春兰与丝核菌共生菌根及结构研究

Ultra-structure of Symbiosis Mycorrhizal BetweenCymbidium goeringii and Rhizoctonia sp.

将丝核菌CLB111和KW214菌株及兰科丝核菌CLB113菌株接种到春兰组培苗,对兰苗生长有不同程度的促进作用。处理苗4.5个月后鲜重分别是初始值的170.6%,170.2%和166.1%,其中CLB111,CLB113菌株处理苗与对照达极显著差异(α=0.01),KW214菌株处理苗与对照达显著差异(α=0.05)。通过光学显微镜和电子显微镜连续切片观察发现,菌根结构与普通营养根的结构基本相同,但在菌根的皮层组织细胞中有着色较深、形状不一的菌丝结。春兰外皮层无通道细胞,真菌是通过破坏根被组织进入皮层细胞,并通过菌丝穿越细胞壁不断向内继续扩展。在电子显微镜下观察发现菌丝结是真菌菌丝围绕细胞核形成的,菌丝结在皮层组织靠外的几层细胞中出现较多,随着菌丝团被逐渐消解吸收,伴随新菌丝生长和入侵,为春兰的生长提供营养。从生物量增长、显微及超微结构表明,CLB111,CLB113及KW214等3个菌株与春兰可形成菌根。

CLB111,KW214 strain(belong to Rhizoctonia sp. ) and CLB113 strain (belong to Orchidaceous rhizotonias)were inoculated to tissue culture seedlings of Cymbidium goeringii. After 4.5 months of inoculation, the growth of seedlings was promoted at different level,The average fresh weight of seedlings treated with CLB111,KW214, CLB113 strain were 170.6%,170.2% and 166.1% respectively that of their initial value, while that of the control is just 145.6%. The statistic showed that fresh weight of the seedlings inoculated with strain CLB111,CLB113 were extremely significantly higher(α=0.01), while fresh weight of seedling inoculated with KW214 was significant higher than that of control (α=0.05) .The observation under optical and electronic microscope for CLB111,CLB113and KW214 found the pathway of infection and structure of mycorrhizal in C.goeringii. For the C.goeringii,mycorrhizal structure was same with the general nutrition roots of control structure .The infection pathway was that fungi invaded velamen firstly, then entered cortical tissue by breaking the velamen and the colonized and infected other cells continuously by means of hyphae penetrating the cell wall. There was a lot of pelotons which appeared in dark colour and in the irregular shapes in the cortical tissue under microscope observation. Under the electronic observation, it was found that pelotons was a cell nuclear surrounding by a group of hyphae. Pelotons mainly appeared in outsider layer cells of the cortical tissue and it could provide the nutrients for plants when it was dissolved and absorbed. With more invasion and growth of young hyphae endophytic fungi can provide nutrition for rapid growth of the plantlets.