Isolation And Culture Of Endophytic Fungi Associlated With D. Huoshanense And Its Effects On The Growth Of Plantlets

Dendroium SW.is the second large genus in Orchidaceae in which many species possess medical function and therefore have been valuable traditional Chinese medicine(TCM)for many years.Three endophytic fungi strains were isolated from the wild D.huoshanense(Dendrobium huoshanense C.Z.Tang et S.J.Cheng)roots by using solidified potato dextrose agar(PDA).These endophytic fungi strains were cultured with D.huoshanense and the results indicated that one of them could promote the growth of the plant obviously.The main research results as followed:1.Three endophytic fungi strains were isolated from 85 plagments of the roots of wild D.huoshanense and they were classified to Deuteromycotina and blong to two different genus.2.One endophytic fungus strain that could promote the growth of the tube plant of D.huoshanense significantly had been screened out through con-culture(SH-01).The increasing on fresh weight of the plant is 1.22 times and the height is 1.69times compared with control after 30 days' con-culture.Repeated experiments showed that SH-01 could promote the growth of the tube plant of D.huoshanense significantly.3.After purification,the most suitable nitrogen source,carbon source and the pH value were researched for its growth,which provides the prerequisite and the application foundation for research on its biological activity.Intrgtreated physiological effects and economic factors,The best culture condition was:200g/L potato+ 10g/L sucrose+5g/L pepton+3g/L KH₂PO₄+1.5g/L MgSO₄,pH6.0.4.Established the con-culture system between the endophytic fungus and the tube plant of D.huoshanense.The best inoculate condition was 1/2 MS+ 10g/Lsucrose+ 10g/L agar,pH5.8.5.Reseached effects of SH-01 on the growth of the tube plant of D.huoshanense.The results show that the increae of the fresh weight and height of the plant was significantly higher than that of controls after the tube plant of D.huoshanense cultured with SH-01 for 30 days and 60 days.Simultaneously the polysaccharide and alkaloid content of the tube plant of D.huoshanense have not certainly affected.In futher research we found that the increasing of all growth target of the tube plant of D.huoshanense after 60days'con-culture was lower than the increasing after 30 days' con-culture,which inditate the growth-promoting function is weakened.The tube plant of D.huoshanense were transplanted after cultured with SH-01.The reasult show that the fresh weight and survival rate are improved than the control.But that role has not reached significant levels.6.Researched effects of the broth of SH-01 on the growth of the tube plant of D.huoshanense.The results showed that a certain volume broth added in the culture medium of the tube plant of D.huoshanense can be significantly enhanced growth of the plantlets.