THE EFFECTS OF CULTIVATED DENSITIES OF HOST PLANT ON THE DEVELOPMENT OF ARBUSCULAR MYCORRHIZAL FUNGI

The effects of host plant(Sorghum vulgare)cultivated densities on the growth of arbuscular mycorrhizal fungus Glomus mosseae were studied. The results revealed that under the treatment of 60 plants/10L the fungus produced higher quantity of spores and external hyphae as compared with other treatments. In the range of 20 plants/10L to 60 plants/10L,the concentration of soluble sugar in roots was significantly and negatively correlated to the length of external hyphae in substrate, and significantly and positively correlated to root colonization. The concentration of P in roots was significantly and positively correlated to the length of external hyphae .The length of external hyphae in substrate was significantly and positively correlated to spore quantity in the substrate. It suggests that increasing the density of host plant properly could enhance the development of AM fungi, although plant growth was somewhat inhabited. Under the condition, the mutualism may start changing to commensalism or weak parasitism. The conclusion is that increasing the density of host plant might be a method of regulation to enhance the development of AM fungi to obtain more colonized roots, external hyphae and spores.