The Effect Of Arbuscular Mycorrhizal Fungi On The Growth Of Astragalus Sinicus. L And Heavy Metal Uptake In Sludge Contaminated Soil

Recent years, witn the rapid development of the sewage treatment plant, agriculture use of sewage sludge was increased daily. Although the sludge is ruch in nutrients that required for plant growth, but the ecological environment was damaged seriously by organic pollutants and heavy metal in sludge, and this have affected the development of agricultural production. This serious probiem has been widespread concern at the time of promoting sustainable development and agriculture.AMF can form mutually benificial symbioss(mycorrhizas) with 80% of the terrestrial plant. Mycorrhizal promote the mineral nutrition absorption of and improve the viability of host plant under the environment stress.This research choose Astragalus sinicus as host plant, study the effect of sewage sludge on the devolopment and colonization of mycorrhizal fungi, the results get were as follows:Uptake of mineral nutrition N, P and plant growth was promoted significant by AMF. The effect of sludge on various AM fungi is different, this reflected the different resistance of sludge among AM fungus. Colonization of Glomus mossea in plant root was inhibited obviously, SDH-and ALP enzyme activity was almost lost, and the growth of external mycellium decreased significantly at the highest added ration of sludge, but Glomus intraradices,Glomus geosporum and mixed inoculum also infected plant effectively and promoted plant growth. Damage of heavy metal on plant was reduced with AMF inoculated treatment at the highest sludge added level. Concentration of Zn was increased in the root and decreased in the shoot with all mycorrhizal treatment; the root/shoot content ration of Cu was increased with G. geosporum inoculated treatment at the highest sludge addition level. This made more heavy metal accumulate in root, and inhibited heavy metal to transfer to shoot. By then, heavy metal damage on plant was weaken, and heaymetal content in soil was reduced, mycorrhizal play an important role in bioremediation of sludge polluted soil in this process. Nested PCR with specific primers was performed on the fresh root of infecting by AMF, the results showed that, interaction among AM fungus was impacted by sewage sludge, colonization of Glomus geosporum in mixed inoculum was promoted, colonization Glomus mosseae was increased. Glomus mosseae show more competitive than other inoculum in normal soil, and in the case of adding sewage sludge, G. geosporum instead of Gmosseae become the dominant fungi.Summary, in the symbiosis formed by AM fungi and Astragalus sinicus, G. geosporum had a higher resistantce on sewage sludge, so this AM fungi can used for mycorrhizoremadiation of sewage sludg pollution.