菌液泡形态构架及其活力

MORPHOLOGY AND ACTIVITY OF ECTOMYCORRHIZAL FUNGI IN VITRO AND IN SYMBIONT WITH PINUS THUNBERGII

为探讨菌根共生体中菌根菌液泡结构及其活力变化对宿主生长的影响,对3种外生菌根菌黄色须腹菌(Rhizopogen luteous,简称Rl)、彩色豆马勃(Pisolithus tinctorius,简称Pt2)、美味牛肝菌(Boletus edulis,简称Be)离体菌丝及与黑松(Pinus thunbergii)形成菌根共生体的冰冻切片进行6-羧基二乙酸荧光素(6-CFDA)染色,观察了真菌液泡形态构架及其活力的变化。结果表明,在Pt2与Rl离体菌丝中既可见单个分散的大液泡,又可见相邻液泡间由细管状连接而成的管状液泡系统,Be离体菌丝的液泡则呈细小颗粒状,密集分布于菌丝体的各个部分;Be离体菌丝的活性强于Pt2和Rl。上述3种菌根菌与黑松形成菌根共生体后,Pt2与Rl对黑松的促生效果好于Be,菌根共生体中菌套和哈氏网菌丝的活性明显强于Be,且仍可见数个液泡连接成管状系统;而在Be菌根中菌丝液泡系统不形成管状,活性较低。结果暗示,菌根共生体中真菌的管状液泡系统及其活力与对黑松的促生作用似存在一定的相关性。该研究对于进一步了解菌根的促生作用机理及菌根真菌与宿主植物的协同进化具有一定的意义。

Aims. The fungal vacuole plays a key role in nutrient transportation and storage, especially in ectomycorrhizal symbionts. Our objective was to explore the effects of fungal activity and vacuole structure changes on host plant growth to further understand the mechanism of growth-promotion of mycorrhizal fungi and coevolution between host plant and mycorrhizal fungi. Methods Hyphae of ectomycorrhizal fungi Rhizopogen luteous （Rl）, Pisolithus tinctorius （Pt2）, and Boletus edulis （Be） cultured in vitro were stained with 6-CFDA, and the morphologies of fungal vacuoles and their activities were examined. Frozen sections of the ectomycorrhizal symbiont formed by the three fungi and Pinus thunbergii seedlings were stained and observed in the same way. Important findings Dispersive large vacuoles in hyphae of Pt2 and Rl and many small dense vacuoles in the hyphae of Be were observed in fungi cultured in vitro, and some vacuoles of Rl and Be linked into tubular vacuole systems. The activity of Be hyphae was higher than Pt2 and Rl, and Be grew faster than the other two. After ectomycorrhizal formation, P. thunbergii seedlings with Pt2 or Rl grew better than those with Be, and the fungal activities vacuole morphologies had changed greatly. Hyphae in mantles and Hartig nets of ectomycorrhiza formed by Pt2 and Rl showed higher activities than those formed by Be, which were hard to label, and tubular vacuole systems were observed sometimes in the hyphae of Hartig nets of Pt2 and Rl syrnbionts. It appears that fungal activity and tubular vacuole systems are related to the growth ofP thunbergii seedlings.