Effects of nitrogen on plant-microorganism interaction
The rhizosphere is a biologically active zone in the soil around the roots of plants. Rootmicroorganism
interaction in the rhizosphere can be both beneficial to the plant, the
microorganisms or to neither of them. Which factors affect the interactions between plants
and microorganisms within this crowded rhizosphere? In order to investigate their interaction,
contrasted tests were carried out. The plants across the nitrogen gradient were incubated with
and without microorganisms. Results showed that nitrogen might play an active role in rootmicroorganism
communication, and thus have an important effect on plant growth. With no
nitrogen nutrient medium, microorganisms did not affect the plants growth obviously and the
statistical interaction intensity of plant-microorganism approached zero. However, with a low
level of nitrogen nutrient medium and an optimal nitrogen nutrient medium, plant biomass in
sterile soil was more than plant biomass in non-sterile soil. The interaction intensity of plantmicroorganism
appeared negative. With a high level of nitrogen nutrient medium, plants grown
in a non-sterile soil had better growth than plants grown in sterile soil. The interaction intensity
of plant-microorganism appeared positive. Additionally, plant growth significantly increased
the microorganism biomass both in the sterile soil and non-sterile soil.