Influence of Different Ammonia Acid on the Tobacco Alternaria alternata Phytotoxin Virulence

To make sure the influence of different ammonia acid on phytotoxin produced by tobacco Alternaria alternata,3 biologic determination methods were done including scrub inoculation method,irrigating root treat method and the method of tobacco seed-root treatment.The conclusion were made that the third method was the best one used to measure the toxin of A.alternata.12 ammonia acid including 5 different consisitence were used to test their influence on phytotoxin produced by Alternaria alternata (GL-6) on tobacco by the method of tobacco seed-root treatment.The root length determination results indicated that all treatments of L-glutamine,L-asparagine,L-histidine could enhance the virulence of the tested toxin,however,the other 9 amino acids could repress the phytotoxin produced by Alternaria alternata (GL-6) on tobacco.Among of them L-methionine,L-leucine,L-lysine when their effective consistence were 0.02mg/ml,0.02mg/ml,0.02～2mg/ml respectivly could depress the morbidity of pathogenic toxin on tobacco obviously.