Ecological And Physiological Research On VA Mycorrhizas Of Amur Cork-tree

Amur Cork-tree (Phellodendron amurense Rupr.), one of three hard-broad-leaf tree species in the east-northem China, is an important medical and timbered plant. The information on the resource investigation of arbuscular mycorrhizal fungi in the root-soil interface and the effect arbuscular mycorrhizal fungi on the growth ofPh. amurense remains rarely.The resource status of arbuscular mycorrhizal fungi in the root-soil interface of Ph. amurense was investigated. The result showed that four genera (including 23 species), Acaulospora, Glomus, Scutellospora and Archaeospora were found, and the former two genus took the predominance. Four species, A. scrobiculata, A. spinosa, G. aggregatum, G. rubiforme and S. calospora, occured frequently.Four species of VA mycorrhizal fungi, Glomus mosseae, G. etunicatum, G. versiforme and G. diaphanum, were be inoculated Ph. amurense, and the result showed that they could form the arbuscular mycorrhiza which obviously promoted the growth of seedlings of Ph. amurense. The height, basal diameter, fresh weight of seedling infected by mycorrhizal fungi were significantly bigger than that un-infected, indicating that VA mycorrhizae was improved significantly the growth of seedlings of Ph. amurense. Comparing to the other mycorrhizae, G. mosseae and G. diaphanum lead to higher infection rate, rapider formation of mycorrhiza and the most obviously rapid growth. After VA mycorrhiza formed, the nutritional contents of.the leaves were increased in different degree, which obviously improved the photosynthesis characteristics, and further promoted the growth and metabolize of the whole plant.The chlorophyll content of seedlings increased significantly through infection by VA mycorrhizal fungi, the chlorophyll total content of infected seedlings increases 9.15% to 23.37%, contrasting with one that not infected, which consequently promoted the produce capacity of photosynthesis production. The content of soluble sugars of leaves also increased, increase the proportion from 1.88 times to 4.24 times,which could improve the osmotic adjustment of the cell. VA mycorrhiza could lead to the increase of the pectin content in the roots which improved the root activity, and the increase of the activity of protective enzyme of inner membrane system which could effectively scavenge superoxide free radical and reactive oxygen and reduce the content of proline and malondialdehyde, and consequently enhance the capability to resist drought stress. The results indicated that mycorrhizal fungi could decrease the influence of water stress on the plant, and alleviate the damage of draught to the cell membrane.VA mycorrhiza could also enhance the activity of nitric acid reductase, polyhphenol oxidase and ascorbic oxldase of the plants, increase the proportion from 1.67 times to 2.49 times ,increase the content of soluble protein and IAA, increase the proportion from 1.65 times to 2.41 times,the capacity of metabolize of nitrogen and energy, and further increase the capacity of secondary metabolize of the plants.As a medical plant, the contents of berberine, jatrorrhizine and palmatine of Ph. amurense were enhanced through infection by VA mycorrhizal fungi, which have significant indication for the research on increasing the medicinal value.The seedlings infected by VA mycorrhizal fungi showed the varied infection rate and growth mass in the different culture medium with the different quality and nutrient content. Ph. amurense showed the significantly difference of infection rate and survival rate of seedlings, through inoculation by the different mixed mycorrhizal fungi, with the most obviously promotion by coinoculation with a mixed inoculum of G. mosseae and G. diaphanum.In summary, VA mycorrhiza could directly or indirectly regulate the growth and metabolize of plants, enhance the capacity of the host plants to resist the hostile external environment, benefit the growth of the host plants, and achieve the mutualistic symbiosis to the host plants. The present study supplied us the knowledge on the resource status of arbuscular mycorrhizal fungi in the root-soil interface of Ph. amurense, and also provided the evidence for selection of fungi to the mycorrhizal breeding. The experiment of incubation of arbuscular mycorrhizal fungi showed that the mycorrhizal fungi affect the growth, physiology and metabolize of seedlings, providing the evidence for mycorrhizal breeding and resource conservation, and important theoretic significance for the basic research of arbuscular mycorrhiza.