The Study Of Microbial Community Structure And The Rhizosphere Effect Of Tobacco In Fujian Tobacco-Growing Area

In this paper,in order to understand microbial community structure diversity and the rhizosphere effect of tobacco with physiological period in Fujian tobacco-growing area,the soil nutrient contents and the distribution of microbes populations of different soil samples texture were investigated in Nanping,Sanming,Ninghua tobacco-grwoing areas.And the bacterial community structure diversity were analyzed by 16S rDNA clone libraries.The dynamic of three major groups of microorganisms,functional microbial populations number,soil physical and chemical properties with tobacco physiological period were analyzed by comparison of rhizosphere soil and non-rhizosphere soil.In the meantime,phosphate-solubilizing bacteria were isolated from soil samples in Fujian tobacco-growing area,the stronger phosphate-solubilizing ability strains were identified.The main results were listed as follows:?1?The tobacco-growing soil samples were slightly acid,the contents of organic matter,alkali-hydro nitrogen and available phosphorus were abundant.The available potassium content was belong to lack or highly lack level in Nanping,Sanming,Longyan soil samples.The soil nutrient had correlation with microbial populations.?2?The results showed 15 phyla were detected in bacterial libraries for Nanping,Sanming,Longyan soil samples.,and dominated by Proteobacteria,Acidobacteria and Actinobacteria.The Shannon-Wiener index and Simpson?s diversity index showed bacterial diversity of loam soil was higher than sandy loam soil and clay soil.The strength level of soil environmental factors impact on the bacterial community structure showed organic matter>total phosphorus>available potassium>totalpotassium>alkali-hydronitrogen>totalnitrogen>pHvalue>available phosphorus.?3?In tobacco physiological period,the pH value in Shaowu tobacco-growth area of rhizosphere soil samples basically was within the scope of the optimal growth of tobacco?pH value 5.5-6.5?,and it was conducive to tobacco growth.The content of organic matter,alkali-hydro nitrogen,available phosphorus and available potassium were abundant.Within tobacco physiological period,the amouts of bacteria,actinomyces and fungi were the maximum at the vigorous growth period and the bottom mature period of tobacco.The rhizosphere effect of nitrogen-fixing bacterial was maximum at the field seedling period and rosette stage of tobacco;the rhizosphere effect of ammonifying bacteria was maximum at the vigorous growth period and the tottom period of tobacco;the rhizosphere effect of organicphosphate-solubilizing bacteria was obvious at the rosette stage of tobacco;the rhizosphere effect of inorganicphosphate-solubilizing bacteria and potassium-solubilizing bacteria was obvious at the bottom mature period of tobacco.?4?After these bacterium being cultivated?28?,160 r/min?for 5 days,the available phosphorus content in the culture of the JL03-Po3 strain reached maximum?26.86 mg/L?and the percent of dissolving phosphatidylcholine was 15.38%;the available phosphorus content in the culture of the NH03-Pi8 strain reached maximum?20.19 mg/L?,the percent of dissolving Ca₃?PO₄?₂ was 2.82%,and the NH03-Pi8 strain was identified as Pseudomonas caryophylli.