Studies On The Mycorrhizal Fungi Of Habenaria Dentata

The orchid family is a very important plant resource,the studies on the orchid mycorrhizal fungi have attracted great attentions in recent years.It has huge economical value and become an important part in the flower industry.And also most of them have very high medicinal value with huge market,there are so many research works having been done on the Orchid mycorrhizae today.Orchid mycorrhizal fungi,which offer nutrition for orchids and promote its growth,can form symbionts with orchidaceous seed,corm and nutritional root.In this paper,wild Habenaria dentata mycorrhizal microstructure and fungal intrusion way were studied.Furthermore the fungal strains isolated from wild Habenaria dentata roots were identified.In additon, mycorrhizal was made and applied in promotion orchid growth.Habenaria dentata belongs to Habenaria in Orchidaceae.The studies on the methodology for isolating,identifying the micorrhizal fungi of Habenaria dentate using morphological biology techniques,propagation of the orchid by symbiotic seed germination,the effect of the production of the single isolate on the tissue culture of it and infection the Habenaria dentata by the part isolates have been carried out.the results are the following:1.The mycorrhizal microstructure of wild Habenaria dentata was the typical mycorrhizal structure of orchids.Mycorrhizal fungi enter the velamen and exodermis through root hair and invade the cortical tissue by the exodermal passage cells,and then form pelotons.2.186 fungal strains have been isolated.Isolates were identified on the basis of colonial morphology and microscopic characteristics of hyphae,spores,conceptacle, number of karyon,fruitbody and molecularly identified.The mycorrhizal microstructure of Habenaria dentate was observed,and isolation has been carried out twice and 186 strains have been isolated,They sum to 186 strains.The dominant isolates were Mitogenic fungi,the superior genus is Orchidaceous rhizoctorias.Them are Ceratobasidium,Epulorhiza,Epulorhiza repens,Monilipsis Ruhland(1908).the other genera each belong to Fusarium,Trichoderma,Geotriehum,Phoma Sacc.3.A phenomena has been discovered that the fungi separated from root of Habenaria dentata is different in fall and spring.In fall,103 strains of fungi was separated that the superior genus is the Orchidaceous rhizoctorias,the other genera each belong to Ceratobasidium,Epulorhiza,Monilipsis,Fusarium,Phoma Sacc.In spring,83 strains of fungi was separated that most of them is Monilipsis,Fusarium;Obviously, the number of strains and quantity of fungi separated in fall is more than that in spring. It is proved that so many strains of fungi is required in different growth stages.The mechanism requires further research.4.The results of the symbiotic seed germination shows that the germination rate,23%, Habenaria dentata of seed is very low.21 strains were tested.85.7%of them(18 strains) can symbios with Habenaria dentata of seed.71.2%of them(16 strains) is good for germination.38.1%of them(8 strains) arrived significance level(p=0.05). 23.8%of them(5 strains) inhibit the germination.5.In growth-promoting experiments,42.9%(9 strains) of tested 21 strains made the no bacteria seedling turn to yellow which is dead finally.57.1%(12 strains) of tested 21 strains don't hurt the seedling,and the seedlings were grew healthy.