Studies On Mycorrhizal Of Cymbidium Goeringii ‘Songmei' And Cymbidium Hybridum (Cymbidium Hybridum ‘Princess Nobuko'×Cymbidium Goeringii ‘Huangshuixian') Plantlets From Tissue Culture

Most species of Orchidaceae are famous medicinal plants or precious ornamental flowers.Chinese orchid belongs to Orchidaceae,Cymbidium,which are widely distributed in China.Orchid mycorrhiza,a joint body of Orchids and fungi symbiosis,plays a siginificant role in orchids' life activities.This study inoculated fungi into Cymbidium plantlets in the stage of domestication using a combination of mycorrhizal technology and tissue culture method,aiming at establishing symbiotic cultivation system,selecting excellent symbiotic fungi of orchid,providing scientific basis for researching of orchid microbial inoculum and highly efficiency cultivating of excellent orchid plantlets.The main results are as follows:1.Under pot-culture conditions,five fungi were configured to microbial inoculum for 200mL/L?400mL/L and 600mL/L,then inoculated into Cymbidium goeringii ‘Songmei' plantlets.Five fungi of Mortierella sp.were isolated from roots of four wild Chinese Cymbidium.The results showed that strain FC5 had obvious promoting effect on Cymbidium goeringii plantlets biomass.The fresh weight growth rate,the number of new leaves and plant height growth of the test group with train FC5 had significant differences with control group,while roots elongation of plantlets were promoted.No significant effect was observed in the change of the number of roots.2.Using solid inoculation and liquid inoculation these two different ways,mycorrhizal symbiosis system between 4 kinds of fungi and Cymbidium hybridum(Cymbidium hybridum ‘Princess Nobuko'×Cymbidium goeringii ‘Huangshuixian')plantlets was established in this study.The results showed that strains FC5 and FC9 liquid inoculum treatments had obvious promoting effect on the growth of Cymbidium hybridum plantlets.While strain FC17 liquid inoculum treatments significantly promoted the growth of Cymbidium hybridum plantlets roots.3.Using permanent paraffin-cut section,the microstructure of mycorrhizal structures were observed.Result indicated that Cymbidium goeringii and Cymbidium hybridum plantlets have typical mycorrhizal structures such as hyphae and pelotons.After 150 d of symbiotic culture,hyphae was founded in test plantlets roots.The hypha intruded into cortex cells by root hair or damaging velamina cells.Hyphae revolve around the nucleus.Acicular crystal were distributed in cortex cells which are close to exodermis cells.Starch granules were distributed in cortex cells which are close to stele.4.Fungal genomic DNA of Cymbidium goeringii and Cymbidium hybridum was extracted using CTAB method.PCR products were purified,connection,and transformation,then send sequencing.Sequence of ITS rDNA segment was obtained,through sequence alignment.Then repair sequence was analyzed in NCBI blast analysis,and compared with the sequence of Mortierella sp.in GenBank,it is found sequence similarity is 99%.Considering the characteristics of isolated strains,it was confirmed that fungi which were isolated from plantlets roots were the same as origin fungi.