Research On The Diversity Of Ammonia Oxidation Function Flora And The Soil Physical And Chemical Properties Of Four Kinds Artificial Forests

By constructing urban forests,the pressure and negative influence thatcities are suffering currently can be reduced.Nitrification is the key part of global circulation of nitrogen,and bacteria is concerned to be the crucial microbiological colony in the process of ammoxidation,acting as the catalyst in the crucial step of natural nitrification progression.In recent years,basing upon metagenomics and cultivation,researches found out that all of the genetic constructions of AOA and AOB.Because the kind of enzyme is able to catalyze the oxidation progress of ammonia and also plays a significant role in the nitrification process,and it attracts great attention of reseachers.Hence,basing on the area of citizen experimental forest of NEFU,the study selected 4 kinds of representative afforestating tree seeds as the research object,namely Betula platyphylla,Larix gmelinii,Picea koraiensis and Fraxinus mandshurica.The thesis analyzed the chemical and physical properties of the soil from these four kinds of trees and the dynamic change principle of the gene copies of amoA in AOA,AOB from soil during the growing period,compare the variation of colony construction and diversity,look into the relationship between the chemical and physical properties of copies of AOA,AOB and amoA soils and the advantaged colony of AOA and AOB in the soil.It purpose is to provide theoretical basis for planting trees properly,and evaluated the quality and function of soils.The result of the studies are listed as follows:Soils from the four types of trees are all acid.Compared with the other types,pH of the soil from Fraxinus mandshurica is higher and that of soil from Picea koraiensis was more susceptible to the season.Also,the conductivity of soil from Picea koraiensis and Fraxinus mandshurica was more susceptible and higher among the four types;the acme of nitrogen distirbution within soils both presents in May,broad-leaved forest was higher than coniferous forest,the same type of trees had a salient variation in the nitrogen distribution within the soil.In terms of integrity,alkali solution nitrogen of broad leaved forest soil content were higher than that of coniferous forest,Betula platyphylla soil alkali solution nitrogen content had a maximum in May and other forest types maximum appeared in October,and significantly higher than those of Betula platyphylla,coniferous forest soil alkali solution of N content increased significantly in October,especially Picea koraiensis,which were significantly higher than those in other forest types.Four types of forest soil ammonium nitrogen content reached the lowest in June,that of Picea koraiensis was significantly higher than that of other forest types in April to July;Overall,soil nitrate nitrogen content of Picea koraiensis and Fraxinus mandshurica were higher than that of Betula platyphylla and Larix gmelinii,Picea koraiensis was easily effected by dynamic effect,Betula platyphylla was on the contrary.Four types of forest soil AOA amount was higher than that of AOB by an order of magnitude,the AOA/AOB of Fraxinus mandshurica was highest,the ratio of Picea koraiensis was the lowest.Overall,the amoA gene abundance of AOA and AOB in Fraxinus mandshurica soil was significantly higher than that of other forest types,amoA gene abundance of 4 kinds of forest soils'AOA and AOB seasonal variation trend were not the same.The amoA gene copy number of AOA and AOB was positively correlated with water content,pH,total nitrogen,alkaline hydrolysis nitrogen,nitrate nitrogen,and electrical conductivity.The trend of the 4 types of forest soil AOA community diversity:Picea koraiensis>Fraxinus mandshurica>Betula platyphylla>Larix gmelinii;Richness index showed a trend for Betula platyphylla>Larix gmelinii=Fraxinus mandshurica>Picea koraiensis,soil AOA community composition had a high similarity between Betula platyphylla and Larix gmelinii,Fraxinus mandshurica and Picea koraiensis also had this similarity.AOA dominant bacterias of Larix gmelinii forest soil were Archaea_norank and Thaumarchaeota and other forest types AOA superior bacteria were Archaea Archaea_norank and Crenarchaeota.Containing content,pH,conductivity,total nitrogen,nitrate nitrogen,ammonium state nitrogen had positive correlation to archaea Archaea_norank,the Candidatus nitrosotalea,Crenarchaeota and alkali solution nitrogen were positively correlated,thaumarchaeota,Nitrososphaera and conductivity was positively correlated.The trend of the 4 types of forest soil AOB community diversity was Betula platyphylla>Picea koraiensis>Fraxinus mandshurica>Larix gmelinii.Richness index trend was the same;AOB community structure composition of 2 kinds of broad-leaved forest soil had a high similarity;Nitrosospira was the predominant bacteria of four types of forest soil.Deformation bacterial phyla(Proteobacteria)and Nitrosospira and ammonium nitrogen,water content,conductivity,pH,total nitrogen and nitrate nitrogen were positive related.Fraxinus mandshurica soil nitrogen content(including total nitrogen,alkali solution nitrogen and nitrate nitrogen)was higher than that of coniferous forest(Larix gmelinii and Picea koraiensis),and amoA gene abundance of AOA and AOB in soil of Fraxinus mandshurica was higher than other forest types,and soil AOA community structure diversity was higher than Betula platyphylla's,AOB community structure diversity was higher than coniferous forest.