Influence Of Arbuscular Mycorrhizal Fungi On The Nutrient Transfer And Distribution Between Individual Plants In Karst Community

Arbuscular mycorrhizal fungi(AMF) is a fungi which established a symbiotic relationship between fungi and host plant roots. AM fungi has a catalytic role on the growth and mineral elements absorption of plants, induces plant resistance and tolerance. the external hyphae and its secondary metabolites glomalin-related soil protein(GRSP) promote the formation of soil aggregates, improve the soil structure, extraradical hyphae formed mycelium bridge among different plants, mycelium bridge can form a huge underground common mycorrhizal nets(CMNs) in the soil, CMNs play an important role on transfer distribution of nutrients among different plants, nutrient can be transferred among different plants in the plant community, the CMNs play an important role on the redistribution of above-ground biomass, reducing the resource monopoly power of the dominant species, promoting the balance of biomass and nutrients content in the plant communities and protecting key species.The interactions of water, soil and plants is significantly vulnerability in karst habitat, but the area has a very highly habitat heterogeneity, it means uneven distribution of resources. The nutrient transfer among different plants become the focus in the research of biodiversity maintaince, the role of AM fungi in nutrient transfer among different plants is becoming our primary focus.This research has three main contents, the mycorrhizal colonized rate of the main plants in karst, nutrient transfer among different in the natural state and the roler of arbuscular mycorrhizal fungi in the nutrient among different plants in simulate natural state.The study of 11 kinds of karst common plants mycorrhizal colonizated rate found that 10 kinds of plants can be observed the structure of mycorrhizal fungi, only one kind of plant was not observed, the percent of mycorrhizal plant is 90.91 %. The arbuscular mycorrhizal spores were observed in the rhizosphere soil of most plants except Viburnum utile and Rhamnus heterophylla.In the natural environment, the study of nutrient transfer among different plants in the plant community showed that the δ15N value of the receiver plant was increased with the sampling time, the receiver was decreased and then increased and the receiver was increased and then decreased in sample plot a; the δ15N value of the receiver plant was increased with sampling time in sample plot b. The result showed that the donor plant transferred 15 N to receiver plants, different plants can transfer nutrient, most of the plants were mycorrhizal plant, the arbuscular mycorrhizal spore was observed in therhizosphere soil, the nutrient transfer among different plants was probably related to arbuscular mycorrhizal fungi.In simulated natural environment, the study of nutrient transfer among different plants showed that the mycorrhizal colonized rate of receiver plant Cinnamomum bodinieri, Broussonetia papyrifera and Bidens pilosa was 55.50 %, 61.75 % and 43.50 % respectively. Under the conditions of mycelium, AMF promoted morphological differentiation of the receiver plants C. bodinieri and B. pilosa, which significantly promoted the morphological differentiation of C. bodinieri, but it had the opposite effect of B. papyrifera; Under the conditions of mycelium, AMF increased nitrogen and phosphorus concentration of different receiver plants; Under the conditions of mycelium, AMF was increased the nitrogen and phosphorus acquisition of the receiver plant C. bodinieriand B. pilosa, significantly increased the nitrogen and phosphorus acquisition of C. bodinieri, but decreased receiver plant B. papyrifera. The donor plant may be transferred and distributed different content nutrients to different receiver plants, the transfer and distribution was different, it has different effects on the growth of different receiver plants. The value of 15 N value in receiver plant C. bodinieri and B. pilosa leaf is 0.0086 mg and 0.0146 mg respectively, this evidence favorable illustrate AMF play an importment role in the nutrient transfer and distribution among different plants.