Explore The Effect Of The Micro-ecological Environment Of The Rhizosphere On The "Black Knot" In Cherry Tree

Nearly hundred Chinese acres cherry gardens has become an important pillar of the shaanxi agricultural development.But in recent years, the region’s cherry tree appeared a serious disease, symptoms of the trunk, branches and bifurcation xylem bulge forming dark brown and black nodular disease spot accompanied by flowing glue phenomenon.Characterization of local farmers according to the conditions described it as "black pimple".The disease spread fastly, high infection rate, seriously can destroy the full garden.Rhizosphere micro-ecological environment and the relationship between the plant health has become a research hotspot in recent years to explore this problem.Therefore, this research adopts the traditional microbiology, molecular biology and biochemistry, the method of combining study of shaanxi White Deer Plain cherry tree rhizosphere soil physical and chemical properties;Soil enzyme activity;Number of culturable microorganisms, advantage bacterial species;Free of bacterial flora diversity and differences in rhizosphere soil.The main results are as follows:First, health of soil elements of phosphorus, available potassium and available phosphorus, alkaline hydrolysis nitrogen, effective magnesium and trace elements zinc, copper, manganese, lead, copper, zinc, average manganese element content is higher than the diseased samples effectively, lead content and organic carbon, effective samples is below the diseased samples;Health rhizosphere protease, urease, invertase and PPO activity was higher than the diseased samples, including health rhizosphere soil urease activity is ten times the diseased samples, biggest difference, and at higher soil enzyme activity is only DHA. Visible,the diseased samples the differential quick-acting fertility of soil and nutrient elements, especially nitrogen, zinc and manganese is lack, most of the enzyme activity also presents the tendency of decrease relatively healthy samples, does not favor the conversion of circulation of nutrients and organic decomposition and metabolism.Second, to cultivate the soil rhizosphere microorganism analysis showed that healthy plant rhizosphere on the number of culturable bacteria, actinomyces and significantly more than the diseased samples, especially the advantages of bacterial species and quantity, and the advantages of bacterial flora structure imbalance, the specific performance in the diseased samples advantage of rhizosphere bacteria corker’s species, tiny coli, bacillus genus density lowered and the lack of soil fungal genera and greedy phagocytosis.Average fungal species number higher than the diseased samples, but lower than the average number of diseased plants soil, no significant difference.Azotobacter is packed at the soil species number more than the healthy samples, the difference was not significant.Third, the analysis of soil rhizosphere microorganism showed that the disease in the rhizosphere soil samples of seven DGGE profiles bacteria isolated from cultured advantage relatively healthy samples were reduced 2 doors (Chloroflexi, Planctomycetes),12 families and 18 genera,8 orders and five classes of 25 kinds of strains, and the proportion of Actinobacteria and Acidobacteria decline;Advantage between classes (Sphingobacteria, Gammaproteobacteria, Alphaproteobacteria) basic remain unchanged;The diseased samples unique section were staphylococcus aureus (Staphylococcaceae) and ((Moraxellaceae);Advantage is a total of two kinds of Bacterium, Verrucomicrobium, rhizosphere soil samples without Agrobacterium than health.Visible, ill rhizosphere bacteria flora diversity relatively healthy samples decrease trend.The diseased samples of nitrogen, zinc, manganese nutrition element deletion, protease, urease, converting enzyme and PPO activity decreased; culturable bacteria, actinomycetes number and species reduction, as well as dominant bacterial flora distribution structure changes; free culture root rhizosphere bacteria group diversity decreased may be the reasons that affect the occurrence of black lump disease, for later prevention and control to provide the scientific basis.