摘要
【目的】探讨6种兰科植物地下营养根的形态解剖结构特征、菌根真菌侵入方式及在菌根内的分布和消长状况,为菌根真菌与兰花共生的相互关系提供理论依据。【方法】利用光学显微镜和电子显微镜连续切片的方法,用分离自野生状态的菌根真菌菌株CLB113和CLB111接种春兰(Cymbidium goeringii)、墨兰(Cymbidiumsinense)、虎头兰(Cymbidium hookerianum)和卡特兰(Cattleyasp.)、齿瓣石斛(Dendrobium devonianum)、长距石斛(Dendrobium longicornu)种子繁育组培苗,使共生形成菌根,观察菌根形成途径及结构,并与自然状态下的菌根结构进行比较。【结果】经光学和电子显微镜观察发现,菌根与非菌根(组培苗根)在根的基本结构上没有明显区别,两者之间的主要差异在于根中是否有入侵的菌根真菌,在皮层细胞中常见到分布不匀、形状不一、着色较深的菌丝结;不同兰科植物真菌的入侵方式不同,地生兰菌根真菌是通过破坏根被组织侵入根皮层细胞,而附生兰菌根真菌是通过通道细胞进入;在光镜下观察到的菌丝结,在电镜下是真菌菌体围绕皮层细胞核所形成的。【结论】兰花与菌根真菌的共生机理是,菌根真菌侵入兰花的皮层细胞内,使其中存在有大量新定殖的菌丝和正在被消化的菌丝,随着菌丝及菌丝团被逐渐消解吸收,伴随新菌丝的生长和侵入,内生真菌可不断地为兰花提供营养,促进兰花快速生长。
[Objective] The mycorrhizal of orchids is a nature phenomenon, but how does the fungus provides nutrition for the orchids to support the growth is the solution to manual cultivation of orchids. [Method] Optical and electronic microscope was used to obserue CLB113 etc. [Result] We found the pathway of infection and structure of mycorrhizal in Cymbidium goeringii, C. sinense, C. hookerianum and Dendrobium devoninum etc, which demonstrated that they had typical orchidaceous roots with velamen and thick cortical tissue. For the terrestrial orchids, the infection pathway was that fungi invaded velamen firstly and then entered cortical tissue by breaking the velamen. But for D. devoninum of orchid, the fungi entered the cortical tissues through passage cell and the colonized and infected other cells continuously by means of hypha penetrating the cell wall. [Conclusion] Thus, it can be concluded that the mechanism of symbiosis between orchid and mycorrhizal is as follows：first,cortical tissues is infected by mycorrhizal. After the infection,there are a lot of pelotons which appear in dark color and in the irregular shapes in the cortical tissue under microscope observation. Under the electronic observation, pelotons are cell nuclear, surrounded by a group of hypha. Pelotons mainly appear in outsider layer cells of the cortical tissue and it will provide nutrients for plants when it is dissolved and absorbed. Then with more invasion and growth of young hyphae,endophytic fungi can provide nutrition for rapid growth of the plantlets.
出处
《西北农林科技大学学报（自然科学版）》
CSCD
北大核心
2009年第7期199-207,共9页
Journal of Northwest A&F University(Natural Science Edition)
基金
国家自然科学基金项目(30671717)
云南省教育厅科学研究基金项目(06Z057B)
国家"十一五"科技支撑计划重点项目(2008BAC39B05)
关键词
兰科植物
菌根
显微结构
超微结构
orchid
mycorrhiza
microscope structure
ultramicroscopic structure
