Isolation Of The Bacteria Degrading Tribenuron-Methyl And Fluroxypyr And The Preliminary Research About Their Morphologies

As a agcutural country,adjusting plant growth structure,improve the plantquantity and quality are the most important things in our country．Company with thegrowth of agricutural technique,weedicides are widely used Tribenuron—methyl andFluroxypyr are commonly used in wheat field,which are highly effective,fast,broad—spectrum,safe and convenient．However,the weedicides still exist in the soil andpollute ecology and people'S health Human pay more attention to this．So to solve theweedicide pollution is the most impartant thing．In this article,we isolate a series of bactria from the long—time Tribenuron-methyland Fluroxypyr feded fields．All of them can degrade the weedicide and use theweedicide as the only carbon source．Four strains named B I,B2,B3 and B4 candegrade Tribenuron—methyl．Three strains named S I．S2 and S3 degrade Fluroxypyr．ThrotIgh cytological observation,biochemical detection and 1 6S rDNA sequenceanalysing,we find B1 is P．aeruginosa．B2 and S1 are Deia sp．．B3 isMicrobacterium sp．B4 is Alcaligenes sp．．S2 and S3 Serratia sp．All the seven strains can grow durin pH6-pH9．B3 grows very well at pH8 0,andthe others grow well at pH7 0．The bacteria can live at 20℃-40℃．35。C is the mostsuitable for B1 while 30℃for the others．Otherwise,the weedicide concentration canalso affect the bactrial growth．The optimal concentration for B3 and S2 is 1 00mg/L．and for others is 200mg/L．Containing 25mlM 50ml liquid volume in 250ml bottle,allstrains can grow．In the 3/10 air volume,BI,B2,B3,B4 and S1 grow well．For S2and S3．2/5 is best．All bacteria carl grow when the bacterial quantity is during 5％～20％．The most suitable quantity for B2,B4,S1,S2 and S3 is 10％while for B1 and B3 is1 5％．Ammonium nitrate is the best nitrogen source for the bacteria during sodiumnitrate,ammonium nitrate,ammonium chloride and ammonium sulfate．As a carbonsource,glucose is the first choice during glucose,sucrose and lactose．When theconcentration of Mg"fluctuates from 50mg/L to 300mg/L,all the seven bacteria carlgrow．For B2 and S 1,the optimal Mg2'concentration is 1 00mg/L,200mg/L for the restThe salt concentration also aft'ects the growth rate．For B 1 and B4,sodium chloride concentration is 20g/L．B3 sodium chloride concentration is 50g/L_while B2 can growwell from 5g/L to 30g/L．for S1,S2 and S3,3CIg/L ofsodium chloride is best．However,all the bactria grow lower when the salt concentration is 1 50g/L．...