Studies On The Efficiency Of Symbiosis Between Tomato And The Arbuscular Mycorrhiza Fungi

Arbuscular mycorrhiza fungi distribute widely in the environment. They exist in various kinds of soil condition and establish closed relationship with many different host plants. It was found that about 80% of the terrestrial plants have Arbuscular mycorrhiza fungi. Arbscular mycorrhiza fungi is a kind of obligate endotrophic mycorrhizas which always produce some special structure such as vesicles and arbuscules in the roots of the plant. The roles of Arbuscular mycorrhiza fungi for the plant is significant, for example, they can promote the absorption of phosphorus in roots, accelerate the growth of plants, protect the plant against disease. Many factor, such as water content,pH,fertility,light and temperature, can obviously influence the symbiosis of plant and Arbuscular mycorrhiza fungi. Moreover, host plant can also affect the growth and development of AM fungi, and produce different infection rate,spore-bearing rate and mycorrhiza effect.Four AM fungi of Glomus intraradices (G intraradices),Scutellospora castanea (S. castanea) ,Glomus mosseae (G mosseae) ,Gigaspora rosea (Gig. Rosea) was selected to inoculate two kinds of tomato named HUAFAN No.1 and A57. In our research, the symbiosis between AM fungi and plant under different amount phosphorus was studied, and different symbiosis relationship between AM fungi and different plants was compared.In the low level of phosphorus, the infect ratio of G. mosseae and Gig. Rosea was more than 80%, and infect extension of mycorrhiza in the whole plant roots was more than 60.7%. The proportion of infect structure of AM fungi in the infected roots was between 65.1%～75.4%, and the proportion of vesicles formed in the roots was comparable, about 49.8%～65.4%.In the high level of phosphorus, the infect ratio and activity of AM fungi decreased, and promoting effects to the growth of tomato was not distinct. When the phosphorus amount was 0 mg kg^-1, the biomass of tomato which was inoculated two kinds of AM fungi was 1.58 and 2.09 times of control respectively. When the phosphorus amount was added to 240mg kg^-1, the biomass of plant above the field and the dry weight of the roots were not obviously different, and those of treatment inoculated Gig. Rosea was less than control which was not inoculated Gig. Rosea.The result show that, in the low level of phosphorus, the infect ratio of AM fungi was high, and the formation and development of vesicles was good, moreover, AM fungi can somewhat promote the growth of host plant. In the high level of phosphorus, however, the promoting effect of AM fungi to plant was not distinct, and even result in negative effect. When the phosphorus amount was increased, the symbiosis effect between them was deteriorated.The interaction between tomato and AM fungi show that: the biomass of the HUAFAN No.1 inoculated G.intraradices was 3.61 times more than control, and that of A57 was 3.05 times; the biomass of the HUAFAN NO.1 inoculated G.mosseae was 3.39...